Validated Liquid Chromatographic Method for Simultaneous Determination of Metformin, Pioglitazone, Sitagliptin, Repaglinide, Glibenclamide and Gliclazide - Application for Counterfeit Drug Analysis

Abstract

A rapid, precise and selective RP-LC method was developed for simultaneous determination of the widely used oral antidiabetic; metformin hydrochloride (MTF), with some commonly prescribed oral antidiabetics, namely; sitagliptin phosphate (SIT), pioglitazone hydrochloride (PGZ), gliclazide (GLZ), glibenclamide (GLB) and repaglinide (RPG). The chromatographic separation carried out using gradient elution mode with acetonitrile: 0.05M potassium dihydrogen phosphate (MKP) and 0.01M sodium octane sulphonate (SOS) (pH 3.55) at flow rate 0.85 ml/min on Kromasil 100-C18, (30 × 0.4 cm, 10 μm) at 40°C. UV detection was carried out at 220 nm. The method was validated according to ICH guidelines. Linearity, accuracy and precision were satisfactory over the concentration ranges (μg/ ml) of 0.05-205 for MTF, 0.05-100 for PGZ, GLB and SIT, 0.1-100 for RPG and 1-100 μg/ml for GLZ. The correlation coefficients were >0.99 for all analytes. Limits of quantification (LOQs) found were 0.002, 0.003, 0.009, 0.012, 0.007 and 0.024 μg/ml for MTF, SIT, PGZ, GLZ, GLB and RPG respectively. The developed method is specific and accurate for quality control and routine analysis of the cited drugs in their pharmaceutical preparations. It is recommended for application in the quality control of the herbal antidiabetic products to detect possible counterfeits.