57Co-bleomycin kinetics in normal and tumour-bearing mice after systemic and local administration

In tumour-free and tumour-bearing mice the body clearance and organ distribution of 57Co-BLM was measured at different time intervals after iv., sc., and it. administration of the drug. No significant difference could be demonstrated in body clearance following different doses and routes of application of labelled BLM in tumour-free and tumour-bearing mice. The organ distribution studies showed higher concentrations following iv. compared to sc. or it. of 57Co-BLM; however, the activity in the ipsilateral injection sites was significantly increased after sc. and it. injection. In tumour-bearing mice the activity in the lymph nodes draining injection site was as high as that seen in the 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 or organ distribution of 57Co-BLM a rational basis for it. treatment of malignant tumours.