Development and validation of a quantification method for oleanolic acid and hederagenin in rat plasma: application...

A rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and validated for simultaneous quantification of oleanolic acid and hederagenin in rat plasma. After the two analytes were extracted with liquid-liquid extraction, chromatographic separation was performed on a C₁₈ column with acetonitrile and water (85:15, v/v) as mobile phase at a flow rate of 0.4 mL/min. Calibration curves exhibited good linearity (r > 0.995) over the ranges of 0.41-82.0 ng/mL for oleanolic acid and 0.32-64.0 ng/mL for hederagenin, respectively. The lower limit of quantifications (LLOQs) in plasma were 0.41 ng/mL for oleanolic acid and 0.32 ng/mL for hederagenin. The established LLOQs were within the concentration needed for the assay in plasma, which met the requirements to evaluate their pharmacokinetics of oleanolic acid and hederagenin. This developed assay was successfully applied in the pharmacokinetic study of oleanolic acid and hederagenin in rats after oral administration of Rhizoma Clematidis extract.