Chitin membrane for wound dressing application--preparation, characterisation and toxicological evaluation.

Chitin, a unique biopolymer based on the N-acetyl-glucosamine monomer is envisioned to promote rapid dermal regeneration and accelerate wound healing. It has many useful and advantageous biological properties for its application as a wound dressing. Chitin membranes were prepared using lithium chloride/dimethylacetamide solvent system and evaluated for use as a wound dressing. Swelling behaviour, moisture vapour transmission rate, microbial impermeability and antimicrobial efficacy of the dressings was evaluated. The chitin dressing provided an effective barrier to microbial penetration and exerted a broad bacteriostatic action against Gram-positive and Gram-negative organisms. Gamma irradiation at 25 kGy was found suitable for sterilisation of the dressings. The thermal decomposition of unirradiated and irradiated chitin membranes was investigated. No significant change in the thermal behaviour because of irradiation at 25 kGy was observed. In vitro biodegradation of unirradiated and irradiated chitin membranes showed the susceptibility of the chitin dressing to lysozyme. Irritant effect of the chitin membrane dressings on skin was tested. Subcutaneous and scarification test in guinea pigs showed no signs of inflammation. This was further supported by the Finkelstein's test performed in rabbits. The chitin membranes were found to have optimal performance characteristics of a wound dressing and showed no toxicity or possible adverse reactions. The study shows the chitin dressings as useful adjunct in wound care.