Effect of porosigen on the swelling behavior and drug release of porous N-isopropylacrylamide/poly(ethylene glycol) monomethylether acrylate copolymeric hydrogels

A series of porous thermoreversible hydrogels were prepared from N-isopropylacrylamide (90 mol %) and poly(ethylene glycol) methylether acrylate (10 mol %), which was derived from poly(ethylene glycol) monomethylether, N,N'-methylenebisacrylamide, and porosigen, or poly (ethylene glycol) (PEG) with different molecular weights (MWs). The influence of pore volume in the gel on the physical properties, swelling kinetics, and solute permeation from these porous gels was investigated. The results show that the surface areas, pore volumes, and equilibrium swelling ratios for the porous gets increased with increasing MW of PEG, but the shear moduli and effective crosslinking densities decreased with increasing MW of PEG. The results from the dynamic swelling kinetics show that the transport mechanism was non-Fickian. The diffusion coefficients of water penetrating into the gels increased with increasing pore volume of the gels. In addition, we also studied solute permeation through the porous gel controlled by temperature. (c) 2006 Wiley Periodicals, Inc.