Determination of 20(S)-protopanaxadiol in rat plasma by LC-MS/MS and its application to the pharmacokinetic study: A comparative study of its solution and two oral formulations

A high-performance liquid chromatography - tandem mass spectrometry method was used in a comparative pharmacokinetic study on 20(S)-protopanaxadiol in its solution, pharmacosomes and hydroxy-propyl-beta-cyclodextrin inclusion compound. The calibration linearity range was 2.5-5000 ng/mL and the limit of quantification was 2.5 ng/mL. The intra- and inter-assay coefficients of variation were less than 7% and the recoveries were 67.4, 63.3 and 69.6% at 5, 250 and 4500 ng/mL. In contrast to 20(S)-protopanaxadiol solution, its pharmacosomes and hydroxypropyl-beta-cyclodextrin inclusion compound improved the oral bioavailability to different extent and meanwhile were much safer in clinical use.