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Fabrication and evaluation of gelatin-PVA-co-poly(2-acrylamido-2-methylpropane sulfonic acid)-based hydrogels for extended-release of sitagliptin and metformin by employing response surface methodology

Maria Tabassum, Fahad Pervaiz, and Hina Shoukat

Department of Pharmaceutics, Faculty of Pharmacy, The Islamia University of Bahawalpur, Bahawalpur, Pakistan



Received: 13 January 2022  Accepted: 2 March 2022


This study aimed to fabricate Gelatin-PVA-co-poly(2-acrylamido-2-methylpropane sulfonic acid)-based hydrogels by applying a free-radical polymerization process to achieve extended-release of sitagliptin and metformin. Gelatin-PVA-co-poly(AMPS)-based hydrogels were developed applying Box–Behnken design of response surface methodology. Gelatin and PVA have been chemically cross-linked with monomer (AMPS) with the help of EGDMA (cross-linker) in the presence of sodium hydrogen sulfate and ammonium peroxo-disulfate as initiators. Sitagliptin and metformin were loaded as the model drug. Sol–gel fraction, FTIR, TGA, DSC, and XRD were performed for the fabricated hydrogel. Properties such as swelling studies as well as in vitro drug release studies were carried out in buffers of pH 1.2 and 6.8. The independent variables such as different concentrations of polymers, cross-linking agent, and monomer affect the dependent variables as swelling and drug release of sitagliptin and metformin from gelatin-PVA-co-Poly(AMPS)-based hydrogels. Successful cross-linking of constituents and formulation of stable hydrogels was confirmed by FTIR and XRD. While the DSC and TGA confirmed the thermodynamic stability of hydrogels. The fabricated hydrogel showed a pH-independent swelling index and drug release was swelling controlled. Gel content increased by increasing polymer concentration. Drug release from formulated hydrogels was compared with drug release from a marketed product which showed extended release of drugs from formulated hydrogel as compared with a marketed product. The fabricated hydrogel could be a potential carrier for extended-release of sitagliptin and metformin for a prolonged course of treatment which can prevent multiple dosing and side effects thus enhancing patient compliance.

Keywords: Hydrogel; Gelatin; AMPS; Sitagliptin; Metformin; Extended-release

Full paper is available at

DOI: 10.1007/s11696-022-02155-7


Chemical Papers 76 (7) 4081–4097 (2022)

Tuesday, August 09, 2022

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