Determination of active ingredients in the pharmaceutical formulations containing hydrochlorothiazide and its binary mixtures with benazepril hydrochloride, triamterene and cilazapril by ratio spectra derivative spectrophotometry and vierordt's method.

Procedures were developed for the simultaneous determination of pharmaceuticals in binary mixtures, containing hydrochlorothiazide-benazepril hydrochloride, hydrochlorothiazide triamterene and hydrochlorothiazide cilazapril by ratio spectra derivative spectrophotometry and Vierordt's method. Mean recoveries, relative standard deviations and linearity ranges in calibration graphs of the methods were compared. These procedures were successfully applied to three pharmaceutical formulations for the determination of active ingredients.