Development of an in vivo radionuclide generator by labeling bleomycin with 191 Os

Bleomycin (BLM) has been labeled with various radioisotopes and widely used in therapy and diagnosis. 191 Os is a parent radionuclide with 15.4 day half-life and decays by beta emission to 191m Ir, which is a radionuclide with 4.96 s half-life. BLM was labeled with 191 Os-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 191 Os-hexachloro-osmate and 191 Os-BLM were carried in wild type-mice up to 14 days. Lungs, liver and spleen uptake increased 24–72 h after administration of 191 Os-BLM. 24 h after administration, the radioactivity of the kidney increased and remained constant.