pH-Sensitive Swelling Behavior and Drug Release Kinetics of Chitosan-Modified Cs/HEMA Hydrogels

This study investigates the pH-sensitive swelling behavior and drug release kinetics of Chitosan-modified Cs/HEMA hydrogels. The influence of cross-linking agents, hydrophilicity, and crosslinking density on the swelling behavior and stability of the hydrogel membranes is examined. The Donnan swelling equilibrium is employed to explain the expansion of the hydrogels, which is controlled by the osmotic pressure gradient between the interior and exterior of the hydrogel. The hydrogels exhibit pH responsiveness, with maximum swelling at low pH levels and minimized swelling at high pH levels. Additionally, temperature is found to affect the swelling behavior, with higher temperatures resulting in increased swelling ratios. The release rate of the drug (5-ASA) is observed to be influenced by both pH and temperature, with higher release rates at pH 8 and elevated temperatures. Moreover, the impact of Chitosan concentration on drug release kinetics is investigated, revealing a significant effect. These findings contribute to the understanding of the behavior of Chitosan-modified Cs/HEMA hydrogels and provide valuable insights for the development of pH-responsive and temperature-responsive drug delivery systems.