An UFLC-MS/MS method for quantification of panaxadiol in rat plasma and its application to a pharmacokinetic study

Panaxadiol is a novel antitumor agent extracted from the Chinese medical herb Panax ginseng. This agent is being developed for the treatment of tumor diseases. A rapid, selective, and simple method based on ultrafast liquid chromatography-tandem mass spectrometry was established and validated to determine panaxadiol in rat plasma following oral and sublingual intravenous administration of panaxadiol. The plasma samples were pretreated with acetic ether, and chromatographic separation was achieved on a Shim-pack XR-ODS III column using isocratic elution with the mobile phase of 0.1 % formic acid and acetonitrile. Analytes and protopanaxadiol (internal standard) were analyzed and identified using electrospray positive ionization mass spectrometry in the multiple reaction-monitoring mode. The MS/MS detection was carried out by monitoring the fragmentation of m/z 461.45 → m/z 127.1 for panaxadiol and m/z 425.4 → m/z 95.1 for protopanaxadiol (internal standard) on a triple-quadrupole mass spectrometer. The result showed good linearity over a wide concentration range (0.1-20 ng/mL) (R2 > 0.999) and its lower limit of detection and quantification were 0.03 and 0.1 ng/mL, respectively. The intra- and interday precision (RSD %) was within 15 % and the accuracy ranged from 94.9 % to 112.0 %. The absolute bioavailability was 12.5 %. The method was fully validated and successfully applied to the pharmacokinetic study of a single dose of panaxadiol.