Chromatographic and Densitometric Analysis of Hydrochlorothiazide, Walsartan, Kandesartan, and Enalapril in Selected Complex Hypotensive Drugs

A new chromatographic and densitometric method was developed for identification and determination of hydrochlorthiazide, walsartan, kandesartan, and enelapril present together in various complex drugs used in hypertension therapy. The TLC F254 plates were used as the stationary phase and two mobile phases were used of the following composition: ethyl acetate-tetrahydrufuran-acetic acid (8:2:0.5 v/v) (I) to determine kandesartan and walsartan present together with hydrochlorthiazide, and butane-1-ol-glacial acetic acid-water (12:3:5 v/v/v) (II) to determine enalapril and hydrochlorthiazide. The densitometric measurements were made at λ = 252 nm for walsartan and kandesartan and at λ = 274 nm and λ = 208 nm, for enalapril and hydrochlorthiazide, respectively. The method was specific to analyte constituents and was of high sensitivity; LOD ranged from 0.036 µg to 0.639 µg, LOQ from 0.210µg to 1.937 µg, recovery varied from 93.96{} to 101.74{}, the range of linearity was 0.078 µg to 6.150 µg. The results obtained for the drugs under examination was of similar precision, RSD ranged from 0.41 to 1.14.