Rapid quantitative determination of epirubicin and its metabolites in plasma using high performance liquid chromatography and fluorescence detection

A rapid sensitive and selective isocratic technique was developed for the analysis of plasma epirubicin and three of its known fluorescent metabolites epirubicinol, 4′-O-β-D-glucuronyl-4′-epidoxorubicin and 4′-O-β-D-glucuronyl 1,3-dihydro-4′-epidoxorubicin, with daunorubicin as an internal standard, by using high performance liquid chromatography (HPLC) with fluorescence detection and a ‘Hypersil ODS’ column. The drugs were easily and efficiently extracted with a Sep-Pak C18 cartridge and the mean recoveries were greater than 85%. Intraassay and Interassay coefficients of variation (plasma samples) were better than 8.25%. An example of pharmacokinetic study obtained in a cancer patient after intravenous injection of epirubicine is described.