RESUMO
Objective To compare the effects of dual-wavelength spectrophotometry and HPLC on the content of trimethoprim(TMP)in Compound Dihydroartemisinin Tablets.Methods HPLC was performed in a column of C 18 with acetonitrile and 0.75% diethylamine(15∶85,adjusting pH to 2.5 by phosphoric acid)as the mobile phase and the detecting wavelength was at 271nm.The detecting wavelength was also at 271nm with reference wavelength at 366nm in dual-wavelength spectrophotomerty.Results Within 20.0～100.0 ?g/mL,TMP has a good linearity(r=0.999 94)by HPLC,and the average recovery was 100.9% with RSD being0.24%(n=5).By dual-wavelength spectrophotometry,a good linearity(r=0.999 95)of TMP was within 5.0～25.0 ?g/mL,and the average recovery was 100.0% with RSD being 0.45%(n=5).Conclusion Both dual-wavelength spectrophotometry and HPLC can be used to determine the content of TMP in Compound Dihydroartemisinin Tablets,but the former can detect the content of TMP directly without the disturbance of piperaquine phosphate and is simple,rapid and accurate.