Radiosynthesis of (N-[C-11]methyl)benperidol for PET investigation of D2 receptor binding

A procedure for the reliable production of the novel P T D2 receptor ligand (N-[C-11]methyl)benperidol ([C-11]NMB) is described. The method is based on N-methylation of benperidol using [C-11]methyl iodide from the PETtrace Mel MicroLab, with product purification via normal-phase HPLC. Batch yields of 2.5 +/- 0.9 GBq (68 +/- 25 mCi) of [C-11]NMB are routinely (n = 16) obtained, with a radiochemical purity > 98% and an average specific activity of over 40.7 TBq (1100 Ci)/mmol. The overall radiosynthesis, purification, and pre-release quality control testing is accomplished within 50 minutes. The procedure described herein produces a radiopharmaceutical product that is suitable for D2 receptor studies using PET or microPET imaging.