A new class of polymerizable dextrans with hydrolyzable groups: hydroxyethyl methacrylated dextran with and without oligolactate spacer

In this paper a synthetic procedure is described towards a new class of methacrylated dextrans which are sensitive to hydrolysis. These methacrylated dextrans, which can be used for the development of biodegradable hydrogels, were obtained by grafting L-lactide onto 2-hydroxyethyl methacrylate (HEMA), followed by activation of the terminal hydroxyl group with N,N'-carbonyldiimidazole (CDI), yielding HEMA-lactateCI. Coupling of this compound to dextran in dimethyl sulfoxide in the presence of dimethylaminopyridine resulted in dexlactateHEMA. In the same way, dex-HEMA was obtained by coupling of CDI-activated HEMA to dextran. The degree of substitution, as determined by H-1-NMR, could be controlled by Varying the molar ratio of HEMA-CI or HEMA-lactateCI to dextran. The incorporation efficiency was 60-85%. The dextran derivatives were obtained in high yield (85-90%) and characterized by NMR, FTIR and GPC. (C) 1997 Elsevier Science Ltd.