Abstract: Objective To establisha HPLC method for the determination of isofraxidin in medofenoxate fruits. Methods Agilent XDB C18(4.6 mm伊150 mm,5μm) column was applied, using methanol-0.2% phosphoric acid (27：73)as mobile phase with the rate of 1.0mL·min^-1. The column temperature was room temperature, the injection volumn was 10μL and the detective wavelength was 343 nm. Results A good linearity was obtained over the range of 0.835～4.176μg·mL^-1 for isofraxidin(r=0.9996). The average recovery(n=6) was 100.74%(RSD=0.44%). Conclusion The method is practical, convenient, accurate, and can be used as the determination of isofraxidin in medofenoxate fruits.

Key words: medofenoxate fruit, isofraxidin, HPLC