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Tian GL, Hsieh CJ, Taylor M, Lee JY, Riad AA, Luedtke RR, Mach RH. Synthesis of bitopic ligands based on fallypride and evaluation of their affinity and selectivity towards dopamine D 2 and D 3 receptors. Eur J Med Chem 2023; 261:115751. [PMID: 37688938 PMCID: PMC10841072 DOI: 10.1016/j.ejmech.2023.115751] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/08/2023] [Accepted: 08/21/2023] [Indexed: 09/11/2023]
Abstract
The difference in the secondary binding site (SBS) between the dopamine 2 receptor (D2R) and dopamine 3 receptor (D3R) has been used in the design of compounds displaying selectivity for the D3R versus D2R. In the current study, a series of bitopic ligands based on Fallypride were prepared with various secondary binding fragments (SBFs) as a means of improving the selectivity of this benzamide analog for D3R versus D2R. We observed that compounds having a small alkyl group with a heteroatom led to an improvement in D3R versus D2R selectivity. Increasing the steric bulk in the SBF increase the distance between the pyrrolidine N and Asp110, thereby reducing D3R affinity. The best-in-series compound was (2S,4R)-trans-27 which had a modest selectivity for D3R versus D2R and a high potency in the β-arrestin competition assay which provides a measure of the ability of the compound to compete with endogenous dopamine for binding to the D3R. The results of this study identified factors one should consider when designing bitopic ligands based on Fallypride displaying an improved affinity for D3R versus D2R.
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Affiliation(s)
- Gui-Long Tian
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Chia-Ju Hsieh
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michelle Taylor
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center-Fort Worth, Texas, TX, 76107, USA
| | - Ji Youn Lee
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Aladdin A Riad
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Robert R Luedtke
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center-Fort Worth, Texas, TX, 76107, USA
| | - Robert H Mach
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Ros T, Kwiek J, Andriot T, Michela A, Vuilleumier P, Garibotto V, Ginovart N. PET Imaging of Dopamine Neurotransmission During EEG Neurofeedback. Front Physiol 2021; 11:590503. [PMID: 33584328 PMCID: PMC7873858 DOI: 10.3389/fphys.2020.590503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 12/09/2020] [Indexed: 11/13/2022] Open
Abstract
Neurofeedback (NFB) is a brain-based training method that enables users to control their own cortical oscillations using real-time feedback from the electroencephalogram (EEG). Importantly, no investigations to date have directly explored the potential impact of NFB on the brain's key neuromodulatory systems. Our study's objective was to assess the capacity of NFB to induce dopamine release as revealed by positron emission tomography (PET). Thirty-two healthy volunteers were randomized to either EEG-neurofeedback (NFB) or EEG-electromyography (EMG), and scanned while performing self-regulation during a single session of dynamic PET brain imaging using the high affinity D2/3 receptor radiotracer, [18F]Fallypride. NFB and EMG groups down-regulated cortical alpha power and facial muscle tone, respectively. Task-induced effects on endogenous dopamine release were estimated in the frontal cortex, anterior cingulate cortex, and thalamus, using the linearized simplified reference region model (LSRRM), which accounts for time-dependent changes in radiotracer binding following task initiation. Contrary to our hypothesis of a differential effect for NFB vs. EMG training, significant dopamine release was observed in both training groups in the frontal and anterior cingulate cortex, but not in thalamus. Interestingly, a significant negative correlation was observed between dopamine release in frontal cortex and pre-to-post NFB change in spontaneous alpha power, suggesting that intra-individual changes in brain state (i.e., alpha power) could partly result from changes in neuromodulatory tone. Overall, our findings constitute the first direct investigation of neurofeedback's effect on the endogenous release of a key neuromodulator, demonstrating its feasibility and paving the way for future studies using this methodology.
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Affiliation(s)
- Tomas Ros
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
| | - Jessica Kwiek
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | - Theo Andriot
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Abele Michela
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Patrik Vuilleumier
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Valentina Garibotto
- Division of Nuclear Medicine and Molecular Imaging, Department of Medical Imaging, Geneva University Hospitals, Geneva, Switzerland
| | - Nathalie Ginovart
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
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Stark AJ, Smith CT, Petersen KJ, Trujillo P, van Wouwe NC, Donahue MJ, Kessler RM, Deutch AY, Zald DH, Claassen DO. [ 18F] fallypride characterization of striatal and extrastriatal D 2/3 receptors in Parkinson's disease. Neuroimage Clin 2018; 18:433-442. [PMID: 29541577 PMCID: PMC5849871 DOI: 10.1016/j.nicl.2018.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/15/2018] [Accepted: 02/07/2018] [Indexed: 12/11/2022]
Abstract
Parkinson's disease (PD) is characterized by widespread degeneration of monoaminergic (especially dopaminergic) networks, manifesting with a number of both motor and non-motor symptoms. Regional alterations to dopamine D2/3 receptors in PD patients are documented in striatal and some extrastriatal areas, and medications that target D2/3 receptors can improve motor and non-motor symptoms. However, data regarding the combined pattern of D2/3 receptor binding in both striatal and extrastriatal regions in PD are limited. We studied 35 PD patients off-medication and 31 age- and sex-matched healthy controls (HCs) using PET imaging with [18F]fallypride, a high affinity D2/3 receptor ligand, to measure striatal and extrastriatal D2/3 nondisplaceable binding potential (BPND). PD patients completed PET imaging in the off medication state, and motor severity was concurrently assessed. Voxel-wise evaluation between groups revealed significant BPND reductions in PD patients in striatal and several extrastriatal regions, including the locus coeruleus and mesotemporal cortex. A region-of-interest (ROI) based approach quantified differences in dopamine D2/3 receptors, where reduced BPND was noted in the globus pallidus, caudate, amygdala, hippocampus, ventral midbrain, and thalamus of PD patients relative to HC subjects. Motor severity positively correlated with D2/3 receptor density in the putamen and globus pallidus. These findings support the hypothesis that abnormal D2/3 expression occurs in regions related to both the motor and non-motor symptoms of PD, including areas richly invested with noradrenergic neurons.
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Affiliation(s)
- Adam J Stark
- Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | | | - Kalen J Petersen
- Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Paula Trujillo
- Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Nelleke C van Wouwe
- Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Manus J Donahue
- Neurology, Vanderbilt University Medical Center, Nashville, TN, United States; Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States; Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Robert M Kessler
- Radiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ariel Y Deutch
- Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, United States; Pharmacology, Vanderbilt University, Nashville, TN, United States
| | - David H Zald
- Psychology, Vanderbilt University, Nashville, TN, United States; Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Daniel O Claassen
- Neurology, Vanderbilt University Medical Center, Nashville, TN, United States.
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Albrecht DS, MacKie PJ, Kareken DA, Hutchins GD, Chumin EJ, Christian BT, Yoder KK. Differential dopamine function in fibromyalgia. Brain Imaging Behav 2016; 10:829-39. [PMID: 26497890 DOI: 10.1007/s11682-015-9459-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Approximately 30 % of Americans suffer from chronic pain disorders, such as fibromyalgia (FM), which can cause debilitating pain. Many pain-killing drugs prescribed for chronic pain disorders are highly addictive, have limited clinical efficacy, and do not treat the cognitive symptoms reported by many patients. The neurobiological substrates of chronic pain are largely unknown, but evidence points to altered dopaminergic transmission in aberrant pain perception. We sought to characterize the dopamine (DA) system in individuals with FM. Positron emission tomography (PET) with [(18)F]fallypride (FAL) was used to assess changes in DA during a working memory challenge relative to a baseline task, and to test for associations between baseline D2/D3 availability and experimental pain measures. Twelve female subjects with FM and 11 female controls completed study procedures. Subjects received one FAL PET scan while performing a "2-back" task, and one while performing a "0-back" (attentional control, "baseline") task. FM subjects had lower baseline FAL binding potential (BP) in several cortical regions relative to controls, including anterior cingulate cortex. In FM subjects, self-reported spontaneous pain negatively correlated with FAL BP in the left orbitofrontal cortex and parahippocampal gyrus. Baseline BP was significantly negatively correlated with experimental pain sensitivity and tolerance in both FM and CON subjects, although spatial patterns of these associations differed between groups. The data suggest that abnormal DA function may be associated with differential processing of pain perception in FM. Further studies are needed to explore the functional significance of DA in nociception and cognitive processing in chronic pain.
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Naylor JE, Hiranita T, Matazel KS, Zhang X, Paule MG, Goodwin AK. Positron emission tomography (PET) imaging of nicotine-induced dopamine release in squirrel monkeys using [ 18F] Fallypride. Drug Alcohol Depend 2017; 179:254-259. [PMID: 28818716 DOI: 10.1016/j.drugalcdep.2017.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 07/14/2017] [Accepted: 07/18/2017] [Indexed: 12/21/2022]
Abstract
BACKGROUND Nicotine, the principal psychoactive tobacco constituent, is thought to produce its reinforcing effects via actions within the mesolimbic dopamine (DA) system. The objective of the current study was to examine the effect of nicotine on DA D2/D3 receptor availability in the nonhuman primate brain with the use of the radioligand [18F]fallypride and positron emission tomography (PET). METHODS Ten adult male squirrel monkeys were used in the current study. Each subject underwent two PET scans, one with an injection (IV) of saline and subsequently one with an injection of nicotine (0.032mg/kg). The DA D2/D3 antagonist, [18F]fallypride, was delivered IV at the beginning of each scan, and nicotine or saline was delivered at 45min into the scan. Regions of interest (ROI) were drawn on specific brain regions and these were used to quantify standard uptake values (SUVs). The SUV is defined as the average concentration of radioactivity in the ROI x body weight/injected dose. Using the cerebellum as a reference region, SUV ratios (SUVROI/SUVcerebellum) were calculated to compare saline and nicotine effects in each ROI. RESULTS Two-way repeated ANOVA revealed a significant decrease of SUV ratios in both striatal and extrastriatal regions following an injection of nicotine during the PET scans. CONCLUSIONS Like other drugs of abuse, these results indicate that nicotine administration may produce DA release, as suggested by the decrease in [18F]fallypride signal in striatal regions. These findings from a nonhuman primate model provide further evidence that the mesolimbic DA system is affected by the use of products that contain nicotine.
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Affiliation(s)
- Jennifer E Naylor
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, United States
| | - Takato Hiranita
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, United States
| | - Katelin S Matazel
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, United States
| | - Xuan Zhang
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, United States
| | - Merle G Paule
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, United States
| | - Amy K Goodwin
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, United States.
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Deutschländer A, la Fougère C, Boetzel K, Albert NL, Gildehaus FJ, Bartenstein P, Xiong G, Cumming P. Occupancy of pramipexole (Sifrol) at cerebral dopamine D2/3 receptors in Parkinson's disease patients. Neuroimage Clin 2016; 12:41-6. [PMID: 27408789 PMCID: PMC4925448 DOI: 10.1016/j.nicl.2016.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 11/19/2022]
Abstract
Whereas positron emission tomography (PET) with the antagonist ligand [18F]fallypride reveals the composite of dopamine D2 and D3 receptors in brain, treatment of Parkinson's disease (PD) patients with the D3-prefering agonist pramipexole should result in preferential occupancy in the nucleus accumbens, where the D3-subtype is most abundant. To test this prediction we obtained pairs of [18F]fallypride PET recordings in a group of nine PD patients, first in a condition of treatment as usual with pramipexole (ON-Sifrol; 3 × 0.7 mg p.d.), and again at a later date, after withholding pramipexole 48–72 h (OFF-Sifrol); in that condition the serum pramipexole concentration had declined by 90% and prolactin levels had increased four-fold, in conjunction with a small but significant worsening of PD motor symptoms. Exploratory comparison with historical control material showed 14% higher dopamine D2/3 availability in the more-affected putamen of patients OFF medication. On-Sifrol there was significant (p ˂ 0.01) occupancy at [18F]fallypride binding sites in globus pallidus (8%) thalamus (9%) and substantia nigra (19%), as well as marginally significant occupancy in frontal and temporal cortex of patients. Contrary to expectation, comparison of ON- and OFF-Sifrol results did not reveal any discernible occupancy in nucleus accumbens, or elsewhere in the extended striatum; present methods should be sensitive to a 10% change in dopamine D2/3 receptor availability in striatum; the significant findings elsewhere in the basal ganglia and in cerebral cortex are consistent with a predominance of D3 receptors in those structures, especially in substantia nigra, and imply that therapeutic effects of pramipexole may be obtained at sites outside the extended striatum. Fallypride PET recordings in nine PD patients, scanned on- and off medication with pramipexole No occupancy in the striatum, despite improved motor symptoms Substantial occupancy in substantia nigra, thalamus and globus pallidus
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Affiliation(s)
| | | | - Kai Boetzel
- Department of Neurology, Ludwig-Maximilians University of Munich, Germany
| | - Nathalie L Albert
- Department of Nuclear Medicine, Ludwig-Maximilians University of Munich, Germany
| | | | - Peter Bartenstein
- Department of Nuclear Medicine, Ludwig-Maximilians University of Munich, Germany
| | - Guoming Xiong
- Department of Nuclear Medicine, Ludwig-Maximilians University of Munich, Germany
| | - Paul Cumming
- Department of Neuropsychiatry and Psychosomatic Medicine, Rikshospitalet, University of Oslo, Oslo, Norway; School of Psychology and Counselling, Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, QIMR Berghofer Medical Research Institute, Brisbane, Australia
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Pandey S, Venugopal A, Kant R, Coleman R, Mukherjee J. ¹²⁴I-Epidepride: a PET radiotracer for extended imaging of dopamine D2/D3 receptors. Nucl Med Biol 2014; 41:426-31. [PMID: 24602412 DOI: 10.1016/j.nucmedbio.2014.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 01/15/2014] [Accepted: 01/23/2014] [Indexed: 11/26/2022]
Abstract
OBJECTIVES A new radiotracer, ¹²⁴I-epidepride, has been developed for the imaging of dopamine D2/3 receptors (D2/3Rs). ¹²⁴I-Epidepride (half-life of ¹²⁴I=4.2 days) allows imaging over extended periods compared to (18)F-fallypride (half-life of ¹⁸F=0.076 days) and may maximize visualization of D2/3Rs in the brain and pancreas (allowing clearance from adjacent organs). D2/3 Rs are also present in pancreatic islets where they co-localize with insulin to produce granules and may serve as a surrogate marker for imaging diabetes. METHODS ¹²⁴I-Epidepride was synthesized using N-[[(2S)-1-ethylpyrrolidin-2-yl]methyl]-5-tributyltin-2,3-dimethoxybenzamide and ¹²⁴I-iodide under no carrier added condition. Rats were used for in vitro and in vivo imaging. Brain slices were incubated with (124)I-epidepride (0.75 μCi/cc) and nonspecific binding measured with 10 μM haloperidol. Autoradiograms were analyzed by OptiQuant. ¹²⁴I-Epidepride (0.2 to 0.3 mCi, iv) was administered to rats and brain uptake at 3 hours, 24 hours, and 48 hours post injection was evaluated. RESULTS ¹²⁴I-Epidepride was obtained with 50% radiochemical yield and high radiochemical purity (>95%). (124)I-Epidepride localized in the striatum with a striatum to cerebellum ratio of 10. Binding was displaced by dopamine and haloperidol. Brain slices demonstrated localization of ¹²⁴I-epidepride up until 48 hours in the striatum. However, the extent of binding was reduced significantly. CONCLUSIONS ¹²⁴I-Epidepride is a new radiotracer suitable for extended imaging of dopamine D2/3 receptors and may have applications in imaging of receptors in the brain and monitoring pancreatic islet cell grafting.
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Affiliation(s)
- Suresh Pandey
- Preclinical Imaging, Department of Radiological Sciences, University of California - Irvine, Irvine, CA 92697, USA
| | - Archana Venugopal
- Preclinical Imaging, Department of Radiological Sciences, University of California - Irvine, Irvine, CA 92697, USA
| | - Ritu Kant
- Preclinical Imaging, Department of Radiological Sciences, University of California - Irvine, Irvine, CA 92697, USA
| | - Robert Coleman
- Preclinical Imaging, Department of Radiological Sciences, University of California - Irvine, Irvine, CA 92697, USA
| | - Jogeshwar Mukherjee
- Preclinical Imaging, Department of Radiological Sciences, University of California - Irvine, Irvine, CA 92697, USA.
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Peyronneau MA, Saba W, Goutal S, Kuhnast B, Dollé F, Bottlaender M, Valette H. [(18)F] Fallypride: metabolism studies and quantification of the radiotracer and its radiometabolites in plasma using a simple and rapid solid-phase extraction method. Nucl Med Biol 2013; 40:887-95. [PMID: 23891202 DOI: 10.1016/j.nucmedbio.2013.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 05/22/2013] [Accepted: 06/13/2013] [Indexed: 11/16/2022]
Abstract
INTRODUCTION [(18)F]Fallypride, a fluorinated and substituted benzamide with high affinity for D2/D3 receptors, is a useful PET radioligand for the study of striatal/extrastriatal areas. Since [(18)F]fallypride is extensively metabolized in vivo and since PET examinations are long lasting in humans, the rapid measurement of the unchanged radiotracer in plasma is essential for the quantification of images. The present study aims: i) to evaluate if the radiometabolites of [(18)F]fallypride cross the blood-brain barrier in rodents, ii) to identify these radiometabolites in baboon plasma and iii) to develop a rapid solid phase extraction method (SPE) suitable for human applications to quantify both [(18)F]fallypride and its radiometabolites in plasma. METHODS The metabolites P450-dependant in rat and human liver microsomes were characterized by LC-MS-MS and compared to those detected in vivo. Sequential solvent elution on Oasis®-MCX-SPE cartridges was used to quantify [(18)F]fallypride and its radiometabolites. RESULT In rat microsomal incubations, five metabolites generated upon N/O-dealkylation or hydroxylation at the pyrrolidine and/or at the benzamide moiety were identified. No radiometabolite was detected in the rat brain. N-dealkylated and hydroxylated derivatives were detected in human microsomal incubations as well as in baboon plasma. The use of SPE (total recovery 100.2%± 2.8%, extraction yield 95.5%± 0.3%) allowed a complete separation of [(18)F]fallypride from its radiometabolites in plasma and evaluate [(18)F]fallypride at 150 min pi to be 22%± 5% of plasma radioactivity. CONCLUSIONS The major in vivo radiometabolites of [(18)F]fallypride were produced by N-dealkylation and hydroxylation. Allowing the rapid analysis of multiple plasma samples, SPE is a method of choice for the determination of [(18)F]fallypride until late images required for quantitative PET imaging in humans.
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