Validated rapid resolution LC-ESI–MS/MS method for simultaneous determination of five pulchinenosides from Pulsatilla chinensis (Bunge) Regel in rat plasma: Application to pharmacokinetics and bioavailability studies

A simple, RRLC–ESI-MS/MS method was developed for the simultaneous determination of five oleanane pulchinenosides (B3, BD, B7, B10, and B11), in rat plasma following solid-phase extraction (SPE). Detection and quantitation were performed by MS/MS using electrospray ionization (ESI) and multiple reaction monitoring (MRM) mode. The MS/MS transitions of the triterpenoidal saponins: m/z 911.4 → 603.2, 749.4 → 471.3, 895.6 → 733.2, 733.5 → 455.3, and 579.3 → 371.1 were monitored for B3, BD, B7 and B10, B11 and internal standard (Forsythin), respectively. The method was validated in plasma samples, showed good linearity over a wide concentration range (r2 > 0.99), and with lower limits of quantification of 1.11 (B3), 0.751 (BD), 0.996 (B7), 0.415 (B10), and 0.332 (B11) ng/mL. The intra- and inter-day assay variability was less than 15% for all analytes. The mean extraction recoveries of analytes and IS from rats plasma were all more than 70.0%. The validation results demonstrate that this method is robust and specific. The validated method was successfully applied for the pharmacokinetic and bioavailability studies of the five pulchinenosides which are potentially active saponins present in P. chinensis saponins (PRS) extracts.