Application of a liquid chromatography–tandem mass spectrometry method to the pharmacokinetics, tissue distribution and excretion in the study of anemoside B4, a novel antiviral agent candidate, in rats

A simple, sensitive and reliable LC-MS/MS method was developed and validated for the quantification of anemoside B4, a potential antiviral constituent isolated from Pulsatilla chinensis in rat plasma, tissue, bile, urine and feces. All biological samples were prepared by protein precipitation method, and ginsenoside-Rg1 was chosen as the internal standard (IS). The analyte and IS were separated using a C₁₈ column (2.1 × 50 mm, 1.8 μm) and a mobile phase consisting of 0.1% formic acid in water (v/v) and acetonitrile running at a flow rate of 0.2 mL/min for 5 min. The multiple reaction monitoring transitions were monitored at m/z 1219.5-749.5 for anemoside B4 and 845.4-637.4 for ginsenoside-Rg1 in electrospray ionization negative mode. The calibration curve was linear in the range of 10-2000 ng/mL for all biological matrices with a lower limit of quantification of 10 ng/mL. The validated method was successfully applied to a pharmacokinetics, tissue distribution and excretion study. These preclinical data will be beneficial for further development of anemoside B4 in future studies.