Invited Speaker

A Comparative Study Between Coacervation and Solvent Evaporation Method for the Encapsulation of Microspheres Designed for Embolization
Faten Madani
France

Indomethacin-loaded dietheylaminoethyl trisacryl microspheres (DEAE-Trisacryl® MS), originally designed for therapeutic embolization, were encapsulated using two methods: coacervation and solvent evaporation/extraction. This encapsulation was achieved using a biocompatible polymer, the PLGA 50:50, and aimed to control the release of the anti-inflammatory non-steroidal drug (AINSD) in the occluded vessel. PLGA degradation study showed that it has an erosion half-life of about 35 days. Scanning electron microscopy (SEM) photographs showed that microcapsules (MC) prepared by coacervation have a wrinkle surface while those prepared using solvent-removal process showed non-porous, smooth surface in comparison with the macro-porous, rough surface of DEAE-MS. The mean diameters were of 61 μm for naked DEAE-MS versus 71 μm and 65 μm for MC prepared by coacervation and solvent evaporation/extraction method, respectively. In vitro release study of indomethacin adsorbed onto MS indicated that drug release from MC was diffusion-controlled. Indomethacin diffusivity from MC was much lower than its free diffusivity from MS (meanly 14.5 and 10.5 times lower for formulas prepared by coacervation and solvent evaporation/extraction method respectively). This indicates that efficient indomethacin concentrations could be maintained over much longer time-periods in the embolized region, which assumed to be benefic in inhibiting normally occurring inflammatory reaction and the subsequent revascularization; responsible for treatment failure when definitive occlusion is required.