Body residue and metabolism of adriamycin and daunorubicin in control and phenobarbital-pretreated mice.

1. Metabolism of adriamycin (ADR) and daunorubicin (DR) was investigated in DBA/2Ha mice after i.p. injection and compared with that in phenobarbital-pretreated animals. At 24 h after drug administration 83% of ADR and 67% of DR derived fluorescence were recovered from cadavers and excreta. Destruction of anthracyclines in excreta to non-fluorescent materials could be partly responsible for the low recoveries. 2. ADR was metabolized to a limited extent in mice. At 24 h 70% dose was detected as the unchanged drug and only 13% as its deoxyaglycones. 3. DR was metabolized more extensively. At 24 h 29% of the dose was as the unchanged drug, while 32% was present as daunorubicinol (DROL) and 16% as aglycones. Phenobarbital did not significantly affect these parameters. 4. In phenobarbital-pretreated mice there was a marked increase in the amount of ADR or DR aglycones in the liver, and a decrease in the levels of unchanged ADR or DR.