Protein-loaded poly(epsilon-caprolactone) microparticles III. Entrapment of superoxide dismutase by the (water-in-oil)-in water solvent evaporation method

This work investigated some process parameters involved in the entrapment o f superoxide dismutase (model protein) in poly(epsilon-caprolactone) microp articles by a multiple emulsion solvent evaporation method. In optimal oper ating conditions, the particles were smooth and spherical (mean diameter 8. 66 +/- 0.18 mu m) with entrapment efficiency and retained biological activi ty of 68 +/- 2% and 8.48 +/- 1.07% (n = 3), respectively. This dramatic act ivity loss was ascribed to the deleterious effect of the polymer solvent. T he use of alpha-cyclodextrin decreased the entrapment efficiency and retain ed biological activity. These two parameters were not considerably influenc ed by the freeze-drying. Moreover, thermal analysis showed that superoxide dismutase did not form a true solution with the polymer and an increase in the polymer crystallization temperature after the entrapment process.