Development and validation of a quantitative liquid chromatography tandem mass spectrometry assay for pristimerin in rat plasma

A sensitive, rapid and simple LC-MS/MS analysis method was developed and validated for the determination of pristimerin (PR) in rat plasma. Protein precipitation with four volumes of acetonitrile as the precipitation reagent was used as the sample preparation method. The analysis process was performed on a Merck ZIC-HILIC column with the mobile phase of acetonitrile-water (containing 5 mM ammonium formate, pH 2.8) (85:15, v/v). PR (m/z 465.3-201.1) and glycyrrhetinic acid (internal standard, m/z 471.5-177.1) were monitored under positive electrospray ionization in multiple reaction monitoring (MRM) mode. Retention time of PR and IS was 2.45 min and 2.4 min, respectively. The limit of detection was 0.5 ng/mL and the linear range was 1-500 ng/mL. The intra-day and inter-day precision were 2.89-6.27% and 4.91-8.98%, and the intra-day and inter-day accuracy ranged from −5.81% to 8.64% and −7.37% to 9.57%, respectively. The matrix effects and absolute recovery ranged from 89.3% to 92.4% and 88.7% to 92.8%, respectively. The method has been successfully applied to the determination of PR concentration in rat plasma after intravenous administration (0.5 mg/kg).