JPH1081618A - Composition for skin lotion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition for skin lotion extremely excellent in percutaneous absorption by formulating an ellagic acid-based compound and its alkali metal salt which possess an extremely small average grain diameter and a specific grain size by fining grains. SOLUTION: This composition is composed of at least one kind of grains selected from an ellagic acid-based compound and its alkali metal salt of formula I [R1 -R4 are each H, an 1-20C alkyl, an 1-20C acyl, a polyoxyalkylene of -(Cn H2m -O)n -H ((m)=2 or 3; (n)>=1) and a saccharide residue of formula II; R5 is H, OH and an 1-8C alkoxy]. The grains possess an average grain diameter of 50μm or less and contain grains with a grain diameter of 70μm or less in an amount of more than 70wt.%. Particularly, it is preferably composed of grains which show an average diameter of 10μm or less and contain grains with a grain diameter of 30μm or less in an amount of more than 70wt.%. This composition possesses excellent skin whitening effect and is useful as a substrate in systems of aqueous solution, solubilization, emulsion and powder dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a composition for external use on skin having an excellent skin whitening effect.

[0002]

2. Description of the Related Art There are many unclear points about the mechanism of pigmentation such as skin spots and freckles, but in general, abnormalities of hormones and stimulation by ultraviolet rays cause excessive production of melanin pigment, It is believed to be abnormally deposited within. For the purpose of preventing or improving such pigmentation, conventionally, hydrogen peroxide, zinc peroxide, peroxides such as magnesium peroxide, or ascorbic acid, glutathione, colloidal sulfur, various natural products and the like as an active ingredient. Attempts have been made to use whitening cosmetics. However, many of these active ingredients have insufficient safety and stability, or have a problem with odor, and their effects are not necessarily sufficient. On the other hand, in the United States and the like, hydroquinone is used as a skin depigmenting agent, but this hydroquinone has irritation and allergic properties, and there is a problem in terms of safety in formulating it as an active ingredient in cosmetics. .

[0003] Therefore, various studies have been made to develop cosmetics having a skin whitening effect without such disadvantages, and an external whitening agent using kojic acid and a kojic acid derivative (Japanese Patent Application Laid-Open JP-A-53-3538, JP-B-56
Nos. 18569, 58-22151 and 6
Nos. 0-9722 and 61-60801), cosmetics containing quercetin as an active ingredient (JP-A-55-92).
No. 305) Cosmetics containing a quercetin fatty acid ester as an active ingredient (JP-A-58-131911),
Cosmetic containing catechin or the like as an active ingredient (JP-A-52-4)
No. 4375 is disclosed.

[0004] However, in all of these cosmetics, the stability of the whitening component is still insufficient in actual use, or the effect is recognized at the cellular level, but the effect is sufficiently exhibited in humans. There is a problem that it is not performed, and it is not always satisfactory.

Therefore, the present inventors have overcome the drawbacks of the conventional skin whitening preparations for the purpose of whitening, and have excellent skin whitening effect, high stability, and high stability. An ellagic acid-based compound and an alkali metal salt thereof have been proposed for the purpose of providing a skin external preparation having no problem with odor or the like (Japanese Patent No. 1839986).

The present inventors have further studied and found that
When the above-mentioned ellagic acid-based compound or its alkali metal salt is blended into a cosmetic or quasi-drug base, the transdermal absorbability is insufficient in any case, and the effect is not obtained at the concentration in a normal external preparation. It turned out to be insufficient.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a composition for external use on the skin which contains particles of an ellagic acid-based compound or an alkali metal salt thereof as an active ingredient, and which has excellent transdermal absorbability. And

[0008]

Means for Solving the Problems In view of the above circumstances, the present inventors have repeatedly studied for the purpose of improving the transdermal absorbability of a preparation containing particles of the above-mentioned ellagic acid-based compound or its alkali metal salt. As a result, it was found that the ellagic acid-based compound having an extremely small average particle size and a specific particle size and an alkali metal salt thereof having an extremely small average particle diameter exhibited excellent effects, and completed the present invention. .

That is, according to the present invention, there is provided a composition for external use on skin containing at least one kind of particle selected from an ellagic acid compound represented by the following general formula (I) and an alkali metal salt thereof. The particles have an average particle size of 50 μm
The composition for external use on skin is characterized in that the composition having a particle size of 70 μm or less is 70% by weight or more.

Embedded image 中 In the formula, R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom and carbon number 1 to
20 alkyl groups, C1-20 acyl groups,-(Cm
_{H 2 m-O) n-} H ( provided that, m is 2 or 3, n polyoxyalkylene group represented by an integer of 1 or more), or the following structural formula

Embedded image And the sugar residues may be the same or different from each other. R ₅ represents a hydrogen atom, a hydroxyl group, or an alkoxy group having 1 to 8 carbon atoms. ｝ According to the invention, the particles have an average particle diameter of 10 μm.
m and a particle diameter of 30 μm or less is 70% by weight or more.

Generally, in the case of dissolving particles, the dissolution amount and dissolution rate are almost proportional to the surface area when the dissolution is limited. The particulate ellagic acid-based compound and its alkali metal salt dissolve in moisture and lipids on the skin and then penetrate into the skin to exert its effect. Therefore, in the present invention, the particles of the ellagic acid-based compound or the alkali metal salt thereof, which is a component to be incorporated into the composition for external use on the skin, are finely divided, and by using particles having a specific particle size, the following effects can be exerted. Elucidated. The surface area of the particles increases, and the solubility and dissolution rate increase. The area of contact with the skin increases. The rate of penetration into the skin and the amount of penetration per unit time increase. Percutaneous absorption is increased. The long-term stability of the composition for external use on the skin is improved. Excellent feeling in use and improved appearance. Such an effect is considered to be due to the fact that the particle size is inversely proportional to the solubility due to the effect of the surface energy of the particles in the case of a very fine substance.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The ellagic acid compound represented by the general formula (I) and an alkali metal salt thereof, which are the active ingredients of the composition for external use on the skin of the present invention, will be specifically described.
In the general formula (I), when R ₁ , R ₂ , R ₃ and R ₄ are an alkyl group having 1 to 20 carbon atoms, specific examples thereof include a methyl group, an ethyl group and a propyl group. And a methyl group and an ethyl group are particularly preferable. R ₁ , R ₂ , R
_{When 3} and R ₄ are an acyl group having 1 to 20 carbon atoms, specific examples thereof include an acetyl group and a propionyl group. Further, R ₁ , R ₂ , R ₃ , and R ₄ are represented by-(CmH ₂ m-
O) When it is n-H, specific examples thereof include a polyoxyethylene group and a polyoxypropylene group, and n is an integer of 1 or more, and particularly preferably 5 to 40. R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different from each other. Further, when R ₅ is an alkoxy group having 1 to 8 carbon atoms, specific examples thereof include a methoxy group, an ethoxy group,
Examples include a propoxy group, and a methoxy group is particularly preferable. Furthermore, examples of the alkali metal salts of these ellagic acid compounds include sodium salts and potassium salts.

The ellagic acid compounds of the present invention include, for example, R ₁ , R ₂ , R ₃ , R ₄ and R _{5 in the} general formula (I).
Are all hydrogen atoms, R ₁ , R ₂ , R ₃ ,
And R ₄ is a hydrogen atom, a methyl group or an ethyl group, and R ₅ is a hydrogen atom, a hydroxyl group or a methoxy group. Further, ellagic acid in which a part of the phenolic hydroxyl group is converted to a sodium salt or a potassium salt is preferable in terms of good solubility. The ellagic acid-based compound and the alkali metal salt thereof may further contain R ₁ , R ₂ , R ₃ and R _{3 in the} general formula (I) in order to adjust the lipophilicity or hydrophilicity in preparing the composition for external use on the skin. Some of R ₄ are a long-chain alkyl group having up to 20 carbon atoms, a long-chain acyl group having up to 20 carbon atoms, a formula — (CmH ₂ m—O) n—H (where m is 2 or 3, n
It may be optionally substituted group selected from among sugar residue represented by the polyoxyalkylene group and the structural formula represented by an integer of one or more) (II), carbon atoms a R ₅ 8 May be substituted with long-chain alkoxy.

Specific examples of the ellagic acid compound and its alkali metal salt include ellagic acid, 3,4-di-o-methylellagic acid, 3,3'-di-o-methylellagic acid,
3′4-tri-o-methylellagic acid, 3,3 ′, 4
4'-tetra-o-methyl-5-methoxyellagic acid, 3
-O-ethyl-4-o-methyl-5-hydroxyellagic acid, amritside (R ₁ : structural formula II, R ₂ : hydrogen atom, R ₃ : hydrogen atom, R ₄ : hydrogen atom, R ₅ : Hydrogen atom) and alkali metal salts of these compounds.

[0014] These ellagic acid compounds include strawberry, cod (Caesalupinia Spinosa), eucalyptus wood (Eucalyptus), apple, poisonous azalea (Korea yaponica), radiata pine, bearberry, pomegranate, ammaroku, kyukyuyou, enfuyo,
Gaijicha, Kakyouju, Oak, Kiju, Kenjin, Konaka, Sankyukon, Sankyuyou,
Shufuboku, Senkutsusai, Sougenroukansou, Daihyousou, Dumouanyou, Haouben,
Banseki ryukan, bunseki ryuhi, bouka, mushroom, yatosaka, yatoseihi, yukankon,
It can be easily obtained from natural products such as Yukanbokuhi, Yukanyou, Ryugasoukon, Banseki Ryuyou, Ukyubakukonpi, Sidkon, Chingshusou, Gennoshoko by the following method (Japanese Patent Publication No. 53-146).
No. 05). That is, the dried and pulverized natural product containing the ellagic acid compound is digested by a usual acidic sulfite method, and then immersed in an aqueous alkali solution of sodium hydroxide or sodium carbonate (pH 10 to 13). After fractionating the immersion liquid, an acid such as sulfuric acid or acetic acid is added to the immersion liquid to adjust the pH to 2-8.
To obtain a precipitate mainly composed of an ellagic acid-based compound. The precipitate is collected by centrifugation or the like, and further washed with water to remove impurities, thereby obtaining a highly pure ellagic acid-based compound.

The ellagic acid compounds used in the composition for external use of the skin according to the present invention are widely present in natural products as described above, and are considered to have extremely high safety. As a result, no practical problems were observed in terms of acute toxicity, skin irritation, skin sensitization, mutagenicity, etc., and the safety was confirmed to be high.

In the present invention, one or more of the above ellagic acid compounds and alkali metal salts thereof are arbitrarily selected and used. The content thereof is preferably 0.001 to 30% by weight, more preferably 0.05 to 10% by weight, in the skin external preparation composition.

Next, the particle size and the particle size of the ellagic acid compound and the alkali metal salt thereof used in the external preparation for skin of the present invention will be described. The average particle size is 50 μm or less,
Those having a particle diameter of 70 μm or less are 70% by weight or more, preferably those having an average particle diameter of 10 μm or less and a particle diameter of 30 μm or less are 70% by weight or more. More preferably, those having an average particle diameter of 1 μm or less and a particle diameter of 3 μm or less are 70% by weight or more.

In order to make the ellagic acid-based compound or its alkali metal salt have the above-mentioned specific average particle size and specific particle size, it can be carried out by a commonly used pulverizing method. That is, for a dry type, a pulverizer such as a colloid mill, a ball mill, or a jet mill is used. This can be achieved by using a high-speed decocting device such as the one manufactured by Toshiba.

A specific method for making ellagic acid fine is described below. Ellagic acid is dispersed in water (aqueous solution) or a liquid solvent (which may contain a specific solute) at room temperature, and crushed for a certain period of time using an ultrasonic wave, a clear mix, a colloid mill, a milder, or the like. The particle size is adjusted by the processing time. For example, in order for the average particle diameter to be 50 μm or less and the particle diameter to be 70 μm or less to be 70% by weight or more, treatment is performed for 1 to 5 minutes in a colloid mill. Average particle size is 10μ
In order to make the particle diameter of m and the particle diameter of 30 μm or less 70% by weight or more, the treatment is performed by ultrasonic wave for 5 to 10 minutes. Further, in order to make the average particle diameter of 1 μm and the particle diameter of 3 μm or less to be 70% by weight or more, treatment with Clear Mix is performed for 20 to 30 minutes. This time is appropriately adjusted depending on the processing amount.

Further, the ellagic acid compound and the alkali metal salt thereof can be made to have the above-mentioned specific average particle size and specific particle size by crystallization. That is, the ellagic acid-based compound and its alkali metal salt are adjusted to pH 12-14.
When dissolved in an aqueous solution of a specific concentration of an alkali metal hydroxide of the above, when adjusting the pH to 2 to 8 with an acid (which may be either an inorganic acid or an organic acid, sulfuric acid is preferred in relation to the treatment) By vigorous stirring, the ellagic acid-based compound and the alkali metal salt thereof can have the specific average particle size and the specific particle size described above.

The composition for external use of the skin of the present invention, if necessary, may contain various components usually used in the composition for external use of the skin, such as oil, water, etc., as long as the effects of the present invention are not impaired.
Surfactants and other humectants, alcohols, thickeners, antioxidants, sequestering agents, pH adjusters, preservatives, fragrances, pigments, ultraviolet absorbers, ultraviolet scattering agents, vitamins,
Amino acids and the like can be blended.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

<Production method of fine ellagic acid compound and alkali metal salt thereof> Production Examples 1 to 6 (ultrasonic wave, clear mix, colloid mill, milder, homomixer, crystallization) Ultrasonic method 1 kg of a dispersion of 2.5% ellagic acid in purified water was treated with an ultrasonic pulverizer for 1 minute to obtain a dispersion having an average particle diameter of 60 μm and a particle size of 7 kg.
75% by weight of particles having a particle size of 0 μm or less was obtained. In the same manner, the particles are treated for 3 minutes, particles having an average particle diameter of 50 μm and particles having a particle diameter of 70 μm or less are 62% by weight, and the particles are treated for 8 minutes, particles having an average particle diameter of 8 μm and particles having a particle diameter of 30 μm are 75% by weight. After treating for 20 minutes, particles having an average particle diameter of 0.5 μm and 3 μm were 74% by weight, respectively. 2. Claremix method 1 kg of a dispersion having a concentration of 2.5% of sodium ellagic acid in purified water was treated with Clearmix for 0.5 minutes to obtain particles having an average particle diameter of 60 μm and particles of 70 μm or less having 75% by weight. . In the same manner, the mixture was treated for 1 minute to obtain an average particle size of 5
The particles having a particle size of 0 μm and 70 μm or less are treated at 58% by weight, and the particles are treated for 3 minutes. The particles having an average particle size of 40 μm and the particles having a particle size of 70 μm are treated at 92% weight. Particles of 95% by weight are treated for 20 minutes, and particles having an average particle diameter of 0.5 μm and 3 μm or less are 70% by weight, and further treated for 60 minutes and an average particle diameter of 0.2 μm and 3 μm or less 99% by weight of particles
Was obtained. 3. Colloid mill method 3,3'-di-o-methylellagic acid 2.5 against purified water
% Of the dispersion was treated in a colloid mill for 0.3 minutes, and 75% or less of particles having an average particle diameter of 60 μm and 70 μm or less were obtained.
% Of particles were obtained. In the same manner, the particles are treated for 0.5 minutes, and the particles having an average particle diameter of 40 μm and particles of 70 μm or less are 67% by weight.
0 μm particles 75% by weight, and also 40%
75% of 1 μm particles with an average particle diameter of 0.6 μm
Weight particles were each obtained. 4. Milder method 1 kg of a dispersion having a concentration of 2.5% ellagic acid in purified water is treated with a milder for 2 minutes to obtain a dispersion having an average particle diameter of 60 μm and a particle size of 70 kg.
75% by weight of particles having a particle size of μm or less were obtained. Similarly, the particles are treated for 5 minutes, the particles having an average particle diameter of 30 μm and particles having a particle diameter of 70 μm or less are 62% by weight, and the particles are treated for 10 minutes, the particles having an average particle diameter of 9 μm and the particles having a particle diameter of 30 μm are 75% by weight. Treated for 40 minutes, 30μ at average particle size 0.8μm
m particles each yielded 97% by weight particles. 5. Homomixer method 1 kg of a dispersion having a concentration of 2.5% ellagic acid in purified water was treated with a homomixer for 20 minutes to obtain a dispersion having an average particle size of 8 μm and a particle size of 3 μm.
0 μm particles gave 75% by weight of the particles. 6. Crystallization Method After stirring and dispersing 20 g of commercially available ellagic acid (manufactured by Tokyo Chemical Industry Co., Ltd., average particle size about 150 μm) in 500 g of purified water,
500 g of IN aqueous sodium hydroxide solution was added and dissolved. While vigorously stirring this liquid with a paddle, 6N sulfuric acid was added dropwise (1 ml / min) and slowly added until the pH reached 2. The resulting precipitate is centrifuged, washed twice more with water and dried, and has an average particle diameter of 0.2 μm and a particle diameter of 1 μm.
Those having a particle size of μm or less obtained 18.2 g of 98% by weight of ellagic acid.

Example 1 Transdermal absorbability is a factor related to the performance of a medicinal ingredient in bioavailability. In this example, the in vitro percutaneous absorption of ellagic acid compounds and their alkali metal salts having various particle diameters was measured by the following method, and the improvement effect due to the difference in particle diameter was compared. That is, guinea pigs (Std: Hartley type,
Male) was cut off from the back skin, and the skin was fixed between a donor and a receptor in a cell for transdermal absorption test. next,
After filling the receptor side with sterile physiological saline, the cell was placed in a water tank and incubated at 32 ° C. with stirring. Subsequently, the various compositions shown in Table 1 were applied on the skin on the donor side for 50 times.
mg was added. Each ellagic acid-based compound and its alkali metal salt may be a mixture of radioactive isotopes obtained by labeling the compound with ¹⁴ C uniformly 10% as it is or under the conditions shown in Table 1 (details described in the above Production Examples). Described) and used as fine particles. Examples 1-3, 1-4, 1
FIG. 1 shows the particle size distributions of sodium ellagate and ellagic acid used in -5 and Comparative Examples 1-3. After the incubation for 24 hours, 1 ml of the receptor solution was sampled, 3 ml of Picoflow (manufactured by Packard Japan) was added, and the radioactivity was measured using a liquid scintillation counter. The amount of metal salt was measured. Next, after thoroughly washing the unabsorbed portion of the drug, a predetermined area of skin was collected with a 1 cm diameter punch, cut into glass vials for measuring liquid synth with scissors so as to be easily dissolved, and then Solen-35 was added.
0 (manufactured by Packard Japan) was added and dissolved by heating at 60 ° C. After dissolution, 20 ml of Hyonic Flow (manufactured by Packard Japan) was added, and the amount of the ellagic acid compound and its alkali metal salt in the skin was measured with a liquid scintillation counter. The amount permeated through the skin and the amount in the skin measured as described above were summed to obtain a percutaneous absorption amount, and the percutaneous absorbability of the ellagic acid compound and the alkali metal salt thereof in various compositions was evaluated. Table 1 shows the measurement results. The results are shown as relative values with the percutaneous absorption of an untreated product (an ellagic acid-based compound and its alkali metal salt before being pulverized) as 1, as per unit. In addition, the compounding amount in the composition is represented by% by weight. <Formulation of various compositions> A component Use the components, amounts and average particle diameters shown in Table 1, 1,3-butylene glycol 5.0 glycerin 5.0 ethanol 8.0 xanthan gum 0.3 purified water balance

[0025]

[Table 1]

From the results in Table 1, it is found that the average particle diameter of 50 μm or less and the particle diameter of 70 μm or less is 70% by weight or more, and that the average particle diameter of 10 μm or less and the particle diameter of 30 μm or less is 70% by weight. From the above, it can be seen that the transdermal absorbability of the ellagic acid-based compound having an average of 1 μm and 3 μm or less and 70% by weight or more and the alkali metal salt thereof is significantly improved.

Example 2 After separately dissolving the oil phase component and the aqueous phase component shown in Table 2 at 70 ° C., mixing and emulsifying the solution while stirring, and cooling to room temperature to prepare a cream shown in Table 2. did. In addition, the compounding amount is represented by weight%.

[0028]

[Table 2]

The effectiveness of the cream thus prepared was evaluated as follows. That is, the backs of colored guinea pigs (6 animals in each group) were shaved and a 1/2 MED amount of U
V-B (the ultraviolet rays) was irradiated for 4 days once a day, after depositing the dye in the range of about 4 cm _2, the cream 0.2
5 g was applied once a day every day for 4 weeks, and the change in skin color was determined by measuring the L value (brightness) with a color difference meter. The larger the L value, the whiter the skin. The appearance at the time of application was evaluated by the following method and criteria. Table 3 shows the results. Black rasha paper 10cm x 10cm (100cm
^{In 2} ), 0.08 g of cream was applied, spread widely, and it was determined whether particles of ellagic acid or potassium ellagate were observed on the surface. No particles can be seen: ○ Some particles can be seen: △ Particles can be seen significantly: ×

[0030]

[Table 3]

From the results shown in Table 3, the average particle size of ellagic acid and its alkali metal salt is 50 μm or less, and the particle size is 7 μm.
The product of the present invention, in which the content was 0 μm or less and 92% by weight, was found to be more effective in fading the pigmentation formed in the colored guinea pig than in the untreated and pulverized treatments of the comparative examples, and a remarkable whitening effect was observed. It can be seen that Further, the product of the present invention was superior in the appearance at the time of application as compared with that of the comparative example.

Example 3 An oil phase component and an aqueous phase component shown in Table 4 were separately heated and melted at 70 ° C., then mixed and emulsified. While cooling, a fragrance was added on the way, and the mixture was further cooled to room temperature to prepare an emulsion. did. In addition, the compounding amount is represented by weight%.

[0033]

[Table 4]

The effectiveness of the emulsion thus prepared was evaluated as follows. That is, the product of the present invention and the comparative example were applied to pigment spots of 15 men and women with pigment spots (stains) twice a day for 5 weeks, and the whitening effect was examined 5 weeks later. Table 5 shows the results. The whitening effect was evaluated according to the following criteria. Significant effect: Pigmentation became almost inconspicuous. Effective: Pigmentation was very thin. Somewhat effective: Pigmentation was slightly lighter. Ineffective: no change In the same manner as in Example 2, the appearance at the time of application was also evaluated.

[0035]

[Table 5]

From the results shown in Table 5, the emulsion having 70% by weight of the ellagic acid of the present invention having an average particle diameter of 0.5 μm and a particle diameter of 3 μm or less was 70% by weight. It was found that the whitening effect was clearly superior to the examples. In addition, no abnormality was observed in the condition of the skin during and after use of the emulsion of the present invention for 5 weeks. Further, the product of the present invention was superior in the appearance at the time of application as compared with the comparative example.

Example 4 A serum was prepared by mixing the components shown in Table 6. In addition,
The compounding amount is represented by% by weight.

[0038]

[Table 6]

The effectiveness of the thus-prepared cosmetic serum of the present invention was the same as in Example 3 (however, the test period was 6
Weeks), and the appearance at the time of application was evaluated in the same manner as in Example 2. Table 7 shows the results.

[0040]

[Table 7] From the results in Table 7, it can be seen that the serum of the present invention, which has an average particle diameter of 8 μm and a particle weight of 30 μm or less and 75% by weight, is clearly superior to the untreated comparative example in whitening effect. I knew it was there. In addition, no abnormality was observed in the condition of the skin during and after the use of the serum of the present invention for 6 weeks. Further, the product of the present invention was superior in the appearance at the time of application as compared with the comparative example.

Example 5 The components shown in Table 8 were mixed to prepare a pack agent shown in Table 8. In addition, the compounding amount is represented by weight%. Ellagic acid used was prepared by the crystallization method shown below. <Method for Preparing Ellagic Acid> 20 g of commercially available ellagic acid (manufactured by Tokyo Chemical Industry Co., Ltd., average particle size: about 150 μm) was stirred and dispersed in 500 g of purified water, and then dissolved by adding 500 g of a 1N aqueous sodium hydroxide solution. While vigorously stirring this solution with a paddle, 6N sulfuric acid was added dropwise (1 ml / min).
Until it reaches 2. The resulting precipitate is centrifuged, washed twice with water and dried, and has an average particle size of 0.2 μm.
In addition, 18.2 g of 98% by weight ellagic acid having a particle diameter of 1 μm or less was obtained.

[0042]

[Table 8]

The effectiveness of the pack thus prepared was evaluated as follows. That is, the pigmentation spots of 10 males and females with pigmentation spots (stains) were packed once every three days, and the whitening effect after 6 months was examined. The evaluation of the whitening effect was performed in the same manner as in Example 3. The appearance at the time of application was evaluated in the same manner as in Example 2. Table 9 shows the results.

[0044]

[Table 9]

From the results shown in Table 9, the ellagic acid compound of the present invention has an average particle size of 0.2 μm and a particle size of 1 μm.
It was found that the essence of 98% by weight or less was clearly superior in whitening effect as compared with the untreated comparative example. In addition, no abnormality was observed in the condition of the skin during and after use of the pack of the present invention for 6 months. Further, the product of the present invention was superior in the appearance at the time of application as compared with the comparative example.

[0046]

The external preparation for skin of the present invention uses particles of an ellagic acid compound or an alkali metal salt thereof useful as a whitening agent, and has an average particle size of 50 μm or less and a particle size of 70 μm or less. By using 70% by weight or more of the composition, it is a composition having excellent transdermal absorbability and high whitening effect. When the particles having an average particle diameter of 10 μm or less and a particle diameter of 30 μm or less are used in an amount of 70% by weight or more, the above effect is further improved, and the particles have an average particle diameter of 1 μm or less and a particle diameter of 1 μm or less. When 3% or less is used and 70% by weight or more is used, the above effect is further improved. In addition, the composition for external use on the skin of the present invention has an extremely excellent appearance when applied. The composition for external use on the skin, containing the ellagic acid compound of the present invention and the alkali metal salt thereof, is an aqueous solution, a solubilizing system, an emulsifying system, a powder dispersing system, a water-oil two-layer system, and a water-oil-powder three layer. It is useful as a base for a wide range of cosmetics, such as creams, emulsions, lotions, essences, basic cosmetics such as packs, makeup cosmetics such as lipsticks, foundations, jelly agents, ointments, etc. It can be widely and suitably used in various forms such as pharmaceuticals and quasi-drugs.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating Examples 1-3, 1-4, and 1-5.
7 is a graph showing the particle size distribution of sodium ellagic acid and ellagic acid used in Comparative Examples 1-3.

Claims (2)

[Claims] 1. An external skin composition comprising at least one particle selected from the group consisting of an ellagic acid compound represented by the following general formula (I) and an alkali metal salt thereof, wherein the particles have an average particle size of: 50 μm or less and the particle diameter is 70 μm
A composition for external use on the skin, wherein the following is 70% by weight or more. Embedded image 中 In the formula, R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom and carbon number 1 to
20 alkyl groups, C1-20 acyl groups,-(Cm
H ₂ m—O) n —H (where m is 2 or 3 and n is an integer of 1 or more), or a structural formula shown below: Which may be the same or different from each other. R ₅ represents a hydrogen atom, a hydroxyl group, or an alkoxy group having 1 to 8 carbon atoms. ｝ 2. The external skin composition according to claim 1, wherein the particles have an average particle diameter of 10 μm or less, and 70% by weight or more of particles having a particle diameter of 30 μm or less.