N-(3-(4-(2-methoxyphenyl) piperaziny-1 -yl)propyl)cyclam: synthesized as a potential 5-HT_(1A) receptor ligand and labelled with ~(99m)Tc-nitrido core

摘要

This paper reports the synthesis of new potential 5-HT_(1A) receptor ligand N-[3-[4-(2-methoxyphenyl)piperaziny-1-yl]propyI]cyclam (MPPC) and radiolabelling of it with ~(99m)Tc-nitrido core. The novel neutral complex ~(99m)TcN-MPPC combines 1,4,8,11-tetraazacyclotetradecane (cyclam) ligand as chelate moiety for ~(99m)Tc-nitrido with a 1-(2-methoxyphenyl)piperazine moiety derived from WAY 100635 via a 3-carbon alkyl chain. This provided a reliable and reproducible method for attaching the technetium to the pharmacophore moiety of WAY 100635. ~(99m)TcN-MPPC was prepared by a two-step procedure and the radiochemical purity was found to be greater than 95%. It was hydrophilic and stable for at least 4h at room temperature. In vivo stability study in normal rats showed that no degradation of ~(99m)TcN-MPPC was found in deproteinated blood samples at 2h post-injection. This effective ~(99m)Tc-labelling strategy for obtaining neutral ~(99)mTc nitrido complexes would be a useful tool to prepare new SPECT agents to image 5-HT_(1A) receptor with cyclam conjugated ligands.