AbstractA 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 C18cartridge 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 intraven