Development and in vitro evaluation of floating rosiglitazone maleate microspheres

Background: Various approaches have been used to retain the dosage form in stomach as a way of increasing the gastric residence time, including floatation systems; high-density systems; mucoadhesive systems; magnetic systems; unfoldable, extensible, or swellable systems; and superporous hydrogel systems. Aim: The objective of this study was to prepare and evaluate floating microspheres of rosiglitazone maleate for the prolongation of gastric residence time. Method: The microspheres were prepared by solvent diffusion-evaporation method using ethyl cellulose and hydroxypropyl methylcellulose. A full factorial design was applied to optimize the formulation. Results: Preliminary studies revealed that the polymer:drug ratio, concentration of polymer, and stirring speed significantly affected the characteristics of microspheres. The optimum batch exhibited a prolonged drug release, remained buoyant for >12 hours, high entrapment efficiency, and particle size in the order of 350 mu m. Conclusion: The results of 32 full factorial design revealed that the concentration of ethylcellulose 7 cps (X-1) and stirring speed (X-2) significantly affected drug entrapment efficiency, percentage release after 8 h and particle size of microspheres.