Determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations using derivative spectrophotometry and chromatographic-densitometric method

摘要

Two methods, spectrophotometric and chromatographic-densitometric ones, were developed for determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations. Spectrophotometric method involved derivative spectrophotometry and zero order spectrophotometry. The measurements were carried out at λ = 224.0 nm for quinapril, λ = 261.0 nm for hydrochlorothiazide and λ = 270.0 nm for losartan when the derivative spectrophotometry was applied and λ = 317.0 nm when zero order spectrophotometry was applied for the determination of hydrochlorothiazide. In chromatographic-densitometric studies high performance thin layer chromatography (HPTLC) plates were used as stationary phase and a mixture of solvents n-butanol : acetic acid : water (15 : 5 : 1, v/v/v) as mobile phase. Under the established conditions good resolution of examined constituents was obtained. Retardation factor for quinapril hydrochloride was Rf ～ 0.70, for losartan potassium Rf ～ 0.85 and for hydrochlorothiazide Rf ～ 0.78. The developed methods are characterized by high sensitivity and accuracy. For quantitative analysis, densitometric measurements were carried out at λ = 218.0 nm for quinapril, λ = 275.0 nm for hydrochlorothiazide and λ = 232.0 nm for losartan.