Abstract
The present investigation was aimed to develop sustained release gastric floating in-situ gels of diclofenac sodium mainly to improve the analgesic activity, and alleviate the gastric problems of diclofenac sodium. Fifteen gastric floating in-situ gel formulations were prepared and optimized using a Box-Behnken design. The independent variables (concentration of gellan gum, calcium carbonate and diclofenac sodium respectively) were improved in order to obtain the required responses. The design expert software was applied to analyze the probable interaction existing between the independent variables. The results revealed the optimized gastric floating in-situ gel with short floating lag time (6.2 minutes); low viscosity (112.1 cps); and the high in-vitro drug release at 24th hr (39.18 %) was obtained using an optimized combination of CaCO3 (0.6 %w/v); gellan gum (0.9 %w/v) and diclofenac sodium (0.5 %w/v); respectively. The analgesic effect of the optimized formulation was found to be better than that of pure diclofenac sodium (8.14 +/- 0.43) at 4th hour. Ulcerogenic study results showed that the optimized formulation produced less damage (almost 43% less) to the gastric mucosa than the severe gastric injury exhibited by free diclofenac sodium. Thus, the existing and established NSAID's delivery systems can be replaced by this study's promising formulation of diclofenac sodium.