Synthesis, Characterization, Swelling Properties, and Biological Applications of pH-Sensitive Polymeric Hydrogels based on Citric Acid, Triethanolamine, and 2-Furoic Acid

Abstract

Introduction: The objective of this endeavor is to create novel hydrogels utilizing three monomers namely Citric acid (CA), Triethanolamine (TEA), and 2-Furoic acid (FA). Citric acid (CA), a crosslinking agent that can overcome the toxicity and connects with other crosslinking substances. FTIR analysis shows that the synthesis of hydrogels based on triethanolamine and citric acid leads to the esterification reaction of carboxylic acid of citric acid with hydroxyl group of triethanolamine to the formation of pre-polyester. The pre-polyester combines with 2-Furoic acid results in hydrogel formation.H¹-NMR and C¹³NMR spectroscopy of the hydrogels have been examined which conforms the ester bond formation. Investigations on swelling and swelling equilibrium were carried out at various pH ranging from 2.0 to 11.0. The swelling e quilibrium was improved by increased CA composition in hydrogels for pH levels of 2.0, 4.0, 7.0, 9.0, and 11.0 than acidic media. The percentage of swelling is larger in neutral (pH 7.0) and alkaline (pH 9.0) medium. With increasing anionic charge, the ionic strength of the medium and the degree of crosslinking are increased and the swelling capacity consequently decreases in pH 11. The hydrogel has shown strong antibacterial activity against Escherichia coli (gram negative) and moderate inhibition in Staphylococcus aureus and Bacillus subtilis(gram positive) bacteria. The antifungal studies were carried out with C.albicans and A.nigerresults into inferior antifungal action with respect to the standard clotrimazole 20 mg/well. Further, cytotoxic studies have also been carried out. The results reveal moderate activity with respect to Ascorbic acid. In overall aspects, the hydrogels of present investigation may be recommended for biomedical applications.