Journal of the Medical Association of Thailand Vol 90, No 4:APRIL 2007 0125-2208 90 4 2007 Jan Evaluation of Dermal Irritancy Potential of Carboxymethyl-Chitosan Hydrogel and Poly-(Acrylic Acid) Chitin Hydrogel 724 EN Wilai Rattanatayarom Somkiat Wattanasirichaigoon Original Article The wound dressing synthesized from carboxymethylchitosan hydrogel (CM) and chitin-(polyacrylic acid) hydrogel (PAA) were examined for their dermal irritation potential response using the Draize test. Eighteen male Sprague-Dawley rats were divided into three groups (6 rats/each). Rats in group 1 were designed as control, group 2 were treated with CM, and group 3 were treated with PAA. The test materials diameter 1x1 cm were topically applied on the skin in group 2 and 3. Two skin sites (1x1 cm in size) were located at the back. One site was intact and the other was abraded in such a way the stratum corneum had no bleeding.Result: After 24 and 72 hours of wrappings, the materials were removed and the test sites were evaluated in terms of erythema and edema using adopted Draize scoring system. At the end of the experiment, all rats were anesthesized with intravenous thiopental sodium. Blood samples from descending aorta were collected for liver and kidney function test and all organs were weighed. The results of this experiment showed 1) no irritation of both materials in this animal model; 2) no material-related induced liver and kidney dysfunction and 3) organ weights had no significant differen Both CM and PAA should be considered safe to use in the purpose of wound dressing in further clinical trials. Carboxymethylchitosan hydrogel Chitin-(polyacrylic acid) hydrogel Draize test