Radiosynthesis of a Novel PET Fluoronicotinamide for Melanoma Tumour PET Imaging; [18F]MEL050

[ 18 F]6-Fluoro-N-[2-(diethylamino)ethyl]nicotinamide [ 18 F]MEL050 is a novel nicotinamide-based radiotracer, designed to target random metastatic dissemination of melanoma tumours by targeting melanin. Preclinical studies suggest that [ 18 F]MEL050 hasan excellent potentialto improvediagnosis andstaging of melanoma. Here wereport the radiochemical optimization conditions of [ 18 F]MEL050 and its large scale automated synthesis using a GE FXFN automated radiosynthesis module for clinical, phase-1 investigation. [ 18 F]MEL050 was prepared via a one-step synthesis using no-carrier added K[ 18 F]F-Krytpofix 222 (DMSO, 1708C, 5min) followed by HPLC purification. Using 6-chloro-N-[2-(diethylamino)ethyl]nicotinamide as precursor, [ 18 F]MEL050 was obtained in 40–46% radiochemical yield (non-decay corrected), in greater than 99.9% radiochemical purity and specific activity ranging from 240 to 325GBqmmol � 1 . Total synthesis time including formulation was 40min and [ 18 F]MEL050 was stable (99.8%) in PBS for 6h.