Reaction of sup(99m)Tc-diphosphonate with N-donor ligands

As a feasible approach to characterizing sup(99m)Tc-radiopharmaceuticals ligand exchange reactions between sup(99m)Tc-HEDP or sup(99m)Tc-MDP and N-donor ligands have been performed. The radiopharmaceuticals were found convertible to cationic complexes with pyridine and ethylenediamine and to a lipophilic agent with o-phenylenediamine. The cationic sup(99m)Tc-pyridine complex readily undergoes further reaction with dithiols to give the corresponding Tc-dithiolato complexes. The reaction route and products could be simulated in carrier experiments starting from sup(99m)Tc(V)-gluconate. (author)