Simultaneous determination of calycosin-7-O-β-D-glucoside, cinnamic acid, paeoniflorin and albiflorin in rat plasma by UHPLC-MS/MS and its application to a pharmacokinetic study of Huangqi Guizhi Wuwu Decoction.

Huangqi Guizhi Wuwu Decoction (HGWWD), consisting of Radix Astragali, Cinnamomi Ramulus, Paeoniae Radix Alba, Zingiberis Rhizoma Recens and Jujubae Fructus, is a widely used Traditional Chinese Medicine (TCM) formula for the treatment of human blood impediment in China for nearly 2000 years. In order to make good and rational use of this formula in the future, a rapid, sensitive and robust ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for simultaneous determination of calycosin-7-O-β-D-glucoside, cinnamic acid, paeoniflorin and albiflorin, the main active constituents of HGWWD, in rat plasma using geniposide as internal standard (IS). The plasma samples were extracted by protein precipitation with acetonitrile and separated on a Shim-pack XR-ODS C18 column (75 mm × 3.0 mm, 2.2 μm) using gradient elution with a mobile phase consisting of water (containing 0.1% formic acid) and acetonitrile at a flow rate of 0.4 mL/min. Mass spectrometric detection was performed on 3200 QTRAP mass spectrometry equipped with electrospray ionization source in negative ionization mode. Quantification was performed using multiple reaction monitoring (MRM) by monitoring the fragmentation of m/z 491.1→282.9 for calycosin-7-O-β-D-glucoside, m/z147.0→103.1 for cinnamic acid, m/z 525.0→120.9 for paeoniflorin, m/z 525.2→121.0 for albiflorin and m/z 433.1→225.1 for IS, respectively. The method was well validated in terms of linearity, precision, accuracy, recovery, matrix effect and stability. All calibration curves had good linearity (r>0.9977) over the concentration range from 0.1-50 ng/mL for calycosin-7-O-β-D-glycoside, 50-25000 ng/mL for cinnamic acid, 5-2500 ng/mL for paeoniflorin and albiflorin. The intra-day and inter-day precisions (relative standard deviation) were within 11.8%, the accuracy (relative error) ranged from -9.4% to 9.1%, and the lower limit of quantification (LLOQ) were 0.1, 50, 5, 5 ng/mL for calycosin-7-O-β-D-glucoside, cinnamic acid, paeoniflorin and albiflorin, respectively. Extraction recovery, matrix effect and stability were satisfactory in rat plasma. The validated method was successfully applied to a pharmacokinetic study of calycosin-7-O-β-D-glucoside, cinnamic acid, paeoniflorin and albiflorin after oral administration of HGWWD to rats.