Labeling and biodistribution studies of Tc-99m radiopharmaceuticals with (o-hydroxyphenyl) diphenylphosphine

New Tc-99m radiopharmaceuticals with the ligand (o- hydroxyphenyl)diphenylphosphine have been prepared and their biodistributions evaluated in rats. The monoxo Tc(V) complex [99mTc(O)CI(PO)2], the Tc(IV) complex [99mTc(OH)2(PO)2], the Tc(III) complex [99mTc(PO)3], and the nitrido Tc(V) complex [99mTc(N)(PO)2] have been characterized by TLC and HPLC chromatography, and their chemical structure elucidated by comparison with the corresponding complexes obtained using the ?-emitting isotope Tc- 99g. Biodistribution studies of these complexes have been carried out in rats.