Optimization and Formulation of Bilayer Floating Tablets of Indomethacin with the Mixed-Solvency Concept

Objective: The present study investigates the use of indomethacin–solubilizers solid dispersions for the development of controlled-release bilayer floating tablet formulations. Materials and Methods: The physical state of the dispersed indomethacin in the solubilizers mixture was characterized by Scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, and IR spectroscopy. The mixture proportions of hydroxypropyl methylcellulose (HPMC), polyethylene glycol (PEG), ac-di-sol, sodium bicarbonate; polyvinyl-pyrrolidone (PVP) and indomethacin was optimized in relation to % drug release at first 30 min, and the percent cumulative drug released after 12 hours and floating properties (tablets floating lag time), employing a 17-run optimization study design combined with statistical and response surface analysis and numerical optimization. Results and Discussion: It was found that indomethacin exists microcrystals in the solid dispersions. The tablets showed good floating properties and controlled-release profiles, with drug release proceeding via the concomitant operation of swelling and erosion of the polymer matrix. Conclusions: Box-Behnken designs proved to be efficient tools in the optimization of the tablet formulation, and the global optimum formulation suggested by the design expert software.