Simultaneous determination of calycosin-7-O-β-d-glucoside, ononin, astragaloside IV, astragaloside I and ferulic acid in rat plasma after oral administration of Danggui Buxue Tang extract for their pharmacokinetic studies by liquid chromatography–mass spe

A sensitive and reliable high-performance liquid chromatography–mass spectrometry (HPLC–MS) was developed and validated for simultaneous quantification of five main bioactive components, i.e., calycosin-7-O-β-d-glucoside, ononin, astragaloside IV, astragaloside I and ferulic acid in rat plasma after oral administration of Danggui Buxue Tang (DBT) extract. Plasma samples were extracted with solid-phase extraction (SPE) separated on an Inertsil ZORBAX C18 column and detected by MS with electrospray ionization (ESI) interface in negative selective ion monitoring (SIM) mode. Calibration curves offered linear ranges of two orders of magnitude with r2 > 0.99. The method had the lower limit quantification of 0.55, 0.46, 1.07, 1.12 and 4.6 ng/mL for calycosin-7-O-β-d-glucoside, ononin, astragaloside IV, astragaloside I and ferulic acid, respectively, with precision less than 10%. The RSD of intra- and inter-day variations ranged from 2.10% to 6.19% and 2.37% to 6.72%. This developed method was subsequently applied to pharmacokinetic studies of the five compounds in rats successfully.