Hiqh-Perfonnance Thin-Laver Chrornatoaraphv for the Determination of Certain Antihypertensive Mixtures

A new simple, precise, accurate and selective high-performance thin-layer chromatographic (HPTLC) method has been developed for the simultaneous deter-mination of five mixtures: atenolol and chlorthalidone (Mix. l), enalapril maleate and hydrochlorothiazide (Mix. ll), amiloride hydrochloride and hydrochlorothiazide (Mix. lll), atenolol, chlorthalidone and amiloride hydrochloride (Mix. lV) and atenolol, hydrochlorottriazide and amiloride hydrochloride (Mix. V) in bulk powders and in pharmaceutical dosage forms. The methods consist of dissolving the drugs in methanol and spotting these solutions on a thin layer Merck HPTLC plates (0.25 mm thickness) pre-coated wrth 60 GF₂₅₄ silica gel on aluminum sheet as the stationary phase, using dioxane:acetonrtrile: 1-propanol:hexane (30:18:23:1; v/v/v/v) , ethylacetate:chlo-roform:methanol:acetic acid (11:8:7.5:1.5; v/v/v/v). ethylacetate:chloroform:1-propanol:25% ammonia solution (12:9:1:0.2; v/v/v/v), di0xan:acetonitrile:1-propanol:tetrahydrofuran (20:13:4:15; v/v/v/v) and dioxane:ethylacetate:acetonitrile:1-propanol (10:7:5.5:3 v/v/v/v) as the mobile phases for mixtures l, ll, lll, lV and V, respectively. Detection was carried out densitometrically using UV detector at 283, 266, 257, 226 and 362 for atenolol, chlorthalidone, enalapril maleate, hydrochlorothiazide and amiloride hydrochloride, respectively. Calibration curves were linear in the range 1–100 µg/ml⁻¹ with correlation coefficients not less than 0.9996. The percentage recoveries ranged from 98.3 ± 1.42 to 100.8 ± 0.79.