Determination of a potential antitumor quassinoid in rat plasma by UPLC–MS/MS and its application in a pharmacokinetic study

[Display omitted] •Brusatol is a naturally occurring quassinoid of Brucea javanica.•An UPLC–MS/MS assay was established for the quantification of brusatol.•This method was applied to support the pharmacokinetic study in rats. A sensitive UPLC–MS/MS method was developed and validated for the determination of brusatol in rat plasma. Chromatographic separation was carried out on a C18 column using methanol and 10mM ammonium acetate containing 0.1% (v/v) formic acid (55:45, v/v). The lower limit of quantification (LLOQ) was 1.0ng/mL for brusatol in plasma. The intra- and inter-day precision for the analyte ranged from 3.2% to 9.2% and 1.3% to 7.8%, and the accuracy was between 97.3% and 108.5%. The method was successfully applied in a pharmacokinetic study of brusatol following intravenous injection (0.5, 1.0, and 2.0mg/kg) of brusatol.