COSTA, J. T. C.; http://lattes.cnpq.br/6596232608750542; COSTA, Joneuso Tércio Cavalcanti da.
Resumo:
Non-ionizing radiation (UV-A, UV-B and UV-C) of the sun's electromagnetic spectrum
cause diseases to human and must be avoided. The proper use of sunscreen
minimizes this problem. Currently, the trend is to introduce natural materials, organic
or inorganic, in the composition of sunscreens, in order to neutralize possible side
effects of synthetic materials. Studies have shown that clays (layered silicates)
incorporated in sunscreens can block ultraviolet radiation in 250 to 400 nm
wavelength range depending on the clay composition. Following this guideline, in this
work, two clays were used in the preparation of sunscreen and its effectiveness was
determined at Universidade Federal de Campina Grande (UFCG) laboratory through
in vitro evaluation by spectrophotomery. The clays tested were Cloisite® Na
+
sodium
montmorillonite and Argel 35 bentonite. The formulations were prepared in
pharmacies in three different cities, Guarabira, Joao Pessoa and Campina Grande, in
Paraíba state. The method chosen to evaluate the Sun Protection Factor (SPF) was
in vitro method, developed by Mansur, due to the excellent correlation with in vivo
method. Besides, there are other advantages like low cost and less damage to health
since the volunteer is not exposed to the experiments. Before the evaluation of SPF
of prepared formulations with the clay, the SPF of commercial sunscreens was
determined and it was confirmed that the in vitro method was proper to define
sunscreen SPF. The introduction of clay in the sunscreens composition, as natural
materials, replacing TiO2 synthetic material was effective, especially for Argel
bentonite clay. The legitimacy of studying the photoprotective effect of clay materials
in the composition of sunscreens is justified by great social relevance, since they are
inexpensive and found easily in nature.