The ultraviolet rays (UV) included in sunlight influence the human bodies in ways such as photoaging, immune suppression, DNA damage, spots, wrinkles and skin cancers. Nowadays these influences of UV are known to be due to photoaging. Therefore, consumers need sunscreen products with UV protection. There are a lot of sunscreen products whose use depends on the situation. For example, the sunscreen functions should include higher UV protection and water resistance when people use a product in the sea or swimming pool during the summer. On the other hand, for daily use such as commuting and shopping, products should be composed mainly considering their texture in order to get a better feeling. In these situations, to develop products depending on each set of circumstances is important. The main points are the function of having higher UV protection and a texture which is related to better feeling. However, it can be said that the function and the texture are mutually incompatible. In this article, ways of combining these two elements are described.

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We determined fundamental properties and efficacy for a cosmetic ingredient of 2-(dimethyldocosylammonio) ethyl octadecyl ethyl phosphate (DOEP). It is a gemini compound that has a phosphorylcholine-like moiety. A gemini compound is known to exert unique properties such as high self-assembly and surface activity. The phosphorylcholine moiety is widely used in the life science field due to its high biocompatibility and safety. With these facts, DOEP was expected to have the doubled benefit of a gemini compound and a phosphorylcholine moiety. As an evaluation of fundamental properties, we observed the same assembly of DOEP in water that other gemini compounds tend to exert. We understood that DOEP has high self-assembly in the water phase, because it could form nano-size multi lamellar vesicles easily just by being stirred with a homogenizer. In this study, we evaluated both skin and hair for efficacies of DOEP as a cosmetic ingredient. About effects for the skin, DOEP had remarkable functions to cure the stratum corneum with improved transepidermal water loss and rising water content level. Observation of the hair surface with SEM showed DOEP also effected recovery of damaged hair cuticle. We considered these functions to have been brought about by the high self-assembly of DOEP. It formed multi lamellar-like hydrophobic layers on the surface of the skin and hair.

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In order to develop a procedure for scalp massage that increases the blood circulation effectively, the changes in the scalp blood flow after the stimulation of several basic massage methods against the scalp were investigated comparing the blood flow changes against the soft tissue body. Among the basic methods, it was found that the “pressing” method increased the blood flow most for the scalp while the “friction” method only increased the blood flow against the forearm. Then a scalp massage which could be done for about 3 minutes by oneself was assembled. The scalp blood flow increased by 120% against the baseline and continued for more 20 minutes after the single treatment of this massage, and it was also found that daily massage treatment for 7 days increased the score of the scalp mobility by the hand. This procedure for scalp massage could be feasible for investigating the physiological effects of blood flow promotion and hair growth by continuous application for a long period.

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We investigated the transdermal penetration-enhancing effect of 2-(Dimethyldocosylammonio) ethyl octadecyl ethyl phosphate (DOEP). In recent years, several reports have shown that various kinds of vesicle-forming compounds can enhance dermal penetration of a drug. DOEP also self-assembled to form vesicles in water, thus it was expected to enhance penetration. We investigated this function using three-dimensional cultured human skin to determine the penetration-enhancing effect on both of hydrophilic (Antipyrine) and hydrophobic (Flurbiprofen) substances. DOEP has a penetration-enhancing effect for both substances, but significant difference was obtained for the hydrophilic substance only. The results of calculation analysis of transdermal permeation suggested that the function was brought about by advancing the partition parameter but not the diffusion parameter. This means that DOEP might improve migration from the test solution to the stratum corneum.

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Methods for applying cosmetics to the facial skin have significant influence on the texture and make-up finish. We newly developed an electrical tapping puff embodied with up-and-down vibration, and examined its usefulness as compared with make-up techniques of a consumer and a make-up artist. Using an O/W liquid foundation as a cosmetic product, the thickness, adhesion force and uniformity of the make-up layers on the skin were evaluated. These properties of the make-up layer from the tapping puff were nearly equivalent to those of the make-up artist, and were superior to those of the consumer's hand technique. We concluded that, by the use of the tapping puff, the average consumer can expect make-up effects similar to those achieved by make-up artists.

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