ABSTRACT Colon targeting would be valuable when such a delay in absorption is therapeutically desirable in treatment of chronic medical conditions like nocturnal asthma. Objective: The major objective was to modulate drug release of prepared matrices to target the nocturnal peak symptoms of asthma. Materials and methods: Colon-specific drug delivery based on a polysaccharide, okra gum, was evaluated using in vitro and in vivo methods. Release kinetics was evaluated by using United States Pharmacopoeia (USP) type I dissolution apparatus. Results and discussion: Dissolution study revealed that okra gum preparation was able to protect the drug from being released under conditions mimicking mouth to colon transit with 27.7 ± 3.1% drug releases. Studies in pH 6.8 phosphate buffered saline (PBS) containing 4% w/v rat cecal contents have demonstrated the susceptibility of okra gum to colonic bacterial enzyme action with consequent drug release. In vivo ingestion in rabbits showed controlled release pharmacokinetic profile of theophylline from the formulation prepared using 400 mg okra gum with Cmax of 22.2 mcg/mL at 4.5 hours (Tmax). Conclusion: Thus the study clearly established that okra gum, in the form of matrix former, is a potential carrier for drug targeting to colon
