Synthesis of glutamic acid/polyvinyl alcohol based hydrogels for controlled drug release: In-vitro characterization and in-vivo evaluation

The aim of the current study was to prepare glutamic acid/polyvinyl alcohol based hydrogels by the free radical polymerization technique. The FTIR analysis of glutamic acid, polyvinyl alcohol, acrylic acid, and ketorolac tromethamine indicated the development and loading of the drug by the prepared hydrogels. DSC and TGA revealed the increase in the thermal stability of glutamic acid and polyvinyl alcohol after crosslinking and polymerization process, thus revealed high thermal stability for the fabricated hydrogel as compared to hydrogel contents. XRD depicted a reduction in the crystallinity of the reagents, which indicated the strong crosslinking and formation of a new polymeric network of hydrogel. SEM indicated a hard and dense surface of the prepared hydrogel, which may be correlated with the strong polymerization among hydrogel contents. Similarly, the ef-fects of cross-linked polymers and monomer on polymer volume fraction, dynamic swelling and in-vitro drug release studies were investigated in three different pH values i.e., pH 1.2, 4.6, and 7.4, respectively. High swelling and drug release were observed as the pH of the medium was enhanced from 1.2 to 4.6 and 7.4, thus, revealed a pH-responsive nature of the prepared hydrogels. Moreover, percent porosity and drug loading were performed for fabricated hydrogels. Increase in percent porosity and drug loading was seen with the increasing composition of glutamic acid and acrylic acid while a decrease was perceived with the increase in the compo-sition of polyvinyl alcohol. Results of sol-gel analysis revealed an increase in the cross-linking degree of the hydrogels with the increasing composition of glutamic acid, polyvinyl alcohol, and acrylic acid, while a decrease in un-crosslinking was observed, respectively. The degradation rate of hydrogel was decreased as the compo-sitions of glutamic acid, polyvinyl alcohol, and acrylic acid was increased, which indicated a compatible network formation of hydrogel with the incorporation of high hydrogel contents. Similarly, in-vivo study was performed on rabbits and the results of pharmacokinetic parameters indicated a controlled release of the drug from the developed hydrogels for a long period of time. HET-CAM test revealed no toxic effect of the polymeric hydrogel on the chorioallantoic membrane of the fertilized chicken eggs. Therefore, regarding the results of all studies, we can conclude that the prepared hydrogels could be used for the controlled drug delivery system.