Swelling of high acyl gellan gum hydrogel: characterization of network strengthening and slower release

This study examined the mechanism of swelling for high acyl (HA) gellan gum and the impacts on the hydrogel mechanical properties and the release of a model drug (glucose). Controlling the material properties and the release of entrapped drugs during use in aqueous environments, such as the stomach or bodily fluids, are crucial in designing functional applications. Swelling of HA gellan gum was controlled by varying the osmotic environment with salts and solvents, and effects on the gel network were characterized by uniaxial compression tests, DSC, and rheology. Low ionic strength solutions caused the greatest degree of swelling (up to 400 %) and corresponded to a more brittle gel with a greater modulus and greater network enthalpy. Swelling slowed the release of glucose by decreasing the diffusion flux. The osmotic environment was found to produce different functional properties, and it is crucial to consider these changes in the design of formulations.