Kinetic study of Chondroitin Sulphate release from Chondroitin Sulphate/Chitosan complex hydrogel

Hydrogels based on complexes of Chitosan/Chondroitin Sulphate (CT/CS) can be formed just by mixing and have been applied as devices for CS releasing. In the CT/CS complex investigated in this work, the release of CS occurs mainly at pHs higher than 6.5, the value of pKa(CT), and the maximum fraction of CS released is close to 0.5. In this work, the release of CS was treated as a diffusional transport process and as a partition phenomenon in which a partitioning of solutes between the solvent phase and the hydrogel phase occurs. Mathematical models for predicting the in vitro CS release profile from CT/CS polymer network were used. The hydrogel showed to be pH-responsive and values of half-time for CS releasing are compatibles for the application of CT/CS hydrogels in pharmacological field as devices for CS controlled release. (C) 2010 Elsevier B.V. All rights reserved.