Swelling and Viscoelastic Characterisation of pH-Responsive Chitosan Hydrogels for Targeted Drug Delivery

Chitosan hydrogels have been investigated as potential vehicles for targeted drug delivery. The gels were permanently crosslinked with conventional crosslinking agent, glutaraldehyde and the naturally occurring non-toxic crosslinking agent genipin in both the monomer and polymerised states. The swelling behaviour of all the gels was highly pH dependent. The gels with the lowest crosslink density not only had an increased rate of diffusion but also an increased total release. It is shown that by altering the type and degree of crosslinking in a chitosan hydrogel it is possible to change the swelling and elastic characteristics of the material, which could be of potential interest as an environment responsive drug delivery matrix.