Simultaneous Determination of Losartan Potassium and Hydrochlorothiazide in Pure Form and in Tablets Using Octadecyl-Modified Aleppo Bentonite in TLC

Abstract

A new octadecyl-modified Aleppo bentonite (B_AC₁₈) in TLC was developed to determine losartan potassium and hydrochlorothiazide in pure form and tablets with mobile phase ammonium phosphate buffer (10 mmol L^-1; pH 3.2 with orthophosphoric acid) and acetonitrile (60:40, v/v), at wavelength l = 260 nm. The particles of Aleppo bentonite with diameter less than 45 μm were treated by concentrated HCl (B_A), after that grafted firstly by dimethyldichlorosilane, then secondly by Grignard reagent (octadecylmagensium bromide). The surface properties of octadecyl-modified bentonite were studied by nitrogen adsorption at 77 K, IR and NIR techniques. The retardation factors (R_f) of losartan potassium and hydrochlorothiazide were 0.266 and 0.757, respectively. Linearity for determination of losartan potassium and hydrochlorothiazide was in the range 1.00-10.0 μg/spot. The minimum determined concentration was 1.0 μg/spot for losartan potassium and hydrochlorothiazide with per cent relative standard deviation (RSD %) does not exceed 3.08 and 1.74 %, respectively. The limits of quantification (LOQ) were 0.85 and 0.72 μg/spot and the limits of detection (LOD) were 0.28 and 0.24 μg/spot for determination of losartan potassium and hydrochlorothiazide, respectively.