Síntese de microesferas e nanopartículas de quitosana e goma do chichá (Sterculia striata) como matriz para liberação controlada de fármaco para tratamento da malária

• Ano de defesa: 2012
• Autor(a) principal: Magalhães Júnior, Guilherme Augusto
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Nanopartículas; Sterculia striata; Quitosana
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/9730

The aim of this work was the synthesis and characterization of nano and microparticles for malaria drug delivery system. Chitosan microspheres of high molar mass (QTa) and chichá gum (CH) were synthesized by polyelectrolyte complexation and crosslinked with glutaraldehyde. The diameters of the microspheres crosslinked and non-crosslinked were 544 ± 3 μm and 558 ± 2 μm, respectively. The crosslinked beads were not soluble in acidic medium (pH 1.2). The swelling of microspheres was higher in pH 1.2 and that the crosslinked beads have less swelling than non-crosslinked. The sequential release of chloroquine from the microspheres was performed for 2 h followed by a release in pH 7.4. The crosslinked microsphere released 64% of chloroquine at pH 1.2, with a total of drug released of 92%. The release profile of the same sample at pH 7.4 provides a controlled release of the drug for about 50h. QT and CH nanoparticles were prepared using polyelectrolyte complexation and formation of Schiff base. In the formation of polyelectrolyte complex, parameters such as molecular weight of chitosan, the molar ratio of charge (n+/ n-), order of addition and concentration of the polyelectrolyte influence the size, zeta potential, polydispersity index and stability of the nanoparticles in solution. The zeta potential of particles in excess of QT was positive and when the charg molar ratio (n+/ n ) decreases to 0.1 the potential becomes negative due to the excess of CH. The nanoparticles diameters vary from 80 to 1,200 nm depending on the concentration of the polyelectrolyte and the chitosan used. Chitosan nanoparticles formed by a low molecular weight (QTb) were larger than those formed by chitosan of high molecular weight (QTa). The decrease of the charge ratio (n+/n-) and the polyelectrolyte concentrations lead to small size nanoparticle. The release of chloroquine in matrices of CH, QTa and QTb ratio ratio 5 and 0.1 lasted 15 days by releasing up to 99% of the drug, however only the ratio influenced the release profile. Nanoparticles formed by Schiff base reaction were produced. The influence of parameters such as degree of oxidation of CH, chitosan molar mass, addition and masses ration of polysaccharides on size, zeta potential and stability were investigated. The zeta-potential was positive for particles with an excess of QT and negative with excess CH. The particle diameters ranged from 30 to 450 nm, depending on the degree of oxidation of CH and the molar mass of QT. Particle formed with low oxidation of CH and high molar mass chitosan are bigger than those formed with low molar mass chitosan. A inverse behavior was observed when high oxidated CH was used.