Study On PLA/SiO₂ Hybrid Microspheres And Loading Drug And Preparation Of PVA/SiO₂ Hybrid Microspheres

Using 3-aminopropyltriethoxysilane (APTES) as coupling agent, polylactic acid/SiO₂ hybrid material was prepared, and then polylactic acid/SiO₂ hybrid microspheres (PLAHs) with porous structure were prepared by the oil-in-water single-emulsion solvent evaporation method. Field scanning electron microscope (FSEM) result shows that PLAHs are porous microspheres sized about 20μm in diameter, and the opening outside holes in PLAHs are not very complicated. Nitrogen adsorption-desorption experiment show the nitrogen adsorbed in holes is easily desorbed, and the specific surface area of PLAHs is calculated to be 6.87 m²/g. This characteristic holes are convenient for embedding drug. Transform infrared spectroscopy (FTIR) results show that PLA has been amidated with APTES successfully and formed a kind of organic-inorganic hybrid material by hydrolysis and polycondensation with tetraethoxysilane (TEOS), moreover the molecular structure of the hybrid material is confirmed by X-ray photoelectron spectroscopy (XPS). Differential scanning calorimetry (DSC) results show the melting point of PLAHs is higher than that of PLA about 11.2℃. These PLAHs may be used in controlled-release of drug by embedding drug in the holes of PLAHs, and the drug loading amount can controlled by the size and number of hole of PLAHs.Aspirin polylactic acid/SiO₂ (ASA-PLA/SiO₂) microsphereswere prepared by solvent evaporation method. The size of microspheres, encapsulation efficiency, drug loading and in vitro drug release were investigated. Field scanning electron microscope (FSEM) results show that microspheres are sized about 15μm in diameter. This size may be used in controlled-release of drug. Moreover, Higuchi equation was Q=0.3598+0.03t^1/2, ρ=0.9961. It was obvious that aspirin was released from the microspheres in a sustained fashion.Polyvinyl alcohol /SiO₂ hybrid microspheres (PVAHs) were prepared by the water-in-oil single-emulsion solvent evaporation method. Optic microscope result shows that PVAHs are microspheres sized about 15μm in diameter. FTIR, DSC, XRD results show that PVA has formed a kind of organic-inorganic hybrid material by hydrogen-bond with SiO₂.