Colloidal and physicochemical characterization of proteincontaining poly(lactide-co-glycolide) (PLGA) microspheres before and after drying
Résumé
AbstractIn the present work, the double emulsion (W/O/W) method was used to microencapsulate a protein model (Bovine Serum Albumin) in a biodegradable polymer poly(lactide-co-glycolide) (50:50) (PLGA). Colloidal and physicochemical characterization of PLGA based microspheres was investigated after their \textquotedblleftcrude\textquotedblright preparation and after drying and redispersion processes. Particle morphology and size were studied by scanning electron microscopy and by laser diffraction analysis. Electrokinetic study and colloidal stability were also studied as a function of pH and salinity of the medium. Atomic force microscopy (AFM) was used to study the surface properties. It was found that smooth microspheres were obtained after the drying process. The Atomic force microscopy results of microspheres stored for one month in water show softness and surface irregularity caused by the microspheres degradation. The colloidal stability of theses microspheres is mainly governed by repulsive electrostatic interaction due to the PLGA charge. The used amount of stabilizing agent poly(vinyl alcohol) (PVA) is low enough to ensure the sterical stabilization. Drying process has no effect on the surface properties and colloidal stability of the prepared microspheres.