Synthesis and preliminary biological evaluation of [99mTc(CO)3(IDA–PEG3–CB)]− for tumor imaging

This work reports the synthesis, radiolabeling and preliminary biodistribution results in tumor-bearing mice of [99mTc(CO)3(IDA–PEG3–CB)]−. The novel chlorambucil derivative was successfully synthesized by conjugation of iminodiacetic acid (IDA) to chlorambucil via a pegylated linker. The ligand could be labeled by [99mTc(CO)3]+ core in high yield to get [99mTc(CO)3(IDA–PEG3–CB)]−, which was very hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that [99mTc(CO)3(IDA–PEG3–CB)]− accumulated in the tumor with favorable uptake and retention. The good accumulation in tumor tissue with high tumor/muscle ratios warrants further research to improve tumor targeting efficacy and pharmacokinetic profile of radiolabeled chlorambucil derivative by structural modification.