A Sensitive LC–MS–MS Method for Simultaneous Quantification of Two Structural Isomers, Hyperoside and Isoquercitrin: Application to Pharmacokinetic Studies

We report the development and validation of a rapid, specific, and sensitive liquid chromatographic–tandem mass spectrometric (LC–MS–MS) method for analysis and pharmacokinetic study, in rats, of hyperoside and isoquercitrin, two bioactive structural isomers present in the leaves of Apocynum venetum L. After simple deproteinization by addition of acetonitrile, the analytes were separated on a C18 column. Detection was by tandem mass spectrometry in multiple reaction monitoring mode. The method was linear over the concentration range 3.9–195 ng mL−1 for both hyperoside and isoquercitrin. Intra-day and inter-day precision for both hyperoside and isoquercitrin were <13.1%, and relative errors were all within 7.1% at all QC levels. The method was used to study the pharmacokinetic performance of the compounds after oral administration of an extract of Apocynum venetum L. leaves to rats.