For to be used in controlled releasing of piperacillin-tazobactam, a series of semi and full IPN type hydrogels composed of acrylic acid (AA), acrylamide (AAm) and Chitosan (CS) were prepared via free-radical polymerization. Ethylene glycol dimethacrylate (EGDMA) was used for crosslinking of PAAm and PAA chains to form semi-IPN hydrogels. However, the full-IPN type hydrogels were prepared by using glutaraldehyde (GA) and EGDMA as cocrosslinkers. Characteristics of the hydrogels were investigated by swelling experiments and SEM and FTIR analysis. Generally, full-IPN type hydrogels swell much more than the semi-IPN types. By comparing the full-IPN type hydrogels in between, it is found that the increasing amount of GA causes the decreasing in S% values from 4860 to 4300%. Releasing of piperacillin-tazobactam from selected three hydrogels were investigated in phosphate buffer solution at pH = 7.4, 37 degrees C. The kinetic release parameters, n and k were calculated and non-Fickian type diffusion was established for these hydrogels. The behaviors of the piperacillin-tazobactam loaded hydrogels in Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) culture suspensions were also studied and the statistically significant differences for the microorganism growth values were determined. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 441-450, 2011