Determination of the Related Substances of Difenidol Hydrochloride by RP-HPLC

OBJECTIVE To establish an HPLC method for determination of related substances of difenidol hydrochloride. METHODS VP-ODS C18 column (250 mm 4.6 mm, 5 μm) was adopted. The mobile phase consisted of 0.5% triethylamine solution (adjusted to pH 4.0 with phosphoric acid)-methanol (44∶56) and the flow rate was 0.8 mL·min-1. The detection wavelength was 210 nm and the column temperature was 30 ℃. RESULTS Related substances and degraded substances were completely separated from difenidol hydrochloride. The method was good repeatability and stability. The LOD was 1 ng. CONCLUSION The method was selective, sensitive, accurate, and it is suitable for determination of related substances in difenidol hydrochloride.