Two methods for determination of a binary mixture of Amlodipine besylate and Atorvastatin calcium using dual-wavelength spectrophotometry

Abstract

Two simple, clear, and accurate spectrophotometric methods based on two-wavelength selections, were developed for the simultaneous determination of Amlodipine besylate (AML) and Atorvastatin calcium (ATO) in tablet dosage forms. The ratio difference method uses amplitudes between 238 and 288 nm. The measured amplitudes for the parameters: linear range 4-40 µg/ ml; precision for AML is 100.22±0.7856, repeatability is 0.9122, precision for ATO is 100.12±0.6439, repeatability is 0.8968. The absorption ratio method using two wavelengths is 221 and 238 nm. The absorption rate method for parameters: linear range 4-40 µg/ml; precision for AML is 100.6±0.9562, repeatability is 1.0124, precision for ATO is 100.86±0.8596, repeatability is 1.1045. Both quantitative methods showed that AML and ATO could be quantified in their mixtures without any extraction at all. The absorption ratio method exhibited quick, simple applicability to both laboratory and commercial drug mixtures.