Estudo da estabilidade de emulsão cosmética contendo óleo de castanha-do-brasil (Bertholletia excelsa)

Abstract

Through the search for beauty that accompanies generations, the current scenario that stands out in the phytocosmetics industry is focused on creating multifunctional bioproducts with a direct effect from raw materials derived from plants. In this context, the present work has the objective of evaluating the stability of cosmetic emulsions elaborated with Brazil nut oil, in order to characterize the oil, determine its hydrophilic-lipophilic balance (HLB) value, analyze the agitation method influence in the formation of the most stable emulsion and to carry out preliminary stability tests on the selected emulsion, measuring its organoleptic and physical chemical parameters. The Brazil nut oil used in this work was provided by the company D'Amazônia Origens. The oil was characterized and its EHL was determined from the use of surfactants Span 60® and Tween 80®. The emulsions were developed by the phase inversion method, while the analysis of the agitation method influence used two types of stirrers with different rotation speeds, to comparatively define the most stable emulsion to be taken to the preliminary stability tests determined by ANVISA. The EHL found for Brazil nut oil was 4.7, where the formulation had 5 g of Span 60®, without Tween 80®. In relation to the influence of the agitation method, it was noticed the greater stability of the emulsion formulated at 4000 rpm using the high shear agitator of the Turrax type, which was observed through the microscopic analysis, with droplets of regular formation and more homogeneous distribution. In addition, the emulsion taken as the more stable containing Brazil nut oil showed satisfactory results in the preliminary stability tests, with small organoleptic variations. Physico-chemically, the emulsion must undergo further studies related to the stabilization of its pH and its conductivity. Also, through rheological analysis of the formulation obtained after 15 days, it was possible to characterize the emulsion as a non-Newtonian liquid. The formulation did not present a thixotropic behavior, which could influence the profile of actives release. Therefore, the selected emulsion serves as the basis for future work more focused on its cosmetic and rheological properties, aiming at the development of Amazonian bioproducts of commercial value.