Formulation, development and evaluation of colon-specific ketorolac tromethamine compression coated tablets
The major intention to formulate and develop colon targeted tablets is to improve the therapeutic efficacy by increasing therapeutic drug concentrations in colon. The present study was aimed to develop guar gum compression coated tablets ketorolac tromethamine to achieve the colon-specific drug release. In this study, both core and compression coated tablets were prepared by direct compression method. The prepared colon targeted tablets were characterized for different pre-compression and post-compression evaluations. In vitro drug release studies were performed by using USP XXIV Type II dissolution apparatus in simulated gastrointestinal fluids. From the in vitro dissolution studies, the formulation F4 showed 4.72±0.76% drug release in 5 h and it was progressively increased to 99.12±0.42% in 24 h that indicates retardation of drug release in stomach and small intestine and significant amount of drug release was observed in colonic environment. The accelerated stability studies proved the stability of guar gum compression coated tablets. From the above results, achievement of colon specific drug release might be due to substantial integrity of the compression coated guar gum in the upper gastrointestinal trac , but microbial degradation in the colon. In conclusion, development of microbial degradation compression coated tablets was suitable to target the ketorolac tromethamine to colon. Further the efficacy of the developed formulations has to be assessed by pharmacokinetic studies.
Keywords: In vitro drug release, Microbial degradation, Pre-compression, Post-compression, Simulated gastrointestinal fluids, Upper gastrointestinal tract