1
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Ford J, Ortalli S, Chen Z, Sap JBI, Tredwell M, Gouverneur V. Expedient Access to 18F-Fluoroheteroarenes via Deaminative Radiofluorination of Aniline-Derived Pyridinium Salts. Angew Chem Int Ed Engl 2024; 63:e202404945. [PMID: 38624193 DOI: 10.1002/anie.202404945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 04/17/2024]
Abstract
Herein, we disclose that pyridinium salts derived from abundant (hetero)anilines represent a novel precursor class for nucleophilic aromatic substitution reactions with [18F]fluoride. The value of this new 18F-fluorodeamination is demonstrated with the synthesis of over 30 structurally diverse and complex heteroaryl 18F-fluorides, several derived from scaffolds that were yet to be labelled with fluorine-18. The protocol tolerates heteroarenes and functionalities commonly found in drug discovery libraries, and is amenable to scale-up and automation on a commercial radiosynthesiser.
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Affiliation(s)
- Joseph Ford
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, United Kingdom
| | - Sebastiano Ortalli
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, United Kingdom
| | - Zijun Chen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, United Kingdom
| | - Jeroen B I Sap
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, United Kingdom
- Current address: Department of Translational Imaging, Genentech Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Matthew Tredwell
- Wales Research and Diagnostic PET Imaging Centre, Cardiff University, University Hospital of Wales, Heath Park, Cardiff, CF14 4XN, United Kingdom
- School of Chemistry, Cardiff University Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
| | - Véronique Gouverneur
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, United Kingdom
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2
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Wodtke R, Laube M, Hauser S, Meister S, Ludwig FA, Fischer S, Kopka K, Pietzsch J, Löser R. Preclinical evaluation of an 18F-labeled N ε-acryloyllysine piperazide for covalent targeting of transglutaminase 2. EJNMMI Radiopharm Chem 2024; 9:1. [PMID: 38165538 PMCID: PMC10761660 DOI: 10.1186/s41181-023-00231-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 12/15/2023] [Indexed: 01/03/2024] Open
Abstract
BACKGROUND Transglutaminase 2 (TGase 2) is a multifunctional protein and has a prominent role in various (patho)physiological processes. In particular, its transamidase activity, which is rather latent under physiological conditions, gains importance in malignant cells. Thus, there is a great need of theranostic probes for targeting tumor-associated TGase 2, and targeted covalent inhibitors appear to be particularly attractive as vector molecules. Such an inhibitor, equipped with a radionuclide suitable for noninvasive imaging, would be supportive for answering the general question on the possibility for functional characterization of tumor-associated TGase 2. For this purpose, the recently developed 18F-labeled Nε-acryloyllysine piperazide [18F]7b, which is a potent and selective irreversible inhibitor of TGase 2, was subject to a detailed radiopharmacological characterization herein. RESULTS An alternative radiosynthesis of [18F]7b is presented, which demands less than 300 µg of the respective trimethylammonio precursor per synthesis and provides [18F]7b in good radiochemical yields (17 ± 7%) and high (radio)chemical purities (≥ 99%). Ex vivo biodistribution studies in healthy mice at 5 and 60 min p.i. revealed no permanent enrichment of 18F-activity in tissues with the exception of the bone tissue. In vivo pretreatment with ketoconazole and in vitro murine liver microsome studies complemented by mass spectrometric analysis demonstrated that bone uptake originates from metabolically released [18F]fluoride. Further metabolic transformations of [18F]7b include mono-hydroxylation and glucuronidation. Based on blood sampling data and liver microsome experiments, pharmacokinetic parameters such as plasma and intrinsic clearance were derived, which substantiated the apparently rapid distribution of [18F]7b in and elimination from the organisms. A TGase 2-mediated uptake of [18F]7b in different tumor cell lines could not be proven. Moreover, evaluation of [18F]7b in melanoma tumor xenograft models based on A375-hS100A4 (TGase 2 +) and MeWo (TGase 2 -) cells by ex vivo biodistribution and PET imaging studies were not indicative for a specific targeting. CONCLUSION [18F]7b is a valuable radiometric tool to study TGase 2 in vitro under various conditions. However, its suitability for targeting tumor-associated TGase 2 is strongly limited due its unfavorable pharmacokinetic properties as demonstrated in rodents. Consequently, from a radiochemical perspective [18F]7b requires appropriate structural modifications to overcome these limitations.
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Affiliation(s)
- Robert Wodtke
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany.
| | - Markus Laube
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Sandra Hauser
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Sebastian Meister
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Friedrich-Alexander Ludwig
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318, Leipzig, Germany
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318, Leipzig, Germany
| | - Klaus Kopka
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318, Leipzig, Germany
- School of Science, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstraße 4, 01069, Dresden, Germany
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
- School of Science, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstraße 4, 01069, Dresden, Germany
| | - Reik Löser
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany.
- School of Science, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstraße 4, 01069, Dresden, Germany.
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3
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Craig A, Kogler J, Laube M, Ullrich M, Donat CK, Wodtke R, Kopka K, Stadlbauer S. Preparation of 18F-Labeled Tracers Targeting Fibroblast Activation Protein via Sulfur [ 18F]Fluoride Exchange Reaction. Pharmaceutics 2023; 15:2749. [PMID: 38140090 PMCID: PMC10747913 DOI: 10.3390/pharmaceutics15122749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/14/2023] [Accepted: 12/02/2023] [Indexed: 12/24/2023] Open
Abstract
Early detection and treatment of cancers can significantly increase patient prognosis and enhance the quality of life of affected patients. The emerging significance of the tumor microenvironment (TME) as a new frontier for cancer diagnosis and therapy may be exploited by radiolabeled tracers for diagnostic imaging techniques such as positron emission tomography (PET). Cancer-associated fibroblasts (CAFs) within the TME are identified by biomarkers such as fibroblast activation protein alpha (FAPα), which are expressed on their surfaces. Targeting FAPα using small-molecule 18F-labeled inhibitors (FAPIs) has recently garnered significant attention for non-invasive tumor visualization using PET. Herein, two potent aryl-fluorosulfate-based FAPIs, 12 and 13, were synthetically prepared, and their inhibition potency was determined using a fluorimetric FAP assay to be IC50 9.63 and 4.17 nM, respectively. Radiofluorination was performed via the sulfur [18F]fluoride exchange ([18F]SuFEx) reaction to furnish [18F]12 and [18F]13 in high activity yields (AY) of 39-56% and molar activities (Am) between 20-55 GBq/µmol. In vitro experiments focused on the stability of the radiolabeled FAPIs after incubation with human serum, liver microsomes and liver cytosol. Preliminary PET studies of the radioligands were performed in healthy mice to investigate the in vivo biodistribution and 18F defluorination rate. Fast pharmacokinetics for the FAP-targeting tracers were retained and considerable bone uptake, caused by either 18F defluorination or radioligand accumulation, was observed. In summary, our findings demonstrate the efficiency of [18F]SuFEx as a radiolabeling method as well as its advantages and limitations with respect to PET tracer development.
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Affiliation(s)
- Austin Craig
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, D-01328 Dresden, Germany; (A.C.)
| | - Jürgen Kogler
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, D-01328 Dresden, Germany; (A.C.)
- Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, D-01062 Dresden, Germany
| | - Markus Laube
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, D-01328 Dresden, Germany; (A.C.)
| | - Martin Ullrich
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, D-01328 Dresden, Germany; (A.C.)
| | - Cornelius K. Donat
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, D-01328 Dresden, Germany; (A.C.)
| | - Robert Wodtke
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, D-01328 Dresden, Germany; (A.C.)
| | - Klaus Kopka
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, D-01328 Dresden, Germany; (A.C.)
- Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, D-01062 Dresden, Germany
| | - Sven Stadlbauer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, D-01328 Dresden, Germany; (A.C.)
- Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, D-01062 Dresden, Germany
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4
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Kolks N, Neumaier F, Neumaier B, Zlatopolskiy BD. Preparation of NIn-Methyl-6-[ 18F]fluoro- and 5-Hydroxy-7-[ 18F]fluorotryptophans as Candidate PET-Tracers for Pathway-Specific Visualization of Tryptophan Metabolism. Int J Mol Sci 2023; 24:15251. [PMID: 37894930 PMCID: PMC10607147 DOI: 10.3390/ijms242015251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/09/2023] [Accepted: 10/14/2023] [Indexed: 10/29/2023] Open
Abstract
Tryptophan (Trp) is an essential proteinogenic amino acid and metabolic precursor for several signaling molecules that has been implicated in many physiological and pathological processes. Since the two main branches of Trp metabolism-serotonin biosynthesis and kynurenine pathway-are differently affected by a variety of neurological and neoplastic diseases, selective visualization of these pathways is of high clinical relevance. However, while positron emission tomography (PET) with existing probes can be used for non-invasive assessment of total Trp metabolism, optimal imaging agents for pathway-specific PET imaging are still lacking. In this work, we describe the preparation of two 18F-labeled Trp derivatives, NIn-methyl-6-[18F]fluorotryptophan (NIn-Me-6-[18F]FTrp) and 5-hydroxy-7-[18F]fluorotryptophan (5-HO-7-[18F]FTrp). We also report feasible synthetic routes for the preparation of the hitherto unknown boronate radiolabeling precursors and non-radioactive reference compounds. Under optimized conditions, alcohol-enhanced Cu-mediated radiofluorination of the respective precursors afforded NIn-Me-6-[18F]FTrp and 5-HO-7-[18F]FTrp as application-ready solutions in radiochemical yields of 45 ± 7% and 29 ± 4%, respectively. As such, our work provides access to two promising candidate probes for pathway-specific visualization of Trp metabolism in amounts sufficient for their preclinical evaluation.
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Affiliation(s)
- Niklas Kolks
- Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., 52428 Jülich, Germany; (N.K.); (F.N.); (B.D.Z.)
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Felix Neumaier
- Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., 52428 Jülich, Germany; (N.K.); (F.N.); (B.D.Z.)
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Bernd Neumaier
- Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., 52428 Jülich, Germany; (N.K.); (F.N.); (B.D.Z.)
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Boris D. Zlatopolskiy
- Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., 52428 Jülich, Germany; (N.K.); (F.N.); (B.D.Z.)
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
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5
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Haveman LYF, Vugts DJ, Windhorst AD. State of the art procedures towards reactive [ 18F]fluoride in PET tracer synthesis. EJNMMI Radiopharm Chem 2023; 8:28. [PMID: 37824021 PMCID: PMC10570257 DOI: 10.1186/s41181-023-00203-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND Positron emission tomography (PET) is a powerful, non-invasive preclinical and clinical nuclear imaging technique used in disease diagnosis and therapy assessment. Fluorine-18 is the predominant radionuclide used for PET tracer synthesis. An impressive variety of new 'late-stage' radiolabeling methodologies for the preparation of 18F-labeled tracers has appeared in order to improve the efficiency of the labeling reaction. MAIN BODY Despite these developments, one outstanding challenge into the early key steps of the process remains: the preparation of reactive [18F]fluoride from oxygen-18 enriched water ([18O]H2O). In the last decade, significant changes into the trapping, elution and drying stages have been introduced. This review provides an overview of the strategies and recent developments in the production of reactive [18F]fluoride and its use for radiolabeling. CONCLUSION Improved, modified or even completely new fluorine-18 work-up procedures have been developed in the last decade with widespread use in base-sensitive nucleophilic 18F-fluorination reactions. The many promising developments may lead to a few standardized drying methodologies for the routine production of a broad scale of PET tracers.
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Affiliation(s)
- Lizeth Y F Haveman
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam, The Netherlands
| | - Danielle J Vugts
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | - Albert D Windhorst
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands.
- Neuroscience Amsterdam, Amsterdam, The Netherlands.
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6
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Gröner B, Willmann M, Donnerstag L, Urusova EA, Neumaier F, Humpert S, Endepols H, Neumaier B, Zlatopolskiy BD. 7-[ 18F]Fluoro-8-azaisatoic Anhydrides: Versatile Prosthetic Groups for the Preparation of PET Tracers. J Med Chem 2023; 66:12629-12644. [PMID: 37625106 PMCID: PMC10510393 DOI: 10.1021/acs.jmedchem.3c01310] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Indexed: 08/27/2023]
Abstract
18F-Fluorination of sensitive molecules is often challenging, but can be accomplished under suitably mild conditions using radiofluorinated prosthetic groups (PGs). Herein, 1-alkylamino-7-[18F]fluoro-8-azaisatoic anhydrides ([18F]AFAs) are introduced as versatile 18F-labeled building blocks that can be used as amine-reactive or "click chemistry" PGs. [18F]AFAs were efficiently prepared within 15 min by "on cartridge" radiolabeling of readily accessible trimethylammonium precursors. Conjugation with a range of amines afforded the corresponding 2-alkylamino-6-[18F]fluoronicotinamides in radiochemical conversions (RCCs) of 15-98%. In addition, radiolabeling of alkyne- or azide-functionalized precursors with azidopropyl- or propargyl-substituted [18F]AFAs using Cu-catalyzed click cycloaddition afforded the corresponding conjugates in RCCs of 44-88%. The practical utility of the PGs was confirmed by the preparation of three 18F-labeled PSMA ligands in radiochemical yields of 28-42%. Biological evaluation in rats demonstrated excellent in vivo stability of all three conjugates. In addition, one conjugate ([18F]JK-PSMA-15) showed favorable imaging properties for high-contrast visualization of small PSMA-positive lesions.
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Affiliation(s)
- Benedikt Gröner
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
- Faculty
of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University
of Cologne, Kerpener
Straße 62, 50937 Cologne, Germany
| | - Michael Willmann
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Lisa Donnerstag
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
- Faculty
of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University
of Cologne, Kerpener
Straße 62, 50937 Cologne, Germany
| | - Elizaveta A. Urusova
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
- Faculty
of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University
of Cologne, Kerpener
Straße 62, 50937 Cologne, Germany
| | - Felix Neumaier
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
- Faculty
of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University
of Cologne, Kerpener
Straße 62, 50937 Cologne, Germany
| | - Swen Humpert
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Heike Endepols
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
- Faculty
of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University
of Cologne, Kerpener
Straße 62, 50937 Cologne, Germany
- Faculty
of Medicine and University Hospital Cologne, Department of Nuclear
Medicine, University of Cologne, Kerpener Straße 62, 50937 Cologne, Germany
| | - Bernd Neumaier
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
- Faculty
of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University
of Cologne, Kerpener
Straße 62, 50937 Cologne, Germany
- Max
Planck Institute for Metabolism Research, Gleueler Straße 50, 50931 Cologne, Germany
| | - Boris D. Zlatopolskiy
- Forschungszentrum
Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear
Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428 Jülich, Germany
- Faculty
of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University
of Cologne, Kerpener
Straße 62, 50937 Cologne, Germany
- Max
Planck Institute for Metabolism Research, Gleueler Straße 50, 50931 Cologne, Germany
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7
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Humpert S, Hoffmann C, Neumaier F, Zlatopolskiy BD, Neumaier B. Validation of analytical HPLC with post-column injection as a method for rapid and precise quantification of radiochemical yields. J Chromatogr B Analyt Technol Biomed Life Sci 2023; 1228:123847. [PMID: 37634390 DOI: 10.1016/j.jchromb.2023.123847] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/27/2023] [Accepted: 07/29/2023] [Indexed: 08/29/2023]
Abstract
Accurate assessment of isolated radiochemical yields (RCYs) is a prerequisite for efficient and reliable optimization of labeling reactions. In practice, radiochemical conversions (RCCs) determined by HPLC analysis of crude reaction mixtures are often used to estimate RCYs. However, incomplete recovery of radioactivity from the stationary phase can lead to significant inaccuracies if RCCs are calculated based on the activity eluted from the column (i.e. the summed integrals of all peaks). Here, we validate a simple and practical method that overcomes problems associated with retention of activity on the column by determination of the total activity in the sample using post-column injection. Post-column injections were carried out using an additional injection valve, which was placed between the outlet of the HPLC column and the inlet of the detectors. 2-[18F]Fluoropyridine ([18F]FPy) and 8-cyclopentyl-3-(3-[18F]fluoropropyl)-1-propylxanthine ([18F]CPFPX) were prepared with radiochemical purities of > 99.8% and mixed with [18F]fluoride at a ratio of 1:1 to simulate reaction mixtures obtained by radiolabeling reactions with an RCC of 50%. The samples were analyzed on three different C18 HPLC columns using neutral and acidic mobile phases. RCCs determined using the summed area of all peaks in the chromatograms were compared with those determined using post-column injection. Additionally, RCCs determined by post-column injection were corrected for activity losses before, during and after radiosyntheses to afford analytical RCYs, which were compared with isolated RCYs. Determination of RCCs based on the summed area of all peaks gave correct results under certain chromatographic conditions, but led to overestimation of the actual RCCs by up to 50% in other cases. In contrast, determination of RCCs using post-column injection provided precise results in all cases, and often significantly reduced analysis time. Moreover, analytical RCYs calculated from RCCs determined by post-column injection showed excellent agreement with isolated RCYs (<3% deviation). In conclusion, HPLC analysis using post-column injection enables reliable determination of RCCs independent of the chromatographic conditions and, together with a simple activity balance, rapid and accurate prediction of isolated RCYs.
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Affiliation(s)
- Swen Humpert
- Forschungszentrum Jülich GmbH, Institute of Neurosciences and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Chris Hoffmann
- Forschungszentrum Jülich GmbH, Institute of Neurosciences and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Felix Neumaier
- Forschungszentrum Jülich GmbH, Institute of Neurosciences and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Boris D Zlatopolskiy
- Forschungszentrum Jülich GmbH, Institute of Neurosciences and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Bernd Neumaier
- Forschungszentrum Jülich GmbH, Institute of Neurosciences and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany.
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8
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Willuweit A, Humpert S, Schöneck M, Endepols H, Burda N, Gremer L, Gering I, Kutzsche J, Shah NJ, Langen KJ, Neumaier B, Willbold D, Drzezga A. Evaluation of the 18F-labeled analog of the therapeutic all-D-enantiomeric peptide RD2 for amyloid β imaging. Eur J Pharm Sci 2023; 184:106421. [PMID: 36889654 DOI: 10.1016/j.ejps.2023.106421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 02/16/2023] [Accepted: 03/05/2023] [Indexed: 03/08/2023]
Abstract
Positron emission tomography (PET) imaging with radiotracers that bind to fibrillary amyloid β (Aβ) deposits is an important tool for the diagnosis of Alzheimer's disease (AD) and for the recruitment of patients into clinical trials. However, it has been suggested that rather than the fibrillary Aβ deposits, it is smaller, soluble Aβ aggregates that exert a neurotoxic effect and trigger AD pathogenesis. The aim of the current study is to develop a PET probe that is capable of detecting small aggregates and soluble Aβ oligomers for improved diagnosis and therapy monitoring. An 18F-labeled radioligand was prepared based on the Aβ-binding d-enantiomeric peptide RD2, which is currently being evaluated in clinical trials as a therapeutic agent to dissolve Aβ oligomers. 18F-labeling was carried out using palladium-catalyzed S-arylation of RD2 with 2-[18F]fluoro-5-iodopyridine ([18F]FIPy). Specific binding of [18F]RD2-cFPy to brain material from transgenic AD (APP/PS1) mice and AD patients was demonstrated with in vitro autoradiography. In vivo uptake and biodistribution of [18F]RD2-cFPy were evaluated using PET analyses in wild-type and transgenic APP/PS1 mice. Although brain penetration and brain wash-out kinetics of the radioligand were low, this study provides proof of principle for a PET probe based on a d-enantiomeric peptide binding to soluble Aβ species.
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Affiliation(s)
- Antje Willuweit
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany.
| | - Swen Humpert
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Michael Schöneck
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Heike Endepols
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany; Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany
| | - Nicole Burda
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Lothar Gremer
- Institute of Biological Information Processing (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf 40225, Germany
| | - Ian Gering
- Institute of Biological Information Processing (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany
| | - Janine Kutzsche
- Institute of Biological Information Processing (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany
| | - N Jon Shah
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; JARA - Brain - Translational Medicine, Aachen 52074, Germany; Department of Neurology, RWTH Aachen University, Aachen 52074, Germany
| | - Karl-Josef Langen
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; Department of Nuclear Medicine, RWTH Aachen University, Aachen 52074, Germany
| | - Bernd Neumaier
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany
| | - Dieter Willbold
- Institute of Biological Information Processing (IBI-7), Forschungszentrum Jülich, Jülich 52425, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf 40225, Germany
| | - Alexander Drzezga
- Institute of Neuroscience and Medicine-4 (INM-2, INM-4, INM-5, INM-11), Forschungszentrum Jülich, Jülich 52425, Germany; Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany
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9
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Orlovskaya VV, Fedorova OS, Viktorov NB, Vaulina DD, Krasikova RN. One-Pot Radiosynthesis of [18F]Anle138b—5-(3-Bromophenyl)-3-(6-[18F]fluorobenzo[d][1,3]dioxol-5-yl)-1H-pyrazole—A Potential PET Radiotracer Targeting α-Synuclein Aggregates. Molecules 2023; 28:molecules28062732. [PMID: 36985703 PMCID: PMC10052605 DOI: 10.3390/molecules28062732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 03/12/2023] [Accepted: 03/13/2023] [Indexed: 03/22/2023] Open
Abstract
Availability of PET imaging radiotracers targeting α-synuclein aggregates is important for early diagnosis of Parkinson’s disease and related α-synucleinopathies, as well as for the development of new therapeutics. Derived from a pyrazole backbone, 11C-labelled derivatives of anle138b (3-(1,3-benzodioxol-5-yl)-5-(3-bromophenyl)-1H-pyrazole)—an inhibitor of α-synuclein and prion protein oligomerization—are currently in active development as the candidates for PET imaging α-syn aggregates. This work outlines the synthesis of a radiotracer based on the original structure of anle138b, labelled with fluorine-18 isotope, eminently suitable for PET imaging due to half-life and decay energy characteristics (97% β+ decay, 109.7 min half-life, and 635 keV positron energy). A three-step radiosynthesis was developed starting from 6-[18F]fluoropiperonal (6-[18F]FP) that was prepared using (piperonyl)(phenyl)iodonium bromide as a labelling precursor. The obtained 6-[18F]FP was used directly in the condensation reaction with tosylhydrazide followed by 1,3-cycloaddition of the intermediate with 3′-bromophenylacetylene eliminating any midway without any intermediate purifications. This one-pot approach allowed the complete synthesis of [18F]anle138b within 105 min with RCY of 15 ± 3% (n = 3) and Am in the range of 32–78 GBq/µmol. The [18F]fluoride processing and synthesis were performed in a custom-built semi-automated module, but the method can be implemented in all the modern automated platforms. While there is definitely space for further optimization, the procedure developed is well suited for preclinical studies of this novel radiotracer in animal models and/or cell cultures.
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Affiliation(s)
- Viktoriya V. Orlovskaya
- N.P. Bechtereva Institute of the Human Brain, Russian Academy of Science, 197376 St. Petersburg, Russia
| | - Olga S. Fedorova
- N.P. Bechtereva Institute of the Human Brain, Russian Academy of Science, 197376 St. Petersburg, Russia
| | - Nikolai B. Viktorov
- St. Petersburg State Technological Institute, Technical University, 190013 St. Petersburg, Russia
| | - Daria D. Vaulina
- N.P. Bechtereva Institute of the Human Brain, Russian Academy of Science, 197376 St. Petersburg, Russia
| | - Raisa N. Krasikova
- N.P. Bechtereva Institute of the Human Brain, Russian Academy of Science, 197376 St. Petersburg, Russia
- Correspondence:
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10
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Zhou D, Chu W, Xu J, Schwarz S, Katzenellenbogen JA. [ 18F]Tosyl fluoride as a versatile [ 18F]fluoride source for the preparation of 18F-labeled radiopharmaceuticals. Sci Rep 2023; 13:3182. [PMID: 36823435 PMCID: PMC9950486 DOI: 10.1038/s41598-023-30200-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 02/17/2023] [Indexed: 02/25/2023] Open
Abstract
Positron emission tomography (PET) is an in vivo imaging technology that utilizes positron-emitting radioisotope-labeled compounds as PET radiotracers that are commonly used in clinic and in various research areas, including oncology, cardiology, and neurology. Fluorine-18 is the most widely used PET-radionuclide and commonly produced by proton bombardment of 18O-enriched water in a cyclotron. The [18F]fluoride thus obtained generally requires processing by azeotropic drying in order to completely remove H2O before it can be used for nucleophilic radiofluorination. In general, the drying step is important in facilitating the radiofluorination reactions and the preparation of 18F-labeled PET radiotracers. In this communication, we have demonstrated the feasibility of using [18F]tosyl fluoride ([18F]TsF) as a versatile [18F]fluoride source for radiofluorination to bypass the azeotropic drying step, and we have developed a continuous flow solid-phase radiosynthesis strategy to generate [18F]TsF in a form that is excellent for radiofluorination. [18F]TsF shows high reactivity in radiofluorination and provides the features suitable for preparing PET radiotracers on a small scale and exploring novel radiolabeling technologies. Thus, using [18F]TsF as a [18F]fluoride source is a promising strategy that facilitates radiofluorination and provides a convenient and efficient solution for the preparation of 18F-labeled radiopharmaceuticals that is well matched to the emerging trends in PET imaging technologies.
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Affiliation(s)
- Dong Zhou
- Department of Radiology, School of Medicine, Washington University in Saint Louis, 510 S. Kingshighway Blvd, Saint Louis, MO, 63110, USA.
| | - Wenhua Chu
- Department of Radiology, School of Medicine, Washington University in Saint Louis, 510 S. Kingshighway Blvd, Saint Louis, MO, 63110, USA
| | - Jinbin Xu
- Department of Radiology, School of Medicine, Washington University in Saint Louis, 510 S. Kingshighway Blvd, Saint Louis, MO, 63110, USA
| | - Sally Schwarz
- Department of Radiology, School of Medicine, Washington University in Saint Louis, 510 S. Kingshighway Blvd, Saint Louis, MO, 63110, USA
| | - John A Katzenellenbogen
- Department of Chemistry and Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
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11
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Hoffmann C, Kolks N, Smets D, Haseloer A, Gröner B, Urusova EA, Endepols H, Neumaier F, Ruschewitz U, Klein A, Neumaier B, Zlatopolskiy BD. Next Generation Copper Mediators for the Efficient Production of 18 F-Labeled Aromatics. Chemistry 2023; 29:e202202965. [PMID: 36214204 PMCID: PMC10100267 DOI: 10.1002/chem.202202965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Indexed: 11/07/2022]
Abstract
Cu-mediated radiofluorination is a versatile tool for the preparation of 18 F-labeled (hetero)aromatics. In this work, we systematically evaluated a series of complexes and identified several generally applicable mediators for highly efficient radiofluorination of aryl boronic and stannyl substrates. Utilization of these mediators in nBuOH/DMI or DMI significantly improved 18 F-labeling yields despite use of lower precursor amounts. Impressively, application of 2.5 μmol aryl boronic acids was sufficient to achieve 18 F-labeling yields of up to 75 %. The practicality of the novel mediators was demonstrated by efficient production of five PET-tracers and transfer of the method to an automated radiosynthesis module. In addition, (S)-3-[18 F]FPhe and 6-[18 F]FDOPA were prepared in activity yields of 23±1 % and 30±3 % using only 2.5 μmol of the corresponding boronic acid or trimethylstannyl precursor.
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Affiliation(s)
- Chris Hoffmann
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.,Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Niklas Kolks
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.,Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Daniel Smets
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Institute of Inorganic Chemistry, University of Cologne, Greinstr. 6, 50939, Cologne, Germany
| | - Alexander Haseloer
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Institute of Inorganic Chemistry, University of Cologne, Greinstr. 6, 50939, Cologne, Germany
| | - Benedikt Gröner
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.,Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Elizaveta A Urusova
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.,Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Heike Endepols
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.,Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428, Jülich, Germany.,Faculty of Medicine and University Hospital Cologne, Department of Nuclear Medicine, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Felix Neumaier
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.,Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Uwe Ruschewitz
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Institute of Inorganic Chemistry, University of Cologne, Greinstr. 6, 50939, Cologne, Germany
| | - Axel Klein
- Faculty of Mathematics and Natural Sciences, Department of Chemistry, Institute of Inorganic Chemistry, University of Cologne, Greinstr. 6, 50939, Cologne, Germany
| | - Bernd Neumaier
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.,Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Boris D Zlatopolskiy
- Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.,Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52428, Jülich, Germany
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12
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Cressy D, Akula M, Frederick A, Shipley K, Osborne D. A method for the nucleophilic fluorination of 4-dimethylaminopyridine (DMAP) pyridinium salts. RESULTS IN CHEMISTRY 2023. [DOI: 10.1016/j.rechem.2022.100706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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13
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Andersen IV, García-Vázquez R, Battisti UM, Herth MM. Optimization of Direct Aromatic 18F-Labeling of Tetrazines. Molecules 2022; 27:molecules27134022. [PMID: 35807267 PMCID: PMC9268649 DOI: 10.3390/molecules27134022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/15/2022] [Accepted: 06/20/2022] [Indexed: 11/24/2022] Open
Abstract
Radiolabeling of tetrazines has gained increasing attention due to their important role in pretargeted imaging or therapy. The most commonly used radionuclide in PET imaging is fluorine-18. For this reason, we have recently developed a method which enables the direct aromatic 18F-fluorination of tetrazines using stannane precursors through copper-mediated fluorinations. Herein, we further optimized this labeling procedure. 3-(3-fluorophenyl)-1,2,4,5-tetrazine was chosen for this purpose because of its high reactivity and respective limited stability during the labeling process. By optimizing parameters such as elution conditions, precursor amount, catalyst, time or temperature, the radiochemical yield (RCY) could be increased by approximately 30%. These conditions were then applied to optimize the RCY of a recently successfully developed and promising pretargeting imaging agent. This agent could be isolated in a decay corrected RCY of 14 ± 3% and Am of 201 ± 30 GBq/µmol in a synthesis time of 70 min. Consequently, the RCY increased by 27%.
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Affiliation(s)
- Ida Vang Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark; (I.V.A.); (R.G.-V.); (U.M.B.)
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Rocío García-Vázquez
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark; (I.V.A.); (R.G.-V.); (U.M.B.)
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Umberto Maria Battisti
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark; (I.V.A.); (R.G.-V.); (U.M.B.)
| | - Matthias M. Herth
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark; (I.V.A.); (R.G.-V.); (U.M.B.)
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
- Correspondence:
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14
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Walter N, Bertram J, Drewes B, Bahutski V, Timmer M, Schütz MB, Krämer F, Neumaier F, Endepols H, Neumaier B, Zlatopolskiy BD. Convenient PET-tracer production via SuFEx 18F-fluorination of nanomolar precursor amounts. Eur J Med Chem 2022; 237:114383. [DOI: 10.1016/j.ejmech.2022.114383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 12/31/2022]
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15
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Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics. Molecules 2022; 27:molecules27031044. [PMID: 35164308 PMCID: PMC8838713 DOI: 10.3390/molecules27031044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 02/05/2023] Open
Abstract
We present a quantum chemical analysis of the 18F-fluorination of 1,3-ditosylpropane, promoted by a quaternary ammonium salt (tri-(tert-butanol)-methylammonium iodide (TBMA-I) with moderate to good radiochemical yields (RCYs), experimentally observed by Shinde et al. We obtained the mechanism of the SN2 process, focusing on the role of the –OH functional groups facilitating the reactions. We found that the counter-cation TBMA+ acts as a bifunctional promoter: the –OH groups function as a bidentate ‘anchor’ bridging the nucleophile [18F]F− and the –OTs leaving group or the third –OH. These electrostatic interactions cooperate for the formation of the transition states of a very compact configuration for facile SN2 18F-fluorination.
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16
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Bratteby K, Shalgunov V, Battisti UM, Petersen IN, van den Broek SL, Ohlsson T, Gillings N, Erlandsson M, Herth MM. Insights into Elution of Anion Exchange Cartridges: Opening the Path toward Aliphatic 18F-Radiolabeling of Base-Sensitive Tracers. ACS Pharmacol Transl Sci 2021; 4:1556-1566. [PMID: 34661074 PMCID: PMC8506604 DOI: 10.1021/acsptsci.1c00133] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Indexed: 01/16/2023]
Abstract
![]()
Aliphatic nucleophilic
substitution (SN2) with [18F]fluoride is the
most widely applied method to prepare 18F-labeled positron
emission tomography (PET) tracers. Strong
basic conditions commonly used during 18F-labeling procedures
inherently limit or prohibit labeling of base-sensitive scaffolds.
The high basicity stems from the tradition to trap [18F]fluoride
on anion exchange cartridges and elute it afterward with basic anions.
This sequence is used to facilitate the transfer of [18F]fluoride from an aqueous to an aprotic organic, polar reaction
medium, which is beneficial for SN2 reactions. Furthermore,
this sequence also removes cationic radioactive contaminations from
cyclotron-irradiated [18O]water from which [18F]fluoride is produced. In this study, we developed an efficient
elution procedure resulting in low basicity that permits SN2 18F-labeling of base-sensitive scaffolds. Extensive
screening of trapping and elution conditions (>1000 experiments)
and
studying their influence on the radiochemical yield (RCY) allowed
us to identify a suitable procedure for this. Using this procedure,
four PET tracers and three synthons could be radiolabeled in substantially
higher RCYs (up to 2.5-fold) compared to those of previously published
procedures, even from lower precursor amounts. Encouraged by these
results, we applied our low-basicity method to the radiolabeling of
highly base-sensitive tetrazines, which cannot be labeled using state-of-art
direct aliphatic 18F-labeling procedures. Labeling succeeded
in RCYs of up to 20%. We believe that our findings facilitate PET
tracer development by opening the path toward simple and direct SN2 18F fluorination of base-sensitive substrates.
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Affiliation(s)
- Klas Bratteby
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Umberto Maria Battisti
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark
| | - Ida Nyman Petersen
- Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Sara Lopes van den Broek
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark
| | - Tomas Ohlsson
- Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden
| | - Nic Gillings
- Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Maria Erlandsson
- Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden
| | - Matthias M Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
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17
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Ajenjo J, Destro G, Cornelissen B, Gouverneur V. Closing the gap between 19F and 18F chemistry. EJNMMI Radiopharm Chem 2021; 6:33. [PMID: 34564781 PMCID: PMC8464544 DOI: 10.1186/s41181-021-00143-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/03/2021] [Indexed: 11/10/2022] Open
Abstract
Positron emission tomography (PET) has become an invaluable tool for drug discovery and diagnosis. The positron-emitting radionuclide fluorine-18 is frequently used in PET radiopharmaceuticals due to its advantageous characteristics; hence, methods streamlining access to 18F-labelled radiotracers can make a direct impact in medicine. For many years, access to 18F-labelled radiotracers was limited by the paucity of methodologies available, and the poor diversity of precursors amenable to 18F-incorporation. During the last two decades, 18F-radiochemistry has progressed at a fast pace with the appearance of numerous methodologies for late-stage 18F-incorporation onto complex molecules from a range of readily available precursors including those that do not require pre-functionalisation. Key to these advances is the inclusion of new activation modes to facilitate 18F-incorporation. Specifically, new advances in late-stage 19F-fluorination under transition metal catalysis, photoredox catalysis, and organocatalysis combined with the availability of novel 18F-labelled fluorination reagents have enabled the invention of novel processes for 18F-incorporation onto complex (bio)molecules. This review describes these major breakthroughs with a focus on methodologies for C-18F bond formation. This reinvigorated interest in 18F-radiochemistry that we have witnessed in recent years has made a direct impact on 19F-chemistry with many laboratories refocusing their efforts on the development of methods using nucleophilic fluoride instead of fluorination reagents derived from molecular fluorine gas.
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Affiliation(s)
- Javier Ajenjo
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Gianluca Destro
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, OX3 7DQ, UK
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Bart Cornelissen
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Véronique Gouverneur
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK.
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18
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Inkster JAH, Sromek AW, Akurathi V, Neumeyer JL, Packard AB. The Non-Anhydrous, Minimally Basic Synthesis of the Dopamine D 2 Agonist [18F]MCL-524. CHEMISTRY (BASEL, SWITZERLAND) 2021; 3:1047-1056. [PMID: 37830058 PMCID: PMC10569134 DOI: 10.3390/chemistry3030075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The dopamine D2 agonist MCL-524 is selective for the D2 receptor in the high-affinity state (D2high), and, therefore, the PET analogue, [18F]MCL-524, may facilitate the elucidation of the role of D2high in disorders such as schizophrenia. However, the previously reported synthesis of [18F]MCL-524 proved difficult to replicate and was lacking experimental details. We therefore developed a new synthesis of [18F]MCL-524 using a "non-anhydrous, minimally basic" (NAMB) approach. In this method, [18F]F- is eluted from a small (10-12 mg) trap-and-release column with tetraethylammonium tosylate (2.37 mg) in 7:3 MeCN:H2O (0.1 mL), rather than the basic carbonate or bicarbonate solution that is most often used for [18F]F- recovery. The tosylated precursor (1 mg) in 0.9 mL anhydrous acetonitrile was added directly to the eluate, without azeotropic drying, and the solution was heated (150 °C/15 min). The catechol was then deprotected with the Lewis acid In(OTf)3 (10 equiv.; 150 °C/20 min). In contrast to deprotection with protic acids, Lewis-acid-based deprotection facilitated the efficient removal of byproducts by HPLC and eliminated the need for SPE extraction prior to HPLC purification. Using the NAMB approach, [18F]MCL-524 was obtained in 5-9% RCY (decay-corrected, n = 3), confirming the utility of this improved method for the multistep synthesis of [18F]MCL-524 and suggesting that it may applicable to the synthesis of other 18F-labeled radiotracers.
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Affiliation(s)
- James A. H. Inkster
- Division of Nuclear Medicine and Molecular Imaging, Boston Children’s Hospital, 300 Longwood Ave., Boston, MA 02115, USA
- Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA
| | - Anna W. Sromek
- Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA
- Division of Basic Neuroscience, McLean Hospital, 115 Mill St., Belmont, MA 02478, USA
| | - Vamsidhar Akurathi
- Division of Nuclear Medicine and Molecular Imaging, Boston Children’s Hospital, 300 Longwood Ave., Boston, MA 02115, USA
- Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA
| | - John L. Neumeyer
- Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA
- Division of Basic Neuroscience, McLean Hospital, 115 Mill St., Belmont, MA 02478, USA
| | - Alan B. Packard
- Division of Nuclear Medicine and Molecular Imaging, Boston Children’s Hospital, 300 Longwood Ave., Boston, MA 02115, USA
- Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA
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19
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Shinde SS, Bolik KV, Maschauer S, Prante O. 18F-Fluorination Using Tri- Tert-Butanol Ammonium Iodide as Phase-Transfer Catalyst: An Alternative Minimalist Approach. Pharmaceuticals (Basel) 2021; 14:ph14090833. [PMID: 34577533 PMCID: PMC8465076 DOI: 10.3390/ph14090833] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 12/21/2022] Open
Abstract
The 18F syntheses of tracers for positron emission tomography (PET) typically require several steps, including extraction of [18F]fluoride from H2[18O]O, elution, and drying, prior to nucleophilic substitution reaction, being a laborious and time-consuming process. The elution of [18F]fluoride is commonly achieved by phase transfer catalysts (PTC) in aqueous solution, which makes azeotropic drying indispensable. The ideal PTC is characterized by a slightly basic nature, its capacity to elute [18F]fluoride with anhydrous solvents, and its efficient complex formation with [18F]fluoride during subsequent labeling. Herein, we developed tri-(tert-butanol)-methylammonium iodide (TBMA-I), a quaternary ammonium salt serving as the PTC for 18F-fluorination reactions. The favorable elution efficiency of [18F]fluoride using TBMA-I was demonstrated with aprotic and protic solvents, maintaining high 18F-recoveries of 96-99%. 18F-labeling reactions using TBMA-I as PTC were studied with aliphatic 1,3-ditosylpropane and aryl pinacol boronate esters as precursors, providing 18F-labeled products in moderate-to-high radiochemical yields. TBMA-I revealed adequate properties for application to 18F-fluorination reactions and could be used for elution of [18F]fluoride with MeOH, omitting an additional base and azeotropic drying prior to 18F-labeling. We speculate that the tert-alcohol functionality of TBMA-I promotes intermolecular hydrogen bonding, which enhances the elution efficiency and stability of [18F]fluoride during nucleophilic 18F-fluorination.
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20
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Lindner T, Altmann A, Giesel F, Kratochwil C, Kleist C, Krämer S, Mier W, Cardinale J, Kauczor HU, Jäger D, Debus J, Haberkorn U. 18F-labeled tracers targeting fibroblast activation protein. EJNMMI Radiopharm Chem 2021; 6:26. [PMID: 34417894 PMCID: PMC8380212 DOI: 10.1186/s41181-021-00144-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/09/2021] [Indexed: 01/30/2023] Open
Abstract
Background Cancer-associated fibroblasts are found in the stroma of epithelial tumors. They are characterized by overexpression of the fibroblast activation protein (FAP), a serine protease which was already proven as attractive target for chelator-based theranostics. Unfortunately, the value of gallium-68 labeled tracers is limited by their batch size and the short nuclide half-life. To overcome this drawback, radiolabeling with aluminum fluoride complexes and 6-fluoronicotinamide derivatives of the longer-lived nuclide fluorine-18 was established. The novel compounds were tested for their FAP-specific binding affinity. Uptake and binding competition were studied in vitro using FAP expressing HT-1080 cells. HEK cells transfected with the closely related dipeptidyl peptidase-4 (HEK-CD26) were used as negative control. Small animal positron emission tomography imaging and biodistribution experiments were performed in HT-1080-FAP xenografted nude mice. [18F]AlF-FAPI-74 was selected for PET/CT imaging in a non-small cell lung cancer (NSCLC) patient. Results In vitro, 18F-labeled FAPI-derivatives demonstrated high affinity (EC50 = < 1 nm to 4.2 nm) and binding of up to 80% to the FAP-expressing HT1080 cells while no binding to HEK-CD26 cells was observed. While small animal PET imaging revealed unfavorable biliary excretion of most of the 18F-labeled compounds, the NOTA bearing compounds [18F]AlF-FAPI-74 and -75 achieved good tumor-to-background ratios, as a result of their preferred renal excretion. These two compounds showed the highest tumor accumulation in PET imaging. The organ distribution values of [18F]AlF-FAPI-74 were in accordance with the small animal PET imaging results. Due to its less complex synthesis, fast clearance and low background values, [18F]AlF-FAPI-74 was chosen for clinical imaging. PET/CT of a patient with metastasized non-small cell lung cancer (NSCLC), enabled visualization of the primary tumor and its metastases at the hepatic portal and in several bones. This was accompanied by a rapid clearance from the blood pool and low background in healthy organs. Conclusion [18F]AlF-labeled FAPI derivatives represent powerful tracers for PET. Owing to an excellent performance in PET imaging, FAPI-74 can be regarded as a promising precursor for [18F]AlF-based FAP-imaging. Supplementary Information The online version contains supplementary material available at 10.1186/s41181-021-00144-x.
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Affiliation(s)
- Thomas Lindner
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Annette Altmann
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany.,Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Frederik Giesel
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Clemens Kratochwil
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Christian Kleist
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Susanne Krämer
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Walter Mier
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Jens Cardinale
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Hans-Ulrich Kauczor
- Department of Radiology, Heidelberg University Hospital, Heidelberg, Germany.,Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Dirk Jäger
- Department of Medical Oncology, National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Jürgen Debus
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.,Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Uwe Haberkorn
- Department of Nuclear Medicine, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany. .,Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center (DKFZ), Heidelberg, Germany. .,Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany.
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21
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Bowden GD, Chailanggar N, Pichler BJ, Maurer A. Scalable 18F processing conditions for copper-mediated radiofluorination chemistry facilitate DoE optimization studies and afford an improved synthesis of [ 18F]olaparib. Org Biomol Chem 2021; 19:6995-7000. [PMID: 34351339 DOI: 10.1039/d1ob00903f] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A convenient and scalable base-free method for processing [18F]fluoride as [18F]TBAF is reported and applied to copper-mediated radiofluorination radiosyntheses. A central feature of this method is that a single production of [18F]TBAF can be divided into small aliquots that can be used to perform multiple small-scale reactions in DoE optimization studies. The results of these studies can then be reliably translated to full batch tracer productions using automated synthesizers. The processing method was applied to the DoE optimization of [18F]olaparib, affording the tracer in high radiochemical yields via both manual (%RCY = 78 ± 6%, n = 4 (CMRF step only)) and automated (up to 80% (%RCY); 41% activity yield (%AY)) radiosynthesis procedures.
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Affiliation(s)
- Gregory D Bowden
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, Tübingen, Germany.
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22
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Bratteby K, Shalgunov V, Herth MM. Aliphatic 18 F-Radiofluorination: Recent Advances in the Labeling of Base-Sensitive Substrates*. ChemMedChem 2021; 16:2612-2622. [PMID: 34169672 DOI: 10.1002/cmdc.202100303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Indexed: 12/19/2022]
Abstract
Aliphatic fluorine-18 radiolabeling is the most commonly used method to synthesize tracers for PET-imaging. With an increasing demand for 18 F-radiotracers for clinical applications, new labeling strategies aiming to increase radiochemical yields of established tracers or, more importantly, to enable 18 F-labeling of new scaffolds have been developed. In recent years, increased attention has been focused on the direct aliphatic 18 F-fluorination of base-sensitive substrates in this respect. This minireview gives a concise overview of the recent advances within this field and aims to highlight the advantages and limitations of these methods.
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Affiliation(s)
- Klas Bratteby
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark.,Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 222 42, Lund, Sweden.,Department of Clinical Physiology, Nuclear Medicine & PET Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - Matthias Manfred Herth
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark.,Department of Clinical Physiology, Nuclear Medicine & PET Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
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23
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Jeppesen TE, Kristensen JB, Behrens C, Madsen J, Kjaer A. Fluorine-18 labeled aldehydes as prosthetic groups for oxime coupling with a FVIIa protein. J Labelled Comp Radiopharm 2021; 64:198-208. [PMID: 33314295 DOI: 10.1002/jlcr.3900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 11/06/2020] [Accepted: 12/09/2020] [Indexed: 11/07/2022]
Abstract
New 18 F-labeled nonvolatile aldehyde prosthetic groups derived from [18 F]F-Py-TFP and spirocyclic iodonium (III)ylide precursors for late stage 18 F-labeling were developed. These precursors were characterized, 18 F-labeled, and compared in reactivity for oxime coupling. Oxime coupling was performed on an amino-oxy modified inhibited factor VII (FVIIai-ONH2 ) in low concentration to prove the applicability of the proposed method.
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Affiliation(s)
- Troels E Jeppesen
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet, Copenhagen, Denmark
- Cluster for Molecular Imaging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Jacob Madsen
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet, Copenhagen, Denmark
- Cluster for Molecular Imaging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Kjaer
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet, Copenhagen, Denmark
- Cluster for Molecular Imaging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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24
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Humpert S, Omrane MA, Urusova EA, Gremer L, Willbold D, Endepols H, Krasikova RN, Neumaier B, Zlatopolskiy BD. Rapid 18F-labeling via Pd-catalyzed S-arylation in aqueous medium. Chem Commun (Camb) 2021; 57:3547-3550. [PMID: 33870341 DOI: 10.1039/d1cc00745a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We report radiolabeling of thiol-containing substrates via Pd-catalyzed S-arylation with 2-[18F]fluoro-5-iodopyridine, which is readily accessible using the "minimalist" radiofluorination method. The practicality of the procedure was confirmed by preparation of a novel PSMA-specific PET-tracer as well as labeling of glutathione, Aβ oligomer-binding RD2 peptide, bovine serum albumin and PSMA I&S.
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Affiliation(s)
- Swen Humpert
- Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Jülich 52428, Germany.
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25
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Washington JB, Assante M, Yan C, McKinney D, Juba V, Leach AG, Baillie SE, Reid M. Trialkylammonium salt degradation: implications for methylation and cross-coupling. Chem Sci 2021; 12:6949-6963. [PMID: 34123322 PMCID: PMC8153232 DOI: 10.1039/d1sc00757b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse. The dual reactivity of N,N,N-trimethylanilinium salts towards arylation and methylation is decoupled in this mechanistic investigation to enable more strategic application of these salts in either reaction class.![]()
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Affiliation(s)
- Jack B Washington
- WestCHEM Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building 295 Cathedral Street Glasgow UK
| | - Michele Assante
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University Byrom Street Liverpool UK
| | - Chunhui Yan
- WestCHEM Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building 295 Cathedral Street Glasgow UK
| | - David McKinney
- WestCHEM Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building 295 Cathedral Street Glasgow UK
| | - Vanessa Juba
- WestCHEM Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building 295 Cathedral Street Glasgow UK
| | - Andrew G Leach
- Division of Pharmacy and Optometry, University of Manchester Stopford Building Oxford Road Manchester UK
| | | | - Marc Reid
- WestCHEM Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building 295 Cathedral Street Glasgow UK
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26
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Aras O, Demirdag C, Kommidi H, Guo H, Pavlova I, Aygun A, Karayel E, Pehlivanoglu H, Yeyin N, Kyprianou N, Chen N, Harmsen S, Sonmezoglu K, Lundon DJ, Oklu R, Ting R, Tewari A, Akin O, Sayman HB. Small Molecule, Multimodal, [ 18F]-PET and Fluorescence Imaging Agent Targeting Prostate-Specific Membrane Antigen: First-in-Human Study. Clin Genitourin Cancer 2021; 19:405-416. [PMID: 33879400 DOI: 10.1016/j.clgc.2021.03.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/08/2021] [Accepted: 03/13/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND A first-in-human study of [18F]-BF3-Cy3-ACUPA, a small-molecule contrast agent that can be unimolecularly both positron emitting and fluorescent, is conducted to determine its: its safety, biodistribution, radiation dosimetry, feasibility in tumor detection by preoperative positron emission tomography (PET), as well as its intraoperative fluorescence imaging utility in patients with prostate-specific membrane antigen positive (PSMA+) tumors. METHODS Ten patients aged 66 ± 7 years received a 6.5 ± 3.2 mCi intravenous injection of [18F]-BF3-Cy3-ACUPA and underwent PET/computed tomography (CT) imaging. Radiation dosimetry of [18F]-BF3-Cy3-ACUPA, normal organ biodistribution, and tumor uptakes were examined. Two patients were prescheduled for radical prostatectomy (RP) with extended pelvic lymphadenectomy approximately 24 hours following [18F]-BF3-Cy3-ACUPA injection and imaging. Without reinjection, intraoperative fluorescence imaging was performed on freshly excised tissue during RP. Frozen sections of excised tissue during RP were submitted for confirmatory histopathology and multiphoton fluorescence and brightfield microscopy. RESULTS Absorbed doses by organs including the kidneys and salivary glands were similar to 68Ga-PSMA-11 imaging. [18F]-BF3-Cy3-ACUPA physiologic radiotracer accumulation and urinary/biliary excretion closely resembled the distribution of other published PSMA tracers including [18F]-JK-PSMA-7, [18F]-PSMA-1007, [18F]-DCFPyL, and [18F]-DCFBC. 19F-BF3-Cy3-ACUPA was retained in PSMA+ cancer in patients for at least 24 hours, allowing for intraoperative fluorescence assessment of the prostate and of the embedded prostate cancer without contrast reinjection. After 24 hours, the majority of contrast had decayed or cleared from the blood pool. Preoperative PET and fluorescence imaging findings were confirmed with final histopathology and multiphoton microscopy. CONCLUSION Our first-in-human results demonstrate that [18F]-BF3-Cy3-ACUPA is both safe and useful in humans. Larger trials with this PET tracer are expected to further define its capabilities and its clinical role in the management of PSMA+ tumors, especially in prostate cancer.
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Affiliation(s)
- Omer Aras
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Cetin Demirdag
- Department of Urology, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - Harikrishna Kommidi
- Department of Radiology, Molecular Imaging Innovations Institute (MI3), Weill Cornell Medicine, New York, NY, USA
| | - Hua Guo
- Department of Radiology, Molecular Imaging Innovations Institute (MI3), Weill Cornell Medicine, New York, NY, USA; Department of Nuclear Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College Hospital, Beijing, China; Beijing Key Laboratory of Molecular Targeted Diagnosis and Therapy in Nuclear Medicine, Beijing, China
| | - Ina Pavlova
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Aslan Aygun
- Department of Nuclear Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - Emre Karayel
- Department of Nuclear Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - Hüseyin Pehlivanoglu
- Department of Nuclear Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - Nami Yeyin
- Department of Nuclear Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - Natasha Kyprianou
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Nandi Chen
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA; Department of Gastrointestinal Surgery, The Second Clinical Medicine College (Shenzhen People's Hospital) of Jinan University, Shenzhen, Guangdong, China
| | - Stefan Harmsen
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA; Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kerim Sonmezoglu
- Department of Nuclear Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
| | - Dara J Lundon
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Rahmi Oklu
- Department of Radiology, Mayo Clinic Arizona, Phoenix, AZ, USA
| | - Richard Ting
- Department of Radiology, Molecular Imaging Innovations Institute (MI3), Weill Cornell Medicine, New York, NY, USA
| | - Ashutosh Tewari
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Oguz Akin
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Haluk B Sayman
- Department of Nuclear Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
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27
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Wodtke R, Wodtke J, Hauser S, Laube M, Bauer D, Rothe R, Neuber C, Pietsch M, Kopka K, Pietzsch J, Löser R. Development of an 18F-Labeled Irreversible Inhibitor of Transglutaminase 2 as Radiometric Tool for Quantitative Expression Profiling in Cells and Tissues. J Med Chem 2021; 64:3462-3478. [PMID: 33705656 DOI: 10.1021/acs.jmedchem.1c00096] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The transamidase activity of transglutaminase 2 (TGase 2) is considered to be important for several pathophysiological processes including fibrotic and neoplastic tissue growth, whereas in healthy cells this enzymatic function is predominantly latent. Methods that enable the highly sensitive detection of TGase 2, such as application of radiolabeled activity-based probes, will support the exploration of the enzyme's function in various diseases. In this context, the radiosynthesis and detailed in vitro radiopharmacological evaluation of an 18F-labeled Nε-acryloyllysine piperazide are reported. Robust and facile detection of the radiotracer-TGase 2 complex by autoradiography of thin layer plates and polyacrylamide gels after chromatographic and electrophoretic separation owing to irreversible covalent bond formation was demonstrated for the isolated protein, cell lysates, and living cells. By use of this radiotracer, quantitative data on the expression profile of activatable TGase 2 in mouse organs and selected tumors were obtained for the first time by autoradiography of tissue sections.
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Affiliation(s)
- Robert Wodtke
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Johanna Wodtke
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Sandra Hauser
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Markus Laube
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - David Bauer
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany.,Fakultät Chemie und Lebensmittelchemie, Technische Universität Dresden, Mommsenstraße 4, 01062 Dresden, Germany
| | - Rebecca Rothe
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany.,Fakultät Chemie und Lebensmittelchemie, Technische Universität Dresden, Mommsenstraße 4, 01062 Dresden, Germany
| | - Christin Neuber
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Markus Pietsch
- Institut II für Pharmakologie, Zentrum für Pharmakologie, Medizinische Fakultät, Universität zu Köln, Gleueler Straße 24, 50931 Köln, Germany
| | - Klaus Kopka
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany.,Fakultät Chemie und Lebensmittelchemie, Technische Universität Dresden, Mommsenstraße 4, 01062 Dresden, Germany
| | - Jens Pietzsch
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany.,Fakultät Chemie und Lebensmittelchemie, Technische Universität Dresden, Mommsenstraße 4, 01062 Dresden, Germany
| | - Reik Löser
- Institut für Radiopharmazeutische Krebsforschung, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany.,Fakultät Chemie und Lebensmittelchemie, Technische Universität Dresden, Mommsenstraße 4, 01062 Dresden, Germany
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28
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Alonso Martinez LM, DaSilva JN. Development of a novel [ 18 F]fluorobenzyl derivative of the AT 1 receptor antagonist Candesartan. J Labelled Comp Radiopharm 2021; 64:120-128. [PMID: 33084079 DOI: 10.1002/jlcr.3892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/24/2020] [Accepted: 10/13/2020] [Indexed: 11/11/2022]
Abstract
Candesartan is a clinically approved angiotensin II type 1 receptor (AT1 R)-blocker that selectively binds AT1 Rs in high affinity. We report here the radiosynthesis and automation of the novel [18 F]fluorobenzyl derivative of Candesartan using the Sonogashira cross-coupling reaction. [18 F]Fluorobenzyl-Candesartan ([18 F]7) was developed from 4-[18 F]fluoroiodobenzene ([18 F]FIB) that was conjugated with alkyne-trityl-candesartan with the assistance of a Pd (PPh3 )4 /CuI catalyst followed by acid deprotection. The three-step two-reactor 2-HPLC purification process was automated resulting in >90% pure [18 F]7 in a RCY of 4.6 ± 1.1% (decay corrected from EOB) and molar activities of 1,406-5,513 GBq/mmol. [18 F]FIB was reproducibly obtained by direct radiofluorination of the mono-iodinated triphenylsulfonium salt in the presence of K222/K2 CO3 in an ~30% yield (decay-corrected). [18 F]7 was stable (>97%) up to 4 h in solution and up to 1 h in rat plasma at 37°C. However, the use of Sonogashira cross-coupling reaction to produce [18 F]7 in high yields and molar activities was found to be challenging for routine use in radiochemistry labs.
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Affiliation(s)
- Luis Michel Alonso Martinez
- Radiochemistry and Cyclotron Laboratory, University of Montreal Hospital Research Centre, Montréal, Québec, Canada
- Department of Biomedical Engineering, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
- Research Center of the Montreal Heart Institute, Montréal, Québec, Canada
| | - Jean N DaSilva
- Radiochemistry and Cyclotron Laboratory, University of Montreal Hospital Research Centre, Montréal, Québec, Canada
- Department of Biomedical Engineering, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
- Department of Radiology, Radio-oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada
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Zlatopolskiy BD, Endepols H, Krasikova RN, Fedorova OS, Ermert J, Neumaier B. 11C- and 18F-labelled tryptophans as PET-tracers for imaging of altered tryptophan metabolism in age-associated disorders. RUSSIAN CHEMICAL REVIEWS 2020. [DOI: 10.1070/rcr4954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ageing of the world’s population is the result of increased life expectancy observed in almost all countries throughout the world. Consequently, a rising tide of ageing-associated disorders, like cancer and neurodegenerative diseases, represents one of the main global challenges of the 21st century. The ability of mankind to overcome these challenges is directly dependent on the capability to develop novel methods for therapy and diagnosis of age-associated diseases. One hallmark of age-related pathologies is an altered tryptophan metabolism. Numerous pathological processes including neurodegenerative and neurological diseases like epilepsy, Parkinson’s and Alzheimer’s diseases, cancer and diabetes exhibit marked changes in tryptophan metabolism. Visualization of key processes of tryptophan metabolic pathways, especially using positron emission tomography (PET) and related hybrid methods like PET/CT and PET/MRI, can be exploited to early detect the aforementioned disorders with considerable accuracy, allowing appropriate and timely treatment of patients. Here we review the published 11C- and 18F-labelled tryptophans with respect to the production and also preclinical and clinical evaluation as PET-tracers for visualization of different branches of tryptophan metabolism.
The bibliography includes 159 references.
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30
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Haskali MB, Farnsworth AL, Roselt PD, Hutton CA. 4-Nitrophenyl activated esters are superior synthons for indirect radiofluorination of biomolecules. RSC Med Chem 2020; 11:919-922. [PMID: 33479687 PMCID: PMC7517343 DOI: 10.1039/d0md00140f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/28/2020] [Indexed: 12/18/2022] Open
Abstract
Indirect radiolabelling has for a long time been the mainstay strategy for radiofluorination of biomolecules. Acylation of biomolecules through the use of an 18F-labelled activated ester is a standard method for indirect radiolabelling. However, the preparation of 18F-labelled activated esters is typically a complex and multistep procedure. Herein, we describe the use of 4-nitrophenyl (PNP) activated esters to rapidly prepare 18F-labelled acylation synthons in one step. Furthermore, we present a comparative study of PNP activated esters and the commonly utilised 2,3,5,6-tetrafluorphenyl (TFP) activated esters under direct radiofluorination conditions and demonstrate their relative acylation behaviour. We demonstrate the superiority of PNP esters under direct radiofluorination conditions with favourable acylation kinetics.
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Affiliation(s)
- Mohammad B Haskali
- The Centre for Molecular Imaging and Translational Research Laboratory , The Peter MacCallum Cancer Centre , Melbourne , Australia .
- Sir Peter MacCallum Department of Oncology , The University of Melbourne , Victoria 3010 , Australia
| | - Ashleigh L Farnsworth
- School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
- Bio21 Molecular Science and Biotechnology Institute , The University of Melbourne , VIC 3010 , Australia
| | - Peter D Roselt
- The Centre for Molecular Imaging and Translational Research Laboratory , The Peter MacCallum Cancer Centre , Melbourne , Australia .
| | - Craig A Hutton
- School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
- Bio21 Molecular Science and Biotechnology Institute , The University of Melbourne , VIC 3010 , Australia
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31
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Wright JS, Kaur T, Preshlock S, Tanzey SS, Winton WP, Sharninghausen LS, Wiesner N, Brooks AF, Sanford MS, Scott PJH. Copper-Mediated Late-stage Radiofluorination: Five Years of Impact on Pre-clinical and Clinical PET Imaging. Clin Transl Imaging 2020; 8:167-206. [PMID: 33748018 PMCID: PMC7968072 DOI: 10.1007/s40336-020-00368-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 04/24/2020] [Indexed: 12/30/2022]
Abstract
PURPOSE Copper-mediated radiofluorination (CMRF) is emerging as the method of choice for the formation of aromatic C-18F bonds. This minireview examines proof-of-concept, pre-clinical, and in-human imaging studies of new and established imaging agents containing aromatic C-18F bonds synthesized with CMRF. An exhaustive discussion of CMRF methods is not provided, although key developments that have enabled or improved upon the syntheses of fluorine-18 imaging agents are discussed. METHODS A comprehensive literature search from April 2014 onwards of the Web of Science and PubMed library databases was performed to find reports that utilize CMRF for the synthesis of fluorine-18 radiopharmaceuticals, and these represent the primary body of research discussed in this minireview. Select conference proceedings, previous reports describing alternative methods for the synthesis of imaging agents, and preceding fluorine-19 methodologies have also been included for discussion. CONCLUSIONS CMRF has significantly expanded the chemical space that is accessible to fluorine-18 radiolabeling with production methods that can meet the regulatory requirements for use in Nuclear Medicine. Furthermore, it has enabled novel and improved syntheses of radiopharmaceuticals and facilitated subsequent PET imaging studies. The rapid adoption of CMRF will undoubtedly continue to simplify the production of imaging agents and inspire the development of new radiofluorination methodologies.
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Affiliation(s)
- Jay S Wright
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Tanpreet Kaur
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sean Preshlock
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sean S Tanzey
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Wade P Winton
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Nicholas Wiesner
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Allen F Brooks
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Melanie S Sanford
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter J H Scott
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
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32
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Zlatopolskiy BD, Zischler J, Krapf P, Richarz R, Lauchner K, Neumaier B. Minimalist approach meets green chemistry: Synthesis of 18 F- labeled (hetero)aromatics in pure ethanol. J Labelled Comp Radiopharm 2020; 62:404-410. [PMID: 31162691 DOI: 10.1002/jlcr.3776] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 05/27/2019] [Indexed: 01/26/2023]
Abstract
The application of toxic solvents and additives is inevitable for most of the described protocols for 18 F-labeling. Herein, a novel "green" procedure for nucleophilic aromatic radiofluorination of highly activated (hetero)aromatic substrates in pure EtOH is described. Using this method a series of 18 F-labeled (hetero)arenes have been synthesized in radiochemical yields (RCYs) of up to 97%.
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Affiliation(s)
- Boris D Zlatopolskiy
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, Cologne, Germany.,Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Johannes Zischler
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, Cologne, Germany
| | - Philipp Krapf
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, Cologne, Germany
| | - Raphael Richarz
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, Cologne, Germany
| | - Katharina Lauchner
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, Cologne, Germany
| | - Bernd Neumaier
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, Cologne, Germany.,Max Planck Institute for Metabolism Research, Cologne, Germany
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33
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Inkster JAH, Akurathi V, Sromek AW, Chen Y, Neumeyer JL, Packard AB. A non-anhydrous, minimally basic protocol for the simplification of nucleophilic 18F-fluorination chemistry. Sci Rep 2020; 10:6818. [PMID: 32321927 PMCID: PMC7176689 DOI: 10.1038/s41598-020-61845-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/03/2020] [Indexed: 11/30/2022] Open
Abstract
Fluorine-18 radiolabeling typically includes several conserved steps including elution of the [18F]fluoride from an anion exchange cartridge with a basic solution of K2CO3 or KHCO3 and Kryptofix 2.2.2. in mixture of acetonitrile and water followed by rigorous azeotropic drying to remove the water. In this work we describe an alternative "non-anhydrous, minimally basic" ("NAMB") technique that simplifies the process and avoids the basic conditions that can sometimes limit the scope and efficiency of [18F]fluoride incorporation chemistry. In this approach, [18F]F- is eluted from small (10-12 mg) anion-exchange cartridges with solutions of tetraethylammonium bicarbonate, perchlorate or tosylate in polar aprotic solvents containing 10-50% water. After dilution with additional aprotic solvent, these solutions are used directly in nucleophilic aromatic and aliphatic 18F-fluorination reactions, obviating the need for azeotropic drying. Perchlorate and tosylate are minimally basic anions that are nevertheless suitable for removal of [18F]F- from the anion-exchange cartridge. As proof-of-principle, "NAMB" chemistry was utilized for the synthesis of the dopamine D2/D3 antagonist [18F]fallypride.
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Affiliation(s)
- J A H Inkster
- Division of Nuclear Medicine and Molecular Imaging, Boston Children's Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - V Akurathi
- Division of Nuclear Medicine and Molecular Imaging, Boston Children's Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - A W Sromek
- Harvard Medical School, Boston, MA, 02115, USA
- Division of Basic Neuroscience, McLean Hospital, Belmont, MA, 02478, USA
| | - Y Chen
- Harvard Medical School, Boston, MA, 02115, USA
- Division of Basic Neuroscience, McLean Hospital, Belmont, MA, 02478, USA
| | - J L Neumeyer
- Harvard Medical School, Boston, MA, 02115, USA
- Division of Basic Neuroscience, McLean Hospital, Belmont, MA, 02478, USA
| | - A B Packard
- Division of Nuclear Medicine and Molecular Imaging, Boston Children's Hospital, Boston, MA, 02115, USA.
- Harvard Medical School, Boston, MA, 02115, USA.
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34
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Richard M, Specklin S, Roche M, Hinnen F, Kuhnast B. Original synthesis of radiolabeling precursors for batch and on resin one-step/late-stage radiofluorination of peptides. Chem Commun (Camb) 2020; 56:2507-2510. [PMID: 32003763 DOI: 10.1039/c9cc09434b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Radiolabeling of peptides with fluorine-18 is hurdled by their chemical sensitivity and complicated processes. Original triflyl-pyridine intermediates afforded ammonium precursors that were radiolabeled at low temperature. From that study, a generic tag has been designed to allow a simple one-step/late-stage radiolabelling of peptides. The strategy has been transposed to an automated "on-resin" radiolabelling.
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Affiliation(s)
- Mylène Richard
- Université Paris Saclay, CEA, INSERM, CNRS, BioMaps, Service Hospitalier Frédéric Joliot, Bertrand KUHNAST, 4 place du général Leclerc, 91401 Orsay, France.
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35
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Ermert J, Benešová M, Hugenberg V, Gupta V, Spahn I, Pietzsch HJ, Liolios C, Kopka K. Radiopharmaceutical Sciences. Clin Nucl Med 2020. [DOI: 10.1007/978-3-030-39457-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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36
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The chemistry of labeling heterocycles with carbon-11 or fluorine-18 for biomedical imaging. ADVANCES IN HETEROCYCLIC CHEMISTRY 2020. [DOI: 10.1016/bs.aihch.2019.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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37
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Orlovskaya VV, Modemann DJ, Kuznetsova OF, Fedorova OS, Urusova EA, Kolks N, Neumaier B, Krasikova RN, Zlatopolskiy BD. Alcohol-Supported Cu-Mediated 18F-Fluorination of Iodonium Salts under "Minimalist" Conditions. Molecules 2019; 24:molecules24173197. [PMID: 31484375 PMCID: PMC6749259 DOI: 10.3390/molecules24173197] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/29/2019] [Accepted: 09/02/2019] [Indexed: 02/01/2023] Open
Abstract
In the era of personalized precision medicine, positron emission tomography (PET) and related hybrid methods like PET/CT and PET/MRI gain recognition as indispensable tools of clinical diagnostics. A broader implementation of these imaging modalities in clinical routine is closely dependent on the increased availability of established and emerging PET-tracers, which in turn could be accessible by the development of simple, reliable, and efficient radiolabeling procedures. A further requirement is a cGMP production of imaging probes in automated synthesis modules. Herein, a novel protocol for the efficient preparation of 18F-labeled aromatics via Cu-mediated radiofluorination of (aryl)(mesityl)iodonium salts without the need of evaporation steps is described. Labeled aromatics were prepared in high radiochemical yields simply by heating of iodonium [18F]fluorides with the Cu-mediator in methanolic DMF. The iodonium [18F]fluorides were prepared by direct elution of 18F- from an anion exchange resin with solutions of the corresponding precursors in MeOH/DMF. The practicality of the novel method was confirmed by the racemization-free production of radiolabeled fluorophenylalanines, including hitherto unknown 3-[18F]FPhe, in 22-69% isolated radiochemical yields as well as its direct implementation into a remote-controlled synthesis unit.
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Affiliation(s)
| | - Daniel J Modemann
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
| | - Olga F Kuznetsova
- N.P.Bechtereva Institute of the Human Brain, 197376 St.-Petersburg, Russia.
| | - Olga S Fedorova
- N.P.Bechtereva Institute of the Human Brain, 197376 St.-Petersburg, Russia.
| | - Elizaveta A Urusova
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
- Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, 50937 Cologne, Germany.
| | - Niklas Kolks
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
- Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, 50937 Cologne, Germany.
| | - Bernd Neumaier
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
- Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, 50937 Cologne, Germany.
- Max Planck Institute for Metabolism Research, 50931 Cologne, Germany.
| | - Raisa N Krasikova
- N.P.Bechtereva Institute of the Human Brain, 197376 St.-Petersburg, Russia.
- St.-Petersburg State University, 199034 St.-Petersburg, Russia.
| | - Boris D Zlatopolskiy
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
- Institute of Radiochemistry and Experimental Molecular Imaging, University Clinic Cologne, 50937 Cologne, Germany.
- Max Planck Institute for Metabolism Research, 50931 Cologne, Germany.
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38
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A Design of Experiments (DoE) Approach Accelerates the Optimization of Copper-Mediated 18F-Fluorination Reactions of Arylstannanes. Sci Rep 2019; 9:11370. [PMID: 31388076 PMCID: PMC6684620 DOI: 10.1038/s41598-019-47846-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 07/23/2019] [Indexed: 11/08/2022] Open
Abstract
Recent advancements in 18F radiochemistry, such as the advent of copper-mediated radiofluorination (CMRF) chemistry, have provided unprecedented access to novel chemically diverse PET probes; however, these multicomponent reactions have come with a new set of complex optimization problems. Design of experiments (DoE) is a statistical approach to process optimization that is used across a variety of industries. It possesses a number of advantages over the traditionally employed "one variable at a time" (OVAT) approach, such as increased experimental efficiency as well as an ability to resolve factor interactions and provide detailed maps of a process's behavior. Here we demonstrate the utility of DoE to the development and optimization of new radiochemical methodologies and novel PET tracer synthesis. Using DoE to construct experimentally efficient factor screening and optimization studies, we were able to identify critical factors and model their behavior with more than two-fold greater experimental efficiency than the traditional OVAT approach. Additionally, the use of DoE allowed us to glean new insights into the behavior of the CMRF of a number of arylstannane precursors. This information has guided our decision-making efforts while developing efficient reaction conditions that suit the unique process requirements of 18F PET tracer synthesis.
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39
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Hohberg M, Kobe C, Krapf P, Täger P, Hammes J, Dietlein F, Zlatopolskiy BD, Endepols H, Wild M, Neubauer S, Heidenreich A, Neumaier B, Drzezga A, Dietlein M. Biodistribution and radiation dosimetry of [ 18F]-JK-PSMA-7 as a novel prostate-specific membrane antigen-specific ligand for PET/CT imaging of prostate cancer. EJNMMI Res 2019; 9:66. [PMID: 31346821 PMCID: PMC6658635 DOI: 10.1186/s13550-019-0540-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/17/2019] [Indexed: 11/24/2022] Open
Abstract
Aim We investigated the whole-body distribution and the radiation dosimetry of [18F]-JK-PSMA-7, a novel 18F-labeled PSMA-ligand for PET/CT imaging of prostate cancer. Methods Ten patients with prostate cancer and biochemical recurrence or radiologic evidence of metastatic diseases were examined with 329–384 MBq (mean 359 ± 17 MBq) [18F]-JK-PSMA-7. Eight sequential positron emission tomography (PET) scans were acquired from 20 min to 3 h after injection with IRB approval. The kidneys, liver, lungs, spleen, and salivary glands were segmented into volumes of interest using the QDOSE dosimetry software suite (ABX-CRO, Germany). Absorbed and effective dose were calculated using the ICRP-endorsed IDAC 1.0 package. The absorbed dose of the salivary glands was determined using the spherical model of OLINDA 1.1. PSMA-positive lesions were evaluated separately. Quantitative assessment of the uptake in suspicious lesions was performed by analysis of maximum (max) and peak SUV values. The gluteus maximus muscle (SUVmean) served as a reference region for the calculation of tumor-to-background ratios (TBR’s). Results Physiologic radiotracer accumulation was observed in the salivary and lacrimal glands, liver, spleen, and intestines, in a pattern resembling the distribution known from other PSMA-tracers with excretion via urinary and biliary pathways. The effective dose from [18F]-JK-PSMA-7 for the whole body was calculated to be 1.09E−02 mGy/MBq. The highest radiation dose was observed in the kidneys (1.76E−01 mGy/MBq), followed by liver (7.61E−02 mGy/MBq), salivary glands (4.68E−02 mGy/MBq), spleen (1.89E−02 mGy/MBq), and lungs (1.10E-2 mGy/MBq). No adverse effects of tracer injection were observed. Six out of ten patients were scored as PSMA-positive. A total of 18 suspicious lesions were analyzed, which included six bone lesions, nine lymph nodes, and three local lesions within the prostate fossa. The values for the SUVmax and SUVpeak in the PSMA-positive lesions increased until 60 min p.i. and remained at this intensity in the PET/CT scans until 140 min. In the period between 170 and 200 min after injection, a further significant increase in SUVmax and SUVpeak within the PSMA-positive lesions was observed. Conclusions The highest TBR of [18F]-JK-PSMA-7 was found 3 h after injection. From the kinetically collected data, it can be concluded that this trend may also continue in the further course. The start of the PET/CT acquisition should be chosen as late as possible. The high uptake in suspicious lesions in terms of absolute SUVmax and relative TBR values indicates potentially high sensitivity of the tracer for detection of prostate cancer manifestations.
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Affiliation(s)
- Melanie Hohberg
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany. .,Cancer Center Cologne, University Hospital of Cologne, Cologne, Germany.
| | - Carsten Kobe
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Cancer Center Cologne, University Hospital of Cologne, Cologne, Germany
| | - Philipp Krapf
- Institute of Neuroscience and Medicine, INM-5 (Nuclear Chemistry), Research Center Juelich GmbH, Juelich, Germany
| | - Philipp Täger
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Cancer Center Cologne, University Hospital of Cologne, Cologne, Germany
| | - Jochen Hammes
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Cancer Center Cologne, University Hospital of Cologne, Cologne, Germany
| | - Felix Dietlein
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Boris D Zlatopolskiy
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany
| | - Heike Endepols
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany
| | - Markus Wild
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | | | - Axel Heidenreich
- Department of Urology, University Hospital of Cologne, Cologne, Germany
| | - Bernd Neumaier
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine, INM-5 (Nuclear Chemistry), Research Center Juelich GmbH, Juelich, Germany
| | - Alexander Drzezga
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Cancer Center Cologne, University Hospital of Cologne, Cologne, Germany
| | - Markus Dietlein
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Cancer Center Cologne, University Hospital of Cologne, Cologne, Germany
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Pauton M, Gillet R, Aubert C, Bluet G, Gruss-Leleu F, Roy S, Perrio C. The first radiosynthesis of 2-amino-5-[ 18F]fluoropyridines via a "minimalist" radiofluorination/palladium-catalyzed amination sequence from anisyl(2-bromopyridinyl)iodonium triflate. Org Biomol Chem 2019; 17:6359-6363. [PMID: 31218326 DOI: 10.1039/c9ob01187k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The synthesis of 2-amino-5-[18F]fluoropyridines was achieved in 8-85% yields by palladium-catalyzed reaction of 2-bromo-5-[18F]fluoropyridine with piperidine, dimethylamine, butylamine, methylpiperazine, benzylamine, aniline and 3-aminopyridine. 2-Bromo-5-[18F]fluoropyridine was obtained by radiofluorination of anisyl(2-bromopyridinyl-5)iodonium triflate (88% yield). The radiofluorination step was performed under "minimalist" conditions to guarantee a successful subsequent amination reaction.
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Affiliation(s)
- Mathilde Pauton
- Normandie Univ, UNICAEN, CEA, CNRS, ISTCT-UMR 6030, LDM-TEP, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France. and Sanofi R&D, IDD, Isotope Chemistry, 13 Quai Jules Guesde, 94403 Vitry sur Seine Cedex, France
| | - Raphaël Gillet
- Normandie Univ, UNICAEN, CEA, CNRS, ISTCT-UMR 6030, LDM-TEP, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France.
| | - Catherine Aubert
- Sanofi R&D, IDD, Isotope Chemistry, 13 Quai Jules Guesde, 94403 Vitry sur Seine Cedex, France
| | - Guillaume Bluet
- Sanofi R&D, IDD, Isotope Chemistry, 13 Quai Jules Guesde, 94403 Vitry sur Seine Cedex, France
| | - Florence Gruss-Leleu
- Sanofi R&D, IDD, Isotope Chemistry, 13 Quai Jules Guesde, 94403 Vitry sur Seine Cedex, France
| | - Sébastien Roy
- Sanofi R&D, IDD, Isotope Chemistry, 13 Quai Jules Guesde, 94403 Vitry sur Seine Cedex, France
| | - Cécile Perrio
- Normandie Univ, UNICAEN, CEA, CNRS, ISTCT-UMR 6030, LDM-TEP, Cyceron, Boulevard Henri Becquerel, 14000 Caen, France.
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41
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Endepols H, Morgenroth A, Zlatopolskiy BD, Krapf P, Zischler J, Richarz R, Muñoz Vásquez S, Neumaier B, Mottaghy FM. Peripheral ganglia in healthy rats as target structures for the evaluation of PSMA imaging agents. BMC Cancer 2019; 19:633. [PMID: 31242896 PMCID: PMC6595687 DOI: 10.1186/s12885-019-5841-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 06/16/2019] [Indexed: 02/08/2023] Open
Abstract
Background The recent implementation of PET with prostate specific membrane antigen (PSMA)-specific radiotracers into the clinical practice has resulted in the significant improvement of accuracy in the detection of prostate carcinoma (PCa). PSMA-expression in ganglia has been regarded as an important pitfall in prostate carcinoma-PET diagnostics but has not found any practical use for diagnosis or therapy. Methods We explored this phenomenon and demonstrated the applicability of peripheral ganglia in healthy rats as surrogates for small PSMA positive lesions for the preclinical evaluation of diagnostic PCa PET probes. Healthy rats were measured with PET/CT using the tracers [18F]DCFPyL, [Al18F]PSMA-11 and [68Ga]PSMA-11. Sections of ganglia were stained with an anti-PSMA antibody. [18F]DCFPyL uptake in ganglia was compared to that in LNCaP tumor xenografts in mice. Results Whereas [18F]DCFPyL and [68Ga]PSMA-11 were stable in vivo and accumulated in peripheral ganglia, [Al18F]PSMA-11 suffered from fast in vivo deflourination resulting in high bone uptake. Ganglionic PSMA expression was confirmed by immunohistochemistry. [18F]DCFPyL uptake and signal-to-noise ratio in the superior cervical ganglion was not significantly different from LNCaP xenografts. Conclusions Our results demonstrated the non-inferiority of the novel model compared to conventionally used tumor xenografts in immune compromised rodents with regard to reproducibility and stability of the PSMA signal. Furthermore, the model involves less expense and efforts while it is permanently available and avoids tumor-growth associated animal morbidity and distress. To the best of our knowledge, this is the first tumor-free model suitable for the in vivo evaluation of tumor imaging agents.
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Affiliation(s)
- Heike Endepols
- Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937, Cologne, Germany.,Department of Nuclear Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937, Cologne, Germany.,Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Agnieszka Morgenroth
- Department of Nuclear Medicine, University Hospital, RWTH Aachen, Pauwelsstraße 30, Aachen, 52074, Germany
| | - Boris D Zlatopolskiy
- Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937, Cologne, Germany.,Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Philipp Krapf
- Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937, Cologne, Germany.,Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Johannes Zischler
- Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937, Cologne, Germany.,Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | - Raphael Richarz
- Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937, Cologne, Germany
| | - Sergio Muñoz Vásquez
- Department of Nuclear Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937, Cologne, Germany
| | - Bernd Neumaier
- Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937, Cologne, Germany. .,Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Straße, 52428, Jülich, Germany.
| | - Felix M Mottaghy
- Department of Nuclear Medicine, University Hospital, RWTH Aachen, Pauwelsstraße 30, Aachen, 52074, Germany. .,Department of Radiology and Nuclear Medicine, Maastricht University Medical Center X, Maastricht, the Netherlands.
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42
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Roscales S, Kniess T. Access to 18
F-labelled isoxazoles by ruthenium-promoted 1,3-dipolar cycloaddition of 4-[18
F]fluoro-N
-hydroxybenzimidoyl chloride with alkynes. J Labelled Comp Radiopharm 2019; 62:393-403. [DOI: 10.1002/jlcr.3708] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/02/2018] [Accepted: 01/11/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Silvia Roscales
- Institute of Radiopharmaceutical Cancer Research; Helmholtz-Zentrum Dresden-Rossendorf; Dresden Germany
| | - Torsten Kniess
- Institute of Radiopharmaceutical Cancer Research; Helmholtz-Zentrum Dresden-Rossendorf; Dresden Germany
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43
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Maisonial-Besset A, Serre A, Ouadi A, Schmitt S, Canitrot D, Léal F, Miot-Noirault E, Brasse D, Marchand P, Chezal JM. Base/Cryptand/Metal-Free Automated Nucleophilic Radiofluorination of [18
F]FDOPA from Iodonium Salts: Importance of Hydrogen Carbonate Counterion. European J Org Chem 2018. [DOI: 10.1002/ejoc.201801608] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Aurélie Maisonial-Besset
- Université Clermont Auvergne; INSERM U1240; Imagerie Moléculaire et Stratégies Théranostiques; BP 184, 58 rue Montalembert 63000 Clermont Ferrand France
| | - Audrey Serre
- Université Clermont Auvergne; INSERM U1240; Imagerie Moléculaire et Stratégies Théranostiques; BP 184, 58 rue Montalembert 63000 Clermont Ferrand France
| | - Ali Ouadi
- CNRS; IPHC; Université de Strasbourg; 23 rue du Loess BP 28 67000 Strasbourg France
| | - Sébastien Schmitt
- Université Clermont Auvergne; INSERM U1240; Imagerie Moléculaire et Stratégies Théranostiques; BP 184, 58 rue Montalembert 63000 Clermont Ferrand France
| | - Damien Canitrot
- Université Clermont Auvergne; INSERM U1240; Imagerie Moléculaire et Stratégies Théranostiques; BP 184, 58 rue Montalembert 63000 Clermont Ferrand France
| | - Fernand Léal
- Université Clermont Auvergne; INSERM U1240; Imagerie Moléculaire et Stratégies Théranostiques; BP 184, 58 rue Montalembert 63000 Clermont Ferrand France
| | - Elisabeth Miot-Noirault
- Université Clermont Auvergne; INSERM U1240; Imagerie Moléculaire et Stratégies Théranostiques; BP 184, 58 rue Montalembert 63000 Clermont Ferrand France
| | - David Brasse
- CNRS; IPHC; Université de Strasbourg; 23 rue du Loess BP 28 67000 Strasbourg France
| | - Patrice Marchand
- CNRS; IPHC; Université de Strasbourg; 23 rue du Loess BP 28 67000 Strasbourg France
| | - Jean-Michel Chezal
- Université Clermont Auvergne; INSERM U1240; Imagerie Moléculaire et Stratégies Théranostiques; BP 184, 58 rue Montalembert 63000 Clermont Ferrand France
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44
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Zlatopolskiy BD, Endepols H, Krapf P, Guliyev M, Urusova EA, Richarz R, Hohberg M, Dietlein M, Drzezga A, Neumaier B. Discovery of 18F-JK-PSMA-7, a PET Probe for the Detection of Small PSMA-Positive Lesions. J Nucl Med 2018; 60:817-823. [PMID: 30389823 DOI: 10.2967/jnumed.118.218495] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/22/2018] [Indexed: 11/16/2022] Open
Abstract
Prostate-specific membrane antigen (PSMA), expressed by most prostate carcinomas (PCa), is a promising target for PCa imaging. The application of PSMA-specific 18F-labeled PET probes such as 18F-DCFPyL and 18F-PSMA-1007 considerably improved the accuracy of PCa tumor detection. However, there remains a need for further improvements in sensitivity and specificity. The aim of this study was the development of highly selective and specific PSMA probes with enhanced imaging properties, in comparison with 18F-DCFPyL, 18F-PSMA-1007, and 68Ga-PSMA-11. Methods: Eight novel 18F-labeled PSMA ligands were prepared. Their cellular uptake in PSMA-positive LNCaP C4-2 and PSMA-negative PC-3 cells was compared with that of 18F-DCFPyL. The most promising candidates were additionally evaluated by small-animal PET in healthy rats using PSMA-positive peripheral ganglia as a model for small PCa lesions. PET images of the ligand with the best outcome, 18F-JK-PSMA-7, were compared with those of 18F-DCFPyL, 18F-PSMA-1007, and 68Ga-PSMA-11 with respect to key image-quality parameters for the time frame 60-120 min. Results: Compared with 18F-DCFPyL, 18F-JK-PSMA-7 demonstrated increased PSMA-specific cellular uptake. Although target-to-background ratios of 18F-DCFPyL and 18F-PSMA-1007 were comparable, this parameter was higher for 18F-JK-PSMA-7 and lower for 68Ga-PSMA-11. Image acutance was significantly higher for 18F-JK-PSMA-7 and 18F-PSMA-1007 than for 18F-DCFPyL and 68Ga-PSMA-11. Image resolution was similar for all 4 tracers. 18F-PSMA-1007 demonstrated significantly higher blood protein binding and bone uptake than the other tracers. Conclusion: 18F-JK-PSMA-7 is a promising candidate for high-quality visualization of small PSMA-positive lesions. Excellent preclinical imaging properties justify further preclinical and clinical studies of this tracer.
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Affiliation(s)
- Boris D Zlatopolskiy
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Max Planck Institute for Metabolism Research, Cologne, Germany; and
| | - Heike Endepols
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Department of Nuclear Medicine, University Hospital of Cologne, Cologne, Germany
| | - Philipp Krapf
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Mehrab Guliyev
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany
| | - Elizaveta A Urusova
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Raphael Richarz
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Melanie Hohberg
- Department of Nuclear Medicine, University Hospital of Cologne, Cologne, Germany
| | - Markus Dietlein
- Department of Nuclear Medicine, University Hospital of Cologne, Cologne, Germany
| | - Alexander Drzezga
- Department of Nuclear Medicine, University Hospital of Cologne, Cologne, Germany
| | - Bernd Neumaier
- Institute of Radiochemistry and Experimental Molecular Imaging, University Hospital of Cologne, Cologne, Germany .,Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich GmbH, Jülich, Germany.,Max Planck Institute for Metabolism Research, Cologne, Germany; and
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45
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Chao PH, Lazari M, Hanet S, Narayanam MK, Murphy JM, van Dam RM. Automated concentration of [ 18F]fluoride into microliter volumes. Appl Radiat Isot 2018; 141:138-148. [PMID: 30243135 PMCID: PMC6502507 DOI: 10.1016/j.apradiso.2018.06.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/07/2018] [Accepted: 06/20/2018] [Indexed: 11/23/2022]
Abstract
Concentration of [18F]fluoride has been mentioned in literature, however, reports have lacked details about system designs, operation, and performance. Here, we describe in detail a compact, fast, fully-automated concentration system based on a micro-sized strong anion exchange cartridge. The concentration of radionuclides enables scaled-up microfluidic synthesis. Our system can also be used to provide highly concentrated [18F]fluoride with minimal water content. We demonstrate how the concentrator can produce varying concentrations of [18F]fluoride for the macroscale synthesis of N-boc-5-[18F]fluoroindole without an azeotropic drying process, while enabling high starting radioactivity. By appropriate choice of solid-phase resin, flow conditions, and eluent solution, we believe this approach can be extended beyond [18F]fluoride to other radionuclides.
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Affiliation(s)
- Philip H Chao
- Department of Bioengineering, Henry Samueli School of Engineering, UCLA, Los Angeles, CA 90095, USA; Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Mark Lazari
- Department of Bioengineering, Henry Samueli School of Engineering, UCLA, Los Angeles, CA 90095, USA; Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Sebastian Hanet
- Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Maruthi Kumar Narayanam
- Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Jennifer M Murphy
- Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - R Michael van Dam
- Department of Bioengineering, Henry Samueli School of Engineering, UCLA, Los Angeles, CA 90095, USA; Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
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46
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Krüll J, Heinrich MR. [
18
F]Fluorine‐Labeled Pharmaceuticals: Direct Aromatic Fluorination Compared to Multi‐Step Strategies. ASIAN J ORG CHEM 2018. [DOI: 10.1002/ajoc.201800494] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jasmin Krüll
- Department of Chemistry and Pharmacy, Pharmaceutical ChemistryFriedrich-Alexander Universität Erlangen-Nürnberg Nikolaus-Fiebiger-Str. 10 91058 Erlangen
| | - Markus R. Heinrich
- Department of Chemistry and Pharmacy, Pharmaceutical ChemistryFriedrich-Alexander Universität Erlangen-Nürnberg Nikolaus-Fiebiger-Str. 10 91058 Erlangen
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47
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Basuli F, Zhang X, Jagoda EM, Choyke PL, Swenson RE. Rapid synthesis of maleimide functionalized fluorine-18 labeled prosthetic group using "radio-fluorination on the Sep-Pak" method. J Labelled Comp Radiopharm 2018; 61:599-605. [PMID: 29575176 PMCID: PMC6295906 DOI: 10.1002/jlcr.3623] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/06/2018] [Accepted: 03/09/2018] [Indexed: 01/05/2023]
Abstract
Following our recently published fluorine-18 labeling method, "Radio-fluorination on the Sep-Pak", we have successfully synthesized 6-[18 F]fluoronicotinaldehyde by passing a solution (1:4 acetonitrile: t-butanol) of its quaternary ammonium salt precursor, 6-(N,N,N-trimethylamino)nicotinaldehyde trifluoromethanesulfonate (2), through a fluorine-18 containing anion exchange cartridge (PS-HCO3 ). Over 80% radiochemical conversion was observed using 10 mg of precursor within 1 minute. The [18 F]fluoronicotinaldehyde ([18 F]5) was then conjugated with 1-(6-(aminooxy)hexyl)-1H-pyrrole-2,5-dione to prepare the fluorine-18 labeled maleimide functionalized prosthetic group, 6-[18 F]fluoronicotinaldehyde O-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexyl) oxime, 6-[18 F]FPyMHO ([18 F]6). The current Sep-Pak method not only improves the overall radiochemical yield (50 ± 9%, decay-corrected, n = 9) but also significantly reduces the synthesis time (from 60-90 minutes to 30 minutes) when compared with literature methods for the synthesis of similar prosthetic groups.
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Affiliation(s)
- Falguni Basuli
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland, USA
| | - Xiang Zhang
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland, USA
| | - Elaine M. Jagoda
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Peter L. Choyke
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Rolf E. Swenson
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland, USA
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49
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Iwata R, Pascali C, Terasaki K, Ishikawa Y, Furumoto S, Yanai K. Practical microscale one-pot radiosynthesis of 18 F-labeled probes. J Labelled Comp Radiopharm 2018. [PMID: 29520821 DOI: 10.1002/jlcr.3618] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
High specific activity is often a significant requirement for radiopharmaceuticals. To achieve that with fluorine-18 (18 F)-labeled probes, it is mandatory to start from no-carrier-added fluoride and to reduce to a minimum the amount of precursor in order to decrease the presence of any pseudocarrier. In the present study, a feasible and efficient method for microscale one-pot radiosynthesis of 18 F-labeled probes is described. It allows a substantial reduction in precursor, solvent, and reagents, thus reducing also possible side reaction in the case of base-sensitive precursors. The method is based on the use of a small amount of Kryptofix 2.2.2/potassium [18 F]fluoride in MeOH (K.222/K[18 F]F-MeOH) obtained using Oasis MAX and MCX cartridges. Five methods, differing in terms of MeOH evaporation and precursor addition, for the radiosynthesis of [18 F]fallypride and [18 F]FET in ≤50-μL scale, were examined and evaluated. The method using the addition of DMSO to the K.222/K[18 F]F-MeOH solution prior to MeOH evaporation is proposed as a versatile procedure for feasible one-pot 10- to 20-μL scale radiosyntheses. This method was successfully applied also to the radiosynthesis of [18 F]FES, [18 F]FLT, and [18 F]FMISO, with radiochemical yields comparable with those reported in the literature. Purification of a crude product by an analytical HPLC column was also demonstrated.
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Affiliation(s)
- Ren Iwata
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Claudio Pascali
- S.C. Medicina Nucleare, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | | | - Yoichi Ishikawa
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Shozo Furumoto
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Kazuhiko Yanai
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan.,Graduate School of Medicine, Tohoku University, Sendai, Japan
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50
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Robu S, Schmidt A, Eiber M, Schottelius M, Günther T, Hooshyar Yousefi B, Schwaiger M, Wester HJ. Synthesis and preclinical evaluation of novel 18F-labeled Glu-urea-Glu-based PSMA inhibitors for prostate cancer imaging: a comparison with 18F-DCFPyl and 18F-PSMA-1007. EJNMMI Res 2018; 8:30. [PMID: 29651565 PMCID: PMC5897267 DOI: 10.1186/s13550-018-0382-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 03/23/2018] [Indexed: 11/13/2022] Open
Abstract
Background Due to its high and consistent expression in prostate cancer (PCa), the prostate-specific membrane antigen (PSMA) represents an ideal target for molecular imaging and targeted therapy using highly specific radiolabeled PSMA ligands. To address the continuously growing clinical demand for 18F-labeled PSMA-probes, we developed two novel Glu-urea-Glu-(EuE)-based inhibitors, EuE-k-18F-FBOA (1) and EuE-k-β-a-18F-FPyl (2), both with optimized linker structure and different 18F-labeled aromatic moieties. The inhibitors were evaluated in a comparative preclinical study with 18F-DCFPyl and 18F-PSMA-1007. Results Radiolabeling procedures allowed preparation of (1) and (2) with high radiochemical yields (67 ± 7 and 53 ± 7%, d.c.) and purity (> 98%). When compared with 18F-DCFPyl (IC50 = 12.3 ± 1.2 nM) and 18F-PSMA-1007 (IC50 = 4.2 ± 0.5 nM), both metabolically stable EuE-based ligands showed commensurable or higher PSMA affinity (IC50 = 4.2 ± 0.4 nM (1), IC50 = 1.1 ± 0.2 nM (2)). Moreover, 1.4- and 2.7-fold higher internalization rates were observed for (1) and (2), respectively, resulting in markedly enhanced tumor accumulation in LNCaP-tumor-bearing mice ((1) 12.7 ± 2.0% IA/g, (2) 13.0° ± 1.0% IA/g vs. 7.3 ± 1.0% IA/g (18F-DCFPyl), 7.1 ± 1.5% IA/g (18F-PSMA-1007), 1 h p.i.). In contrast to (1), (2) showed higher kidney accumulation and delayed clearance kinetics. Due to the high hydrophilicity of both compounds, almost no unspecific uptake in non-target tissue was observed. In contrast, due to the less hydrophilic character (logP = − 1.6) and high plasma protein binding (98%), 18F-PSMA-1007 showed uptake in non-target tissue and predominantly hepatobiliary excretion, whereas, 18F-DCFPyl exhibited pharmacokinetics quite similar to those obtained with (1) and (2). Conclusion Both 18F-labeled EuE-based PSMA ligands showed excellent in vitro and in vivo PSMA-targeting characteristics. The substantially higher tumor accumulation in mice compared to recently introduced 18F-PSMA-1007 and 18F-DCFPyl suggests their high value for preclinical studies investigating the effects on PSMA-expression. In contrast to (2), (1) seems to be more promising for further investigation, due to the more reliable 18F-labeling procedure, the faster clearance kinetics with comparable high tumor uptake, resulting therefore in better high-contrast microPET imaging as early as 1 h p.i. Electronic supplementary material The online version of this article (10.1186/s13550-018-0382-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephanie Robu
- Chair of Pharmaceutical Radiochemistry, Technical University Munich, Walther-Meissner-Strasse 3, 85748, Garching, Germany.
| | - Alexander Schmidt
- Chair of Pharmaceutical Radiochemistry, Technical University Munich, Walther-Meissner-Strasse 3, 85748, Garching, Germany
| | - Matthias Eiber
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Ismaningerstr. 22, 81675, Munich, Germany
| | - Margret Schottelius
- Chair of Pharmaceutical Radiochemistry, Technical University Munich, Walther-Meissner-Strasse 3, 85748, Garching, Germany
| | - Thomas Günther
- Chair of Pharmaceutical Radiochemistry, Technical University Munich, Walther-Meissner-Strasse 3, 85748, Garching, Germany
| | - Behrooz Hooshyar Yousefi
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Ismaningerstr. 22, 81675, Munich, Germany
| | - Markus Schwaiger
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Ismaningerstr. 22, 81675, Munich, Germany
| | - Hans-Jürgen Wester
- Chair of Pharmaceutical Radiochemistry, Technical University Munich, Walther-Meissner-Strasse 3, 85748, Garching, Germany
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