Design, synthesis, and imaging of small amphiphilic rhenium and (99m)technetium tricarbonyl complexes

The design, synthesis, radiolabeling, evaluation of stability, and in vivo investigation are presented of three variably charged, novel, short C(8) chain derivatized chelators for the [M(CO)(3)](+) core (M = (99m)Tc or Re). Labeling with [(99m)Tc(CO)(3)](+) showed complex formation in under 1 h reaction time and high stability toward 24 h histidine and cysteine challenges, as well as distinctive log P values for each complex. Distinct localization of small amphiphilic molecules in in vivo systems depends on the charge of the polar moiety and was studied via biodistribution (4 h) and imaging (15 min, 1, 2, and 4 h) in female C57Bl/6 mice.