Simultaneous determination of 8 constituents of Desmodii Styracifolii Herba in rat bile with HPLC-MS/MS and their excretion pharmacokinetics

Abstract

To establish a HPLC-MS/MS quantitative method for analysis of 8 constituents in rat bile. The method was applied in the biliary excretion study after oral administration of Desmodii Styracifolii Herba extract. The rat bile samples were collected during 0-1, 1-2, 2-4, 4-6, 6-8, 8-12, 12-24 h. Diamonsil C₁₈column (4.6 mm×150 mm, 5 μm) was adopted and eluted with methanol and 0.01% acetic acid in a gradient mode. The flow rate was 0.8 mL•min⁻¹, and the column temperature was set at 40 ℃. The detection was carried out by a triple quadrupole linearion trap mass spectrometer in the negative ion mode with an electrospray source. Multiple reactions monitoring (MRM) mode was employed. The calibration curves showed a good linearity, with correlation coefficients (r≥0.991 5) for all of the analytes within the concentration range. The intra-day and inter-day precisions (RSD) were both less than 15%, and the accuracies (RE) ranged from -15% to 15%. The method had a good stability, and was suitable for the content determination of 8 constituents in rat bile. The extraction recoveries of the 8 analytes were more than 63.2%, and the RSD of IS-normalized matrix factors were no more than 15%, which met the requirements for analysis. According to the biliary excretion study, the bile excretion rates of the 8 analytes were relatively low, with great difference among the individuals. The results showed that the established method was simple, selective and specific, thus could be applied in the biliary excretion study of the 8 analytes in rat bile.