Pharmacokinetics study of 16 representative components from Baoyuan Decoction in rat plasma by LC-MS/MS with a large-volume direct injection method

Background: Baoyuan decoction (BYD), a well-known traditional Chinese medicine (TCM) formula, is clinically used for the treatment of aplastic anemia, chronic renal failure, coronary heart disease, etc. Purpose: The purpose of this study was to develop a large-volume direct injection liquid chromatography-mass spectrometry (LC-MS) method for simultaneous determination of 16 representative flavonoids and saponins in rat plasma after oral administration of BYD. Methods: The rat plasma sample was injected directly into a pre-column, which was eluted firstly by 0.05% formic acid in water. Then, the accumulated components were eluted from the pre-column and transferred into a Waters BEH C18 column with acetonitrile and water system (contain 0.05% formic acid) as the mobile phase at a rate of 0.3 ml/min. The detection was accomplished in a negative mode using the schedule multiple-reaction monitoring (sMRM). Results: The correlation coefficients for calibration curves were all higher than 0.9920 for formononetin, ononin, calycosin, liquiritigenin, isoliquiritigenin, glycyrrhizic acid, glycyrrhetinic acid, liquiritin, isoliquiritin, liquiritin apioside, isoliquiritin apioside, ginsenoside Rb1, ginsenoside Re, ginsenoside Rd, ginsenoside Rg1 and astragaloside. The intra-and inter-day precisions (RSD) and accuracy (RE) for the investigated components were in the range of -10.9 to 13.7%. The average recoveries were in the range of 75.7-108.6%. This method was successfully applied to investigate the pharmacokinetics of 16 compounds of BYD in rats. The absorption and elimination rates of the representative saponins were significantly slower than most of the targeted-flavonoids after oral administration of BYD in rats. Conclusion: The results demonstrated that the large-volume direct injection LC-MS method provided a rapid and efficient approach for multi-components pharmacokinetics of TCM.