HIGH-YIELD RADIOSYNTHESIS AND PRELIMINARY IN-VIVO EVALUATION OF P-[F-18]MPPF, A FLUORO ANALOG OF WAY-100635

No-carrier added henyl)-1-piperazinyl]ethyl-N-2-pyridinyl-benzamide (p -[F-18]MPPF) was synthesized by nucleophilic substitution of the corre sponding nitro compound in the presence of Kryptofix 222 and K2CO3 by microwave heating (3 min, 500 W) using a remotely controled radiosynth esis. Baseline separation of p-[F-18]MPPF from the nitro derivative wa s performed on a semipreparative HPLC C18 column. After Sep-Pak formul ation, the radiopharmaceutical was obtained with a radiochemical yield of 25% (EOS) in about 70 min. Specific radioactivity averaged between 1-5 Ci/mu mol EOS. Labelling of the ortho and meta derivatives was al so attempted. Brain uptake of p-[F-18]MPPF was studied with PET on flu othane-anesthetized cats. Following intravenous injection of p-[F-18]M PPF, high accumulation of radioactivity was observed in the hippocampu s and cerebral cortex. Low levels of radioactivity were observed in ce rebellum. At 30 min, the mean hippocampus/cerebellum and cortex/cerebe llum ratios were 5 and 3.8, respectively. The accumulation of the trac er was blocked by prior administration of reference WAY-100635, demons trating the specificity of the ligand. (C) 1998 Elsevier Science Inc.