RESUMO
With two different methods, ibuprofen was entrapped into porous hollow silica nanoparticles (PHSNs) carriers, which were synthesized through a sol-gel route by using CaCO3 nanoparticles as the inorganic templates. By employing pressured CO2 as the loading medium, the amount of ibuprofen that was pressed into the carriers was approximately 52% higher than that by simply soaking. The drug release behaviors of the ibuprofen-loaded PHSNs were investigated in a simulated intestine juice and an artificial gastric fluid, respectively, and it demonstrated a sustained release pattern in all cases and the sample prepared under high pressure had a lower release rate in both fluids and thus owned a greater sustained drug release capacity. In the acidic artificial gastric fluid, no silica was degraded and only 16% of the loaded ibuprofen was released from the matrix in 300 min. However, much more silica was degraded in the simulated intestine juice in a shorter time and almost all the loaded ibuprofen was dissolved into the solution eventually, resulting in a quicker and complete ibuprofen release. Therefore, the PHSNs can be utilized for applications of controlled drug delivery to small intestine.
Assuntos
Portadores de Fármacos/química , Ibuprofeno/administração & dosagem , Ibuprofeno/farmacocinética , Absorção Intestinal/fisiologia , Nanoestruturas/química , Dióxido de Silício/química , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacocinética , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/química , Ibuprofeno/química , Teste de Materiais , Nanoestruturas/ultraestrutura , Tamanho da Partícula , PorosidadeRESUMO
Silica nanotubes were synthesized and used as enzyme immobilization carriers. The immobilization profiles were described by the adsorption of lysozyme molecules from aqueous solution onto the hydrophilic silica surface. The driving force of the adsorption, structure changes in the immobilized lysozyme molecules, and enzymatic activities were investigated. A study of the zeta potentials of silica with and without the immobilized lysozyme showed that there was an increase in the isoelectric point with the increase in the loading amount of lysozyme. FTIR spectra indicated that protein secondary structure was maintained well in the immobilized molecules. It was observed that enzymatic activities first increased and then decreased with increasing surface coverage of silica nanotubes by lysozyme, which suggested that the overlap and aggregation of lysozyme molecules reduced enzymatic activities of the adsorbed lysozyme molecules at high surface coverage.
Assuntos
Enzimas Imobilizadas/química , Muramidase/química , Nanotubos/química , Dióxido de Silício/química , Adsorção , Ativação Enzimática , Tamanho da Partícula , Sensibilidade e Especificidade , Dióxido de Silício/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Propriedades de Superfície , Água/químicaRESUMO
Porous hollow silica nanoparticles (PHSNP) with a diameter of 60-70 nm and wall thickness of approximately 10nm were synthesized by using CaCO(3) nano-particles as the inorganic template. The characterization of PHSNP by TEM and BET indicated that PHSNP were uniform spherical particles with good dispersion, and had a specific surface area of 867 m(2)/g. The as-synthesized PHSNP were subsequently employed as drug carrier to investigate in vitro release behavior of cefradine in simulated body fluid. UV-spectrometry and TG analyses were performed to determine the amount of cefradine entrapped in the carrier. The BJH pore size distribution of PHSNP before and after entrapping cefradine was examined. Cefradine release profile from PHSNP followed a three-stage pattern and exhibited a delayed release effect.
