Simultaneous determination of scutellarin and tetrahydropalmatine of Deng-yan granule in rat plasma by UFLC-MS/MS and its application to a pharmacokinetic study

Deng-yan granule, consisting of Herba Erigerontis Breviscapi, Rhizoma Corydalis Yanhusuo and Radix Astragali Mongolici, is a widely used Traditional Chinese Medicine preparation for treatment of coronary heart disease. Scutellarin and tetrahydropalmatine are main active constituents in Herba Erigerontis Breviscapi and Rhizoma Corydalis Yanhusuo, and have been used as marker components for quality control of Deng-yan preparations. In order to make good and rational use of Deng-yan granule in the future, a rapid, sensitive and high throughput ultra-fast liquid chromatography with tandem mass spectrometry (UFLC-MS/MS) method was developed for the simultaneous determination of scutellarin and tetrahydropalmatine in rat plasma using rutin as internal standard (IS). The plasma samples were extracted by liquid-liquid extraction with ethyl acetate after acidification and separated on a Shim-pack XR-ODS C18 column (75 mm × 3.0 mm, 2.2 μm) with a mobile phase consisting of methanol-0.1% formic acid water (50:50, v/v) at a flow rate of 0.4 mL/min. Mass spectrometric detection was conducted on an API 3200 QTRAP mass spectrometry equipped with electrospray ionization source in positive ionization mode. Quantification was performed using multiple reaction monitoring (MRM) by monitoring the fragmentation of m/z 463.2 → 287.1 for scutellarin, m/z 356.1 → 192.1 for tetrahydropalmatine and m/z 611.2 → 303.2 for IS, respectively. The linear range was 10-5000 ng/mL for both scutellarin and tetrahydropalmatine with lower limit of quantitation (LLOQ) of 10 ng/mL. The intra- and inter-day precisions were below 12.2% for scutellarin and below 9.7% for tetrahydropalmatine in terms of relative standard deviation (RSD), and the accuracy was within ±9.1% for scutellarin and within ±11.2% for tetrahydropalmatine in terms of relative error (RE). Extraction recovery, matrix effect and stability were satisfactory in rat plasma. The validated method was successfully applied to a pharmacokinetic study of scutellarin and tetrahydropalmatine after oral administration of Deng-yan granule to rats.