FORMULATION, DEVELOPMENT AND EVALUATION OF A DUALCOATED TABLET OF METFORMIN HYDROCHLORIDE WITH SITAGLIPTIN PHOSPHATE COMBINATION
Formulation, Development And Evaluation of Dual-Coated Tablet
Abstract
Introduction: Diabetes mellitus is a chronic metabolic disorder that often requires combination therapy for effective glycemic control. Conventional oral dosage forms frequently produce rapid drug release, fluctuating plasma drug concentrations, and require repeated dosing, which may reduce therapeutic efficacy and patient compliance. This study aimed to formulate, develop, and evaluate a dual-coated tablet containing a sustained-release core of Metformin Hydrochloride and an immediate-release outer coating of Sitagliptin Phosphate for biphasic drug delivery.
Materials and Methods: Metformin Hydrochloride core tablets were prepared by the wet granulation method using different formulations (F1–F7). The optimized core was coated with a hydroxypropyl methylcellulose (HPMC 5 cps) seal coat followed by an outer drug coating containing Sitagliptin Phosphate. The formulations were evaluated for flow properties, FTIR compatibility, physicochemical characteristics, drug content, disintegration, and in vitro dissolution.
Results: The optimized formulation (F7) demonstrated excellent flow properties with a Carr's Index of 9.09%, Hausner Ratio of 1.10, and Angle of Repose of 29.24°. FTIR analysis confirmed drug–excipient compatibility. The formulation exhibited acceptable physicochemical properties with 97.10% drug content and 95.93% assay. Dissolution studies showed rapid release of Sitagliptin Phosphate (95.00% within 15 minutes) followed by sustained release of Metformin Hydrochloride (88.83% at 540 minutes).
Discussion: The developed dual-coated tablet successfully achieved biphasic drug release and demonstrated satisfactory pharmaceutical performance. The formulation offers a promising approach for improving therapeutic efficacy, reducing dosing frequency, and enhancing patient compliance in type 2 diabetes mellitus.