The harmful effects of UV rays on living organisms are well-documented. Many newly developed cosmetics, including skin-care and make-up products, now incorporate UV-protection technology.
In this report, development of raw materials for sun protection, dispersparticle dispersion technology and procedures for the evaluation of make-up cosmetics are discussed.

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The sunscreens labeling the highest sun protection factor (SPF) number launched each year in Japan. Although the highest SPF number was 30 in 1990, in 1997 the SPF value reached 87 at last on the market. However we know the sunscreen with high SPF can not completely protect us against suntan and pigment darkening, because UVA is also responsible for these reactions. So consumers demand to be informed of UVA protection efficacy of sunscreens.
Therefore, protection grade of UVA (PA) which classifies the degree of UVA protective effect, has become labeled on the sunscreens together with SPF since the beginning of 1996. This PA indication is to be labeled based on the protection factor of UVA (PFA) measured according to the standard methods of UVA protection effect established by the Ultraviolet Task force in Technical Committee of The Japan Cosmetic Industry Association.
This paper reports the technical information for determining the Standards and more previous reports for UVA and UVB protection measuring method are introduced.

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The development of the water-based nail enamel has been a dream of cosmetic scientists for a long time, because of many improvable points. The most difficult point is to obtain good wearability of the applied film. When polymer emulsions are used as a film forming material, the wearability depends mostly on the polymer's chemical compositions and its film's physicochemical properties. According to our studies on various factors, we found out that the incomplete coalescence between the polymer particles was one of the main cause of poor wearability.
To get a completely coalesced film, and at the same time satisfy the basic properties generally required for nail enamels such as fast dryability at room temperature and sufficient film strength etc., we investigated numerous types of polymers. And finally, we could successfully develop a novel polymer emulsion including a coalescence accelerating compound inside the polymer particles. The film formed from this polymer emulsion showed complete coalescence between the polymer particles and good wearability on the nail. We named this a coalescence accelerating polymer emulsion.
In this paper, we'd like to report about its properties, the unique coalescing mechanism and some interesting characteristics of the water-based nail enamel prepared from this polymer emulsion.

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Recently it has been recognized that UVA protection would be one of the targets in the cosmetic industry because UVA causes pigmentation, photoaging or augmentative effects to responses by UVB. Furthermore, consumers have demanded to know what degree of protective efficacy against UVA each sunscreen had. Thus, we, Japan Cosmetic Industry Association-Ultraviolet Task Force, attempted to establish the standard test methods in Japan.
The skin responses in Japanese were investigated after exposure to UVA. Immediate pigment darkening was elicited immediately after exposure to a small amount of UVA, and they were faded out rapidly. However, black tanning on the site exposed to large amount of UVA turned to brown about 2 hrs after exposure and this tanning was stable. On the other hand erythema didn't appear in almost all volunteers. From these results we selected the tanning observed between 2 and 4 hrs after exposure as a marker in the UVA test method. This tanning was termed “persistent pigment darkening, ” and “minimal persistent pigment darkening dose” (MPPD) is the minimal amount of UVA required to elicit persistent pigment darkening. The protection factor of UVA (PFA) was expressed as a ratio of MPPD on a protected site to that on a non-protected site.
Next, we selected standard sample and then investigated the effects of observation time after exposure, skin type of volunteers and light sources of UVA on PFA using the standard sample (including 3% p-methoxycinnamic acid 2-ethylhexyl and 5% 4-tert-butyl-4′-methoxybenzoylmethane). The results showed that PFA didn't depend on these factors. The obtained PEA of the standard sample was 3.75 (SD: 1.01).
Based on these results, we established the standard test methods for UVA protection. Since these PFA values do not directly reflect the preventive effect on sunlight induced tanning in actual daily life, we decided that the grade of UVA protective potency of sunscreens should be labeled as PA+, PA++, PA+++ depending on their potential.

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The relationship between apparent darkening evaluated with the naked eye and age-associated changes in the physical properties of the skin (e.g., roughness or transparency) was clarified by defining two new physical properties: micro roughness and spectral transparency. Also, ways to quantify these properties were sought. The relationship between the degree of darkening, Y, discussed in the previous report and these two physical properties was investigated. The results showed that by adding these two physical properties (micro roughness and spectral transparency) to the existing parameters, namely the degree of coloring caused by melanin quantity, M₁, and the quality of blood circulation and flow, M₃. it was possible to more accurately and objectively quantify the degree of apparent darkening evaluated with the naked eye.

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Cosmetics and quasi-drugs will play new important roles in the aging and stressful society. We have proposed 3 clinical concepts, i.e., anti-drying, anti-UV radiation and anti-oxidation to prevent the skin aging. Especially, the importance of anti-oxidation is discussed in this paper. The results of the investigation of the peroxidation on skin surface using a CL-HPLC system, it was considered that ringlet oxygen was the key active oxygen on a human skin. We have clarified the reaction rate constants of the skin surface lipids and hypotaurine with singlet oxygen. And we have also confirmed that hypotaurine had a preventive effect against the peroxidation of squalene in a photo-oxidation system. Hypotaurine is known as a compound in a metabolism of sulfur containing amino acids and it exits in skin, eyeball, liver, brain, heart, serum and etc. And the “raison d'être” is also discussed in the living system for anti-oxidation. We propose that the re-structure and the reinforcement of the anti-oxidation mechanism in the living system will be the useful new concept in cosmetics.

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