Methacrylic acid grafted inulin and carboxymethyl cellulose as additives in the development of pH sensitive hydrogel matrix for colon targeting

Compression-coated matrix tablets were developed to target budesonide (BUD) in the colonic region using methacrylic acid (MAA) grafted inulin (INU) and carboxymethyl cellulose (CMC). INU was grafted with MAA to impart anionic characteristics to the gum, making it feasible to form a hydrogel by cross-linking with calcium gluconate (CG). The core matrix made up of MAA-g-INU alone disintegrated within 30 min and the core matrix made up of CMC alone completely released BUD within 6 h. The combination of MAA-g-INU and CMC produced a rigid matrix, which was able to completely release BUD after 7 h. Compression coating of the core tablets with MAA-g-INU and CMC did not release BUD in the first 4 h, and complete BUD release took place in the next 4 h. Compression coating led to the formation of a rigid and viscous gel layer outside the core matrices, which hindered BUD release. We conclude that compression coating with CG cross-linked CMC and MAA-g-INU could be used as a matrix for colonic delivery of drugs.

Highlights

• Compression coated matrices were developed for colonic delivery of BUD.
• The matrix retained drug release up to 4 h in upper gastrointestinal tract (GIT).
• The matrix exhibited complete drug release in the next 4 h in the colon.