RADIOSYNTHESIS OF [F-18] N-(4-PHENYLBUTYL)-4-(4-FLUOROBENZOYL)PIPERIDINE FOR STUDYING SEROTONIN 5-HT2A RECEPTORS

N-(4-Phenylbutyl)-4-(4-fluorobenzoyl)pipe [4-PBFBP] shows highly selec tive binding to serotonin 5-HT2A receptors with high affinity. In this study, we prepared [F-18]4-PBFBP for in vivo study of 5-HT2A receptor s in the brain using positron emission tomography (PET). Nucleophilic aromatic displacement of N-(4-phenylbutyl)-4-(4-nitrobenzoyl)piperidin e by no carrier added [F-18]fluoride which was solubilized by Kryptofi x 222 in DMSO produced [F-18]4-PBFBP with high specific radioactivity. The product was purified by reversed phase preparative HPLC and was e xtracted from the collected eluate by SEP-PAK(R) C18 cartridge prior t o formulation. The radiochemical yield of the final product was 15 +/- 1.8 % (mean +/- S.D. of three experiments) with decay correction and the specific activity was 113 +/- 27 GBq/mu mol (mean +/- S.D. of thre e experiments) at E.O.S. after a total preparation time of about 160 m in. The radiochemical purity of [F-18]4-PBFBP was more than 99%. The r egional distribution of [F-18]4-PBFBP in mouse brain was also examined .