Determination of Diphenylmethanol and Diphenylmethanone in Diphenhydramine Hydrochloride Injection by HPLC

OBJECTIVE　To establish an HPLC method for determining the contents of diphenylmethanol and diphenylmethanone in diphenhydramine hydrochloride injection. METHODS　The condition of detection were: Agilent CN column (4.6 mm×250 mm, 5 μm), the mobile phase consisted of acetonitrile and 20 mmol·L^-1 ammonium acetate (adjust with formic acid to pH 6.5) (50∶50), the UV detection wavelength was 255 nm. RESULTS　The calibration curves were linear in the range of 0.531 0-53.10 μg·mL^-1 for diphenylmethanol (r=1.000); the calibration curves were linear in the range of 0.021 22-53.05 μg·mL^-1 for diphenylmethanone (r=1.000). The average recovery of diphenylmethanol was 99.8%(RSD=0.8%); the average recovery of diphenylmethanone was 100.4%(RSD=1.3%). CONCLUSION　The method is simple, accurate, reliable and can be used for the quality control of diphenylmethanol and diphenylmethanone in diphenhydramine hydrochloride injection.