Synthesis and in vivo behavior of a copper-64-labeled dithiosemicarbazone derivative coupled to a dihydropyridine carrier

The dihydropyridine ↔ pyridinium salt redox delivery system was used to develop a perfusion agent that could be labeled with a generator-produced positron emitter 62Cu-labeled dithiosemicarbazone (DTS) molecule attached to a dihydropyridine carrier (PDTS-DHC) was synthesized by the simple mixing of 64Cu acetate and Zn-PDTS-DHC. The latter was prepared by dithionite reduction of the Zn complex of a corresponding pyridinum precursor (PDTS-QC+). When injected into mice, 64Cu-PDTS-DHC showed a high myocardial uptake and high heart-to-blood and heart-to-lung ratios. These results demonstrate that it may be possible to develop 62Cu-PDTS-DHC compounds as radiopharmaceuticals for myocardial perfusion studies using positron emission tomography. (Author)