Modeling Oil-in-Water Dispersed System Utilizing Sorbus aucuparia L. Extract: A Study on Physical Properties Assessment

Abstract

Sorbus aucuparia L. contains carotenoid compounds, that enhance skin's innate resistance against UVBinduced erythema, act as an antioxidant and prevent aging-related collagen I degradation in the dermis [1]. In order to formulate an oil-in-water (O/W) type dispersion system, gelling agents are employed to provide the necessary stability and viscosity. Carbomer polymers, derived from acrylic acid, are hydrophilic, white powders, providing acidic pH to the formulations, thus their pH value is adjusted to skin using a 1% NaOH solution [2]. The aim of this study was to analyze the physical properties of the (O/W) type dispersion system using Carbomer 980 as a gelling agent. Rheological properties (rheometer MCR102, temperature controlled via Peltier system) and particle size (Mastersizer 3000) were assessed on diverse emulgel formulations: containing almond oil and containing S. aucuparia extracts. The concentrations of S. aucuparia and almond oil in the emulgels varied as follows: 10%, 20%, 30%, and 40%, with an additional 5% consisting of the surfactant Tween 80, and the rest being Carbomer 980. Particle size measurements, indicated by percentiles (Dx10, Dx50, and Dx90), showed consistent particle sizes across different concentrations of almond oil in the studied emulgels. Moreover, the freeze– thaw test was completed, which consisted of 72 hr freezing (−20 ± 1 °C) followed by 24 hr thawing (20 ± 1 °C). Although emulgels subjected to freezing remained visually stable, with no apparent phase separation, particle size measurements revealed that after the freezing process, the increase of Dx50 is found to be negligible, but Dx90 showed significant increase (43,70 (8,98) μm) compared to pre-freezing particle size (3,30 (0,16) μm). Post-freezing emulgels with a 10% oil concentration exhibited the largest particle sizes. The incorporation of rowanberry extract into the O/W dispersed system resulted in particle sizes (Dx90) remaining relatively consistent (3,23 (0,20) μm), compared to emulgel particles composed solely of oil and not subjected to freezing. A temperature-based test was employed to determine how the consistency of formulations fluctuates with temperature changes. Temperature tests were conducted on formulations containing S. aucuparia extract and those with only almond oil. Results indicated changes in emulgel structure as storage modulus varied. The obtained data showed that over the temperature range (0-40°C) emulgels maintained their semi-solid consistency, regardless of the oil content, indicating stability. Similar research results are evident in emulgels containing both rowanberries extract and almond oil.