Detalhes bibliográficos
| Ano de defesa: |
2014 |
| Autor(a) principal: |
Negretto, Carla Maria Uggeri |
| Orientador(a): |
Gomes, Patricia |
| Banca de defesa: |
Duarte, Marta Maria Medeiros Frescura,
Mortari, Sergio Roberto |
| Tipo de documento: |
Dissertação
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Centro Universitário Franciscano
|
| Programa de Pós-Graduação: |
Programa de Pós-Graduação em Nanociências
|
| Departamento: |
Biociências e Nanomateriais
|
| País: |
Brasil
|
| Palavras-chave em Português: |
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| Palavras-chave em Inglês: |
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| Área do conhecimento CNPq: |
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| Link de acesso: |
http://www.tede.universidadefranciscana.edu.br:8080/handle/UFN-BDTD/522
|
Resumo: |
Vitamin E is an important agent in the prevention of skin aging, which is associated with oxidative stress generated, mainly, by free radicals. It is considered a potent antioxidant, which acts protecting membranes against lipid peroxidation. As most of the antioxidants, vitamin E has low water solubility and high sensitivity to light, heat, and oxygen, representing a problem in the preparation of cosmetic formulations. The incorporation of this important antioxidant to a nanostructure is a promising system capable of protecting the drug against degradation and making the formulation stable and acceptable for cosmetic use. Among the various nanostructured systems, we can highlight the nanostructured lipid carriers (NLC), since they present occlusive adhesive properties increasing the bioavailability of the drug in the skin. In this context, various analytical methods can be used to determine and quantify nanostructured vitamin E. Among these methods, we highlight UV spectrophotometry and UV derivative spectrophotometry (UVD) because they have low cost, are easy to use, and are simple to read the results. It is also important to evaluate the antioxidant power of these nanostructures through assays such as the ferric-reducing antioxidant power (FRAP), which is considered a simple, reproducible and inexpensive assay. The objectives of this study were to characterize the vitamin E – loaded nanoestrutured lipid carriers (NCL-VITE), to develop and to validate methods using UV and UVD spectrophotometry for the quantitative determination of vitamin E in NLC, to compare the analytical methods, and to evaluate the antioxidant activity of vitamin E and NCL-VITE, using FRAP assay. The characterization of NCL-VITE samples showed particle size of 169.20 ± 1.01 nm, 0.11 ± 0.01 polydispersity index (PDI) and zeta potential -25.50 mV ± 3.84. The analytical parameters studied in the validation by UV and UVD spectrophotometry indicated specificity, linearity, precision, accuracy and robustness of both methods. Likewise, the antioxidant activity of vitamin E and NCL-VITE evaluated using the FRAP assay was considered acceptable. We can conclude that the NCL-VITE showed good homogeneity and average diameter in acceptable range. All these features enabled the sample to be used in the development and validation of the methods. The UV and UVD spectrophotometry were considered analytical methods that can be applied with safety and reliability in the determination of NCL-VITE. Moreover, the FRAP assay showed to be simple and with good reproduction regarding vitamin E and NCL-VITE. |
