Content Determination of Diphenhydramine Hydrochloride and Ephedrine Hydrochloride in Compound Diphenhydramine Nasal Drops by Ion-pair RP-HPLC

OBJECTIVE:To establish the method for the content determination of diphenhydramine hydrochloride and ephedrine hydrochloride in Compound diphenhydramine nasal drops.METHODS:Ion-pair RP-HPLC method was adopted.Agilent ZORBAX Eclipse XDB-C18 column was used with 0.02 mol·L-1 sodium laurylsulfate solution(pH adjusted to 2.85 with 85% phosphate acid solution)-methanol-triethanolamine(52 ∶ 48 ∶ 0.5)at the flow rate of 1.0 mL·min-1.The UV detection wavelength was set at 256 nm.The column temperature was 30 ℃.RESULTS:Diphenhydramine hydrochloride and ephedrine hydrochloride could be well isolated from other substances.The calibration curve was linear in the range of 0.500 2 to 5.002 0 μg for diphenhydramine hydrochloride(r=0.999 8,n=6).The calibration curve was linear in the range of 4.005 8 to 40.058 0 μg for ephedrine hydrochloride(r=0.999 4,n=6).The average recovery of diphenhydramine hydrochloride was 100.2%(RSD=1.2%,n=9),and that of ephedrine hydrochloride was 99.5%(RSD=1.1%,n=9).CONCLUSION:The method is specific,accurate and reliable for the content determination of diphenhydramine hydrochloride and ephedrine hydrochloride in Compound diphenhydramine nasal drops.