pH-Responsive Studies of Bacterial Cellulose/Chitosan Hydrogels Crosslinked with Genipin: Swelling and Drug Release Behaviour

Semi interpenetrating hydrogels (semi-IPN) of bacterial cellulose (BC) and chitosan (Ch) crosslinked with genipin were prepared and characterised using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Infrared spectra showed amide I and II absorption peaks at 1632 and 1554 cm(-1) and C-N stretching absorptions at 1250 and 1020 cm(-1), respectively, for crosslinked hydrogels. The fibrous structure of BC and the porosity in the hydrogels were revealed by SEM. Swelling of hydrogels was sensitive to pH, and maximum at pH 1.0. Swelling of non-crosslinked samples decreased as the pH increased. However, with crosslinked hydrogels, swelling increased as chitosan ratio increased at low pH, as well as with increase in BC ratio at high pH. Free, bound and intermediate water types in hydrogels were revealed by DSC. The release kinetics of Quetiapine fumarate (QF), an antipsychotic drug used for the treatment of Schizophrenia was studied using UV spectrometry, followed predominantly, the Higuchi model at all pH for crosslinked hydrogels. The transport mechanism of hydrogels was a combination of non-Fickian and Super Case II. Crosslinked hydrogels showed controlled drug release behaviour. These hydrogel systems possess potential application in pharmaceutical field as all chemicals used in the development of the hydrogels are non-toxic, with BC-Ch 60:40 showing most promising potential.