A series of pH-sensitive semi-IPN hydrogels, composed of varying amounts of monomer acrylic acid(AAc), crosslinker N,N methylene bisacrylamide, polymer cellulose acetate (CA) were synthesized via photoinitiated polymerization in dimethyl formamide (DMF) medium. The CA/P (AAc) hydrogels were characterized by FTIR, and TG analysis. The equilibrium water uptake data was used to determine various network parameters. For all the samples synthesized, the swelling exponent n, initial diffusion coefficient D and average diffusion coefficient D-ave were found to be in the range of 0.51-0.72, 3.16 to 7.14 x 10(-6) cm(2) min(-1) and 94.16-120.56 cm(2) min(-1), respectively. The hydrogel demonstrated fair pH-dependent swelling behavior, with nearly 20% swelling in the medium of pH 1.0 and 615% in the medium of pH 7.4 at 37 degrees C, respectively. The gel showed excellent swelling-deswelling cycles which were interpreted quantitatively by first order kinetic swelling and deswelling models. Finally, the preliminary insulin release study, carried out in the media of varying pH, observed almost 16% release of entrapped drug in the simulating gastric fluid (SGF) of pH 1.0 in first 2 h and nearly 51% in next 6 h in simulating intestinal fluid(SIF) of pH 7.4 at 37 degrees C. POLYM. ENG. SCI., 53:2129-2140, 2013. (c) 2013 Society of Plastics Engineers