Fabrication and Evaluation of Colon Targeted Uricase Containing Microbeads for Treatment of Gout

Gout is a painful disease of joints generated because of the deposition of urate crystals within the joints. Uricase is an enzyme capable of degrading less water soluble urate crystals into a compound allantoin, which is more water soluble and hence is easily excreted. Uricase being proteinaceous is degraded by the protein digestive enzymes of gastro intestinal tract (GIT) when administered orally. Colonic part of GIT lacks protein digestive enzymes and thus provides suitable conditions for the absorption of uricase. Colon consists of several microbial flora which secrete enzymes capable of degradation of alginates and pectin which are not digested by upper GI tract. Eudragit S-100 (pH sensitive polymer) coated alginate - pectinate microbeads were found to be effective for delivery of uricase directly to the colonic site. Sodium taurocholate, a bile salt, was found to be suitable for the effective absorption of uricase from colonic site into the systemic circulation.