Detalhes bibliográficos
| Ano de defesa: |
2021 |
| Autor(a) principal: |
Gonçalves, Káren do Carmo
 |
| Orientador(a): |
Valadares, Marize Campos
|
| Banca de defesa: |
Valadares , Marize Campos,
Silva Neto, Benedito Rodrigues da,
Santos Filho, Edvande Xavier dos |
| Tipo de documento: |
Dissertação
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Federal de Goiás
|
| Programa de Pós-Graduação: |
Programa de Pós-graduação em Ciências Farmacêuticas (FF)
|
| Departamento: |
Faculdade de Farmácia - FF (RMG)
|
| 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://repositorio.bc.ufg.br/tede/handle/tede/13753
|
Resumo: |
Phototoxicity is defined as an adverse response caused by photoreactive/photounstable substances, as a result of exposure to sunlight, which can be administered topically or systemic. The field of phototoxicity is a mandatory parameter for the registration of a new chemical, as the photosafety assessment ensures the prevention or minimization of adverse effects induced by products that are used in everyday life, or even during occupational exposures, and with that, studies , standards and guidelines are designed to reduce such biological interactions. The new conducts in accordance with the guidelines for new candidates for chemical, cosmetic or drug products, require inspection for the potential of inducing adverse reactions after exposure to UV rays, in particular, the adverse reaction coming from photochemical reactions In photochemical reactions and /or phototoxic reactions are necessary for the substances to absorb the photon at a wavelength between 290 to 700nm, after light absorption there is the release of chemically unstable derivatives that will react with tissues/cells and release Reactive Oxygen Species (ROS) o which is a determining event for the induction of phototoxicity. The evaluation of ROS production has been recommended as an initial screening to assess the photoreactivity of pharmaceuticals, as photochemical assays of ROS can predict the phototoxicity potential of chemicals and classify them according to their performance, although there is still a risk of false-positive predictions with the current tests developed. The objective of the work is to develop an innovative method free from animal models capable of differentiating different substances into phototoxic and non-phototoxic, after excitation of the substances under a UV light source. As for the methodology, 18 substances were selected, represented in two categories: phototoxic and non-phototoxic. Subsequently, the optimal conditions for ROS induction tests were established, such as temperature and exposure time, concentration of substances, concentration of the ROS probe. Then, for detection of ROS in chemical substances when exposed to ultraviolet light and without exposure. As a result of this developed methodology, it was observed that, when exposed to ultraviolet light, only phototoxic substances released ROS, but the same substances, when not exposed to ultraviolet light, did not produce ROS. It was also observed that non-phototoxic substances did not show ROS even under exposure to ultraviolet light and without exposure to light. Another methodology was developed with the same objective, to detect ROS through exposure to ultraviolet light in phototoxic and non-phototoxic substances using cells. The results obtained through this research were satisfactory since, phototoxic substances with exposure to ultraviolet light were detected ROS already without exposure to ultraviolet light there was no production of ROS, the same qualifies for non-phototoxic substances there was no detection of ROS with exposure and no ROS exposure. It was found that substances not exposed to ultraviolet light are not able to activate mechanisms to trigger photoreactivity reactions, which is the precursor for the production of ROS. On the other hand, phototoxic substances do not have the ability to form ROS, as they do not have molecules for the formation of ROS in their structures. |
