Objective:To establish an HPLC method for the determination of content and related substances in schizonepetin.Method:Two stability columns based on silica gel were used respectively（Waters XTerra MS C18 column for related substances analysis;And Kromasil C18 column for content determination）.The mobile phase consisted of methanol-water（45:55）

and when analyzing substances destroyed by alkali

the pH value of the mobile phase should be adjusted to 10.0 by sodium hydroxide.Both of the two columns were maintained at a constant temperature of about 30 ℃.The flow rate was 0.8 mL per minute.The UV detection wavelength was set at 216 nm.Result:Related substances and degraded substances were completely separated from schizonepetin.The linear range of determination was 0.012 6-0.403 6 g·L-1 with the correlation coefficient of 0.999 9.The LOD was 0.25 μg

and the LOQ was 0.63 μg.The average recovery was 100.04%

RSD 1.40%.Conclusion:The method is simple

rapid

accurate

and sensitive and it is suitable for the determination of the content and related substances in schizonepetin.