Ultra-high-performance liquid chromatography tandem mass spectrometry method for the determination of gambogenic acid in dog plasma and its application to a pharmacokinetic study

A highly sensitive and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of gambogenic acid in dog plasma. Gambogic acid was used as an internal standard (IS). After a simple liquid-liquid extraction by ethyl acetate, the analyte and internal standard were separated on an Acquity BEH C-18 (100x2.1mm, 1.7 mu m; Waters ) column at a flow rate of 0.2mL/min, using 0.1% formic acid-methanol (10:90, v/v) as mobile phase. Electrospray ionization source was applied and operated in the positive ion mode. Multiple reaction monitoring mode with the transitions m/z 631.3507.3 and m/z 629.1573.2 was used to quantify gambogenic acid and the internal standard, respectively. The calibration curves were linear in the range of 5-1000ng/mL, with a coefficient of determination (r) of 0.999 and good calculated accuracy and precision. The low limit of quantification was 5ng/mL. The intra-and inter-day precisions (relative standard deviations) were <15%. The methodology recoveries were more than 66.63%. This validated method was successfully applied to a pharmacokinetic study after intravenous injection administration of gambogenic acid in dogs at a dose of 1mg/kg. Copyright (c) 2014 John Wiley & Sons, Ltd.