Validated spectrophotometric methods for determination of some oral hypoglycemic used drugsAuthor(s): Omar Abdel-Aziz, Maha Farouk, Osama Abd El-Sattar, Maya Shaaban
Four accurate, precise, rapid, reproducible and simple spectrophotometric methodswere validated for determination of repaglinide (RPG), pioglitazone hydrochloride (PGL) and rosiglitazone maleate (RGL). The first two methods were based on the formation of Âcharge-transfer purple-colored complex, between chloranilic acid (CLA) and (RPGand RGL)withmolar absorptivity 1.23ï´103 and 8.67ï´102 L.mol-1.cm-1 and sandellÂs sensitivity 0.367 and 0.412 ïg.cm-2, respectivelyÂ and Âion-pair yellow-colored complex between bromophenol blue (BPB) and (RPG, PGLand RGL)withmolar absorptivity 8.86ï´103, 6.95ï´103 and 7.06ï´103 L.mol-1.cm-1, respectively and sandellÂs sensitivity 0.051 ïg.cm-2 for all ion-pair complexesÂ. The influence of different parameters on the color formation was studied to determine the optimum conditions for the visible spectrophotometric methods. The other spectrophotometric methods were adopted for determination of the studied drugs in presence of their acid, alkaline and oxidative-degradates by computing derivative and pH-induced difference spectrophotometry, as stability-indicating methods. All the proposed methods were validated according to the International Conference on Harmonization (ICH) guidelines and successfully applied for determination of the studied drugs in pure form and in pharmaceutical preparations with good extraction recoveries ranges between 98.71-101.35%, 98.24-101.26%and 99.88-101.43%forRPG,PGLand RGL, respectively. Results of relative standard deviation did not exceed 1.636 %, indicating that the proposed methods having good repeatability and reproducibility. All the obtained results were statistically compared to the officialmethod used for RPG analysis and the manufacturer methods used for PGL and RGL analysis, respectively, where there is No significant differences were found.