An investigation into the characteristics of chitosan/Kollicoat SR30D free films for colonic drug delivery

The purpose of the study was to establish the physico-mechanical, digestibility, permeability and swelling properties of chitosan/Kollicoat SR30D films as potential coatings for colonic drug delivery. Free films containing different ratios of chitosan to Kollicoat SR30D were prepared by casting/solvent evaporation method. The resultant mixed films were characterized in terms of puncture strength and elongation (%), glass transition temperature, swellability, polymer miscibility, permeability, and digestibility under different media. The mixed films possessed good mechanical properties, which could be used as film-coating materials for drug delivery. The extent of digestion was directly proportional to the amount of chitosan present within the film. No apparent miscibility was detected between the chitosan and Kollicoat SR30D, regardless of the film composition. The films were found to be susceptible to digestion by bacterial or beta-glucosidase enzymes in simulated colonic fluid (SCF). The SCF with rat cecal bacterial enzymes had a more profound hydrolytic activity than that with beta-glucosidase enzyme for the digestion of chitosan within the mixed films. Overall, the results indicated that such chitosan/Kollicoat SR30D films had potential as a coating system for drug delivery to the colon. (C) 2008 Elsevier B.V. All rights reserved.