High-performance liquid chromatographic method for the estimation of the novel investigational anti-cancer agent SR271425 and its metabolites in mouse plasma

A simple and reliable HPLC method was developed for the estimation of a new anti-cancer agent that belongs to the thioxanthone class, SR271425 in mouse plasma. SR271425, it’s metabolites and internal standard (SR233377) were separated from plasma by liquid–liquid extraction using dichloromethane after quenching the plasma proteins with acetonitrile. Chromatography was performed on a reversed-phase C18 column using methanol–10 mM phosphate buffer, pH 3.5 (45:55) as mobile phase at a flow-rate of 0.8 ml/min for first 10 min and 1.4 ml/min for the next 15 min with UV–Vis detection at 264 nm and SR233377 as internal standard. The retention times of SR271425 and internal standard were 18.6 and 14.8 min, respectively. The limit of detection was 40 ng/ml and the limit of quantification was 78 ng/ml. This method was also able to detect the three metabolites of SR271425. The intra- and inter-day relative standard deviations were less than 13% at all concentrations. This analytical method was precise and reproducible for pharmacokinetics and metabolism studies of the drug in mice. SR271425 is proceeding to phase I clinical trials in 2001.