A UPLC-MS/MS approach for simultaneous determination of eight flavonoids in rat plasma, and its application to pharmacokinetic studies of Fu-Zhu-Jiang-Tang tablet in rats.

The purpose of this study is to establish and validate a UPLC-MS/MS approach to determine eight flavonoids in biological samples and apply the method to pharmacokinetic study of Fu-Zhu-Jiang-Tang tablet. A Waters BEH C UPLC column was employed with methanol/0.1% formic acid-water as mobile phases. The mass analysis was carried out in a triple quadrupole mass spectrometer using multiple reaction monitoring with negative scan mode. A one-step protein precipitation by methanol was used to extract the analytes from blood. Eight major flavonoids were selected as markers. Our results showed that calibration curves for 3'-hydroxypuerarin, mirificin, puerarin, 3'-methoxypuerarin, daidzin, rutin, astragalin and daidzein displayed good linear regression (r  > 0.9986). The intra-day and inter-day precisions (RSD) of the eight flavonoids at high, medium and low levels were <8.03% and the bias of the accuracies ranged from -5.20 to 6.75%.The extraction recoveries of the eight flavonoids were from 91.4 to 100.5% and the matrix effects ranged from 89.8 to 103.8%. The validated approach was successfully applied to a pharmacokinetic study in Sprague-Dawley rats after oral administration of FZJT tablet. Double peaks were emerged in curves of mean plasma concentration for 3'-methoxypuerarin, which was reported for the first time.