An LC-MS/MS method for quantification of demethylzeylasteral, a novel immunosuppressive agent in rat plasma and the application to a pharmacokinetic study.

In this study, a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of demethylzeylasteral in rat plasma. Electrospray ionization was operated in the negative ion mode while demethylzeylasteral and oleanolic acid (internal standard) were measured by selected reaction monitoring (demethylzeylasteral: m/z 479.2 → 436.0; oleanolic acid: m/z 454.9 → 407.2). This LC-MS/MS method had good selectivity, sensitivity, accuracy and precision. The pharmacokinetic profiles of demethylzeylasteral were subsequently examined in Wistar rats after oral or intravenous administration.

Quantitative bioanalysis of bavachalcone in rat plasma by LC-MS/MS and its application in a pharmacokinetics study.

This study aims to develop and validate a simple and sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for investigating the pharmacokinetic characteristics of bavachalcone. Liquid-liquid extraction was used to prepare plasma sample. Chromatographic separation of bavachalcone and IS was achieved using a Venusil ASB C18 (2.1 × 50 mm, 5 µm) column with a mobile phase of methanol (A)-water (B) (70:30, v/v). The detection and quantification of analytes was performed in selected-reaction monitoring mode using precursor → product ion combinations of m/z 323.1 → 203.2 for bavachalcone, and m/z 373.0 → 179.0 for IS. Linear calibration plots were achieved in the range of 1-1000 ng/mL for bavachalcone (r2 > 0.99) in rat plasma. The recovery of bavachalcone ranged from 84.1 to 87.0%. The method was precise, accurate and reliable. It was fully validated and successfully applied to pharmacokinetic study of bavachalcone.