Particle size and morphological characterization of cosmetic emulsified systems by Optical Coherence Tomography (OCT)

Abstract

The physicochemical attributes of emulsified systems are influenced by the characteristics of their internal phase droplets (concentration, size and morphology), which can be modified not only by the formulation components, but also by the analytical methodology employed. Thus, the aim of this work involved the physicochemical characterization of cosmetic emulsions obtained from different surfactants, as well as the introduction of the optical coherence tomography (OCT) as the analytical technique employed for the morphological characterization and particle size determination of the formulations. Three emulsions were prepared, differing at the type and concentration of the surfactant used, and their droplet sizes were evaluated through optical microscopy, laser diffraction and OCT. The microscopic analysis and the laser diffraction techniques provided an average particle size minor than 6.0 µm, not detected by the OCT technique, which could identify only bigger particles of the emulsified systems' internal phase. The results testify that OCT was suitable for the morphological characterization of cosmetic emulsions; however, the technique needs to be improved to ensure a better sensitivity in the analysis of smaller particles.Uniterms: Cosmetic emulsions/physicochemical characterization. Surfactants. Optical coherence tomography/morphological characterization. Optical microscopy/morphological characterization. Laser diffraction/morphological characterization.Os atributos físico-químicos de sistemas emulsionados são influenciados pelas características de suas gotículas de fase interna (concentração, tamanho e morfologia), as quais podem ser modificadas não apenas pelos componentes da formulação, mas também pela metodologia analítica empregada. Desta forma, o objetivo deste trabalho envolveu a caracterização físico-química de emulsões cosméticas obtidas a partir de diferentes tensoativos, bem como a introdução da tomografia de coerência óptica (OCT) como a técnica analítica utilizada para a caracterização morfológica e determinação do tamanho de partícula das formulações. Três emulsões foram preparadas, diferindo no tipo e concentração do tensoativo empregado, e seus tamanhos de gotícula foram avaliados por meio das técnicas de microscopia óptica, difração a laser e OCT. As técnicas de microscopia óptica e difração a laser forneceram tamanhos de partícula médios menores de 6.0 µm, não detectados pela técnica de OCT, que permitiu apenas a identificação de partículas maiores pertencentes à fase interna dos sistemas emulsionados. Os resultados reforçam a introdução da OCT como metodologia promissora para a caracterização morfológica de emulsões cosméticas; no entanto, a técnica requer aprimoramento para garantir maior sensibilidade na análise de partículas de menor tamanho.Unitermos: Emulsões cosméticas/caracterização físico-química. Tensoativos. Tomografia de coerência óptica/caracterização morfológica. Microscopia óptica/ caracterização morfológica. Difração a laser/ caracterização morfológica.

Development, characterization, and evaluation by cutaneous bioengineering of a natural emulsion, to provide a standardized vehicle base for topical compounded preparations

“…However, these methods do not allow to examine the droplet diameter as in microscopic analysis. For this reason, microscopic analysis cannot be compared with these other instrumental methods (Prestes et al, 2016).…”

The Simulation of Granular Particle on Dry and Moisturized Porous Horizontal Surfaces

“…Pores can be enlarged in size and amount based on exposure to sunlight and lifestyle, which is an open problem for the skin [8]. The size of cosmetics in the market is very diverse and is taken as samples in the diameter range of 1 to 3 μm [9][10][11]. Recently there has also been an interest in the presence of nanoparticles in products such as cosmetics, which are under 100 nm [10], [12].…”