Pharmacokinetics of Ro 03-8799 in mice bearing melanosarcoma: comparison with tumors without melanin.

The pharmacokinetics of Ro 03-8799 has been studied in melanic and non-melanic tumor bearing mice after iv administration of 150 mg/kg. The peak concentration in B16 melanosarcoma tumor reached 152 micrograms/g, that is 7.6-fold higher than the plasma concentration at the same time. This concentration is 3-times greater than that obtained in the tumor of mice bearing non melanic sarcoma (DB16) or Lewis lung carcinoma (3LL). The exposure of B16 tumor (AUC) is respectively 15-times and 11-times higher than the 3LL and the DB16 ones. These experimental data confirm that this 2-nitro-imidazol compound has an important affinity for melanin and suggest that it might be used as a radiosensitizer for the treatment of malignant melanoma.