ABSTRACTS 175 in the middle section, and finally to the cortical cell surfaces and the intercellular cement at the tip end in long hair. The resulting increase in fluorescence emission intensity is indicative of progressive damage to the cuticular structure, ultimately resulting in the loss of the cuticular sheath. Scanning electron microscopic observations show detailed features of progressive cuticle erosion and ablation. Characteristic changes in the ph ys ical nature and sha pe of the cuticle cell compared to it appearance as it emerged from the follicle are indicative of environmental and mechanical damage inflicted upon hair. Change of the smoothly contoured scale edge to its jagged shape, frequent appearance of »failed endocuticular material« left behind after the inextensible A-layer and exocuticle have been chipped away, and »tear lines« or »seams«, which are the loci where the surface cuticle cells were originally attached, are indicative of progressive cuticle erosion. Resolving the Conflict of a Simultaneously Highly Moisturizing and Occlusive Emulsion Film Yuji Sakai, Masashi Suzuki, Yasuhiro Ohara, Shinya Okabe Skin Care Products R&D Department, POLA Chemical Industries, Inc., 27-1 Takashimadai, Kanagawa-ku, Yokohama 221-0833, Japan Two basic functions of emulsion-based cosmetic products, moisturization and occlusion, are markedly affected by the ratio of hydrophilic to li po philic parts in the emulsion. However, due to their conflicting r eq uirements, it is difficult to simultaneously improve both functions. In studies to resolve this problem, we focused on the emulsion film structure because an applied emulsion film is in contact with skin directly and performs functions of the emulsion. We h yp othesized that if an emulsion film were similar in structure to healthy stratum comeum, it would be possible to simultaneously enhance the moisturizing and occlusive functions because healthy stratum comeum contains large amount of water and the amount of water loss from the skin surface is low. To disperse a large quantity of water in the lipophilic part, just as comeocytes of healthy stratum comeum contain a large quantity of water, we focused on the dispersant Polyglycerin-type surfactants and cetyl alcohol proved useful. To strengthen the hydrophilic part, just as intercellular lipids of the stratum comeum are rigid, we focused on the emulsification method and hydrophilic surfactant. Due to the properties of a polyglycerin-type surfactant, it is generally difficult to form a liquid crystal structure, but we were able to do this using po lyglycerin-13- polyoxybutylene-14-stearyl ether and the D-phase emulsification method. We confirmed through laser microscopic studies that droplets in conventional emulsions disappear quickly after the film has formed and dried, whereas in our experimental emulsions the droplet shape is even retained. We also found that the inherent film- moisturizing index (IFM) and the inherent film-occlusive index (IFO) were both high for the experimental emulsions. Furthermore, after one month of continuous use, stratum comeum removal (an indicator for skin moisture) and corneocyte arrangement (an indicator for barrier function) also improved significantly. The results of this study show that by focusing on the structure of emulsion films, particularly the relationship between lipophilic and hydrophilic parts, emulsion functions can be enhanced and certain limitations overcome. How Skincare Ingredient Concentrations Can Modulate the Effect of Polyols and Oils on Skin Moisturiz.ation and Skin Surface Roughness 1 Ki 1 J K. 1 J" H Gae Won Nam , Seung Hun m , Eun oo mt , m an Kim 2 , Byeong Gun cha/, Hae Kwang Lee 1 , Seong-Joon Moon 1, Hak-Hee Kang 2 , and Ih Seop Chang 1 1 Skin Research Institute, Amore-Pacific Corporation/R&D Center, Yongin, Korea, 129-749 2 Cosmetic Research Institute, Amore-Pacific Corporation/R&D Center, Yongin, Korea, 129-749 The aim of this study was to evaluate the influence of different skincare ingredient concentrations on the effect of polyols and oils on human skin moisturization and skin surface roughness. Polyols and oils are essential ingredients in a skin care formulation, but it is still not understood how their concentrations affect their efficacy and senso ry properties on human skin. We studied various concentrations of in gr edients from cosmetic companies using noninvasive methods. The polyols consisted of glycerin and butylene glycol (BG) in a ratio of 1:1, and the oils consisted of eq ual parts of hydrogenated po lydecene, cetyl ethylhexanoate and pentaerythrityl tetraethylhexanoate. All compounds were tested in O/W emulsions in concentrations ranging from 0~27% for polyols and from 0~35% for oils. We investigated the effect on water content and stratum comeum roughness on forearm skin after application of the compounds. The skin water content was determined by skin capacitance measurements and the skin surface roughness by visual scoring of skin surface biopsies in the scanning electron microcrographs. The water content of the skin correlated highly with the polyol (up to 20%) and oil (up to 12%) concentrations, respectively. Two hours after application the correlation coefficients were 0.971 and 0.985, respectively (p0.01). Skin surface roughness not only showed a strong concentration-dependence on polyols and up to 6% on oils, but in a multiple regression analysis also correlated with a ratio of 2.5 to 1 (polyols and oils). Further studies will be conducted with other ingredients such as surfactants, lipid and aqueous materials, and with other method'l for noninvasive measurement Formulating for Fast Efficacy: Influence of Liquid Crystalline Emulsion Structure on the Skin Delivery of Active Ingredients Johann W. Wiechers 1 , Caroline Kell/, Trevor G. Blaese 2 , and J. Chris Dederen 3 1 Uniqema Applied Research, Skin R&D, P.O. Box 2, 2800 AA Gouda, The Netherland 2 Uniqema Applied Research, Wilton Centre, Redcar, UK 3 Uniqema Applied Research, Meerbeek, Belgium In a previous publication, we described how the extent of skin delive ry of an active ingredient can be optimized in a cosmetic formulation by the choice of a primary and secondary emollient. This paper describes our initial attempts to explain the influence of the emulsifier system on the

176 JOURNAL OF COSMETIC SCIENCE dermal delivery of an active ingredient Some of the emulsifiers studied in this investigation induced liquid crystal formation in the formulations and were found to interact in two different ways. On the one hand, they prevented the eva po ration of water from the formulation when applied on the skin and in doing so prolonged the delivery phase of water-soluble active ingredients as only solubilized molecules penetrate the skin at reasonable rates. On the other hand, when combined with lipophilic active ingredients, the location to which the active ingredient is delivered was changed. This can be explained by a po ssible interaction of these emulsifiers with the skin lipid bilayers. These are present in an orthorhombic, an hexagonal and a liquid packing, which co-exist simultaneously and are characterized by a relatively low, an intermediate and a high permeability, respectively. The results obtained in this study suggest that the use of these liquid crystal formation inducing surfactant systems favors the presence of the more permeable packing states. In a given time, an active ingredient will therefore penetrate deeper into skin with emulsifier systems that induce liquid crystal formation than with systems that do not. It is therefore suggested that such emulsifier systems be used when fast delivery of a lipophilic active ingredient or more delivery of a hydrophilic active ingredient is required, and non-liquid crystalline systems if slower or less delivery is required. The use of liquid crystalline emulsifier systems therefore allows cosmetic formulators to regulate the extent (hydrophilic active ingredients) or speed (lipophilic active ingredients) of active ingredient delivery and thus to formulate for fast efficacy.