(1) Catalytic activity of pigments often causes problems in mixture systems used in cosmetics, such as oxidation of oils and decomposition of perfumes. These pigments generally contain transition elements, such as chromium, iron, and manganese. Linalool, a common component of perfumes, is dehydrated via a carbonium-ion intermediate at acidic sites of the pigments. Linalool molecules experience allyl rearrangement to form a cyclized structure. The cyclized molecules are further dehydrogenated to result in p-cymene, which is a main cause of unpleasant odor in certain pigmented cosmetics.
(2) Surfaces of the pigments used in cosmetics were modified with various chemical substances, which include metal oxides, metallic soap, silicone-and fluorine-contained compounds. In particular, a novel two-step method to produce pigments possessing various functional groups was developed. The method consists of chemical vapor deposition of 1, 3, 5, 7-tetramethylcyclotetrasiloxane and hydrosilylation of various vinyl compounds. The silicone film formed on the pigments at the first step has a thickness of less than 1.0nm and various functional groups could be attached to the film.

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A new instrumental method for determining the combability of human hair, which measures dynamic combing force (DCF) during the shampooing process from washing to drying, has been developed.
The data obtained from DCF measurements for various surfactant solutions, model conditioning shampoos and rinses have been discussed in terms of the qualitative changes in DCF-pattern and the quantitative standardized values (Q/Q₀).
Results of DCF tests for various hair treatment agents clearly indicate that changes in the condition of the hair surface make a major contribution to the combability.
The application of DCF technique has enabled us to evaluate one characteristic of hair care products (shampoo, rinse, conditioner, etc.), and will aid in the search for new conditioning agents which will improve combability.

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Age related alterations in characteristics and morphology were studied in 144 healthy females (18-62 years old). In this research, questionnaires, macroscopic observation of external appearance, measurement of physiology, elasticity, blood flow, skin color, and analysis of skin surface microtopography from replica were conducted.
Questionnaires indicated many panelers to suffer from neck beauty, but to hardly seek neck treatment. Wrinkles and skin slackening due to reduction of elasticity were mostly observed, followed by suntan and pigmentation. Wrinkles and acrochordon increased after 25 years of age and were observed in 70-80% of the panelers after 25 years of age. Angioma senile was observed in 30-40% in almost all age groups and had no relation to aging. Pigmentation was hardly observed until 30s, and increased after the 40s. However, the frequency of pigmentation was less in neck than face or head. Significant reduction in elasticity was observed with aging, the degree in the neck being less than that of the face. Change in blood flow and skin color was not significant with aging. Morphological change in the skin surface with aging was analyzed from replica. Results in vertical and horizontal directions differed and change in the horizontal sulcus cutis was observed to a greater extent than in the vertical sulcus cutis. Change rate in the horizontal sulcus cutis compared to the vertical sulcus cutis increased with aging.

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The peroxidation of human skin surface lipids was investigated by a CL-HPLC (chemiluminescence-high performance liquid chromatography) system. Squalene mono-hydroperoxide was produced at the forehead and the scalp as well as in the dandruff under daily life conditions in most of the cases. Therefore it was considered that squalene was the first target lipid on a human skin surface by an oxidative stress. In order to confirm the effect of squalene monohydroperoxide on proliferation of cultured cells and TESTSKIN^TM (Living Skin Equivalent), an authentic squalene mono-hydroperoxide was prepared by a dye-sensitized photooxidation and its chemical structure was identified by ¹H-NMR, ¹³C-NMR and FAB-MS. Detection limit of squalene mono-hydroperoxide in CL-HPLC system was as little as 1 pmol. We also found that cosmetics containing antioxidants had a preventive effect against the lipid peroxidation on a Human Skin Surface.

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Psychophysical factors structuring the feel of skin lotion were determined from the subjective estimation of tactile sensation and whole impression. First, 300 words expressing the feel of skin lotion were collected, synonyms were reduced, and then 41 words were selected to make a questionnaire. The 41 words were deviled into 3 categories; the tactile sensations of skin lotion in application (A), the tactile sensations of skin surface after application (B), and the impressions as a whole (C). Subjects were 240 female volunteers (aged 20-49yr), who were classified into three groups according to the self-reported skin surface conditions; oily, normal, and dry. In the experiment 16 skin lotions were used, each of which had different textural properties. Subjects were assigned to each lotion according to our experimental design, and they were asked to use the lotion and to estimate their feel by an 8-point scale on each of 41 words.
Factor analysis was applied to each words category, and 7 factors could be identified; sticky BETATSUKI and slimy NUMERI obtained from category A, sticky BETATSUKI, softness YAWARAKA and smooth SARASARA obtained from category B, and comfortableness KAITEKIKAN and refreshed SAPPARIKAN obtained from category C. Factor analysis was applied to each of oily, normal, and dry skin group. No obvious difference could be found between these three groups concerning the psychophysical factors structuring the feel of skin lotion. Furthermore, the multiple regression analysis applied to the factor scores showed that the higher the estimation of skin softness is, the higher the scores of comfortableness are (standard partial regression coefficient: 0.44). The study showed an approach to survey the relationship between comfortableness and tactile sensation of skin lotions.

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A method for systematic analysis of esters of nonionic surfactants was carried out.
When the UV/RI ratio were plotted against the elution volume for Tween type and Span type surfactants, relationship between the UV/RI ratio and elution volume was displayed specific pattern to each surfactants.
When nonionic surfactants were analyzed with methanol-tetrahydrofuran (1:9) as a mobile phase on the Gel Permeation Chromatography, systematic analysis of two esters of nonionic surfactants were quantitatively enabled.
By the use of calibration curves of standard polystyrene were known to be measurable the molecular weight Tween type and Span type surfactants.

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