Planejamento, síntese, caracterização e avaliação de um novo composto candidato a protótipo de fotoprotetor
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Data
2012
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Universidade Federal de Goiás
Resumo
In Brazil, the estimates for the year 2012 point to approximately 134,000 new cases
of skin cancer, being mostly related to exposure to ultraviolet radiation. According to
current consensus, such damage can be minimized by prophylactic use of
sunscreens, which aims to protect human skin against harmful effects of UV
radiation.
This way, this study proposed to plan, synthesize, characterize and evaluate a new
compound to be a sunscreen (17). The structural planning is made from
photoprotective triazona ethylhexyl prototypes (12) and cinnamate (4) having the
compound 15 which was produced from vanillin, a natural abundant and low cost
product. In addition, 17 compound has molecular weight above 800 Daltons, which is
in accordance with the photoprotective recently launched on the market, because it
minimizes or even prevents its absorption through the skin. The synthetic route
proposal consisted of two stages, which after optimized lead to obtain the 17
compound in 78.6% overall yield. It is noteworthy that the 15 compound was
obtained in quantitative yield and the 17 compound was purified by Soxhlet extractor,
using amyl alcohol as solvent. These facts make its synthesis a bit laborious and
inexpensive, fundamental characteristics of a technological product, from the
financial point of view. All the synthesized compounds were characterized by
spectrometric techniques of nuclear magnetic resonance of hydrogen-dimensional
and two-dimensional, infrared, mass and ultraviolet, in equal ways. From the
spectrophotometric absorption technique it was identified that 17 compound had two
peaks of maximum absorption (λmax.) in the UV, and 306 nm in the region of UVB and
344 nm for UVA. It is also possible to calculate the parameters of the molar
absorptivity (ε) and specific extinction coefficient (E), whose values were above 104
-1 cm-1 for ε and 5,843 4,337 for E. Moreover, the 15 and 17 compounds were also
M
evaluated on their redox profile using the technique of cyclic voltammetry which
showed that the 17 compound keeps stable considering the applied potential. The
thermogravimetric thermal analysis the 17 compound showed a weight loss of
47.88% in the range of 330 °C under an atmosphere of synthetic air, characterized
as a stable compound at high temperatures. From the in vitro evaluation by the
spectrophotometric method described by Mansur it presented SPF equal to 4.58,
while under the same conditions the methoxycinnamato of octyl (4), sunscreen sold
worldwide, presented SPF equal to 2.79.
At the end of this work it is possible to observe that the proposed synthetic route to
obtain the 17 compound was effective, given the obtained high yields, laborious and
low cost steps. Finally, we conclude that the structural planning employee was
ratified, since the described physical-chemicals organic evaluated had great
similarities with the prototype sunscreen (12) and (4) used in its planning.
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VINHAL, Daniela Cristina. Planejamento, síntese, caracterização e avaliação de um novo composto candidato a protótipo de fotoprotetor. 2012. 133 f. Dissertação (Mestrado em Ciências da Saúde - Farmácia) - Universidade Federal de Goiás, Goiânia, 2012.