MACROPOROUS POLY(SUCROSE ACRYLATE) HYDROGEL FOR CONTROLLED-RELEASE OFMACROMOLECULES

We have studied the controlled release of proteins from poly(sucrose a crylate) hydrogels. The hydrogels were prepared by a two-step procedur e in which sucrose was first acylated to sucrose-1'-acrylate followed by free radical polymerization. By adjusting the cross-link ratio and initial monomer concentration, the swelling ratio of the hydrogel was varied from five to 28. The mechanical strength of these hydrogels was comparable to that of other hydrogels with approximately the same swe lling ratio. Scanning electron micrographs and mesh size calculations indicate that the hydrogel is macroporous, suggesting it may be suitab le for a variety of biomedical applications. The release kinetics of P -lactoglobulin, bovine serum albumin and gamma-globulin were studied a s a function of initial monomer concentrations for the sucrose-based h ydrogel. All of the release profiles were characterized by an initial burst of protein in the first 25 h followed by a long period of sustai ned release (> 500 h). The magnitude of the initial burst was reduced by increasing the initial monomer concentration and by increasing the molecular weight of the protein. A quantitative model based on the het erogeneous nature of the hydrogel was developed to explain the observe d release kinetics. (C) 1996 Elsevier Science Limited