Multiple emulsions containing amazon oil: açaí oil (Euterpe oleracea)

Abstract

Abstract:The aim of this work was to formulate O/W/O multiple emulsions containing açaí oil as a model system and to evaluate their physical stability and in vivo Sun Protection Factor (SPF). Multiple emulsions are complex dispersion systems, known also as, "emulsions of emulsions". These emulsion systems, have significant potential in the cosmetic industry. Euterpe oleracea Mart., Arecaceae, popularly known in Brazil as "açaí", is an economically important plant. Açaí oil has been used as antioxidant and as anti-inflammatory activities. The multiple emulsions were prepared using a two-step procedure. The investigated formulations were characterized and their stability over time was evaluated by preliminary and accelerated stability. O/W/O multiple emulsions containing the same concentration of sunscreens with and without açaí oil were evaluated by the International Sun Protection Factor Test Method. The samples containing 70% (w/w) of primary emulsion, 5% (w/w) PEG-30-dipolyhydroxystearate, 10% (w/w) of açaí oil and 5% (w/w) of sucrose polybehenate have been found to be stable. The rheological measurements revealed that the samples exhibited non-Newtonian pseudoplastic flow behavior and thixotropy. To conclude, no statistical difference could be observed on the in vivo SPF to both multiple systems with or without açaí oil.

Development of O/W emulsions containing Euterpe oleracea extract and evaluation of photoprotective efficacy

“…Ferrari and Rocha-Filho (2011) demonstrated that the association between the polymeric surfactants and rheology modifier improved the stabilization of emulsion on the centrifugation test. According to Tadros (2004) the absence of rheology modifier in the formulations resulted in phase separation after centrifugation because there was an insufficient increase in the viscosity of the external phase of the vehicles to maintain the integrity of the emulsions.…”

“…at room temperature . The appearance, homogeneity and organoleptic characteristics were evaluated by macroscopic analyses (Ferrari, Rocha-Filho, 2011).…”

“…The samples were maintained under these conditions for 90 days. The macroscopic analyses (appearance, homogeneity and organoleptic characteristics), pH value determinations and rheological behavior (minimal apparent viscosity, rheogram curves, flow index and hysteresis area) were evaluated at different time intervals (24 h after preparation of formulations and on 30 th , 60 th and 90 th days) (Ferrari, Rocha-Filho, 2011).…”

“…Statistical analyses of the preliminary and accelerated stability data were performed using the analysis of normality of the sampling distribution, evaluated by parametric analysis of variance (ANOVA) as well as the Tukey test (p<0.05) (Ferrari, Rocha-Filho, 2011) using SPSS 13.0 for Windows.…”

“…However, emulsions are thermodynamically unstable systems and in technological development, the aim is to delay phase separation for as long as possible. Stability is affected by several factors, such as the composition and size of the globules, viscosity, volume of the phases, pH, presence of electrolytes, osmotic gradient and the properties of the interfacial film formed (Ferrari, Rocha-Filho, 2011;Poyato et al, 2013). Changes in these rheological properties may represent important early predictors of impending failure of the products.…”