Simultaneous determination and pharmacokinetic study of polyphyllin I,polyphyllin II,polyphyllin VI and polyphyllin VII in beagle dog plasma after oral administration of Rhizoma Paridis extracts by LC‐MS‐MS

For the first time, a rapid and specific LC‐MS‐MS method has been developed for the analysis of polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII in beagle dog plasma. The method was applied to study the pharmacokinetics of Rhizoma Paridis extracts containing polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII. The analysis was carried out on an Agilent Zorbax XDB‐C₁₈ reversed‐phase column (100 × 2.1 mm, 1.8 µm) by isocratic elution with acetonitrile and water (50:50, v/v). The flow rate was 0.25 mL/min. All analytes including internal standards were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII ranging from 10 to 5000 ng/mL. The intra‐and inter‐day precisions (RSDs) were less than 6.66 and 9.15%. The extraction recovery ranged from 95.53 to 104.21% with RSD less than 8.69%. Stability studies showed that polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII were stable in preparation and analytical process. The validated method was successfully used to determine the concentration–time profiles of polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII. Copyright © 2012 John Wiley & Sons, Ltd.