Objective: To establish a high-performance liquid chromatographic/tandem mass spectrometry (HPLC-MS/MS) method for determining 20(S)-protopanaxadiol (PPD) in rat plasma, in order to analyze pharmacokinetic characteristics of PPD and PPD cubic nanoparticles.
Method: Sprague-Dawley rats were administered orally with PPD and PPD cubic nanoparticles, respectively. Their blood samples were obtained from fossa orbitalis at regular time points. The mobile phase was 0.05% formic acidac etonitrile-0.05% formic acidac water (95:5). Electrospray ionization (ESI) was adopted for the quadrupole tandem mass spectrum. SCAN mode was used for the quantitative analysis, with m/z 460. 4/425.3 and m/z 622.9/318.3 (Rh2, interior label) as secondary fragment ions. The concentration of PPD in plasma was analyzed. The concentration-time curve was mapped. The data were calculated by DAS program.
Result: The linearity of the PPD plasma concentration determination method ranged between 10-1 407 microg x L(-1), with the limit of quantification of 2.5 microg x L(-1). Both of the inter-day and intra-day precisions (RSD) were less than 13.25%, and the accuracy (relative error) was between +/- 8.50%.
Conclusion: The method was so highly specific and sensitive with less plasma that it is suitable for pharmacokinetic studies. The prepared 20(S)-protopanaxadiol lipid cubic nanoparticles can enhance its absorption in vivo. Its relative bioavailability is 166% of the raw material.