Abstract

In the present study, an attempt has been made to develop polystyrene microspheres for controlled drug delivery. The microspheres were prepared by solvent evaporation technique with different polystyrene-ibuprofen ratio (1:1, 1:2 and 2:1). The microspheres were characterised by loading efficiency, percentage of entrapment, percentage of encapsulation, particle size distribution, scanning electron microscopy, infrared spectroscopy, differential scanning calorimetry and in vitro release studies. Depending upon drug polymer ratio, the loading, entrapment, and encapsulation was found to be 30-52 %, 84-90 % and 70-80 % respectively. The spheres were spherical, discrete, compact and free flowing. The particle size of microspheres was found to be in the range of 4-25 μm. Drug loaded spheres were found to be larger than unloaded one. Infrared spectrum and thermogram revealed the stability of ibuprofen in microspheres. The microspheres released ibuprofen more than 24 h. Depending on drug polymer ratio, polystyrene microspheres are able to deliver 30 to 80% of the loaded drug by the end of 24 h. The microspheres prepared with 1:2 polymer drug ratio shows better release pattern and control the drug release over a period of 24 h. The release followed Higuchi kinetics rather than first order kinetics, indicating diffusion controlled drug release.