A validated LC-MS/MS method for the determination of hederasaponin C: Application to pharmacokinetics-pharmacodynamics studies in the therapeutic area of acetic acid-induced ulcerative colitis in rats.

Hederasaponin C (HSC), one of the main components of Pulsatilla chinensis, is considered as a potential drug for the treatment of inflammatory bowel disease. In the present research, we developed a pharmacokinetics-pharmacodynamics model to describe the concentration-effect course of drug action following the intraperitoneal injection of HSC in colitis rats. A sensitive UPLC-MS/MS method was established for the the determination of HSC in rat plasma to explore the pharmacokinetics properties. The separation was performed on an Accucore C column (2.1 × 100 mm, 2.6 μm) with a flow phase consisting of acetonitrile and 0.1% formic acid water. The assay method was validated and demonstrated good adaptability for application in the pharmacokinetics study. Then the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in colon tissues were measured using an ELISA assay. The levels of TNF-α, IL-1β and IL-6 were decreased after HSC administration, suggesting that HSC can significantly improve the level of inflammatory syndrome factor. The pharmacokinetics study showed that the time to peak concentration of HSC was 1 h. The concentration-effect curves showed a hysteresis loop. There was also a hysteresis between the peaked concentration and the maximum effect of HSC. The present study established in vivo pharmacokinetics-pharmacodynamics models and the results showed a great potential of HSC for treating ulcerative colitis.