Synthesis, radiolabeling and biodistribution studies of [99mTc(CO)3(MN-TZ-BPA)]+ in tumor-bearing mice

This study reports the synthesis, radiolabeling and preliminary biodistribution results of [99mTc(CO)3(MN-TZ-BPA)]+ in tumor-bearing mice. The novel nitroimidazole derivative was successfully synthesized by conjugation of bis(pyridin-2-ylmethyl)amine (BPA) to 2-methyl-5-niroimidazole via “click” reaction. The ligand could be labeled by [99mTc(CO)3]+ core in high yield to get [99mTc(CO)3(MN-TZ-BPA)]+, which was very hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that [99mTc(CO)3(MN-TZ-BPA)]+ accumulated in the tumor with certain initial uptake while poor retention. The rapid clearance from normal organs with favorable tumor/muscle ratios warrants further research to improve tumor targeting efficacy and pharmacokinetic profile of radiolabeled nitroimidazoles by structural modification.