Combination of inulin-shellac as a unique coating formulation for design of colonic delivery dosage form of ibuprofen

Abstract

A combination of inulin and shellac, when applied as a film coat, has a potential value as a colon-specific delivery system for ibuprofen. The inulin-based multi-unit pellet system is prepared by coating inulin and shellac sequentially around drug-loaded cores in a fluid-bed coater. The outer shellac coating protects the system against gastrointestinal environment and dissolves rapidly in small intestine, where a lumen pH around 7 triggers the dissolution of the enteric polymer. The inner inulin coating works as a time-controlled retardant and offers additional protection of the pellets until it is degraded by microbial enzymes at the colon region. In vitro data indicates that inulin is a promising coating material to obtain timed and enzyme-triggered ibuprofen release. Pharmacokinetic study in New Zealand rabbit confirmed the in vitro data and revealed a delayed absorption of about 3 h but with higher AUC. This result suggests that inulin-shellac system shows potential materials to provide a microbial triggered drug in the colon compartment. The higher AUC of ibuprofen from double coated pellet dosage form may indicate that absorption of ibuprofen in colonic compartment is more extensive than in gastric.