Objective: To develop a UPLC-MS-MS method to simultaneously determine the concentration of ferulic acid

vanillic acid

peoniflorin and albiflorin in beagle plasma and study the pharmacokinetics of these four components after ig administration of Angelicae Sinensis Radix-Paeoniae Radix Alba drug pair extract to beagle dogs. Method: Following a protein precipitation with methanol for plasma samples at different time after ig Angelicae Sinensis Radix-Paeoniae Radix Alba drug pair extract to Beagle dogs. The analysis was achieved by BEH C18 column and the mobile phase was consisted of water (0.1% formic acid included) and acetonitrile followed step gradient elution. A TQ tandem mass spectrometry equipped with electrospray ionization source was used as detector and operated by multiple reaction monitoring (MRM). The ion pairs for quantitation were m/z 195.3-144.5 for ferulic acid

m/z 169.0-92.9 for vanillic acid

and m/z 481.3-197.1 for albiflorin in positive ion mode and m/z 525.4-449.2 for peoniflorin in negative ion mode. The pharmacokinetic parameters were calculated by DAS 2.0 program. Result: Ferulic acid

vanillic acid

peoniflorin and albiflorin showed a good liner relationship of 1.13-1 089

1.23-1 080

0.82-787.5

0.36-337.5 μg·L-1

respectively. The method was validated according to the requirements. The pharmacokinetic characteristics of ferulic acid and vanillic acid were similar

both of their absorption was very fast. Elimination of ferulic acid was fast while the elimination of vanillic acid was slower. The pharmacokinetic characteristics of peoniflorin and albiflorin were very similar

both of their absorption and elimination were slow in beagle dogs. Conclusion: The method is proved to be sensitive

selective

rapid and successfully applied to a pharmacokinetic study of major components of Angelicae Sinensis Radix-Paeoniae Radix Alba drug pair in beagle dogs. This research laid a good foundation for the study of compatibility of Angelicae Sinensis Radix-Paeoniae Radix Alba drug pair.