Gelatin and rice starch-based phase-separated hydrogel formulations for controlled drug delivery applications

Abstract The present research work was intended to prepare phase-separated physical hydrogel formulations of gelatin (protein) and rice starch (RS) (polysaccharide). The prepared hydrogel formulations were thoroughly characterized by various studies, such as microscopy, Fourier-transform infrared (FTIR) spectroscopy, thermal analysis, impedance spectroscopy, mechanical studies, and drug release studies. The microstructure of the hydrogel formulations demonstrated the presence of RS inclusions within the homogenous matrices of the gelatin phase. Meanwhile, the size of these aggregated structures was dictated by the RS content. FTIR analysis revealed that the extent of intermolecular hydrogen bonding within the hydrogel formulations was varied as the composition was altered. The incorporation of RS within the gelatin matrices significantly reduced the elastic component within the hydrogel formulations. Additionally, RS suspension containing hydrogels showed higher enthalpy values due to the evaporation of water molecules compared to gelatin hydrogel. Furthermore, the incorporation of RS increased the resistive component of the hydrogel formulations. In vitro drug release study demonstrated Fickian diffusion-mediated drug (ciprofloxacin HCl) release molecules from the hydrogel matrices. Drug-loaded hydrogels showed excellent antimicrobial effect against Escherichia coli.