JPH0363211A - Cosmetic for fair skin and beauty - Google Patents

Abstract

PURPOSE:To obtain a cosmetic for hair skin and beauty having excellent skin safety and inhibitory action on melanin dyestuff formation, rapidly lightening dark skin by blending a cosmetic base with gamma-aminobutyric acid and urocanic acid and/or urocanic acid ethyl ester. CONSTITUTION:A well-known cosmetic base is blended with 0.05-3.0wt.% gamma- aminobutyric acid and 0.05-3.0wt.% urocanic acid or urocanic acid ethyl ester or 0.05-3.0wt.% total amounts of urocanic acid and urocanic acid ethyl ester and prepared by a conventional procedure to give the objective material. The material may be optionally mixed with a dyestuff, perfume, antiseptic, antioxidant, surfactant, etc. The material can be processed into a dosage form such as cream, milky lotion or lotion. The cosmetic for fair skin and beauty further extremely improves beautifying effects by early use after exposure especially to sunlight.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a whitening cosmetic that has excellent skin safety, has the effect of preventing dark skin, and has the effect of quickly lightening dark skin.

(Prior Art) Dark skin due to sunburn is said to be caused by the fact that tyrosine present in the skin is oxidized to melanin pigment by the action of tyrosinase, and this melanin is produced in excess. In order to prevent or treat this pigmentation, whitening cosmetics containing L-ascorbic acid and its derivatives, colloidal sulfur, hydrogen peroxide, hydroquinone, etc. have been proposed. However, these whitening cosmetics either have insufficient storage stability or do not have sufficient whitening effects, or they have the effect of lightening dark skin, but they do not work well on the skin. This poses a safety problem, and it has been difficult to obtain an excellent whitening cosmetic.

(Disclosure of the Invention) Therefore, the present inventors have aimed to: 1) rapidly eliminate melanin present in excess in the epidermis, 2) suppress new melanin generation within the skin, and 2) ensure skin safety. As a result of intensive research with the aim of creating a whitening cosmetic that satisfies no sexual problems, we have found a whitening cosmetic that is a combination of γ-anobutyric acid and urocanic acid and/or its ethyl ester. The inventors have found that the object can be achieved and have completed the present invention.

(Objective of the Invention) That is, the object of the present invention is to provide an excellent whitening cosmetic that does not cause skin irritation, has the effect of inhibiting melanin pigment formation, and has the effect of quickly lightening dark skin.

(Structure of the Invention) The present invention is a whitening cosmetic comprising T-aminobutyric acid and urocanic acid and/or its ethyl ester.

(Specific explanation of the structure) The γ-aminobutyric acid according to the present invention is a known substance, and is disclosed in Japanese Patent Application Laid-Open No. 148041/1983 that it has an anti-aging effect on the skin due to the skin and tissue activation effect. is listed. In addition, urocanic acid and its ethyl ester are also known substances, and Japanese Patent Publication No. 58-35513 describes a method for producing urocanic acid ethyl ester and that these substances are effective as ultraviolet absorbers. .

The present inventors have discovered that T-aminobutyric acid and urocanic acid or their ethyl ester coexisting in a cosmetic base exhibit a synergistic effect that is significantly superior to that of their individual effects that have been known in the past. The present invention was completed after confirming that the present invention was effective.

In other words, T-aminobutyric acid activates the skin tissue, accelerates the turnover rate of the stratum corneum, and rapidly eliminates melanin together with the stratum corneum to lighten dark skin, and urocanic acid or The effect of suppressing the latent skin melanin formation ability of the ethyl ester and preventing new dark-skinned skin is combined to lighten dark-skinned skin under conditions favorable to skin physiology. It has been newly recognized that this drug is effective.

Therefore, the whitening cosmetic of the present invention is applied to skin that has not darkened or has darkened after exposure to sunlight, especially skin that has become physiologically unstable.
It exhibits a remarkable effect in darkening the skin color or lightening dark skin without causing skin irritation.

The whitening cosmetic of the present invention includes the above-mentioned T-7 minobutyric acid and urocanic acid and/or its ethyl ester in a cosmetic base such as well-known creams, milky lotions, and rosilons.
It is prepared by blending in a conventional manner.

The amount of γ-aminobutyric acid is 0.05 to 3.0% by weight (hereinafter abbreviated as wt%) based on the total amount of the cosmetic, and the amount of urocanic acid and its ethyl ester is: 0.05 to 3 for each alone or the total amount of both
．． Q w t% is sufficient. Even if the upper limit of these blending amounts is exceeded, no effect commensurate with the exceeding blending amount can be expected, and if the blending amount is less than the lower limit, it will not be possible to achieve the purpose of the present invention. It's something that doesn't exist.

The whitening cosmetic of the present invention may contain pigments, fragrances, preservatives, antioxidants, surfactants, skin nutrients, pigments, and the like as appropriate within the scope of achieving the purpose of the present invention.

(Example) The present invention will be explained below with reference to Examples.

In addition, (1) skin irritation test, (2) stratum corneum turnover rate measurement test, (2) skin color brightness recovery test, and (2) whitening practical test described in Examples are shown below.

■ Skin irritation test 0.05 g of sample was applied to the side skin of the forearm layer of 25 subjects exposed to summer sunlight for 6 hours (3 hours a day for 2 days) with a diameter of 1.5 g. After 24 hours of occlusive application using a batch test bandage with Q cm circular lint cloth, each sample was applied to 25 subjects according to the criteria in Table 2 below.
The condition of the skin was evaluated. The evaluation results were determined based on the stronger reaction between 1 hour and 24 hours after removal of the bandage, and expressed as the number of people who rated (±) or higher.

Table 1 Judgment Criteria■ Test for measuring the turnover rate of the stratum corneum An ointment containing 5 wt% of the fluorescent dye danzyl chloride in white petrolatum was prepared and applied as an occluded patch on the skin of the flexor side of the forearm of 20 subjects for 24 hours. and allows danzyl chloride to penetrate and bind to the stratum corneum. Thereafter, a test sample was applied to the area twice a day (morning and evening), the fluorescence of danzyl chloride was examined every day, and the number of days until the fluorescence disappeared was defined as the turnover rate of the skin stratum corneum. The measurement results were shown as the average value of the number of days for each M examiner.

Note that the normal turnover rate of the stratum corneum of the skin is 14
~16th.

■ Skin color brightness recovery test The back skin of 20 test subjects was irradiated with ultraviolet rays in the UV-B region at twice the minimum amount of erythema, and after one round, the irradiated area was divided into areas where the sample was applied and areas where the sample was not applied. The reference brightness (Vo value, Vo' value) of each skin was measured. Subsequently, the sample was continuously applied to the application site once a day for 3 months.
8. After 13 weeks, the skin brightness (Vn value, Vn' value) of the applied and non-applied areas was measured, and skin color recovery was evaluated according to the criteria in Table 2. .

In addition, the brightness of the skin (Munsell color system V value) was calculated from the x, y, and z values obtained by measurement with a high-speed spectrocolorimeter. Moreover, the evaluation was shown as the average value of the evaluation scores of 20 test subjects after 13 weeks.

■ Whitening practical test The skin on the side of the forearm layer of 20 subjects who were exposed to sunlight for 3 hours (1.5 hours a day for 2 days) in the summer was tested. Starting from the day after the day of exposure and from 7 days after the day of exposure to sunlight, each sample was continuously applied once in the morning and evening for 13 weeks on the flexor side of the right forearm.

The evaluation was expressed by the number of subjects who answered that the skin area to which the sample was applied had a fairer complexion (lightening) than other skin areas.

Examples 1 to 4, Comparative Examples 1 to 4 Type 4 lotion] In the following composition, the amounts of γ-aminobutyric acid, urocanic acid and its ethyl ester were changed as shown in the left column of Table 3, Each two-layer lotion was prepared and tested. The results are summarized in Section 3 (1).
The components and component (B) are mixed, stirred and dispersed, and then filled into a container.

When using, shake and disperse the contents uniformly.

(3) Properties As shown in Table 3, the two-layer lotion bases of Comparative Examples 1 to 4 and the lotions in which γ-aminobutyric acid, urocanic acid, and urocanic acid ethyl ester were each individually blended with the bases showed that the stratum corneum The skin whitening cosmetics of the present invention of Examples 1 to 4 were found to have the effect of slightly increasing the turnover rate and reducing the number of days, but no sufficient effect was obtained in the skin color brightness recovery test and the whitening practical test. All tests have been evaluated favorably.

Examples 5 to 9, Comparative Examples 5 to 7 [Skin cream] In the same manner as in Example 1, each skin cream was prepared with the following composition and various tests were conducted, and the composition was determined) Preparation method (^ ), (B) components are each uniformly heated and dissolved to bring the temperature to 80°C, then the (^) component is poured into the (B) component and mixed with stirring.Next, the temperature is cooled to 30°C while stirring. .

(3) Properties As shown in Table 4, Examples 5 to 9, which are the whitening cosmetics of the present invention, showed better results in all tests compared to Comparative Examples 5 to 7, and the whitening effect was also excellent ( Effects of the Invention) As described above, it is clear that the whitening cosmetic of the present invention has high skin safety, has the effect of inhibiting melanin pigment formation, and has the effect of quickly lightening dark skin, and is particularly effective against sunlight. By using it immediately after exposure to light, etc.
Furthermore, it was observed that the whitening effect was further improved.

Claims (1)

[Claims] A whitening cosmetic containing γ-aminobutyric acid and urocanic acid and/or its ethyl ester.