Development and validation of a quantification method for ziyuglycoside I and II in rat plasma: Application to their pharmacokinetic studies

This study provided a novel and generally applicable method to determine ziyuglycoside I and ziyuglycoside II in rat plasma based on liquid chromatography with tandem mass spectrometry. A single step of liquid–liquid extraction with  n ‐butanol was utilized, and ginsenoside Rg3 was chosen as internal standard. Final extracts were analyzed based on liquid chromatography with tandem mass spectrometry. Chromatographic separation was achieved using a Thermo Golden C 18 column, and the applied gradient elution program allowed for the simultaneous determination of two ziyuglycosides in a one‐step chromatographic separation with a total run time of 10 min. The fully validated methodology for both analytes demonstrated high sensitivity (the lower limit of quantitation was 2.0 ng/mL), good accuracy (% RE ≤ ± 15) and precision (% RSD ≤ 15). The average recoveries of both ziyuglycosides and internal standard were all above 75% and no obvious matrix effect was found. This method was then successfully applied to the preclinical pharmacokinetic studies of ziyuglycoside I and ziyuglycoside II. The presently developed methodology would be useful for the preclinical and clinical pharmacokinetic studies for ziyuglycoside I and ziyuglycoside II.