Abstract
Chitosan membranes were prepared by a solvent evaporation technique, followed by crosslinking with glutaraldehyde and coating with BSA. The effects of crosslinking and BSA coating on the pore structure of such prepared hydrogel chitosan membranes were determined. The diffusion rates of 12 non‐electrolytes ranging in molecular radius between 2.5 and 14 Å through the membranes were measured, and the results were interpreted in terms of the capillary pore model and free volume model of solute diffusional transport through hydrogel membranes. Glutaraldehyde crosslinking was found to reduce the membrane water content and consequently the membrane pore size and surface porosity, whereas further BSA coating brought about the opposite effect. The latter effect lessened with an increase in glutaraldehyde pretreatment of the membranes. The optimal chitosan membrane preparation, compromising between the solute flux and membrane stability and durability was obtained when the membranes were crosslinked with glutaraldehyde at concentrations between 0.01 and 0.1% (w/w). The knowledge of transport properties and of physical strength of the membranes is of importance for the development of chitosan‐based controlled release systems.
© 2001 Society of Chemical Industry