A simple and sensitive ultra‐high performance liquid chromatography tandem mass spectrometry method for the quantitative analysis of VX‐548 in monkey plasma: Method validation and application to pharmacokinetic study

Abstract VX‐548 is an orally active and highly selective NaV 1.8 inhibitor that is undergoing development for the treatment of acute pain. The aim of this study was to develop a liquid chromatography‐tandem mass spectrometric (LC–MS/MS) method for the measurement of VX‐548 in monkey plasma. VX‐548 was extracted from the plasma using acetonitrile‐mediated protein precipitation. The quantitative analysis was performed on a Thermo Vantage TSQ mass spectrometer with ibrutinib as an internal standard. Chromatography was performed on a Waters ACQUITY UPLC BEH C 18 column with 0.1% aqueous formic acid and acetonitrile as mobile phase. The precursor‐to‐product ion transitions were m/z 474.2 > 165.0 and m/z 441.2 > 138.1 for VX‐548 and internal standard, respectively. This developed method was successfully validated in the concentration range of 1–1000 ng/mL. The calibration curve showed excellent linearity with a correlation coefficient of >0.999. The precision expressed as relative standard deviation (RSD) was <8.4%, whereas the accuracy denoted as relative error (RE) ranged from −5.0% to 9.1%. The mean recovery was >84%. VX‐548 was stable in monkey plasma after storage under certain conditions. The validated method was successfully applied to the pharmacokinetic study of VX‐548 in monkey plasma after single oral (2 mg/kg) and intravenous (1 mg/kg) administrations.