Fabrication and Evaluation of 2-Hydroxyethyl Methacrylate-co-Acrylic Acid Hydrogels for Sustained Nicorandil Delivery

Purpose: To fabricate and evaluate oral 2-hydroxyethyl methacrylate-co-acrylic acid hydrogels as a drug delivery system for sustained release of nicorandil.
Methods: HEMA-co-AA hydrogels using different monomer concentrations were prepared by free radical polymerization. N, N-methylene bis acrylamide (MBA) was used as crosslinker and potassium persulphate (KPS) as initiator. Nicorandil (20 mg) loaded hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis and differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) . Swelling ratio, equilibrium swelling (ES), gel content (gc), porosity measurement (P) and in vitro drug release of the delivery system were evaluated.
Results: Swelling ratio and ES decreased as AA concentration (%) was reduced from 3.173 to 2.93 (pH 1.2) and 16.42 to 15.01 (pH 7.4) and 68.49 to 65.90 (pH 1.2) and 93.91 to 93.34 (pH 7.4), respectively, while HEMA and MBA showed opposite effects. Gel content (%) and porosity (%) ranged from 83.76 to 88.0, respectively from F1 to F9. With increase monomer content (AA), drug release increased from 85.99 to 89.38 %. However, when the concentrations of HEMA and MBA were raised, drug release decreased.
Conclusion: HEMA-co-AA hydrogels are potential pH-sensitive and sustained-release system for nicorandil.

Keywords
Hydrogel; 2-Hydroxyethyl methacrylate-co-acrylic acid; Sustained drug release; Monomer; Nicorandil; Swelling ratio; Porosity