A novel pH-sensitive hydrogel system composed of itaconic acid (IA) and N-[3-(dimethylamino) propyl] methacrylamide was designed. This system was prepared by aqueous copolymerization with N,N-methylene bisacrylamide as a chemical crosslinker. The chemical structure of the hydrogels was characterized by Fourier transform infrared (FTIR) spectroscopy. The microstructure and morphology of the hydrogels were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The SEM study of hydrogels on higher magnification revealed a highly porous morphology with uniformly arranged pores ranging from 40 to 200 mu m in size. XRD analysis revealed the amorphous nature of the hydrogels, and it was found that an increase in the IA content in the monomer feed greatly reduced the crystallinity of the hydrogels. Swelling experiments were carried out in buffer solutions at different pH values (1.2-10) at 37 degrees C +/- 1 degrees C to investigate their pH-dependent swelling behavior and dimensional stability. An increase in the acid part (IA) increased the swelling ratio of the hydrogels. Temperature-sensitive swelling of the hydrogels was investigated at 20-70 degrees C in simulated intestinal fluid. The hydrogels swelled at higher temperatures and shrank at lower temperatures. 5-Aminosalicylic acid (5-ASA) was selected as a model drug, and release experiments were carried out under simulated intestinal and gastric conditions. 5-ASA release from the poly N-[ 3-(dimethylamino) propyl] methacrylamide-co-itaconic acid-80 (PDMAPMAIA-80) hydrogel was found to follow non-Fickian diffusion mechanism under gastric conditions, and a super case II transport mechanism was found under intestinal conditions. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 3199-3206, 2011