Development and Validation of an LC-MS/MS Method for Determination of Catalpol and Harpagide in Small Volume Rat Plasma: Application to a Pharmacokinetic Study

摘要

A rapid and sensitive liquid chromatography-tandem mass chromatography (LC-MS/MS) method has been developed and validated for simultaneous determination of catalpol and harpagide in rat plasma. The samples were extracted by one-step protein precipitation and separated on a SunFireTM C_(18) column (100 mm × 2.1 mm, 3.5 μ m; Waters) using acetonitrile-10 mM ammonium formate as mobile phase at a flow rate 0.3 mL/min in gradient mode. The analytes were detected without interference in Multiple Reaction Monitoring (MRM) mode with negative electrospray ionization. Linear responses were obtained for catalpol ranging from 20 to 5000 ng/mL and harpagide ranging from 10 to 2500 ng/mL. Coefficients of correlation (r) for the calibration curves were more than 0.99 for both analytes. Intra- and inter-day accuracy and precision were within the acceptable limits of less than 15.0% at all concentrations. The quantitation method was successfully applied for simultaneous estimation of catalpol and harpagide after oral administration of Zeng Ye Decoction.