JPS6251607A - Beautifying and whitening cosmetic - Google Patents

Abstract

PURPOSE:A beautifying and whitehing cosmetic, obtained by incorporating diisopropylamine dichloroacetate with a urocanic acid having inhibitory effect on melanization and rapidly reducing the color of black skin without skin irritation. CONSTITUTION:A beautifying and whitening cosmetic, obtained by incorporating (A) diisopropylamine dichloroacetate with (B) urocanic acid and/or ethyl ester thereof in an amount each of 0.05-3.0wt% based on the total weight of the above-mentioned cosmetic in a cosmetic base, e.g. well-known cream, milky lotion or lotion, and having effect on reduction in color of the skin under dermal physiologically favorable conditions by synergistic effect of the component (A) on promotion of the turn over rate of the keratinous layer by activation of the skin tissue and rapid removal of melanin with the keratinous layer at the same time to reduce the color of black skin and effect of the component (B) on suppresssion of the latent melanization ability of the skin and prevention of new black skin formation.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a whitening cosmetic that is excellent in skin safety, has the effect of preventing dark skin, and has the effect of rapidly 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. Whitening cosmetics containing pigments such as keratin pigment and hydroquinone 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 aimed to: 1) quickly eliminate melanin that is excessively present in the epidermis; 2) suppress the new production of melanin within the skin; and 2) With the aim of creating a whitening cosmetic that satisfies no skin safety issues, as a result of intensive research, we have created a whitening cosmetic that is a combination of diisopropylacone dichloroacetate and urocanic acid and/or its ethyl ester. The inventors have found that the above objects 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 diisopropylamine dichloroacetate and urocanic acid and/or its ethyl ester.

(Specific description of the structure) Diisopropylamine dichloroacetate according to the present invention is a known substance, and JP-A-53-136528 describes that it has an anti-aging effect on skin due to skin tissue activation effect. ing. In addition, urocanic acid and its ethyl ester are also known substances.
Publication No. 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 diisoprobilamine dichloroacetate and urocanic acid or its ethyl ester, which coexist in a cosmetic base, exhibit remarkable i and excellent synergy compared to the previously known individual effects. The present invention was completed after confirming that the present invention is effective.

In other words, diisopropylamine dichloroacetate activates skin tissues, accelerates the turnover rate of the stratum corneum, and quickly eliminates melanin together with the stratum corneum, lightening dark skin. In combination with the effect of S and tile ester to suppress the latent melanin formation ability of the skin and prevent new dark skin,
It has been newly discovered that it has the effect of lightening dark skin under conditions favorable to skin physiology.

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

The whitening cosmetic of the present invention comprises the above-mentioned diisopropylamine.
It is prepared by blending dichloroacetate, urocanic acid and/or its ethyl ester into a cosmetic base such as a well-known cream, emulsion, or lotion using a conventional method.

The blending amount of diisopropylamine dichloroacetate is 0.05 to 8.0% based on the total amount of the cosmetic. O
TfL t % (hereinafter abbreviated as w t 96)
, Mata, urocanic acid and its ethyl ester are blended in amounts of 0.05 to B, each alone or the total amount of both.
It is sufficient if it is 0wt96. Even if these amounts exceed the upper limits, no effect commensurate with the exceeded amounts can be expected, and if the amounts are less than the lower limits, the object of the present invention cannot be achieved.

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 A sample of 0.05 mm in diameter was applied to the skin of the flexor side of the forearm of 25 subjects who were exposed to summer sunlight for 6 hours (3 hours a day for 2 days). Q: After 24 hours of occlusion using a c+m circular lint cloth patch test adhesive, evaluate the skin condition of 25 subjects for each sample according to the criteria in Table 2 below. I judged it. The judgment result is based on the stronger reaction between 1 hour and 24 hours after the removal of the bandage.
The evaluation is indicated by the number of people with (- 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 made and ointment was applied to the skin on the side of the forearm of 20 subjects for 24 hours. It is applied and danzyl chloride penetrates and binds to the stratum corneum. Thereafter, the test sample was applied to the same area twice a day (morning and evening), and the fluorescence of danzyl chloride was examined every day.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 subject.

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 twice the amount of the minimum erythema, and after one week, the irradiated areas were divided into sample application areas and non-application areas. to set the standard brightness (V) of each skin.

value, vo' value) were measured. Subsequently, the sample was continuously applied to the application site once a day for 3 months, and the skin brightness (Vn...
The skin color recovery was evaluated according to the criteria shown in Table 2.

In addition, the brightness of the skin (Munsell color system V value) is X, Y obtained by measuring with a high-speed spectrocolorimeter.

Calculated from two values. In addition, the evaluation was conducted by 13 of the 20 test subjects.
It is shown as the average value of the evaluation score after a week.

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

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 [Double-layered rosy resin] In the following composition, the amounts of diisopropylamine dichloroacetate, urocanic acid, and its ethyl ester were adjusted as shown in the left column of Table 3. After preparing each two-layer lotion and dissolving each of the (1) composition (2) preparation method (4) and ω) components uniformly, the (A) component and (6) component were mixed. Stir and disperse, then fill into containers.

When using, shake and disperse the contents uniformly.

(3) Characteristics As shown in Table 3, the two-layer lotion bases of Comparative Examples 1 to 4 and the lotion bases containing diisopropylamine dichloroacetate, urocanic acid, and urocanic acid ethyl ester each contained the stratum corneum layer. Although the effect of speeding up the turnover rate and reducing the number of days is observed, sufficient effects were not obtained in the skin color brightness recovery test and the skin whitening practical test. The whitening cosmetics of the present invention in Examples 1 to 4 were evaluated favorably in all tests, and samples were applied especially from the day after exposure to sunlight, before excess melanin was formed in the skin. The skin on the left forearm has been clearly shown to be effective in preventing dark skin, and has an improved whitening effect compared to the right forearm.

Examples 5 to 9, Comparative Examples 5 to 7 [Skin Cream] Same as Example 1) Each skin cream was prepared with the following composition and various tests were conducted, and the results are shown in Table 4 on the right. Shown in the column.

(1) Composition (2) Preparation method (A), ■) Dissolve each component by heating uniformly to a temperature of 80℃.
After cooling to °C, component (2) is poured into component (IIB) and mixed with stirring. The temperature is then cooled to 30''C while stirring.

(3) Properties As shown in Table 4, Examples 5 to 9, which are whitening cosmetics of the present invention, showed better results in all tests and had superior whitening effects compared to Comparative Examples 5 to 7. It was clear that there was.

In addition, similar to Examples 1 to 4, especially in the whitening practical test, the effect of preventing the skin of the applied area on the left forearm from becoming dark skin was improved (effect of the invention). Thus, it is clear that the whitening cosmetic of the present invention has poor skin safety, has an effect of suppressing melanin pigment formation, and has an effect of quickly lightening dark skin, especially when exposed to sunlight etc. By using it promptly after
Furthermore, it was observed that the whitening effect was further improved.

Claims (1)

[Claims] A whitening cosmetic containing diisopropylamine dichloroacetate and urocanic acid and/or its ethyl ester.