Abstract

The present study hollow microsphere of Aceclofenac was prepared by emulsion– solvent diffusion method by using Eudragit RS100 and HPMC as a polymer. Mean particle size range for all formulation was varied from 613.74 to 869.1μm, due to change in drug and polymer ratio. Drug entrapment of all formulation were found in range of 60.14 to 75.12% w/w and its efficiency slightly decrease with increasing the HPMC content. True density, tapped density values for all formulation were less than that of gastric fluid (1.004gm/cm3), suggested that it exhibit good buoyancy. Angle of repose (<40) for all formulation showed excellent flowability. Shape of the hollow microsphere was found to be spherical by SEM study, small cavity was present on surface, which may due to solvent evaporation during drying process. It is responsible for floating property. In FTIR study, all characteristic peaks were appeared in hollow microsphere spectra with out any remarkable change in the position after successful encapsulation, indicated no chemical interaction and stability of drug during microencapsulation process. Ideal property of hollow microspheres include high buoyancy and sufficient release of drug in pH 6.8. Percent drug release rate of F 1, F2, F3 formulations (45.80%, 66.69%, 81.89%) in 12 hours, which is slow and incomplete drug release. In order to increases the percent drug release rate, the ratio of Eudragit and HPMC is decreased and increased respectively. F5, F6 formulations showed high release rate (97.85%, 98.89%) in 10 hours and F7, F8 formulations showed high release rate (98.20%, 99.24%) in 9 hours, with less buoyancy. F4 formulation showed appropriate balance between buoyancy and drug release rate 94.68% in 12 hours, it may considered as a best formulation. The in-vitro release data was applied to various kinetic models to predict the drug release kinetic mechanism. The zero order plots for all formulation were found linear in both dissolution medium. Result shows that, drug release rate may follow zero order mechanism. Higuchi and Peppas plot was found good linear, which indicates diffusion may be the mechanism of drug release and n>0.5, that indicated drug release may follow anomalous diffusion.

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