COMPARISON OF EMULSIONS IN THE CARE OF DEMANDING AND ATOPIC SKINS 413 Stefanów–Wólka Kosowska, Poland), soy lecithin (Hortimex, Konin, Poland), carboxy- methylcellulose (Barentz, Hoofddorp, Netherlands), sodium benzoate (Galfarm, Kraków, Poland), and aloe vera leaf pulp (own breeding). The following 10 commercial products (fi ve creams and fi ve balms) for AD obtained from local pharmacies and drugstores were used: (a) Cream (C1) and balm (B1) producer: Pierre Fabre (b) Cream (C2) and balm (B2) producer: DermaProfi l (c) Cream (C3) and balm (B3) producer: Nepentes (d) Cream (C4) and balm (B4) producer: Oceanic (e) Cream (C5) and balm (B5) producer: Pierre Fabre METHODS FATS INTERESTERIFICATION Mutton tallow and sesame oil in the ratio 2:3 (w/w) were interesterifi ed using sodium methoxide (0.6%) as a catalyst. The reaction was performed at 90°C (in an oil bath) for 2 h. The process was stopped by the addition of diluted H3PO4 to neutralize the catalyst. The fats were extracted with diethyl ether and dried with anhydrous magnesium sulfate. The detailed description of the aforementioned procedure is given in (10). EMULSION PREPARATION The accurately weighed fat and lecithin blend was transferred to a beaker and heated in a water bath to about 50°–55°C. After melting of the components, the blend was mixed to obtain a uniform consistency. Constant temperature was maintained during the whole process. Carboxymethylcellulose was dispersed in water using a mechanical stirrer, and the solution was heated to about 50°–55°C in a water bath. The oil phase was slowly added to the aqueous phase by manual stirring then, homogenization was performed. The aloe vera leaf pulp was added, previously prepared by aloe leaf crushing. After cooling the emulsion to 30°C, a preservative was added. Table I shows composition and homogenization param- eters of the prepared emulsion. Table I Composition and Homogenization Parameters of the Prepared Emulsions Component (% w/w) Interesterifi ed mutton tallow with sesame oil in the ratio (2:3 w/w) 30.0 Lecithin 5.2 Carboxymethylcellulose 1.0 Water Up to 100.0 Aloe vera 0.8 Sodium benzoate 0.3 Homogenization parameters Time (min) 4.0 Speed (rpm × 1,000) 18.5

JOURNAL OF COSMETIC SCIENCE 414 DROPLET SIZE MEASUREMENTS Microtrac Particle Size Analyzer (Leeds and Northrup, Philadelphia, PA) was used to deter- mine droplets’ size and their distribution of our own formulation. The measurement was based on dynamic laser diffraction and performed 24 h after the emulsion preparation (the emulsion was stored at 7°C). The result was given as an average of three measurements. TURBISCAN TEST Stability of our own preparation was evaluated using Turbiscan Lab (Formulaction, Toulouse, France). The device enables to detect invisible, unfavorable physicochemical changes occurring in a sample. The instrument uses pulsed near infrared light (880 nm) and measures the intensity of transmitted and backscattered light as a function of sample height (11). Our own formulation was divided into three samples stored for the same time (1 mo) in different conditions (8°C, 40°C, and room temperature). The results were presented as a delta backscattered light intensity (ΔBS) in the reference mode (ΔBS = BSt - BS0). SKIN HYDRATION MEASUREMENTS Skin hydration (skin capacitance) was measured by means of Cutometer MPA (Multi Probe Adapter) using Corneometer probe (CM 825 Courage & Khazaka, Cologne, Ger- many). The device is used to determine the degree of stratum corneum hydration up to 0.45 μm of skin depth (12). Measurements are carried out by means of a capacitive method, based on a dielectric constant of water and other substances (usually 7). Corne- ometer shows variations of skin capacitance depending on moisture level changes. The measurements were performed under standard conditions of temperature and humidity (T°C = 20°–22°C, humidity 40–60%), away from direct sunlight. A control point was pure skin without any preparation. The test included measurements performed immediately after a time t 30 min, 60 min, and 120 min of product application (~0.01 g) on a forearm skin fragment. Ten women participated in the test, with no special symptoms of atopic skin but having dry and sensitive skin because of the fact that presented own preparation was model emulsion. Research was conducted by a trained person. To have valid results, the readout was always taken three times. To obtain the results of skin hydration percentage difference, the following formula was used: 0 % (SC SC ) SH SC0 % q100% t ΔSH%—skin hydration percentage difference (%), SCt—skin capacitance after a time t (AU), and SC0—skin capacitance of the control point (AU). The results are presented as a mean value of skin hydration percentage increase for all the respondents after t for each commercial product and the authors’ formulation. TEWL MEASUREMENTS Transepidermal water loss was determined by means of Cutometer MPA using Tewameter probe (TM 300 Courage & Khazaka). The measurement was based on Fick’s diffusion