Quantitative Determination of Amlodipine and Valsartan in Pharmaceutical Dosage Form

Abstract

Two simple spectrophotometric methods had been developed for simultaneous determination of amlodipine (AMD) and valsartan (VAL) in their tablet dosage form. These methods include absorption correction method and dual wavelength method. The first method was based on the measurement of absorbance at 360 nm for AMD and 257.1 nm for VAL, while the second depended on measuring the absorbance difference (A) in zero order spectra between (226.5-250 nm) for determination of VAL while AMD was determined directly by measuring absorbance at 360 nm. Both methods were validated according to International Council for Harmonisation (ICH) guidelines. The linearity range was found to be 8-25 μg/mL for determination of AMD and 6-35 μg/mL for determination of VAL. The methods were successfully applied for the simultaneous determination of AMD and VAL in the commercially available Exforge ® tablets. The average values of percent recovery  standard deviation was found to be consistent with the label claim of the dosage form. The results were also compared to a reported method using t-test and F-test at confidence level of 95%, no significant differences were observed. The presented methods permit simple, rapid, and direct determination of AMD and VAL in commercially available combined dosage form using zero-order UV spectra without previous separations and were suitable for routine analysis.