RESUMO
AIM: Production of Matryoshka-type gastroresistant microparticles containing antibiotic-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (NP) against Mycobacterium tuberculosis. MATERIALS & METHODS: The emulsification and evaporation methods were followed for the synthesis of PLGA-NPs and methacrylic acid-ethyl acrylate-based coatings to protect rifampicin from degradation under simulated gastric conditions. RESULTS & CONCLUSION: The inner antibiotic-loaded NPs here reported can be released under simulated intestinal conditions whereas their coating protects them from degradation under simulated gastric conditions. The encapsulation does not hinder the antituberculosis action of the encapsulated antibiotic rifampicin. A sustained antibiotic release could be obtained when using the drug-loaded encapsulated NPs. Compared with the administration of the free drug, a more effective elimination of M. tuberculosis was observed when applying the NPs against infected macrophages. The antibiotic-loaded PLGA-NPs were also able to cross an in vitro model of intestinal barrier.
Assuntos
Antibacterianos/farmacologia , Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Nanopartículas/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Antibacterianos/administração & dosagem , Antituberculosos/administração & dosagem , Transporte Biológico , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Humanos , Concentração de Íons de Hidrogênio , Microesferas , Tamanho da Partícula , Preparações Farmacêuticas/química , Rifampina/química , Rifampina/farmacologia , Estômago , Propriedades de SuperfícieRESUMO
The photosensitized oxidation of 9,10-dimethylanthracene with singlet oxygen in acetonitrile was investigated using a safranin O/silica composite as an heterogeneous delivery system of the photosensitizer. The only detected product was the corresponding endoperoxide (9,10-endoperoxianthracene) and its formation rate depended on the initial concentration of DMA, the light intensity and the amount of the composite. The kinetics of this reaction was compared with that of the reported kinetic model of photosensitized oxidations of organic compounds in homogeneous reactions. It was found that both reactions followed the same model, suggesting that the actual reaction between photoproduced singlet oxygen and 9,10-dimethylanthracene was performed in homogeneous media and the surface of the composite was not involved in the reaction.