Release of protein from highly cross-linked hydrogels of poly(ethylene glycol) diacrylate fabricated by UV polymerization

Highly crosslinked hydrogel spheres were fabricated using UV photopolymeriz ation of poly(ethylene glycol) diacrylate (PEG-DA) and pentaerythritol tria crylate (PETA) with 2,2'-dimethoxy-2-phenyl-acetophenone (DMPA) as the phot oinitiator. Spheres were fabricated both with and without one of three como nomers: acrylic acid, acrylamide or allylamine. Photopolymerization rates a nd polymer morphology were determined using attenuated total reflectance/Fo urier transform infrared spectroscopy and electron microscopy. respectively . These gels were further characterized for volume change, equilibrium wate r content, diffusivity of the expanding gel, molecular weight between cross links and polymer mesh size. Hydrogels with comonomers generally demonstrat ed an increase in equilibrium water content, average molecular weight betwe en crosslinks and mesh size. Bovine serum albumin was incorporated into the hydrogel to simulate delivery of a model protein drug. The protein diffusi on coefficients, based a Fickian release model, were calculated to be betwe en 10(-10) and 10(-12) cm(2)/s with slight variance due to PETA concentrati on and the type of comonomer used. (C) 2001 Elsevier Science Ltd. All right s reserved.