Semi-interpenetrating polymer network hydrogels with different compositions of chitosan (Cs), acrylic acid, and citraconic acid were synthesized via free-radical polymerization with ethylene glycol dimethacrylate as a crosslinker. The variations of the swelling percentages of the hydrogels with time, temperature, and pH were determined, and Cs-poly(acrylic acid) (PAA) hydrogels were found to be most swollen at pH 7.4 and 37 degrees C. Scanning electron micrographs of Cs-PAA and Cs-P(AA-co-CA)-1 (Cs-poly(acrylicacid-co-citraconir acid)(-1)) were taken to observe the morphological differences in the hydrogels. Although the less swollen hydrogel, Cs-P(AA-co-CA)-1, had a sponge-type structure, the most swollen hydrogel, Cs-PAA, displayed a uniform porous appearance. Fluconazole was entrapped in Cs-P(AA-co-CA)-1 and Cs-PAA hydrogels, and the release was investigated at pH 4.0 and 37 C. The kinetic release parameters of the hydrogels (the gel characteristic constant and the swelling exponent) were calculated, and non-Fickian diffusion was established for Cs-PAA, which released fluconazole much more slowly than the Cs-P(AA-co-CA)-1 hydrogel. A therapeutic range was reached at close to 1 h for both hydrogels. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 2613-2619, 2009