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Qiu L, Jiang H, Cho K, Yu Y, Jones LA, Huang T, Perlmutter JS, Gropler RJ, Brier MR, Patti GJ, Benzinger TLS, Tu Z. Metabolite Study and Structural Authentication for the First-in-Human Use Sphingosine-1-phosphate Receptor 1 Radiotracer. ACS Chem Neurosci 2024; 15:1882-1892. [PMID: 38634759 PMCID: PMC11103254 DOI: 10.1021/acschemneuro.4c00077] [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] [Indexed: 04/19/2024] Open
Abstract
The sphingosine-1-phosphate receptor 1 (S1PR1) radiotracer [11C]CS1P1 has shown promise in proof-of-concept PET imaging of neuroinflammation in multiple sclerosis (MS). Our HPLC radiometabolite analysis of human plasma samples collected during PET scans with [11C]CS1P1 detected a radiometabolite peak that is more lipophilic than [11C]CS1P1. Radiolabeled metabolites that cross the blood-brain barrier complicate quantitative modeling of neuroimaging tracers; thus, characterizing such radiometabolites is important. Here, we report our detailed investigation of the metabolite profile of [11C]CS1P1 in rats, nonhuman primates, and humans. CS1P1 is a fluorine-containing ligand that we labeled with C-11 or F-18 for preclinical studies; the brain uptake was similar for both radiotracers. The same lipophilic radiometabolite found in human studies also was observed in plasma samples of rats and NHPs for CS1P1 labeled with either C-11 or F-18. We characterized the metabolite in detail using rats after injection of the nonradioactive CS1P1. To authenticate the molecular structure of this radiometabolite, we injected rats with 8 mg/kg of CS1P1 to collect plasma for solvent extraction and HPLC injection, followed by LC/MS analysis of the same metabolite. The LC/MS data indicated in vivo mono-oxidation of CS1P1 produces the metabolite. Subsequently, we synthesized three different mono-oxidized derivatives of CS1P1 for further investigation. Comparing the retention times of the mono-oxidized derivatives with the metabolite observed in rats injected with CS1P1 identified the metabolite as N-oxide 1, also named TZ82121. The MS fragmentation pattern of N-oxide 1 also matched that of the major metabolite in rat plasma. To confirm that metabolite TZ82121 does not enter the brain, we radiosynthesized [18F]TZ82121 by the oxidation of [18F]FS1P1. Radio-HPLC analysis confirmed that [18F]TZ82121 matched the radiometabolite observed in rat plasma post injection of [18F]FS1P1. Furthermore, the acute biodistribution study in SD rats and PET brain imaging in a nonhuman primate showed that [18F]TZ82121 does not enter the rat or nonhuman primate brain. Consequently, we concluded that the major lipophilic radiometabolite N-oxide [11C]TZ82121, detected in human plasma post injection of [11C]CS1P1, does not enter the brain to confound quantitative PET data analysis. [11C]CS1P1 is a promising S1PR1 radiotracer for detecting S1PR1 expression in the CNS.
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Affiliation(s)
- Lin Qiu
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Hao Jiang
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Kevin Cho
- Center for Mass Spectrometry and Metabolic Tracing, Department of Chemistry, Department of Medicine, Washington University, Saint Louis, Missouri 63130, United States
| | - Yanbo Yu
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Lynne A Jones
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Tianyu Huang
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
- Departments of Neurology, Neuroscience, Physical Therapy and Occupational Therapy, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Robert J Gropler
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Matthew R Brier
- Departments of Neurology, Neuroscience, Physical Therapy and Occupational Therapy, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Gary J Patti
- Center for Mass Spectrometry and Metabolic Tracing, Department of Chemistry, Department of Medicine, Washington University, Saint Louis, Missouri 63130, United States
| | - Tammie L S Benzinger
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri 63110, United States
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Li F, Hicks JW, Yu L, Desjardin L, Morrison L, Hadway J, Lee TY. Plasma radio-metabolite analysis of PET tracers for dynamic PET imaging: TLC and autoradiography. EJNMMI Res 2020; 10:141. [PMID: 33226509 PMCID: PMC7683627 DOI: 10.1186/s13550-020-00705-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/18/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In molecular imaging with dynamic PET, the binding and dissociation of a targeted tracer is characterized by kinetics modeling which requires the arterial concentration of the tracer to be measured accurately. Once in the body the radiolabeled parent tracer may be subjected to hydrolysis, demethylation/dealkylation and other biochemical processes, resulting in the production and accumulation of different metabolites in blood which can be labeled with the same PET radionuclide as the parent. Since these radio-metabolites cannot be distinguished by PET scanning from the parent tracer, their contribution to the arterial concentration curve has to be removed for the accurate estimation of kinetic parameters from kinetic analysis of dynamic PET. High-performance liquid chromatography has been used to separate and measure radio-metabolites in blood plasma; however, the method is labor intensive and remains a challenge to implement for each individual patient. The purpose of this study is to develop an alternate technique based on thin layer chromatography (TLC) and a sensitive commercial autoradiography system (Beaver, Ai4R, Nantes, France) to measure radio-metabolites in blood plasma of two targeted tracers-[18F]FAZA and [18F]FEPPA, for imaging hypoxia and inflammation, respectively. RESULTS Radioactivity as low as 17 Bq in 2 µL of pig's plasma can be detected on the TLC plate using autoradiography. Peaks corresponding to the parent tracer and radio-metabolites could be distinguished in the line profile through each sample (n = 8) in the autoradiographic image. Significant intersubject and intra-subject variability in radio-metabolites production could be observed with both tracers. For [18F]FEPPA, 50% of plasma activity was from radio-metabolites as early as 5-min post injection, while for [18F]FAZA, significant metabolites did not appear until 50-min post. Simulation study investigating the effect of radio-metabolite in the estimation of kinetic parameters indicated that 32-400% parameter error can result without radio-metabolites correction. CONCLUSION TLC coupled with autoradiography is a good alternative to high-performance liquid chromatography for radio-metabolite correction. The advantages of requiring only small blood samples (~ 100 μL) and of analyzing multiple samples simultaneously, make the method suitable for individual dynamic PET studies.
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Affiliation(s)
- Fiona Li
- Department of Medical Biophysics, The University of Western University, 1151 Richmond Street North, London, ON, N6A 3K7, Canada.,Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada.,Robarts Research Institute, London, ON, Canada
| | - Justin W Hicks
- Department of Medical Biophysics, The University of Western University, 1151 Richmond Street North, London, ON, N6A 3K7, Canada.,Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada
| | - Lihai Yu
- Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada
| | - Lise Desjardin
- Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada
| | - Laura Morrison
- Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada
| | - Jennifer Hadway
- Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada.,Robarts Research Institute, London, ON, Canada
| | - Ting-Yim Lee
- Department of Medical Biophysics, The University of Western University, 1151 Richmond Street North, London, ON, N6A 3K7, Canada. .,Lawson Health Research Institute, Grosvenor Campus, 268 Grosvenor Street, London, ON, N6A 4V2, Canada. .,Robarts Research Institute, London, ON, Canada.
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3
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Ghosh KK, Padmanabhan P, Yang CT, Mishra S, Halldin C, Gulyás B. Dealing with PET radiometabolites. EJNMMI Res 2020; 10:109. [PMID: 32997213 PMCID: PMC7770856 DOI: 10.1186/s13550-020-00692-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/07/2020] [Indexed: 02/08/2023] Open
Abstract
Abstract Positron emission tomography (PET) offers the study of biochemical,
physiological, and pharmacological functions at a cellular and molecular level.
The performance of a PET study mostly depends on the used radiotracer of
interest. However, the development of a novel PET tracer is very difficult, as
it is required to fulfill a lot of important criteria. PET radiotracers usually
encounter different chemical modifications including redox reaction, hydrolysis,
decarboxylation, and various conjugation processes within living organisms. Due
to this biotransformation, different chemical entities are produced, and the
amount of the parent radiotracer is declined. Consequently, the signal measured
by the PET scanner indicates the entire amount of radioactivity deposited in the
tissue; however, it does not offer any indication about the chemical disposition
of the parent radiotracer itself. From a radiopharmaceutical perspective, it is
necessary to quantify the parent radiotracer’s fraction present in the tissue.
Hence, the identification of radiometabolites of the radiotracers is vital for
PET imaging. There are mainly two reasons for the chemical identification of PET
radiometabolites: firstly, to determine the amount of parent radiotracers in
plasma, and secondly, to rule out (if a radiometabolite enters the brain) or
correct any radiometabolite accumulation in peripheral tissue. Besides,
radiometabolite formations of the tracer might be of concern for the PET study,
as the radiometabolic products may display considerably contrasting distribution
patterns inside the body when compared with the radiotracer itself. Therefore,
necessary information is needed about these biochemical transformations to
understand the distribution of radioactivity throughout the body. Various
published review articles on PET radiometabolites mainly focus on the sample
preparation techniques and recently available technology to improve the
radiometabolite analysis process. This article essentially summarizes the
chemical and structural identity of the radiometabolites of various radiotracers
including [11C]PBB3,
[11C]flumazenil,
[18F]FEPE2I, [11C]PBR28,
[11C]MADAM, and
(+)[18F]flubatine. Besides, the importance of
radiometabolite analysis in PET imaging is also briefly summarized. Moreover,
this review also highlights how a slight chemical modification could reduce the
formation of radiometabolites, which could interfere with the results of PET
imaging. Graphical abstract ![]()
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Affiliation(s)
- Krishna Kanta Ghosh
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore
| | - Parasuraman Padmanabhan
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore.
| | - Chang-Tong Yang
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore.,Department of Nuclear Medicine and Molecular Imaging, Radiological Sciences Division, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore.,Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Sachin Mishra
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore
| | - Christer Halldin
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore.,Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76, Stockholm, Sweden
| | - Balázs Gulyás
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore. .,Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76, Stockholm, Sweden.
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Ludwig FA, Fischer S, Houska R, Hoepping A, Deuther-Conrad W, Schepmann D, Patt M, Meyer PM, Hesse S, Becker GA, Zientek FR, Steinbach J, Wünsch B, Sabri O, Brust P. In vitro and in vivo Human Metabolism of ( S)-[ 18F]Fluspidine - A Radioligand for Imaging σ 1 Receptors With Positron Emission Tomography (PET). Front Pharmacol 2019; 10:534. [PMID: 31263411 PMCID: PMC6585474 DOI: 10.3389/fphar.2019.00534] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/29/2019] [Indexed: 12/26/2022] Open
Abstract
(S)-[18F]fluspidine ((S)-[18F]1) has recently been explored for positron emission tomography (PET) imaging of sigma-1 receptors in humans. In the current report, we have used plasma samples of healthy volunteers to investigate the radiometabolites of (S)-[18F]1 and elucidate their structures with LC-MS/MS. For the latter purpose additional in vitro studies were conducted by incubation of (S)-[18F]1 and (S)-1 with human liver microsomes (HLM). In vitro metabolites were characterized by interpretation of MS/MS fragmentation patterns from collision-induced dissociation or by use of reference compounds. Thereby, structures of corresponding radio-HPLC-detected radiometabolites, both in vitro and in vivo (human), could be identified. By incubation with HLM, mainly debenzylation and hydroxylation occurred, beside further mono- and di-oxygenations. The product hydroxylated at the fluoroethyl side chain was glucuronidated. Plasma samples (10, 20, 30 min p.i., n = 5-6), obtained from human subjects receiving 250–300 MBq (S)-[18F]1 showed 97.2, 95.4, and 91.0% of unchanged radioligand, respectively. In urine samples (90 min p.i.) the fraction of unchanged radioligand was only 2.6% and three major radiometabolites were detected. The one with the highest percentage, also found in plasma, matched the glucuronide formed in vitro. Only a small amount of debenzylated metabolite was detected. In conclusion, our metabolic study, in particular the high fractions of unchanged radioligand in plasma, confirms the suitability of (S)-[18F]1 as PET radioligand for sigma-1 receptor imaging.
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Affiliation(s)
- Friedrich-Alexander Ludwig
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Steffen Fischer
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Richard Houska
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | | | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Dirk Schepmann
- Department of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Marianne Patt
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany
| | - Philipp M Meyer
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany
| | - Swen Hesse
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany.,Integrated Research and Treatment Center (IFB) Adiposity Diseases, Leipzig University, Leipzig, Germany
| | | | - Franziska Ruth Zientek
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany.,Integrated Research and Treatment Center (IFB) Adiposity Diseases, Leipzig University, Leipzig, Germany
| | - Jörg Steinbach
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
| | - Bernhard Wünsch
- Department of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, Leipzig University, Leipzig, Germany
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany
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5
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Rokka J, Grönroos TJ, Viljanen T, Solin O, Haaparanta-Solin M. HPLC and TLC methods for analysis of [ 18F]FDG and its metabolites from biological samples. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1048:140-149. [PMID: 28236580 DOI: 10.1016/j.jchromb.2017.01.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 12/04/2016] [Accepted: 01/29/2017] [Indexed: 10/20/2022]
Abstract
The most used positron emission tomography (PET) tracer, 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG), is a glucose analogue that is used to measure tissue glucose consumption. Traditionally, the Sokoloff model is the basis for [18F]FDG modeling. According to this model, [18F]FDG is expected to be trapped in a cell in the form of [18F]FDG-6-phosphate ([18F]FDG-6-P). However, several studies have shown that in tissues, [18F]FDG metabolism goes beyond [18F]FDG-6-P. Our aim was to develop radioHPLC and radioTLC methods for analysis of [18F]FDG metabolites from tissue samples. The radioHPLC method uses a sensitive on-line scintillation detector to detect radioactivity, and the radioTLC method employs digital autoradiography to detect the radioactivity distribution on a TLC plate. The HPLC and TLC methods were developed using enzymatically in vitro-produced metabolites of [18F]FDG as reference standards. For this purpose, three [18F]FDG metabolites were synthesized: [18F]FDG-6-P, [18F]FD-PGL, and [18F]FDG-1,6-P2. The two methods were evaluated by analyzing the [18F]FDG metabolic profile from rodent ex vivo tissue homogenates. The HPLC method with an on-line scintillation detector had a wide linearity in a range of 5Bq-5kBq (LOD 46Bq, LOQ 139Bq) and a good resolution (Rs ≥1.9), and separated [18F]FDG and its metabolites clearly. The TLC method combined with digital autoradiography had a high sensitivity in a wide range of radioactivity (0.1Bq-2kBq, LOD 0.24Bq, LOQ 0.31Bq), and multiple samples could be analyzed simultaneously. As our test and the method validation with ex vivo samples showed, both methods are useful, and at best they complement each other in analysis of [18F]FDG and its radioactive metabolites from biological samples.
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Affiliation(s)
- Johanna Rokka
- Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland.
| | - Tove J Grönroos
- Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; MediCity Research Laboratory, University of Turku, Turku, Finland
| | - Tapio Viljanen
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland
| | - Olof Solin
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland; Turku PET Centre, Accelerator Laboratory, Åbo Akademi University, Turku, Finland; Department of Chemistry, University of Turku, Turku, Finland
| | - Merja Haaparanta-Solin
- Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; MediCity Research Laboratory, University of Turku, Turku, Finland
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LC-MS Supported Studies on the in Vitro Metabolism of both Enantiomers of Flubatine and the in Vivo Metabolism of (+)-[(18)F]Flubatine-A Positron Emission Tomography Radioligand for Imaging α4β2 Nicotinic Acetylcholine Receptors. Molecules 2016; 21:molecules21091200. [PMID: 27617996 PMCID: PMC6273452 DOI: 10.3390/molecules21091200] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 12/27/2022] Open
Abstract
Both enantiomers of [18F]flubatine are promising radioligands for neuroimaging of α4β2 nicotinic acetylcholine receptors (nAChRs) by positron emission tomography (PET). To support clinical studies in patients with early Alzheimer’s disease, a detailed examination of the metabolism in vitro and in vivo has been performed. (+)- and (−)-flubatine, respectively, were incubated with liver microsomes from mouse and human in the presence of NADPH (β-nicotinamide adenine dinucleotide 2′-phosphate reduced tetrasodium salt). Phase I in vitro metabolites were detected and their structures elucidated by LC-MS/MS (liquid chromatography-tandem mass spectrometry). Selected metabolite candidates were synthesized and investigated for structural confirmation. Besides a high level of in vitro stability, the microsomal incubations revealed some species differences as well as enantiomer discrimination with regard to the formation of monohydroxylated products, which was identified as the main metabolic pathway in this assay. Furthermore, after injection of 250 MBq (+)-[18F]flubatine (specific activity > 350 GBq/μmol) into mouse, samples were prepared from brain, liver, plasma, and urine after 30 min and investigated by radio-HPLC (high performance liquid chromatography with radioactivity detection). For structure elucidation of the radiometabolites of (+)-[18F]flubatine formed in vivo, identical chromatographic conditions were applied to LC-MS/MS and radio-HPLC to compare samples obtained in vitro and in vivo. By this correlation approach, we assigned three of four main in vivo radiometabolites to products that are exclusively C- or N-hydroxylated at the azabicyclic ring system of the parent molecule.
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7
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Nakao R, Amini N, Halldin C. Simultaneous Determination of Protein-Free and Total Positron Emission Tomography Radioligand Concentrations in Plasma Using High-Performance Frontal Analysis Followed by Mixed Micellar Liquid Chromatography: Application to [11C]PBR28 in Human Plasma. Anal Chem 2013; 85:8728-34. [DOI: 10.1021/ac401742v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryuji Nakao
- Department
of Clinical Neuroscience, Center for Psychiatric
Research, Karolinska Institute, Stockholm, Sweden
| | - Nahid Amini
- Department
of Clinical Neuroscience, Center for Psychiatric
Research, Karolinska Institute, Stockholm, Sweden
| | - Christer Halldin
- Department
of Clinical Neuroscience, Center for Psychiatric
Research, Karolinska Institute, Stockholm, Sweden
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8
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Nakao R, Halldin C. Improved radiometabolite analysis procedure for positron emission tomography (PET) radioligands using a monolithic column coupled with direct injection micellar/high submicellar liquid chromatography. Talanta 2013; 113:130-4. [DOI: 10.1016/j.talanta.2013.03.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 03/04/2013] [Accepted: 03/08/2013] [Indexed: 10/27/2022]
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9
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Nakao R, Halldin C. A simplified radiometabolite analysis procedure for PET radioligands using a solid phase extraction with micellar medium. Nucl Med Biol 2013; 40:658-63. [DOI: 10.1016/j.nucmedbio.2013.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 02/13/2013] [Accepted: 02/14/2013] [Indexed: 10/26/2022]
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10
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Xu H, Wang Z, Wang Y, Hu S, Liu N. Biodistribution and elimination study of fluorine-18 labeled Nε-carboxymethyl-lysine following intragastric and intravenous administration. PLoS One 2013; 8:e57897. [PMID: 23505446 PMCID: PMC3591457 DOI: 10.1371/journal.pone.0057897] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 01/28/2013] [Indexed: 12/15/2022] Open
Abstract
Background Nε-carboxymethyl-lysine (CML) is a major advanced glycation end-product (AGEs) widely found in foods. The aim of our study was to evaluate how exogenous CML-peptide is dynamically absorbed from the gastrointestinal tract and eliminated by renal tubular secretion using microPET imaging. Methods The present study consisted of three investigations. In study I, we synthesized the imaging tracer 18F-CML by reacting N-succinimidyl 4-18F-fluorobenzoate (18F-SFB) with CML. In study II, the biological activity of 18F-CML was evaluated in RAW264.7 cells and HepG2 cells. In study III, the biodistribution and elimination of AGEs in ICR mice were studied in vivo following tail vein injection and intragastric administration of 18F-CML. Result The formation of 18F-CML was confirmed by comparing its retention time with the corresponding reference compound 19F-CML. The radiochemical purity (RCP) of 18F-CML was >95%, and it showed a stable character in vitro and in vivo. Uptake of 18F-CML by RAW264.7 cells and HepG2 cells could be inhibited by unmodified CML. 18F-CML was quickly distributed via the blood, and it was rapidly excreted through the kidneys 20 min after tail vein injection. However, 18F-CML was only slightly absorbed following intragastric administration. After administration of 18F-CML via a stomach tube, the radioactivity was completely localized in the stomach for the first 15 min. At 150 min post intragastric administration, intense accumulation of radioactivity in the intestines was still observed. Conclusions PET technology is a powerful tool for the in vivo analysis of the gastrointestinal absorption of orally administered drugs. 18F-CML is hardly absorbed by the gastrointestinal tract. It is rapidly distributed and eliminated from blood following intravenous administration. Thus, it may not be harmful to healthy bodies. Our study showed the feasibility of noninvasively imaging 18F-labeled AGEs and was the first to describe CML-peptide gastrointestinal absorption by means of PET.
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Affiliation(s)
- Hongzeng Xu
- Department of Cardiology, Zhongda Hospital, Southeast University, Nanjing, China
| | - Zhongqun Wang
- Department of Cardiology, Zhongda Hospital, Southeast University, Nanjing, China
| | - Yan Wang
- Jiangsu Institute of Nuclear Medicine, Wuxi, China
| | - Shengda Hu
- Department of Cardiology, Zhongda Hospital, Southeast University, Nanjing, China
| | - Naifeng Liu
- Department of Cardiology, Zhongda Hospital, Southeast University, Nanjing, China
- * E-mail:
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Nakao R, Halldin C. “Mixed” anionic and non-ionic micellar liquid chromatography for high-speed radiometabolite analysis of positron emission tomography radioligands. J Chromatogr A 2013; 1281:54-9. [DOI: 10.1016/j.chroma.2013.01.071] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/10/2013] [Accepted: 01/15/2013] [Indexed: 10/27/2022]
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12
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Rapid metabolite analysis of positron emission tomography radioligands by direct plasma injection combining micellar cleanup with high submicellar liquid chromatography with radiometric detection. J Chromatogr A 2012; 1266:76-83. [DOI: 10.1016/j.chroma.2012.10.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 10/03/2012] [Accepted: 10/09/2012] [Indexed: 11/22/2022]
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Nakao R, Schou M, Halldin C. Direct plasma metabolite analysis of positron emission tomography radioligands by micellar liquid chromatography with radiometric detection. Anal Chem 2012; 84:3222-30. [PMID: 22409870 DOI: 10.1021/ac2032657] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Determination of radio-metabolites in plasma samples taken during a positron emission tomography (PET) study is an important component in the pharmacokinetic evaluation of PET radioligands. We have developed and validated a new analytical procedure for the plasma metabolite analysis of PET radioligands based on micellar liquid chromatography using an anionic surfactant mobile phase. Chromatographic separation was performed on an octadecyl semipreparative column (10 mm I.D. × 160 mm, 10 μm) using 100 mM sodium dodecyl sulfate (SDS) and 1-butanol in 10 mM sodium-phosphate (pH 7.2) at a flow rate of 5 mL/min. The samples taken from monkey or human plasma during PET measurements were directly injected into a liquid chromatographic (LC) system coupled to an online radiometric detector under micellar conditions using 1-2% (v/v) 1-butanol mobile phase to remove plasma proteins and concentrate the analytes at the column head. At 2 min, mobile phase was changed to elute and separate PET radioligand and its radiometabolites with high peak capacity under high submicellar conditions (10-25% 1-butanol). This procedure allowed direct plasma injection (up to 2 mL) into the LC column without any pretreatment with a short analysis-time of 8-10 min. Satisfactory reproducibility, linearity, sensitivity, accuracy and recovery were obtained in the validation study. The developed method was successfully applied to study the metabolism for diverse groups of PET radioligands and provided reliable determination of PET radioligands in human and monkey plasma. This method is advantageous in terms of simplifying and shortening the processes required to analyze short-lived radioligands as well as in providing a more accurate estimation of the metabolite corrected input function, especially for the radioligands with lower recoveries or degradation potential during the deproteination process in a conventional procedure.
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Affiliation(s)
- Ryuji Nakao
- Karolinska Institutet, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden.
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Franck D, Nann H, Davi P, Schubiger PA, Ametamey SM. Faster analysis of radiopharmaceuticals using ultra performance liquid chromatography (UPLC) in combination with low volume radio flow cell. Appl Radiat Isot 2009; 67:1068-70. [PMID: 19328705 DOI: 10.1016/j.apradiso.2009.02.077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 02/16/2009] [Accepted: 02/18/2009] [Indexed: 11/24/2022]
Abstract
With the aim of reducing analysis time of radiopharmaceuticals, especially for carbon-11 and fluorine-18, radio-high performance liquid chromatography (radio-HPLC) is the analysis method of choice. Faster and more sensitive analytic methods are needed. Recently, ultra performance liquid chromatography (UPLC) has become an accepted analysis method but has not yet been established in radiopharmacy. This study demonstrates with the established positron emission tomography (PET) tracer [(18)F]fluoromisonidazole (FMISO) the applicability of using UPLC) in combination with low volume radio flow cell for a fast, sensitive and efficient analytic method. The developed UPLC) method showed a sharp and high radio signal. The total analysis time was thus reduced from 15 to 2 min.
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Affiliation(s)
- Dominic Franck
- Center for Radiopharmaceutical Science, ETH Zurich, 8093 Zürich, Switzerland.
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15
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Efficient purification and metabolite analysis of radiotracers using high-performance liquid chromatography and on-line solid-phase extraction. J Chromatogr A 2008; 1189:323-31. [DOI: 10.1016/j.chroma.2007.10.084] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 10/21/2007] [Accepted: 10/26/2007] [Indexed: 11/19/2022]
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16
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Martiniova L, Ohta S, Guion P, Schimel D, Lai EW, Klaunberg B, Jagoda E, Pacak K. Anatomical and Functional Imaging of Tumors in Animal Models: Focus on Pheochromocytoma. Ann N Y Acad Sci 2006; 1073:392-404. [PMID: 17102108 DOI: 10.1196/annals.1353.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This review focuses on anatomical (computed tomography, magnetic resonance imaging) and functional (positron emission tomography) imaging methods for tumor localization and identification of experimentally induced tumors in animal models, especially pheochromocytoma. Although anatomical imaging can precisely locate primary and metastatic tumors, functional imaging has high specificity for some tumors, especially those of endocrine origin. This is due to the fact that endocrine tumor cells take up hormone precursors, express hormone receptors and transporters, and synthesize, store, and release hormones. These characteristic properties of endocrine tumors enable investigators to create highly specific radiopharmaceuticals, particularly for positron emission tomography. For example, localization of pheochromocytoma involves [18F]-6F-dopamine. It is a highly specific radiopharmaceutical since it uses the norepinephrine transporter system expressed in most pheochromocytoma cells. Here we review both anatomical and functional imaging methods that are used conjointly in order to localize and identify specific characteristics of tumors.
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Affiliation(s)
- Lucia Martiniova
- D.Sc., Building 10, Room 1E3140, National Institutes of Health, 10 Center Drive MSC-1583, Bethesda, MD 20892-1583.
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17
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Bergmann R, Pietzsch J. Small animal positron emission tomography in food sciences. Amino Acids 2005; 29:355-76. [PMID: 16142524 DOI: 10.1007/s00726-005-0237-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 07/13/2005] [Indexed: 02/07/2023]
Abstract
Positron emission tomography (PET) is a 3-dimensional imaging technique that has undergone tremendous developments during the last decade. Non-invasive tracing of molecular pathways in vivo is the key capability of PET. It has become an important tool in the diagnosis of human diseases as well as in biomedical and pharmaceutical research. In contrast to other imaging modalities, radiotracer concentrations can be determined quantitatively. By application of appropriate tracer kinetic models, the rate constants of numerous different biological processes can be determined. Rapid progress in PET radiochemistry has significantly increased the number of biologically important molecules labelled with PET nuclides to target a broader range of physiologic, metabolic, and molecular pathways. Progress in PET physics and technology strongly contributed to better scanners and image processing. In this context, dedicated high resolution scanners for dynamic PET studies in small laboratory animals are now available. These developments represent the driving force for the expansion of PET methodology into new areas of life sciences including food sciences. Small animal PET has a high potential to depict physiologic processes like absorption, distribution, metabolism, elimination and interactions of biologically significant substances, including nutrients, 'nutriceuticals', functional food ingredients, and foodborne toxicants. Based on present data, potential applications of small animal PET in food sciences are discussed.
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Affiliation(s)
- R Bergmann
- Positron Emission Tomography Center, Institute of Bioinorganic and Radiopharmaceutical Chemistry, Research Center Rossendorf, Dresden, Germany.
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Gester S, Wuest F, Pawelke B, Bergmann R, Pietzsch J. Synthesis and biodistribution of an 18F-labelled resveratrol derivative for small animal positron emission tomography. Amino Acids 2005; 29:415-28. [PMID: 15997411 DOI: 10.1007/s00726-005-0205-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2004] [Accepted: 02/07/2005] [Indexed: 11/25/2022]
Abstract
Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a naturally occurring phytoalexin and polyphenol existing in grapes and various other plants, and one of the best known 'nutriceuticals'. It shows a multiplicity of beneficial biological effects, particularly, by attenuating atherogenic, inflammatory, and carcinogenic processes. However, despite convincing evidence from experimental and clinical studies, data concerning the role of resveratrol and other members of the large polyphenols family for human health is still a matter of debate. One reason for this is the lack of suitable sensitive and specific methods, which would allow direct assessment of biodistribution, biokinetics, and the metabolic fate of these compounds in vivo. The unique features of positron emission tomography (PET) as a non-invasive in vivo imaging methodology in combination with suitable PET radiotracers have great promise to assess quantitative information on physiological effects of polyphenols in vivo. Herein we describe the radiosynthesis of an (18)F-labelled resveratrol derivative, 3,5-dihydroxy-4'-[(18)F]fluoro-trans-stilbene ([(18)F]-1), using the Horner-Wadsworth-Emmons reaction as a novel radiolabelling technique in PET radiochemistry for subsequent functional imaging of polyphenol metabolism in vivo. In a typical "three-step/one-pot" reaction, (18)F-labelled resveratrol derivative [(18)F]-1 could be synthesized within 120-130 min including HPLC separation at a specific radioactivity of about 90 GBq/mumol. The radiochemical yield was about 9% (decay-corrected) related to [(18)F]fluoride and the radiochemical purity exceeded 97%. First radiopharmacological evaluation included measurement of biodistribution ex vivo and positron emission tomography (PET) studies in vivo after intravenous application of [(18)F]-1 in male Wistar rats using a dedicated small animal PET camera with very high spatial resolution. Concordantly with data on bioavailability and metabolism of native resveratrol from the literature, these investigations revealed an extensive uptake and metabolism in the liver and kidney, respectively, of [(18)F]-1. This study represents the first investigation of polyphenols in vivo by means of PET.
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Affiliation(s)
- S Gester
- Positron Emission Tomography Center, Institute of Bioinorganic and Radiopharmaceutical Chemistry, Research Center Rossendorf, Dresden, Germany
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