Determination of paclitaxel in human plasma using single solvent extraction prior to isocratic reversed-phase high-performance liquid chromatography with ultraviolet detection

Abstract

An isocratic reversed-phase high-performance liquid chromatographic method with ultraviolet detection at 230 nm has been developed for the determination of paclitaxel in human plasma. Plasma samples were prepared by a selective one-step liquid–liquid extraction involving a mixture of acetonitrile– n-butyl chloride (1:4, v/v). Paclitaxel and the internal standard docetaxel were separated using a column packed with ODS-80A material, and a mobile phase consisting of water–methanol–tetrahydrofuran–ammonium hydroxide (37.5:60:2.5:0.1, v/v). The calibration graph for paclitaxel was linear in the range 10–500 ng/ml, with a lower limit of quantitation of 10 ng/ml, using 1 ml plasma samples. The extraction recoveries of spiked paclitaxel and docetaxel to drug-free human plasma were 89.6±8.52 and 93.7±5.0%, respectively. Validation data showed that the assay for paclitaxel is sensitive, selective, accurate and reproducible. The assay has been used in a single pharmacokinetic experiment in a patient to investigate the applicability of the method in vivo.