Preparation of Indomethacin-Loaded Lipid Particles by Membrane Emulsification

Lipid particles are interesting delivery systems produced from solid lipids. The present study investigated the preparation of indomethacin-loaded lipid particles using a membrane emulsification process. The lipid phase was pressed, at a temperature above the melting point of the lipid, through the membrane pores allowing the formation of small droplets. The aqueous phase circulated inside the membrane device, and swept away the droplets forming at the pore outlets. Three formulations were prepared with Compritol or Precirol as the lipid phase, and with Compritol and Mygliol as the lipid and oil phases, respectively. The lipid particles were evaluated for their size distribution, drug entrapment efficiency, drug release, and stability properties. Mean particle size in the nanometric range were obtained for Compritol, and Compritol and Mygliol lipid particles (0.7 mu m), and mean size in the micrometric range for Precirol lipid particles (2.7 mu m). For the three formulations, high entrapment efficiencies were obtained (between 93 and 96%) and the release curve showed burst effects. This result was explained by the drug-enriched shell model.