MECHANICAL, WATER-UPTAKE AND PERMEABILITY PROPERTIES OF CROSS-LINKED CHITOSAN GLUTAMATE AND ALGINATE FILMS

Films of chitosan glutamate and sodium alginate were obtained by a cas ting/solvent evaporation method, and crosslinked with their counterion s, tripolyphosphate (TPP) and calcium chloride (CaCl2), respectively. The crosslinked films were characterized with respect to the mechanica l properties in the dry and wet state, water vapor transmission, water uptake in different media and permeability to model drugs, The crossl inked films were water-insoluble but permeable to water vapor. The wat er vapor transmission rate of chitosan films linearly decreased with i ncreasing concentration of crosslinking agent; An optimum crosslinking agent concentration was found with alginate. Wet alginate films had l ower puncture strength and higher elongation values when compared with dry films the mechanical properties were a function of the CaCl2 conc entration. In acidic medium, the swelling of the alginate films was in dependent of the CaCl2 concentration. The permeability to chlorphenira mine maleate and guaifenesin varied with pH and CaCl2 concentration. C hitosan films showed swelling and permeability characteristics, which were dependent on pH and on the concentration of the crosslinking agen t. Diffusion of chlorpheniramine maleate through chitosan films increa sed with increasing concentration of glycerin.