Preparation and evaluation of cationic 99Tc/99mTc dimethoxy- and diethoxy-hexanedione dioxime complexes

The new ligands 1,6-dimethoxy-3,4-hexanedione dioxime (DMHD) and 1,6-diethoxy-3,4-hexanedione dioxime (DEHD) were synthesized and their boron containing 99Tc/99mTc complexes, formed by reduction of pertechnetate with BH4-, were isolated, purified and characterized by IR/UV/VIS spectroscopy and FAB mass spectrometry. These rather stable cationic complexes differ significantly in lipophilicity as assessed by their octanol/saline partition coefficients and HPLC capacity factors. Unexpectedly the organ uptake and clearance of both complexes in mice proved to be very similar with only the uptake of 99mTc-DMHD in the kidneys being enhanced. (author)