A validated LC-MS/MS method for determination of periplogenin in rat plasma and its application in pharmacokinetic study.

A method coupling high performance liquid chromatography with tandem mass spectrometry has been developed and validated for quantifying periplogenin in rat plasma using psoralen as an internal standard (IS). Plasma samples were pretreated using a simple liquid-liquid extraction with ethyl acetate and the chromatographic separation of periplogenin and psoralen was achieved on a Waters XBridge™ BEH C18 column with 0.1% formic acid and acetonitrile as mobile phase at a flow rate of 0.4mL/min. The detection was performed on a positive ion mode with electrospray ionization (ESI) source. The optimized ion transition pairs for quantitation were m/z 391.3→m/z 337.2 for periplogenin and m/z 187.0→m/z 131.0 for IS. The total run time was 9.0min. The calibration curve was linear over the range of 0.2-250ng/mL (r>0.99) with the lower limit of quantitation (LLOQ) at 0.2ng/mL. The intra- and inter-day precision were below 9.85% and the mean accuracy were from -10.03% to 10.26%. The average recoveries of periplogenin in plasma ranged from 85.1% to 95.6%. The proposed method was successfully applied in evaluating the pharmacokinetics of periplogenin after an oral dose of 30mg/kg Cortex Periplocae extract in rats.