Acrylic polymers for colonspecific drug delivery

Acrylic polymers are widely used in specific deliver)' of drugs to the human colon, primarily in the form of enteric coating formulations. Over the last decade new studies have been reported in which azo bondcontaining polymers were developed and tested in vivo. In contrast to enteric coating polymers, which function primarily by protecting their drug load in the proximal sections of the alimentary canal, azo polymers are designed to function by specific enzymaticdegradation in the large intestine. Saccharidecontainingpolymershavealsobeendevelopedformucoadhesion and enzymatic (glycosidic) degradation. In this study, two series of hydrogels comprising different ratios of methacrylic acid and the aerylosaceharide monomer, 1methacrylamido1 deoxycellobiitol, were synthesized. The mechanical strength of the hydro gels was engineered either by crosslinking the copolymer with ethylene glycol dimethacrylate or by using a third comonorner, hydroxyethyl methacrylate. The physical properties of the hydrogels were assessed by measuring their swelling characteristics and their mechanical strength. Also, the hydrogels were loaded with a model drug (indomethacin) and its release kinetics were measured to account for the differences in their swelling properties. These studies were performed to define anacrylosaccharidic polymer with optimal swelling properties in order to serve as colonspecific drug carriers which will release the least amount of drug possible in the upper part of the gastrointestinal tract and degrade specifically in the colon.