RESUMO
PURPOSE: The objective of this study was to develop nanocapsules and nanospheres of polylactide-co-glycolide (PLGA) containing magnetic nanoparticles and rapamycin. METHOD: Magnetic nanoparticles (MP) were obtained by the co-precipitation of Fe(ll) and Fe(III) salts by addition of ammonium hydroxide. Nanocapsules (NC) and nanospheres (NS) containing either uncoated magnetic nanoparticles (MP), MP coated with oleic acid monolayer (MPOA) or MP coated with oleic acid bilayer (MPOA-OA) were prepared by the emulsion evaporation method. Rapamycin was also encapsulated into NC and NS. Morphology, size, size distribution, entrapment efficiency, stability and magnetization characteristics were determined. RESULTS: Non-contact AFM images showed that the composite nanoparticles were almost spherical in shape. The resulting polymeric nanocarriers were found to have a mean diameter of approximately 120 nm with a narrow size distribution. The influence of some experimental parameters on the entrapment efficiency and stability was determined. Nanocapsules and nanospheres prepared with uncoated magnetic nanoparticles exhibited higher entrapment efficiency and stability. Superparamagnetic behavior of the magnetic nanocomposite was demonstrated by magnetization data. These findings may contribute to the development of potential controlled release drug targeting devices based on magnetic polymeric nanocarriers.
