Mechanical, water uptake and permeability properties of crosslinked chitosan glutamate and alginate films

Abstract Films of chitosan glutamate and sodium alginate were obtained by a casting/solvent evaporation method, and crosslinked with their counterions, tripolyphosphate (TPP) and calcium chloride (CaCl 2 ), respectively. The crosslinked films were characterized with respect to the mechanical properties in the dry and wet state, water vapor transmission, water uptake in different media and permeability to model drugs. The crosslinked films were water-insoluble but permeable to water vapor. The water vapor transmission rate of chitosan films linearly decreased with increasing concentration of crosslinking agent. An optimum crosslinking agent concentration was found with alginate. Wet alginate films had lower puncture strength and higher elongation values when compared with dry films the mechanical properties were a function of the CaCl 2 concentration. In acidic medium, the swelling of the alginate films was independent of the CaCl 2 concentration. The permeability to chlorpheniramine maleate and guaifenesin varied with pH and CaCl 2 concentration. Chitosan films showed swelling and permeability characteristics, which were dependent on pH and on the concentration of the crosslinking agent. Diffusion of chlorpheniramine maleate through chitosan films increased with increasing concentration of glycerin.