RESUMO
OBJECTIVE:To establish the method for simultaneous determination of related substances in Amlodipine hydrochlo-rothiazide and valsartan tablets. METHODS:HPLC method was used. The determination was performed on Symmetry C18 column with mobile phase consisted of water-acetonitrile-trifluoroacetic acid(90:10:0.1,V/V/V)and water-acetonitrile-trifluoroace-tic(10:90:0.1,V/V/V)(gradient elution)at the flow rate of 0.6 mL/min. The detection wavelength was set at 237 nm(impurity A) and 225 nm(impurity B,C,D). The column temperature was 30 ℃. RESULTS:The linear range of impurity A,B,C,D were 93.43-987.34 ng/mL(r=0.9994),12.27-255.92 ng/mL(r=0.9996),78.96-657.17 ng/mL(r=0.9999),28.39-218.16 ng/mL(r=0.9997),respectively. The limits of quantitation were 91.27,11.35,78.31,26.56 ng;the limits of stability and detection were 22.98,3.13,19.17,8.16 ng. RSDs of precision tests were lower than 2.0%. Only impurity A was found in repeatability test,RSD=0.79%. Recoveries were 99.4%-100.6%(RSD=0.41%,n=9),98.9%-102.0%(RSD=1.04%,n=9),99.4%-100.9%(RSD=0.56%,n=9),98.6%-101.2%(RSD=0.92%,n=9),respectively. CONCLUSIONS:The method is simple,rapid,sensitive and repeatable,and can be used for the determination of related substance in Amlodipine hydrochlorothiazide and valsartan tablets.