Objective: To develop a high performance liquid chromatographic (HPLC) method for simultaneous determination of ferulic acid

5-methoxypsoralen

imperatorin

isoimperatorin in Duliang dropping pills. Method: Duliang dropping pills were extracted supersonically with 75% methanol for 30 min. The supernatant was separated on Agilent Zorbax SB C18 (4.6 mm×150 mm

5 μm) by gradient program with methanol (A)-water with 0.1% phosphoric acid (B) as the mobile phase at a flow rate of 1.0 mL·min-1

and determined by diode array detector at 254

320

330 nm respectively. Result: The limits of quantification of four compounds were in the range of 3-15 mg·kg-1

this method showed a good linearity between 0.5-50 mg·L-1 and the correlation coefficient (R2) was more than 0.999 0. The average recoveries were from 96.6% to 102.5% with relative standard deviation from 0.16% to 2.07%. Conclusion: This method is simple and rapid and suitable for determination of the four compounds in Duliang dropping pills.