Clinical pharmacology of oral and intravenous 4-demethoxydaunorubicin

The clinical pharmacology of 4-demethoxydaunorubicin (4-DMDNR) was studied in 28 patients with advanced breast cancer, using a sensitive reverse-phase HPLC technique. All patients had normal renal and hepatic function. The serum levels of 4-DMDNR after a single i.v. bolus injection followed a triple exponential decay curve (T 1/2 alpha = 9.6 min, T 1/2 beta = 3.2 h and T 1/2 gamma = 34.7 h) and conformed to a three-compartment model. Comparison of the area under the curve (AUC) and urinary excretion for the oral and i.v. routes suggests an oral bioavailability of approximately 24%. In patients treated with a schedule of weekly oral administration for periods of up to 12 months there was no significant alteration in either AUC or elimination half-life for the parent drug or its principal metabolite 13-OH4DMDNR. Moreover, there was no evidence of accumulation of the metabolite although measurable amounts were present 7 days after administration of 4-DMDNR.