Modification and swelling kinetic study of kappa-carrageenan-based hydrogel for controlled release study

In this article, the physical stability of carrageenan hydrogels was improved for in vitro controlled drug delivery in different pH mediums. Physical property changes were studied using various characterization tests. The effect of modification on swelling behavior of hydrogels as well as swelling kinetics of hydrogels was also investigated. It was found that the addition of genipin to the hydrogels can increase the physical properties of carrageenan hydrogels. An optimum genipin concentration in which molecular structure of hydrogel can be in its most stable form is also determined. The study of swelling kinetics revealed that the modification has resulted in the relaxation of carageenan molecules and the swelling mechanism from a diffusion-controlled mechanism is changed to a polymer relaxation-controlled mechanism. Release study shows that by changing the genipin concentration in the hydrogel drug release can be controlled. (C) 2012 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.