Pharmacokinetics Study of Rabdosia rubescens Drop Pills Based on UPLC-MS/MS

Background: Rabdosia rubescens drop pills have the effects of clearing away heat and toxin, detumescence, relieving pain. Objective: A simple and sensitive method for simultaneous determination of oridonin, ponicidin, and rosmarinic acid in rat plasma was developed based on ultra performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS). Methods: Chromatographic separation was performed on a Waters ACQUITY UPLC BEH C18 column (2.1 × 100 mm, 1.7 μm) with a mobile phase consisting of water containing 0.2% formic acid (mobile phase A) and methanol (mobile phase B) at a flow rate of 0.3 mL/min over a total run time of 3.8 min. All analytes were measured with optimized multiple reaction monitoring (MRM) in positive and negative ion ESI mode. Results: The transitions of oridonin, ponicidin, rosmarinic acid, diphenhydramine, and chloramphenicol were 365.3→347.3, 363.3→345.2, 359.0→160.9, 256.0→167.2, and 321.1→151.9, respectively. The linear ranges were 1-256 ng/mL for ponicidin and rosmarinic acid and 2-512 ng/mL for oridonin. The validated method was stable and reliable. There was no significant difference in the half-life (t1/2) of the three analytes at three doses. The area under the curve (AUC0-t) and peak concentration (Cmax) of the three analytes decreased linearly in each dose range, and the linear correlation R² of each analyte under the three doses was greater than 0.95. Conclusion: This method was successfully applied to pharmacokinetic studies of oridonin, ponicidin, and rosmarinic acid in rat plasma after intragastric administration of Rabdosia rubescens drop pills.