Development of a dynamic multiple reaction monitoring method for determination of digoxin and six active components of Ginkgo biloba leaf extract in rat plasma

A new liquid chromatography–tandem mass spectrometry (LC–MS/MS) method by using dynamic multiple reaction monitoring (DMRM) has been developed and validated for the simultaneous determination of digoxin (DGX) and six main components of Ginkgo biloba leaf extract (GBE) in rat plasma. Comparing with the conventional multiple reaction monitoring (MRM), DMRM dramatically decreases the number of concurrent MRM transitions, and significantly extended the dwell time, which provided much higher sensitivity and reproducibility than MRM when complex multi-component samples were quantified. The plasma samples were protein precipitated with methanol, the detection was accomplished with electro-spray ionization (ESI) as the ion source operating in the negative ionization mode, with methanol and water as mobile phase, and with an Agilent Zorbax eclipse plus C18 column (4.6 × 100 mm, 3.5 μm) as the analytical column. The total run time was 12.0 min. The validation of the method was implemented including specificity, linearity, accuracy, precision, recovery, matrix effect and stability. This method was successfully applied to the herb–drug pharmacokinetic interaction study of DGX combined with GBE after oral administration to rats. The result indicated that co-administration of GBE and DGX significantly influenced the pharmacokinetics of DGX when compared to that of single DGX-treated rats.