Novel Ion Pair HPLC Methods for the Assessment of Sitagliptin and Pioglitazone in Tablets

Objective: Developing simple, rapid and accurate ion-pair reversed phase high performance liquid chromatographic methods for the determination of pioglitazone hydrochloride, and sitagliptin phosphate in pure and tablet forms. These methods would be practical additional choices in quality control laboratories. Methods: pioglitazone hydrochloride and sitagliptin phosphateanalysis were performed depending on (Method A), the chromatographic conditions comprised of a classical C18-type stationary phase (250×4.6 mm, 5µm), The mobile phase consisting of 10-2 sodium hexane sulfonic acid, in a mixture of 550ml of deionized water and 450ml of acetonitrile, and apparent pH of 2.5 was adjusted with phosphoric acid. (Method B) is an additional method for pioglitazone hydrochloride analysis, the mobile phase consisting of 10-3 M cetrimide, in a mixture of 400 ml of deionized water and 600ml of acetonitrile, leading to measured pH=10. The flow rate was 1ml/min, the detection wavelengths were at 269nm for pioglitazone HCl (Method A,B), and 267nm for sitagliptin phosphate, the temperature was ambient temperature for both Methods A and B. Results: Two methods were validated in accordance to ICH guidelines. The developed methods given accepted linearity (R2>0.999) in the concentration range of (0.01875-0.21)mg/ml for pioglitazone hydrochloride and (0.1-0.6) mg/ml for sitagliptin phosphate, accuracy with mean recovery values between 98-102%, precision with relative standard deviations of the calculated concentrations were less than 2%. Conclusion: The results showed that the two developed methods were effective in separating and determining of pioglitazone HCl, sitagliptin phosphate in their pharmaceutical forms and routine analysis in quality control laboratories simply.