Kinetics of 57Co-bleomycin in mice after intravenous, subcutaneous and intratumoral injection.

In tumor-free and tumor-bearing mice the body clearance and organ distribution of 57Co-BLM was measured in different time intervals after iv, sc, and it administration of the drug. No significant differences could be demonstrated in body clearances following different doses and routes of application of labeled BLM in tumor-free and tumor-bearing mice. The organ distribution studies showed higher concentrations following iv compared to sc or it application of 57Co-BLM; however, the activity in the ipsilateral injection sites were significantly increased after sc and it injection. In tumor-bearing mice the activity in the draining lymph nodes of the injection site were as high as that seen in draining lymph nodes following iv injection. However, on the contralateral side, the lymph node concentration was significantly reduced after it injection. These results indicate on the basis of organ distribution of 57Co-BLM a rational basis for it treatment of malignant tumors.