Spectrophotometric Determination of Rosiglitazone in Pure Form and in Pharmaceutical Formulations

Two simple, rapid and sensitive spectrophotometric methods were developed for the determination of Rosiglitazone either in raw material or in Pharmaceutical formulations. Method A is based on the extraction of Rosiglitazone by Fe³⁺ in acidic medium, and the subsequent interaction of iron (III) with ferricyanide to form purssian blue with the product exhibiting an absorption maxium at 728 nm. Method B is based on the oxidation of Rosiglitazone by Fe³⁺ in presence of orthophosphoric acid was demonstrated at 522 nm with 2, 2'- bipyridyl. The analytical parameters and their effects on the reported systems are investigated. Beer's law was obeyed in the concentration range 5 - 50 μg ml^-1 and 2 - 20 μg ml^-1 with correlation coefficient 0.995 and 0.997 for Method A and B respectively. The molar absorptivity, sandell's sensitivity, detection and quantification limits were also calculated. The proposed methods have been applied successfully for the analysis of the studied drugs in pure and pharmaceutical formulations with percentage recoveries range from 99.30 to 100.08. The results were in good agreement with those obtained by the official methods.