Objective: To establish a
reversed phase ion - pair HPLC method for determining the concentrations of
oxymatrine(OMT) and
matrine( MT) in human plasma. Method:The internal standard was sophoridine. Protein in plasma was first percipitated with 3. 5% perchloric acid,the supernatant solution was subsequently extracted with dichloromethane after basification with 40% sodium hydroxide solution. The chromatographic conditions included: Inertsil ODS -3 column(150 mm ×4. 6mm,5 μm) at a temperature of 35℃ ,the mobile phase consisted of 3. 7 mmol·L-1 SDS,50 mmol . L -1 phosphoric acid and 70 mmol . L-1 triethylamine -20% acetonitrile,adjusted to pH 3. 0 with triethylamine,mobile phase flow rate was 1. 0 mL ·min-1. UV detection at 220 nm. Results:The average recoveries of OMT and MT were 98. 83% and 96. 87% . The detection limits of OMT and MT were each 50μg·L-1. The linear ranges of OMT and MT were each 0. 3 ~ 20μg · mL-1. The correlation coefficients of OMT and MT were 0. 999 8 and 0. 999 9. The RSD for intra - day and inter - day were both less than 7% . Conclusion: The method is simple , a℃urate and sensitive, and suitable for determination of OMT and MT in serum as well as for studying the metabolic pathway of OMT.