Radiosynthesis and Evaluation of an 18F-Labeled Positron Emission Tomography (PET) Radioligand for Metabotropic Glutamate Receptor Subtype 4 (mGlu4)
摘要:
Four 4-phthalimide derivatives of N-(3-chlorophenyl)-2-picolinamide were synthesized as potential ligands for the PET imaging of mGlu4 in the brain. Of these compounds, N-(3-chloro-4-(4-fluoro-1,3-dioxoisoindolin-2-yl)phenyl)-2-picolinamide (3, KALB001) exhibited improved binding affinity (IC50 = 5.1 nM) compared with ML128 (1) and was subsequently labeled with F-18. When finally formulated in 0.1 M citrate buffer (pH 4) with 10% ethanol, the specific activity of [F-18]3 at the end of synthesis (EOS) was 233.5 +/- 177.8 GBq/mu mol (n = 4). The radiochemical yield of [F-18]3 was 16.4 +/- 4.8% (n = 4), and the purity was over 98%. In vivo imaging studies in a monkey showed that the radiotracer quickly penetrated the brain with the highest accumulation in the brain areas known to express mGlu4. Despite some unfavorable radiotracer properties like fast washout in rodent studies, [F-18]3 is the first F-18-labeled mGlu4 radioligand, which can be further modified to improve pharmacokinetics and brain penetrability for future human studies.
Disclosed are mGluR4 positive allosteric modulator ligands of general formula (I) and radiolabeled derivates, their use as therapeutic agents for the treatment of central nervous system disorders modulated by mGluR4 and as ligands for the labeling and diagnostic imaging of mGluR4 in mammals.
The present application provides picolinamide compounds that can be used as allosteric positron emission tomography (“PET”) imaging probes. Methods of using these compounds for treating a neurodegenerative disease are also provided.
Radiosynthesis and Evaluation of an <sup>18</sup>F-Labeled Positron Emission Tomography (PET) Radioligand for Metabotropic Glutamate Receptor Subtype 4 (mGlu<sub>4</sub>)
Four 4-phthalimide derivatives of N-(3-chlorophenyl)-2-picolinamide were synthesized as potential ligands for the PET imaging of mGlu4 in the brain. Of these compounds, N-(3-chloro-4-(4-fluoro-1,3-dioxoisoindolin-2-yl)phenyl)-2-picolinamide (3, KALB001) exhibited improved binding affinity (IC50 = 5.1 nM) compared with ML128 (1) and was subsequently labeled with F-18. When finally formulated in 0.1 M citrate buffer (pH 4) with 10% ethanol, the specific activity of [F-18]3 at the end of synthesis (EOS) was 233.5 +/- 177.8 GBq/mu mol (n = 4). The radiochemical yield of [F-18]3 was 16.4 +/- 4.8% (n = 4), and the purity was over 98%. In vivo imaging studies in a monkey showed that the radiotracer quickly penetrated the brain with the highest accumulation in the brain areas known to express mGlu4. Despite some unfavorable radiotracer properties like fast washout in rodent studies, [F-18]3 is the first F-18-labeled mGlu4 radioligand, which can be further modified to improve pharmacokinetics and brain penetrability for future human studies.
[EN] PHTHALIMIDE DERIVATIVE METABOTROPIC GLUTAMATE R4 LIGANDS<br/>[FR] LIGANDS DU GLUTAMATE MÉTABOTROPIQUE R4 DÉRIVÉ DE PHTALAMIDE
申请人:MERCK & CO INC
公开号:WO2010033349A1
公开(公告)日:2010-03-25
Disclosed are mGluR4 positive allosteric modulator ligands of general formula (I) and radiolabeled derivates, their use as therapeutic agents for the treatment of central nervous system disorders modulated by mGluR4 and as ligands for the labeling and diagnostic imaging of mGluR4 in mammals.