Preparação de nanopartículas de quitosana para liberação de fármacos

• Ano de defesa: 2018
• Autor(a) principal: Barros, Ellen Luna de [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Nanoparticles; Chitosan; Ibuprofen; Controlled release; Ionotropic gelation method; Nanopartículas; Quitosana; Ibuprofeno; Liberação modificada; Gelificação ionotrópica
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=6746807; https://repositorio.unifesp.br/handle/11600/52796

Drug carriers provide a more efficient manner to administer drugs that have restrictions in the use. In this study, chitosan, which is a semi synthetic biopolymer produced from a renewable source, has been transformed into nanoparticles to act as carriers for drugs and other bioactive molecules. The preparation of the nanoparticles was carried out using the coacervation and ionotropic gelation methods. The formed nanoparticles in aqueous dispersion were analyzed by zeta potential and dynamic light scattering of measurements. Nanoparticles isolated by centrifugation were analyzed by X-ray diffractometry and Fourier transformed infrared absorption spectroscopy. Ibuprofen was the model drug used in this study. This drug was incorporated directly into the nanoparticles during the synthesis step. The drug release from the chitosan nanoparticles was evaluated in phosphate buffer with pH 6.0 and 8.0 and also in simulated body fluid (pH 7.2), which is a medium that mimics the physiological chemical conditions of intracellular fluid. Representative kinetic models of different pharmaceutical forms of drug release dosage were applied to the experimental curve of ibuprofen release in simulated body fluid. The synthetic method based on coacervation did not produce the nanoparticles with the desired characteristics of low index of polydispersity and high zeta potential, in none of the experimental conditions evaluated. The ionotropic gelation method produced the nanoparticles with the desired colloidal characteristics when a mass ratio of chitosan and sodium tripolyphosphate of 3 : 1 was used during the preparation of the nanoparticles. The ibuprofen incorporation by using direct synthesis was around 91%, resulting in a material containing 21% by mass of the drug incorporated into the polymer network as tiny crystals and adsorbed molecules. The amount of ibuprofen released after 240 min in acid medium (30 %) was higher than in basic medium (10 %), which is the condition where the drug is way more soluble. This result demonstrated the role of the chitosan nanoparticle in modifing the ibuprofen solubility, as expect for a drug carrier. In simulated body fluid, 32% of the ibuprofen incorporated into the nanoparticles was released after the 240 min of monitoring. The experimental release kinetics adjusted to the Korsmeyer-Peppas model, ascribed for polymer matrices, with the release mechanism dominated in the monitored period by the diffusion of the drug located closest to the surface of the particle.