A Polysaccharide-Based pH-Sensitive Hybrid Hydrogel as a Sustained Release Matrix for Antimicrobial Drugs

This work describes the development of a neutral, water-soluble, low-molecular-weight polysaccharide-dextrin-based hybrid hydrogelator (Dxt-PMAA) fabricated through in situ grafting and cross-linking. Five grades of Dxt-PMAA hydrogelators have been prepared via a potassium persulfate-initiated free radical polymerization (FRP) process using methacrylic acid as a monomer and N,N′-methylene bis(acrylamide) as a cross-linker. An optimized grade has been chosen through the quantification of the percentage of cross-linking. The grade with a higher cross-linking percentage has been used for inclusive characterization and antimicrobial delivery. The significance of inserting methacrylic acid as a stimuli-sensitive unit was observed from the substantial differences in swelling study results, where the optimized Dxt-PMAA showed a mean equilibrium swelling ratio of 0.5 at pH 1.2 and 4.2 at pH 7.4 buffers at 37 ± 0.5 °C. The higher value of elastic modulus compared to viscous modulus in the rheology study confirmed the elasticity and gel state of Dxt-PMAA at pH 1.2, 5.0, and 7.4. In vitro cytocompatibility of the Dxt-PMAA hydrogel was performed using the MCF7 cell line, which indicates more than 98% cell viability. Two antibiotics, namely, amoxicillin trihydrate and ornidazole, were used to prepare Dxt-PMAA hydrogel-based tablet formulations, demonstrating 81–87% of drug release after 24 h at physiological temperature. Therefore, the pH-sensitive and cytocompatible Dxt-PMAA hydrogel could serve as a sustained-release matrix for amoxicillin and ornidazole through the oral route.