Development of a rapid and sensitive UPLC–MS/MS assay for simultaneous quantitation of Vorolanib and its metabolite in human plasma and application to a pharmacokinetics study

•An LC–MS/MS method for the simultaneous quantification of vorolanib and its metabolite was established and fully validated.•Protein precipitation for extraction of vorolanib and X297 in human plasma was used.•The effects of illumination and pH on the conversion kinetics of isomer transformation were evaluated.•This method was applied to the pharmacokinetic evaluation of vorolanib tablets in Chinese solid tumor patients.