Pharmacokinetic properties of paeoniflorin, albiflorin and oxypaeoniflorin after oral gavage of extracts of Radix Paeoniae Rubra and Radix Paeoniae Alba in rats

To establish a HPLC–MS method and investigate the pharmacokinetic properties of paeoniflorin, albiflorin and oxypaeoniflorin and the pharmacokinetics difference of Radix Paeoniae Rubra and Radix Paeoniae Alba. The extracts of Radix Paeoniae Rubra and Radix Paeoniae Alba were separately administrated to rats. The concentrations of paeoniflorin, albiflorin and oxypaeoniflorin in rat plasma were determined by HPLC–ESI-MS method. The plasma samples were pretreated by protein precipitation with methanol and chromatographic separation was performed on a C18 column with a mobile phase consisted of 0.1% formic acid and methanol (67:33, v/v). The detection was accomplished by multiple-reaction monitoring (MRM) scanning via electrospray ionization (ESI) source operating in the negative ionization mode. Main pharmacokinetic parameters were estimated and the total AUC of the three components were compared. The pharmacokinetic parameters of paeoniflorin, albiflorin and oxypaeoniflorin were significantly different. There was significant difference between the pharmacokinetic characteristics of Radix Paeoniae Rubra and Radix Paeoniae Alba. A specific and sensitive HPLC–ESI-MS method was developed for simultaneous determination of paeoniflorin, albiflorin and oxypaeoniflorin in rat plasma and was successfully applied to pharmacokinetic study. The results might be helpful for the investigation of different effects of Radix Paeoniae Rubra and Radix Paeoniae Alba.