Distribution and metabolism of rubidazone and daunorubicin in mice.

A comparative investigation of the distribution and metabolism of rubidazone and daunorubicin was conducted in NMRI mice, after a single IV dose of either rubidazone (8.4 mg/kg) or daunorubicin (7 mg/kg). The anthracyclines were analyzed by high-pressure liquid chromatography and fluorometry. Daunorubicin was the main compound found after daunorubicin administration, except in kidney and urine, where daunorubicinol was the main metabolite with trace amounts of aglycone. In contrast, rubidazone undergoes extensive metabolism into daunorubicin, daunorubicinol, and aglycone. The total drug level is significantly lower after rubidazone administration in kidney, heart, gastrointestinal tract, spleen, and urine, and the biliary excretion of rubidazone is more important than that of daunorubicin. When compared with daunorubicin, significantly less daunorubicinol is produced after rubidazone administration.