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Automated Synthesis of [18F]Flumazenil Application in GABAA Receptor Neuroimaging Availability for Rat Model of Anxiety. Pharmaceuticals (Basel) 2023; 16:ph16030417. [PMID: 36986516 PMCID: PMC10058208 DOI: 10.3390/ph16030417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/03/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
Clinical studies have demonstrated that the γ-aminobutyric acid type A (GABAA) receptor complex plays a central role in the modulation of anxiety. Conditioned fear and anxiety-like behaviors have many similarities at the neuroanatomical and pharmacological levels. The radioactive GABA/BZR receptor antagonist, fluorine-18-labeled flumazenil, [18F]flumazenil, behaves as a potential PET imaging agent for the evaluation of cortical damage of the brain in stroke, alcoholism, and for Alzheimer disease investigation. The main goal of our study was to investigate a fully automated nucleophilic fluorination system, with solid extraction purification, developed to replace traditional preparation methods, and to detect underlying expressions of contextual fear and characterize the distribution of GABAA receptors in fear-conditioned rats by [18F]flumazenil. A carrier-free nucleophilic fluorination method using an automatic synthesizer with direct labeling of a nitro-flumazenil precursor was implemented. The semi-preparative high-performance liquid chromatography (HPLC) purification method (RCY = 15–20%) was applied to obtain high purity [18F]flumazenil. Nano-positron emission tomography (NanoPET)/computed tomography (CT) imaging and ex vivo autoradiography were used to analyze the fear conditioning of rats trained with 1–10 tone-foot-shock pairings. The anxiety rats had a significantly lower cerebral accumulation (in the amygdala, prefrontal cortex, cortex, and hippocampus) of fear conditioning. Our rat autoradiography results also supported the findings of PET imaging. Key findings were obtained by developing straightforward labeling and purification procedures that can be easily adapted to commercially available modules for the high radiochemical purity of [18F]flumazenil. The use of an automatic synthesizer with semi-preparative HPLC purification would be a suitable reference method for new drug studies of GABAA/BZR receptors in the future.
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Nerella SG, Singh P, Sanam T, Digwal CS. PET Molecular Imaging in Drug Development: The Imaging and Chemistry Perspective. Front Med (Lausanne) 2022; 9:812270. [PMID: 35295604 PMCID: PMC8919964 DOI: 10.3389/fmed.2022.812270] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
Positron emission tomography with selective radioligands advances the drug discovery and development process by revealing information about target engagement, proof of mechanism, pharmacokinetic and pharmacodynamic profiles. Positron emission tomography (PET) is an essential and highly significant tool to study therapeutic drug development, dose regimen, and the drug plasma concentrations of new drug candidates. Selective radioligands bring up target-specific information in several disease states including cancer, cardiovascular, and neurological conditions by quantifying various rates of biological processes with PET, which are associated with its physiological changes in living subjects, thus it reveals disease progression and also advances the clinical investigation. This study explores the major roles, applications, and advances of PET molecular imaging in drug discovery and development process with a wide range of radiochemistry as well as clinical outcomes of positron-emitting carbon-11 and fluorine-18 radiotracers.
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Affiliation(s)
- Sridhar Goud Nerella
- Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Priti Singh
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Hyderabad, India
| | - Tulja Sanam
- Department of Microbiology and Applied Sciences, University of Agricultural Sciences, Bangalore, India
| | - Chander Singh Digwal
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Hyderabad, India
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Schimler SD, Ryan SJ, Bland DC, Anderson JE, Sanford MS. Anhydrous Tetramethylammonium Fluoride for Room-Temperature SNAr Fluorination. J Org Chem 2015; 80:12137-45. [DOI: 10.1021/acs.joc.5b02075] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Sydonie D. Schimler
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Sarah J. Ryan
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Douglas C. Bland
- Process Science, Dow Chemical Company, 1710 Building, Midland, Michigan 48674, United States
| | - John E. Anderson
- Process Science, Dow Chemical Company, 1710 Building, Midland, Michigan 48674, United States
| | - Melanie S. Sanford
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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Rensch C, Jackson A, Lindner S, Salvamoser R, Samper V, Riese S, Bartenstein P, Wängler C, Wängler B. Microfluidics: a groundbreaking technology for PET tracer production? Molecules 2013; 18:7930-56. [PMID: 23884128 PMCID: PMC6270045 DOI: 10.3390/molecules18077930] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 06/21/2013] [Accepted: 07/03/2013] [Indexed: 11/16/2022] Open
Abstract
Application of microfluidics to Positron Emission Tomography (PET) tracer synthesis has attracted increasing interest within the last decade. The technical advantages of microfluidics, in particular the high surface to volume ratio and resulting fast thermal heating and cooling rates of reagents can lead to reduced reaction times, increased synthesis yields and reduced by-products. In addition automated reaction optimization, reduced consumption of expensive reagents and a path towards a reduced system footprint have been successfully demonstrated. The processing of radioactivity levels required for routine production, use of microfluidic-produced PET tracer doses in preclinical and clinical imaging as well as feasibility studies on autoradiolytic decomposition have all given promising results. However, the number of microfluidic synthesizers utilized for commercial routine production of PET tracers is very limited. This study reviews the state of the art in microfluidic PET tracer synthesis, highlighting critical design aspects, strengths, weaknesses and presenting several characteristics of the diverse PET market space which are thought to have a significant impact on research, development and engineering of microfluidic devices in this field. Furthermore, the topics of batch- and single-dose production, cyclotron to quality control integration as well as centralized versus de-centralized market distribution models are addressed.
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Affiliation(s)
- Christian Rensch
- GE Global Research, Freisinger Landstrasse 50, Garching bei Munich 85748, Germany; E-Mails: (R.S.); (V.S.)
| | - Alexander Jackson
- GE Healthcare, Life Sciences, The Grove Centre, White Lion Rd., Amersham HP7 9LL, UK; E-Mails: (A.J.); (S.R.)
| | - Simon Lindner
- University Hospital Munich, Department of Nuclear Medicine, Ludwig Maximilians-University, Munich 81377, Germany; E-Mails: (S.L.); (P.B.); (C.W.)
| | - Ruben Salvamoser
- GE Global Research, Freisinger Landstrasse 50, Garching bei Munich 85748, Germany; E-Mails: (R.S.); (V.S.)
| | - Victor Samper
- GE Global Research, Freisinger Landstrasse 50, Garching bei Munich 85748, Germany; E-Mails: (R.S.); (V.S.)
| | - Stefan Riese
- GE Healthcare, Life Sciences, The Grove Centre, White Lion Rd., Amersham HP7 9LL, UK; E-Mails: (A.J.); (S.R.)
| | - Peter Bartenstein
- University Hospital Munich, Department of Nuclear Medicine, Ludwig Maximilians-University, Munich 81377, Germany; E-Mails: (S.L.); (P.B.); (C.W.)
| | - Carmen Wängler
- University Hospital Munich, Department of Nuclear Medicine, Ludwig Maximilians-University, Munich 81377, Germany; E-Mails: (S.L.); (P.B.); (C.W.)
- Biomedical Chemistry, Department of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim of Heidelberg University, Mannheim 68167, Germany
| | - Björn Wängler
- Molecular Imaging and Radiochemistry, Department of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim of Heidelberg University, Mannheim 68167, Germany
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Nolting DD, Nickels ML, Guo N, Pham W. Molecular imaging probe development: a chemistry perspective. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2012; 2:273-306. [PMID: 22943038 PMCID: PMC3430472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 06/29/2012] [Indexed: 06/01/2023]
Abstract
Molecular imaging is an attractive modality that has been widely employed in many aspects of biomedical research; especially those aimed at the early detection of diseases such as cancer, inflammation and neurodegenerative disorders. The field emerged in response to a new research paradigm in healthcare that seeks to integrate detection capabilities for the prediction and prevention of diseases. This approach made a distinct impact in biomedical research as it enabled researchers to leverage the capabilities of molecular imaging probes to visualize a targeted molecular event non-invasively, repeatedly and continuously in a living system. In addition, since such probes are inherently compact, robust, and amenable to high-throughput production, these probes could potentially facilitate screening of preclinical drug discovery, therapeutic assessment and validation of disease biomarkers. They could also be useful in drug discovery and safety evaluations. In this review, major trends in the chemical synthesis and development of positron emission tomography (PET), optical and magnetic resonance imaging (MRI) probes are discussed.
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Affiliation(s)
- Donald D Nolting
- Vanderbilt University Institute of Imaging ScienceNashville, TN, USA
| | - Michael L Nickels
- Vanderbilt University Institute of Imaging ScienceNashville, TN, USA
| | - Ning Guo
- Vanderbilt University Institute of Imaging ScienceNashville, TN, USA
| | - Wellington Pham
- Vanderbilt University Institute of Imaging ScienceNashville, TN, USA
- Department of Biomedical Engineering, Vanderbilt UniversityNashville, TN, USA
- Vanderbilt Ingram Cancer CenterNashville, TN, USA
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Basuli F, Wu H, Li C, Shi ZD, Sulima A, Griffiths GL. A first synthesis of 18F-radiolabeled lapatinib: a potential tracer for positron emission tomographic imaging of ErbB1/ErbB2 tyrosine kinase activity. J Labelled Comp Radiopharm 2011. [DOI: 10.1002/jlcr.1898] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Falguni Basuli
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute; National Institutes of Health; Rockville; MD; 20850; USA
| | - Haitao Wu
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute; National Institutes of Health; Rockville; MD; 20850; USA
| | - Changhui Li
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute; National Institutes of Health; Rockville; MD; 20850; USA
| | - Zhen-Dan Shi
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute; National Institutes of Health; Rockville; MD; 20850; USA
| | - Agnieszka Sulima
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute; National Institutes of Health; Rockville; MD; 20850; USA
| | - Gary L. Griffiths
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute; National Institutes of Health; Rockville; MD; 20850; USA
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Hou S, Phung DL, Lin WY, Wang MW, Liu K, Shen CKF. Microwave-assisted one-pot synthesis of N-succinimidyl-4[ ¹⁸F]fluorobenzoate ([¹⁸F]SFB). J Vis Exp 2011:2755. [PMID: 21730951 DOI: 10.3791/2755] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Biomolecules, including peptides¹⁻⁹, proteins¹⁰⁻¹¹, and antibodies and their engineered fragments¹²⁻¹⁴, are gaining importance as both potential therapeutics and molecular imaging agents. Notably, when labeled with positron-emitting radioisotopes (e.g., Cu-64, Ga-68, or F-18), they can be used as probes for targeted imaging of many physiological and pathological processes.¹⁵⁻¹⁸ Therefore, significant effort has devoted to the synthesis and exploration of ¹⁸F-labeled biomolecules. Although there are elegant examples of the direct ¹⁸F-labeling of peptides,¹⁹⁻²² the harsh reaction conditions (i.e., organic solvent, extreme pH, high temperature) associated with direct radiofluorination are usually incompatible with fragile protein samples. To date, therefore, the incorporation of radiolabeled prosthetic groups into biomolecules remains the method of choice.²³(,)²⁴ N-Succinimidyl-4-[¹⁸F]fluorobenzoate ([¹⁸F]SFB),²⁵⁻³⁷ a Bolton-Hunter type reagent that reacts with the primary amino groups of biomolecules, is a very versatile prosthetic group for the ¹⁸F-labeling of a wide spectrum of biological entities, in terms of its evident in vivo stability and high radiolabeling yield. After labeling with [¹⁸F]SFB, the resulting [F]fluorobenzoylated biomolecules could be explored as potential PET tracers for in vivo imaging studies.¹ Most [¹⁸F]SFB radiosyntheses described in the current literatures require two or even three reactors and multiple purifications by using either solid phase extraction (SPE) or high-performance liquid chromatography (HPLC). Such lengthy processes hamper its routine production and widespread applications in the radiolabeling of biomolecules. Although several module-assisted [¹⁸F]SFB syntheses have been reported²⁹⁻³²,⁴¹⁻⁴² they are mainly based on complicated and lengthy procedures using costly commercially-available radiochemistry boxes (Table 1). Therefore, further simplification of the radiosynthesis of [¹⁸F]SFB using a low-cost setup would be very beneficial for its adaption to an automated process. Herein, we report a concise preparation of [¹⁸F]SFB, based on a simplified one-pot microwave-assisted synthesis (Figure 1). Our approach does not require purification between steps or any aqueous reagents. In addition, microwave irradiation, which has been used in the syntheses of several PET tracers,³⁸⁻⁴¹ can gives higher RCYs and better selectivity than the corresponding thermal reactions or they provide similar yields in shorter reaction times.³⁸Most importantly, when labeling biomolecules, the time saved could be diverted to subsequent bioconjugation or PET imaging step. ²⁸(,)⁴³The novelty of our improved [¹⁸F]SFB synthesis is two-fold: (1) the anhydrous deprotection strategy requires no purification of intermediate(s) between each step and (2) the microwave-assisted radiochemical transformations enable the rapid, reliable production of [¹⁸F]SFB.
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Affiliation(s)
- Shuang Hou
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles, CA, USA
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Basuli F, Wu H, Griffiths GL. Syntheses of meta-[F]Fluorobenzaldehyde and meta-[F]Fluorobenzylbromide from Phenyl(3-Formylphenyl) Iodonium Salt Precursors. J Labelled Comp Radiopharm 2011; 54:224-228. [PMID: 21532942 PMCID: PMC3083861 DOI: 10.1002/jlcr.1853] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
(18)F-labeled fluorobenzaldehydes and fluorobenzylbromides are useful synthons for the preparation of PET radiopharmaceuticals. Whereas ortho- and para-[(18)F]fluorobenzaldehydes can easily be prepared with high yields, the corresponding meta- derivatives are more problematic. In order to improve the yield of meta-[(18)F]fluorobenzaldehyde we used the corresponding diaryliodonium salt precursors, since diaryliodonium salts had already been used as precursors in preparations of (18)F-labeled electron rich, as well as electron deficient, aromatic rings. Diaryliodonium salts with different counter ions [PhIPhCHO]X (X = Cl, Br, OTs, OTf) were synthesized. (18)F radiolabeling was performed using different bases at different temperatures in the presence of a radical scavenger, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO). The best conversion (~80%) to meta-[(18)F] fluorobenzaldehyde was obtained using CsHCO(3) base at a reaction temperature of 110 °C. To study iodonium salt counter ion effects on radiofluorination, each precursor was separately treated with CsF[(18)F]/CsHCO(3) in DMF at 110 °C for 5 min in the presence of TEMPO. Our observed reactivity order was OTs
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Affiliation(s)
- Falguni Basuli
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD 20850
| | - Haitao Wu
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD 20850
| | - Gary L. Griffiths
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD 20850
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Li Z, Conti PS. Radiopharmaceutical chemistry for positron emission tomography. Adv Drug Deliv Rev 2010; 62:1031-51. [PMID: 20854860 DOI: 10.1016/j.addr.2010.09.007] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 09/11/2010] [Accepted: 09/13/2010] [Indexed: 12/13/2022]
Abstract
Molecular imaging is an emerging technology that allows the visualization of interactions between molecular probes and biological targets. Molecules that either direct or are subject to homeostatic controls in biological systems could be labeled with the appropriate radioisotopes for the quantitative measurement of selected molecular interactions during normal tissue homeostasis and again after perturbations of the normal state. In particular, positron emission tomography (PET) offers picomolar sensitivity and is a fully translational technique that requires specific probes radiolabeled with a usually short-lived positron-emitting radionuclide. PET has provided the capability of measuring biological processes at the molecular and metabolic levels in vivo by the detection of the gamma rays formed as a result of the annihilation of the positrons emitted. Despite the great wealth of information that such probes can provide, the potential of PET strongly depends on the availability of suitable PET radiotracers. However, the development of new imaging probes for PET is far from trivial and radiochemistry is a major limiting factor for the field of PET. In this review, we provided an overview of the most common chemical approaches for the synthesis of PET-labeled molecules and highlighted the most recent developments and trends. The discussed PET radionuclides include ¹¹C (t₁(/)₂=20.4min), ¹³N (t₁(/)₂=9.9min), ¹⁵O (t₁(/)₂=2min), ⁶⁸Ga (t₁(/)₂=68min), ¹⁸F (t₁(/)₂=109.8min), ⁶⁴Cu (t₁(/)₂=12.7h), and ¹²⁴I (t₁(/)₂=4.12d).
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Daniels S, Tohid SFM, Velanguparackel W, Westwell AD. The role and future potential of fluorinated biomarkers in positron emission tomography. Expert Opin Drug Discov 2010; 5:291-304. [DOI: 10.1517/17460441003652967] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Glaser M, Årstad E, Luthra SK, Robins EG. Two-step radiosynthesis of [18F]N-succinimidyl-4-fluorobenzoate ([18F]SFB). J Labelled Comp Radiopharm 2009. [DOI: 10.1002/jlcr.1601] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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