Objective: To establish an HPLC method for content determination of loureirin A

B in Sanjie Zhentong capsules. Method: Extracted loureirin A

B with ultrasonic method in the use of 75% methanol

Kromasil C18 column (4.6 mm×250 mm

5 μm) was used with a step gradient of acetonitrile-1% glacial acetic acid at a flow rate of 1.0 mL·min-1. The sample amount was 10 μL and the detection wavelength was set at 278 nm. The column temperature was maintained at 30℃. Result: Loureirin A and B had a good linear relationship during 526.20-4.11 ng (r=0.999 9) and 506.09-3.95 ng (r=0.999 9) respectively. The average recoveries were 101.84% with RSD 0.77%(n=6)

100.54% with RSD 1.46%(n=6). The method also had good reproducibility and stability. Conclusion: The sample preparation is reasonable in the quantitative method

and the accurate results can be used for content determination of loureirin A and B of Sanjie Zhentong Capsules.