Bleomycin (BLM) has been labeled with various radioisotopes and widely used in therapy and diagnosis. 191Os is a parent radionuclide with 15.4 day half-life and decays by beta emission to 191mIr, which is a radionuclide with 4.96 s half-life. BLM was labeled with 191Os-hexachloro-osmate and its distribution and stability in wild-type mice was determined. The complex was obtained at the
pH 2 in normal saline at 90 °C in 48 h. Radio-TLC showed an overall radiochemical yield of 93–97%, radio-chemical purity > 97%.
The biodistribution study for 191Os-hexachloro-osmate and 191Os-BLM were carried in wild type-mice up to 14 days. Lungs, liver and spleen uptake increased 24–72 h after administration
of 191Os-BLM. 24 h after administration, the radioactivity of the kidney increased and remained constant.