Protein encapsulation and release from degradable sugar based hydrogels

Acid labile sugar based hydrogels have been synthesized using a commercially available acid sensitive cross-linker, 3,9-divinyl-2,4,8,10-tetraoxaspiro-[5,5]-undecane. The monomers used for polymerization are N-isopropylacrylamide (NIPAM) and D-gluconamidoethyl methacrylate (GAMA), which when polymerized in the presence of the acid labile cross-linker yield hydrogels that can swell and degrade under acidic conditions, making them ideal for drug delivery. The hydrogels are synthesized using either a photo-initiator, Irgacure-2959 or a conventional initiator, potassium persulfate. The hydrogels obtained by photopolymerization exhibit defined and unique microstructures, when analyzed by scanning electron microscopy (SEM). The swelling capacity and protein release from the hydrogels as a function of pH is studied. The protein release from the hydrogels is found to be dependent upon the degree of cross-linking and the pH of the environment. (C) 2009 Elsevier Ltd. All rights reserved.