Determination of Corosolic Acid, a Natural Potential Anti-Diabetes Compound, in Rat Plasma by High-Performance Liquid Chromatography-Mass Spectrometry and its Application to Pharmacokinetic and Bioavailability Studies

A simple, robust, and sensitive high-performance liquid chromatography/mass spectrometric method was developed for the determination of corosolic acid, a potential anti-diabetes substance, in rat plasma using glycyrrhetinic acid as the internal standard (IS). This method involved a liquid-liquid extraction with acetic ether and a subsequent analysis performed on an LC-MS system which contained an electrospray ionization interface. Chromatographic separation was performed using an ODS column, and the mobile phase was composed of methanol and 5 mmol/L ammonium acetate (88: 12, v/v). Good linearity was observed over the concentration range of 20-10000 ng/mL with a correlation coefficient (r(2)) >= 0.995. The method was proved to be accurate and reliable and was applied to a pharmacokinetic study in the rat following intragastric and intravenous administration of corosolic acid.