Quantification of puerarin in plasma by on-line solid-phase extraction column switching liquid chromatography-tandem mass spectrometry and its applications to a pharmacokinetic study

A highly precise, automatic and rapid method for quantification of puerarin in canine and human plasma using an on-line solid-phase extraction (SPE) column switching procedure combined with liquid chromatography/electrospray ionization tandem mass spectrometry (LC–ESI-MS) was developed. The eluent of SPE column consisted of acetonitrile/methanol/0.1% formic acid (25/25/50) at a flow rate of 0.2 mL min−1. Puerarin was analyzed by a linear ion trap mass spectrometer, LTQ-MS, operating in the negative ion and selective reaction monitoring (SRM) acquisition mode. Method validation results demonstrated that the linear calibration curve covered a wide range of 0.39–400.00 ng mL−1, the correlation coefficients (r2) were above 0.999. The lower limit of detection (LLOD) with the signal-to-noise (S/N) ratio higher than 12 was 0.39 ng mL−1. The intra- and inter-batch precisions were less than 7.61% and 6.42%, respectively. The accuracy was well within the accept limit. The on-line SPE column switching HPLC–MS system was applied to pharmacokinetic (PK) study of puerarin after a single orally dose in beagles. And the optimum conditions were successfully utilized to quantify puerarin in human plasma, which indicated the feasibility and the reliability of this method for application in preclinical and clinical PK studies of isoflavone drugs.