Enzymatic cleavage of disaccharide side groups in insoluble synthetic polymers: A new method for specific delivery of drugs to the colon

A series of water-insoluble acrylic polymers containing disaccharide side groups were synthesized and evaluated in vitro. A cellobiose-derived monomer, 4-O-β-d-glucopyranosyl-1-methacrylamido-1-deoxy-d-glucitol, was prepared and copolymerized with methacrylic acid. Two different modes of polymerization were used to give two products, P-1 and P-2. A homopolymer, P-3, was also synthesized using the same method as P-2. The degradation of the disaccharide side groups in these polymers and the monomer was evaluated by incubation with β-glucosidase and measurement of the amount of glucose cleaved. It was found that the degradation rate increased in those polymers possessing lower contents of the disaccharide side groups (i.e. higher content of methacrylic acid). Scanning electron microscopy (SEM) observations of cross-sectioned slabs of P-1 visualized the degradation of the polymer. The enzymatic reaction caused a porous structure to be formed. The increased porosity may be used for the specific release of drugs into organs that contain large amounts of β-glucosidases, such as the human colon.