Age-related alterations of skin surface condition such as fine wrinkle, roughness, dryness, and uneven pigmentation, are the major problems which could be improved by cosmetic skin care products. The manipulations of the stratum corneum induce a variety of biologic and pathologic responses in the underlying epidermis and even in the dermis. Thus, increased understanding of the alterations of stratum corneum with aging has important implications for the therapy and prevention of aforementioned skin problems. In this paper, I will discuss the changes of the epidermis with aging, focusing on the stratum corneum and its barrier function. I will also show several recent data which would lead to clinical improvements in age-associated skin problems.

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When we evaluated the safety, stability, physical, and surface properties of hydroxylated lecithin, we hypothesized that unsaturated bonds of the fatty acid residues in lecithin that are hydroxylated would cause improved solubility, oxidative stability, color, and smell.
From the result of in vitro test, we found that hydroxylated lecithin showed no toxicity and high safety. We achieved our purpose in greatly improved solubility, oxidative stability, color and smell. We also found that hydraxylated lecithin is not only an excellent emulsifier but it also has solubilizing property as a surface active agent made from natural material.
In order to evaluate the properties of Hydroxylated lecithin contains 70% phosphatidyl choline 50% glycerol solution (SH 50), we dissolved hydroxylated lecithin in glycerol to improve handling. We found SH 50 can be used as an excellent ingredient for cosmetic application. Not only does it have the properties of hydroxylated lecithin but it also has excellent solubilizing property, excellent synergistic solubility, high water-absorbing and retaining properties when compared to hyaluronic acid sodium salt, and reduces irritation caused by sodium laurylsulfate.

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Soap has been the most popular surfactant, because of its low price, rich foam, and refreshed feeling after washing. However, it is sometimes said that soap feels squeaky in rinsing and stretched after dried.
We searched mild surfactants to solve these problems, while preserving good points of soap. As a result, lysine salt of fatty acid is found to be a good surfactant with features as below;
(1) It shows as low primary irritations to both skin and eye mucosa as popular mild surfactants.
(2) It shows better biodegradability than other salts of fatty acid.
(3) It has excellent foaming power under various conditions, i.e. low concentration, weak alkaline region.
(4) In sensory test, it shows rapid foaming, rich foam volume, long lasting foam at washing, and refreshed, moisturized, smooth feeling after dried.

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An amino acid based mild surfactant, potassium cocoylglycinate named GCK, was newly developed. It showed the excellent lathering property from neutral to alkaline region in comparison with soap. The measurements of a Bingham yield value showed that GCK enhanced firmness and elasticity of lather when combined with soap. Desirable feeling of GCK as a cleansing for the skin, such as refreshing, supple and not tight was confirmed by the sensory evaluation. The solubility of GCK was higher than that of soap from neutral to alkaline region indicating that GCK based liquid cleansing compositions can be prepared more easily than soap based compositions. Rheological properties of the GCK solution was investigated for formulating liquid cleansing compositions with desirable viscosity. The additions of sodium chloride increased the viscosity of the GCK solution. The measurement of the complex shear modulus in the GCK/NaCl/water system showed that GCK made gel-like structure when the concentration of GCK is equal to 20wt% and that of NaCl is at least above 8wt%. The liquid crystal structure was confirmed by the polarized microscopic observation when the concentrations of GCK and NaCl are equal to 20wt% and 10wt%, respectively at 25°C.
Safety evaluations such as a Draize test and a human patch tests showed that GCK is less irritating and less harsh to both for skin and eye than soap.
From the results shown above, we conclude that GCK is a desirable ingredient of cleansing compositions for cosmetics and toiletries.

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The interest in the fitness has been highly increased in these days, but it has not been clear how much we can get slim about body parts with a bicycle ergometer training, As the factor of effectiveness related to the 5 months training, we newly employed the change of body parts length (waist, hip, thigh, calf, ankle) in addition to the such conventional one as the change of body weight, body fat, and maximal oxygen uptake. As the result of it, we have confirmed the following effects.
1. Women have got slim easier than men, especially hip and calf of women.
2. Both women and men have got stiffer body since the body fat have been replaced by muscle.
As the energy intake from food stuff were not significant change around the training period, we thought the main reason of those effect was a bicycle ergometer training.

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The water content in stratum corneum (SC) depends on two impotant functions of SC; retention of moisture and prevention of water loss. The effectiveness of most moisturizing agents and synthetic lipids used in cosmetics are very limited because none available today can simultaneously promote both of these functions.
We have synthesized an amphiphlic polymer, poly [2-methacryloyloxyethyl phosphorylcholine (MPC)], and found its unique properties. The application of poly (MPC) on normal skin increases the water contents in SC, reduces transepidermal water loss, and improves the skin surfase condition.
SC contains two types of water: bound water and free water. Bound water content of the abnormal SC with keratosis is 20 to 30% less than that of normal SC, which suggests the importance of bound water on the water retention in SC. Our studies show that poly (MPC) is capable of penetrating into SC to bind water and enhance the water-retaining mechanism. The ability of poly (MPC) to increase bound water was found to be greater than that of typical moisturizers. Bound water content of a lamellar structure increased by poly (MPC) even after the appearance of free water. Poly (MPC) was found to increase bound water in intercellular lamellar structure of SC by a mechanism different from that of proline and sphingolipid.
The clinical tests confirmed that poly (MPC) is effective in treating dry and dry dermatoses on human subjects whose SC functions are severely weakened. It is confirmed that poly (MPC) is an effective material for enhancing SC's both key functions.

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A personal computer calculating system was developed to determine the ideal aqueous phase concentration of parabens in emulsion type cosmetics. The aqueous phase concentration of preservatives was considered to be important to determine the preservativity of emulsion type cosmetics. The proposed calculating method of aqueous phase concentration of parabens was based on the idea of oil-aqueous phase partition.
However, since this calculation was considered to be too difficult to carry out in a short time, a simple system was developed; when concentrations of materials (oil phase, aqueous phase, and parabens) were entered into the computer on the keyboard, the aqueous phase concentrations of parabens were displayed on the computer screen in figures and graphs. This system contained software (MS-EXCEL for Macintosh ver. 5.0) that consisted of a calculation program and data.
Bean's equation and Kurup's equation were used in the calculation program. Partiton coefficients of the simple system were determined and applied to this software.

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In these days, semi-permanent hair-dye products are popular in Japan. Because they are easy to treat hair and change the color. They consist of Acid Dye, Organic Acid and Benzyl Alcohol in general. But carrier ingredients like a benzyl alcohol cause hair damage and unstable emulsion system. So it's very difficult to develop emulsified semi-permanent hair-dyee products. We have studied emusifing method, surfactant and conditioner on the products including carrier ingredients. Then, we have some informations about stable semi-permanent hair-dye in emulsion system.

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