Biodegradable anionic acrylic resin based hollow microspheres of moderately water soluble drug Rosiglitazone Maleate: preparation and in vitro characterization

Background: Most of floating systems have an inbuilt limitation of high variability in the gastric retention time, invariably affecting the bioavailability of drug. An oral sustained release system is formulated to increase gastric residence time by a different way like floating. Aim: The objective of present investigation was to prepare hollow microspheres of Rosiglitazone Maleate in order to increase its bioavailability and reduce the dose frequency. Method: Hollow microspheres of Rosiglitazone Maleate were prepared by O/W emulsion-solvent diffusion technique using biodegradable anionic acrylic resin as a polymer. A mixture of dichloromethane and ethanol (1:1) used as solvent system for drug and polymer with water containing polyvinyl alcohol and salt as external aqueous phase. Result: Entrapment efficiency of drug was increased upto 89.71% as a result of salting out effect. The morphology of Eudragit S100 based microspheres in comparison to Ethyl cellulose and hydroxy propyl methyl cellulose (HPMC) was found to be hollow, spherical, and porous which was analysed by scanning electron microscopy. Microspheres were evaluated for micromeritic profile and found satisfactory. The FT-IR spectra confirmed the absence of drug-polymer interaction. The Eudragit S100 based formulation demonstrated favorable in vitro floating and sustained release profile for longer period of time with increased bioavailability. The anionic acrylic resin based microspheres confirmed to have high floating ability >12 h. Conclusion: Entrapment efficiency and bioavailability of Rosiglitazone Maleate loaded microspheres were increased significantly after modification of method. The release mechanism for formulation was diffusion controlled and had followed first order kinetics, as well as physically and chemically stable as per ICH guidelines.