66 JOURNAL OF COSMETIC SCIENCE beautiful finish with natural skin-transparency and can allow the finish to last longer. In response to this wish, we have attempted to develop an ideal powder material that can yield the dual function described above. Based on the fundamental knowledge of the physiological and optical characteristics of human bare skin, we designed an optimal microstructure for powder with an ideal optical character. A hybrid powder, which is an interference-pearl type TiO2/mica powder covered with a fiber-type ZnO by a morphologically controlled technology, was synthesized. The powder has a dual function. As a physico-chemical function, the powder can absorb and solidify sebum with its nano-scale fiber-type ZnO ( diameter:approximately 50 nm) of which the microstructure is controlled at the crystalline level. As an optical character, the powder can reflect a diffuse interference red light wich is generated from the microstructure of the powder surface. A foundation containing the powder (8w/w%) can maintain the initial natural finishing with a beautiful transparency and give a dry-refreshing feeling for a significant period of time through its physico-chemical ability to absorb and solidify s'ebum on the skin. Since this new hybrid powder provides an optical character and a useful physico-chemical character, it has proven to be a valuable cosmetic ingredient of base-makeup products. Spectroscopic Characterization of Color Polymorphism in the Orbital Skin Yuko Fukuda*2, Hajime Soga*2, Hirayuki Satoh*3, Takashi Kitahara*2, Naonobu Yoshizuka*4, Yoshinori Takema*2 *2 Biological Science Laboratories, *3 Research Center for Characterization and Analytical Science, *4 Global R&D Safety and Environment, Kao Corporation, 2606, Akabane, lchikai-machi, Haga-gun, Tochigi 321-3497, Japan The color and shape of the orbital skin have specific properties, differing from those of the cheek and forehead. Changes in the properties of the orbital skin are recognized as so-called "dark circles." To understand the variety in the color and shape of the orbital skin, we previously observed the orbital skin in 180 healthy females, and found color tone characteristics (brown, red, and blue) and various morphological characteristics. We also established a photographic scale for their scoring and reported the results of the analysis of their correlation with age at the 48th Conference of the SCCJ. In this study, to clarify the association of skin color tone with melanin and regional blood flow, analysis of skin properties by non-invasive spectroscopy and assessment by scoring using the photographic scale were performed in 60 healthy females. The brown tone score was positively correlated with the melanin index. This suggested that the brown tone in the orbital skin is due to melanin. The red tone score was positively correlated with the Hb value and negatively correlated with the blood flow rate. These results suggested that the red tone in the orbital skin is due to increased Hb and blood flow stagnation. The blue tone score was negatively correlated with oxygen saturation and blood flow, suggesting that the blue tone in the orbital skin reflects blood flow stagnation and decreased skin circulation. These results suggested the important role of regional blood flow, and changes in melanin content play important roles in changes in the color tone of the orbital skin. Methodology for Evaluation of Skin Transparency and the Efficacy of an Essence That Can Improve Skin Transparency Yuji Masuda, Naomi Kunizawa, Motoji Takahashi Bioengineering Research Labs., Life Science Research Center, SHISEIDO Research Center, 2-2-1, Hayabuchi, Tsuzuki-ku, Yokohama 224-8558, Japan Transparency of the skin is an important factor for realizing beautiful skin, but there is only a visual sensory evaluation method by a beauty specialist. It is unclear how skin physiological characteristics can give transparency. Our purpose is to establish an objective method for evaluating the transparency of the skin and to develop a special cosmetics product which can enhance skin transparency, after investigating the mechanism of the skin characteristics which yield transparency. We developed an optical instrument that could independently measure a diffuse reflection as well as a specular reflection by assembling a polarizing filter in a gonio-spectrum photometer. We analyzed the relationship among skin transparency, specular reflection light and diffuse reflection light. It was shown that there was a strong positive correlation between the skin transparency and the intensity of the diffuse reflection light (r=0.699) and no correlation between the skin transparency and the intensity of the specular reflection light (r=0.190). The results of partial least squares (PLS) analysis of the skin transparency and the skin physiological characteristics showed that a highly transparent skin has a fine skin

ABSTRACTS 67 surface texture with a high hydration of stratum corneum, a low melanin content and a low hemoglobin content. On the basis of these results, we developed an essence that can improve skin texture and blood flow, reduce melanin content, and increase the moisture in the stratum comeum. After eight weeks' usage of this product by consumer panels (u=30), it was confirmed that the skin transparency was improved by the increase of the intensity of the diffuse reflection light by gonio-spectrum photometer measurement and by consumers' self-assessment. Vol. 39, No. 4, 2005 Basic Knowledge on Cosmetic Dermatitis and Its Future Aspects Hideo Nakayama Nakayama Dermatology Clinic Common cosmetic dermatitis is composed of mainly chronic irritant contact dermatitis, allergic contact dermatitis and pigmented cosmetic dermatitis. Special types include atopic contact dermatitis due to cosmetics, complication of corticosteroid dermatosis, and eyelid dermatitis. Common cosmetic sensitizers are various liquid type oil. It was found that ( 1) using amphiphiles as the solid oil gave a spherical and visible sized particle and (2) behenyl alcohol was the most preferable amphiphile to make a large sized particle. DSC measurement and microscopic observation of the particle showed that the amphiphilic solid oil built a shell on the outer side of the particle and the shell protected the emulsion against aggregation and coalescence. It was found that the preparation of an extremely large emulsion could create innovative functions in the cosmetic field. The visible sized emulsion could provide a freshening feel in the early stages of the application and an emollient feel after rubbing into the skin. Furthermore, since this fragrances, pigments and base components. The best emulsion could protect an unstable lipophilic material from treatment to stop the recrudescence of cosmetic dermatitis is to perform patch testing to discover causative allergens for the patients, so that allergen control becomes possible later. It has been the only effective method to perfectly cure the disastrous pigmented cosmetic dermatitis with Mongoloids in the past. The avoidance of very allergenic fragrances (class A fragrances in the table) and two pigments, D&C Red No.31 and Yellow No.11 is essential to reduce cosmetic dermatitis of the consumers. The introduction of guidelines to avoid strong sensitizers is recommended. Recently, eyelid dermatitis due to allergy or irritation has been common and rubbing itchy eyelids has hydrolysis, it offers a suitable storage for useful cosmetic ingredients such as lipophilic drugs and hydrophobic powders. Polymerization of a Water-Swellable Microgel by a Novel Inverse Microemulsion Polymerization and Its Application as a Viscosity Thickener for Cosmetics Isamu Kaneda, Atsushi Sogabe, Hideo Nakajima led to blindness due to retinal abrasion. Adding various Material Science Research Center, Shiseido Co., Ltd. plant components seemed to have increased the irritation, and it is better to be avoided hereafter. A water-swellable micro gel was polymerized in the inverse The Preparation of Visible Emulsions and Its Applications to Cosmetics Tohru Okamoto* * , Yuji Matsushita* * , Eiko micelle of a nonionic surfactant, namely a confined space. The microgel was polymerized using 2-acrylamido-2- methylpropanesulfonic acid, dimethyl-acrylamide, and methylene-bis-acrylamide. To determine a suitable polymerization system that appeared W / 0 microemulsion at around 6S ° C, the phase diagram of the pseudo-ternary Matsuura * * * , Masaru Masuda * * * Shiseido system was studied. The microgel polymerized in the Material Science Research Center* *, Shiseido Product system was isolated by a reprecipitating method Development Center* * * consequently the samples were obtained as powder. The We developed a preparation method for visible emulsion droplets (0.05-3 mm) consisting of a solid type oil and a rheological properties of the microgel were studied after re- dispersing the powder sample in an aqueous medium. The viscosity-thickening effect of the crosslinked microgel was