Research Journal of Pharmacy and Technology

The objective of present research was to formulate, optimize and characterize silybin microspheres using emulsion solvent evaporation method using a polymer, poly-ε-caprolactone and an emulsifier, poly vinyl alcohol for sustained drug delivery. The microspheres were formulated using emulsion solvent evaporation method. The microspheres were optimized by taking different drug and polymer ratio (1:1 to1:8), emulsifier concentration (1%, 1.5%, 2% and 2.5%) and stirring speed (1000rpm, 1500rpm, 2000rpm, 2500rpm, 3000rpm). Then the microspheres were characterized for particle size, percentage yield, entrapment efficiency, scanning electron microscopy and in vitro drug release. The microspheres prepared by this method showed good entrapment efficiency and percentage yield. From the Fourier Transform Infrared Spectroscopic studies it was revealed that there were no significant interactions between silybin and excipients. Scanning Electron Microscopic photographs revealed that the microspheres were in spherical shape and smooth. Drug release studies revealed good release following korsmeyer peppas model indicating drug Non fickian diffusion mechanism. It was clearly observed that increase in polymer content, increased the dug entrapment up to a certain level, and then decreased. The other process variables like stirring speed and concentration of emulsifier also influenced the entrapment efficiency and drug release. In conclusion, Silybin was conveniently formulated as polymeric microspheres by emulsion solvent evaporation method. Formulation with 1:4 drug polymer ratio, 2% emulsifier with 2000 rpm was selected as optimized formulation.