LC-ESI-MS/MS method for simultaneous determination of eleven bioactive compounds in rat plasma after oral administration of Ling-Gui-Zhu-Gan Decoction and its application to a pharmacokinetics study.

A sensitive and robust LC-MS/MS method has been developed and validated to simultaneous determine the concentrations of tumulosic acid, dehydrotumulosic acid, polyporenic acid C, cinnamic acid, Atractylenolide I, Atractylenolide II, Atractylenolide III, glycyrrhizic acid, glycyrrhetinic acid, liquiritigenin and isoliquiritin in plasma from rats who received Ling-Gui-Zhu-Gan Decoction extract oral administration. The samples were prepared by a liquid-liquid extraction procedure using ethyl ether as the extraction solvent and schisandrin as the internal standard. Chromatographic separation was achieved using a Thermo Hypersil GOLD C18 column (2.1 mm × 100 mm, 1.9 µm) and a gradient mobile phase consisting of acetonitrile-water with 0.1% formic acid. All of the analytes were quantified using negative and positive multiple reaction monitoring mode. The method was validated for selectivity, linearity, accuracy, precision, recovery, matrix effect and sample stability under various storage conditions, whose values are all fell in the acceptable limits. We report the lowest limit of quantification for tumulosic acid, dehydrotumulosic acid and polyporenic acid C as 2 ng/mL. This is the first study for simultaneous determination of so many analytes in rat plasma after oral administration of Ling-Gui-Zhu-Gan Decoction. This validated method was successfully used to study the pharmacokinetics of multiple compounds in rat plasma after oral administration of Ling-Gui-Zhu-Gan Decoction.