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

[F-18]6-Fluoro-N-[2-(diethylamino)ethyl]nicotinamide [F-18]MEL050 is a novel nicotinamide-based radiotracer, designed to target random metastatic dissemination of melanoma tumours by targeting melanin. Preclinical studies suggest that [F-18]MEL050 has an excellent potential to improve diagnosis and staging of melanoma. Here we report the radiochemical optimization conditions of [F-18]MEL050 and its large scale automated synthesis using a GE FXFN automated radiosynthesis module for clinical, phase-1 investigation. [F-18]MEL050 was prepared via a one-step synthesis using no-carrier added K[F-18]F-Krytpofix (R) 222 (DMSO, 170 degrees C, 5 min) followed by HPLC purification. Using 6-chloro-N-[2-(diethylamino)ethyl]nicotinamide as precursor, [F-18]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 325 GBq mu mol(-1). Total synthesis time including formulation was 40 min and [F-18]MEL050 was stable (99.8%) in PBS for 6 h.