Sistemas microemulsionados à base de tensoativos hidrocarbônicos para aplicação como suportes para dispersão de compostos antibióticos

• Autor(a) principal: Cruz, Kelle Gomes
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2164
• topic: Tensoativos não-iônicos; Microemulsões; Agentes bactericidas; Nonionic surfactants; Microemulsions; Bactericides agents; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICA

The solubility of water in lipophilic substances, or vice-versa, can be enhanced upon addition of amphiphilic molecules in determined amounts. These compounds are known as surfactants, and can promote the formation of microemulsions by substantially decreasing the interfacial tension between them. In this work, the effects of temperature, amount of cosurfactant and type of oil were assessed in the preparation of self-assemblies, particularly microemulsions, which are regarded as thermodynamically stable systems. They comprise the commercial nonionic surfactants Tergitol® TMN6 and Tergitol® TMN10, water, cosurfactant and oil in different, specific compositions. Phase behavior studies were conducted to determine the best conditions under which microemulsions can be formed, by means of pseudoternary phase diagrams. The main purpose is to propose their use as templates for the dispersion of antibiotic agents, and compare the efficiency of these novel formulations with the ones obtained by common procedures that do not involve the use of microemulsions. It could be observed that the surfactant TMN6 is less sensitive to temperature changes than TMN10. For both surfactants, in the absence of cosurfactant, the effect of the type of oil is remarkable, in that systems containing n-heptane as oil can be stable over a broader range of composition than systems prepared with a silicone oil. It could also be concluded that the formation of liquid- crystalline systems, or gels, is impaired with the use of butan-1-ol and ethyleneglycol as cosurfactants. The antibiotic agents norfloxacin, ciprofloxacin and amoxicillin were tested in free and microemulsified media. It was demonstrated that TMN6 microemulsions tend to diminish the activity of all antibiotics tested, but TMN10 systems can enhance the action of two of them. A statistical analysis was carried out with the data obtained in the biological assays, further proving that TMN10 systems containing ciprofloxacin are significant. It has then been shown by this study that microemulsions can be effectively employed as templates for antibiotic formulations, whose activity can be increased or optimized, by rendering them selective, according to the established experimental conditions.