Synthesis and biological evaluation of novel ^99mTc‐oxo and ^99mTc‐tricarbonyl complexes with C3′‐functionalized thymidine dithiocarbamate for tumor imaging

Abstract

A novel C3′‐functionalized thymidine dithiocarbamate derivative (3’DTC‐TdR) was successfully synthesized and labelled using [99mTcO]3+ core and [99mTc(CO)3(H2O)3]+ core with high yields. The structures of the 99mTc complexes were verified by preparation and characterization of the corresponding stable rhenium complexes. Both of the complexes were lipophilic and stable in vitro. Cell internalization experiments indicated that the uptakes of 99mTcO‐3’DTC‐TdR were related to nucleoside transporters. Biodistribution of these complexes in mice bearing tumor showed that they had high tumor uptakes, good tumor/muscle ratios and tumor/blood ratios. Especially for 99mTcO‐3’DTC‐TdR, it exhibited the highest tumor/muscle ratio and tumor/blood ratio at 4 h post‐injection. SPECT/CT imaging studies indicated clear accumulation in tumor, suggesting 99mTcO‐3’DTC‐TdR would be a promising candidate for tumor imaging.