FI82887C - Bleaching skin care products - Google Patents

Description

1 82887

Bleaching skin care product Blekande hudvärdsmedel

The invention relates to a whitening cosmetic agent, in particular a skin care agent mixed with kojic acid. In particular, it relates to a whitening skin care agent containing kojic acid, which has not only improved stability against discoloration but also an increased whitening effect.

Kojihapo, i.e. 5-Hydroxy-2-hydroxymethyl-γ-pyrone is a compound which can be obtained by fermentation of, for example, molds of the genus Asperqillus. The compound is known to act as a tyrosinase inhibitor. Bleaching cosmetics which take advantage of the action of the compound are known and are disclosed in JP Patent Publication No. 18569/81 and published JP Patent Application No. 3538/78.

Bleaching cosmetics, especially cosmetic creams containing kojic acid as the active ingredient, are sensitive to discoloration when yellow when exposed to heat or light, and the density of cosmetics tends to increase over time, thus diminishing their value as a commercial product.

It is therefore an object of the invention to provide a whitening cosmetic which has improved stability against discoloration over time. Another object of the present invention is to provide a whitening cosmetic having an increased whitening effect.

It has now been found that the discoloration can be clearly reduced and the whitening effect of kojic acid can be enhanced when cyclodextrins are added with kojic acid to the cosmetic agent or when kojic acid incorporated into the cyclodextrins is added to the cosmetic agent.

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Em. According to the present invention, the present invention provides a whitening skin care agent having not only improved stability against discoloration, but also an increased whitening effect comprising cyclodextrins and kojic acid or cyclodextrins incorporating kojic acid.

Kojic acid is a known compound that can be obtained by fermentation of molds belonging to such genera as Aspergillus, Penicillium, Gluconobacter and the like.

Cyclodextrins used in conjunction with kojic acid in this invention include α-cyclodextrin, β-cyclodextrin and β-cyclodextrin. Of these compounds, ε-cyclodextrin is most preferred.

Cyclodextrins can be used in an amount of 0.5 to 10 parts by weight per part by weight of kojic acid.

Kojic acid can be incorporated into cyclodextrins before being added to cosmetic base materials.

The incorporation of kojic acid into cyclodextrins can be performed as follows: the cyclodextrins are dispersed in water and then kojic acid is added with stirring until completely dissolved. The preparation containing kojic acid or cyclodextrins containing kojic acid thus prepared can be freeze-dried.

Em. cyclodextrins of 0.5 to 10 parts by weight per part by weight of kojic acid may be used in the preparation. Preferably, 4 parts by weight of cyclodextrins are used per part by weight of kojic acid.

In the present invention, a combination of kojic acid and cyclodextrins or kojic acid incorporated in cyclodextrins is mixed with ordinary cosmetic base materials for the preparation of face lotions, face creams, cosmetic skin creams, cosmetic emulsions or milk creams, etc. for use on human skin. Kojic acid can be included in cosmetic bases in an amount of 0.01 to 2% by weight, both when used in combination with cyclodextrins and when it has been incorporated into cyclodextrins in advance before being incorporated into base materials.

The cosmetics of this invention can be formulated into a toner or cosmetic skin cream. In preparing the toners, skin nutrients, etc. of the toners or skin creams of the present invention, the moisturizing ingredients, skin nutrients, etc. are dissolved in distilled water, and the preservatives, perfumes, etc. are dissolved in alcohol. The two solutions are then mixed at room temperature to provide the desired products. Koji acid and cyclodextrins or kojic acid incorporated in cyclodextrins may be added to the aqueous phase before said mixing in the above amounts.

The cosmetic agents of this invention can be formulated into a skin cream, which can be prepared as follows: To form an aqueous phase, hydrophilic ingredients, e.g., moisturizing ingredients such as glycerol and sorbitol, are added to distilled water. The oil phase is prepared by adding oleophilic ingredients such as preservatives and surfactants to the oil, e.g. solid oils such as beeswax, paraffins, fine crystalline wax, ceresin, higher fatty acids and hardened oils; semi-solid oils such as petrolatum, lanolin and glycerides; or liquid oils such as squalane, paraffin oil, and a variety of synthetic oils made from glycerol and fatty acids. The aqueous and oily phases thus prepared are heated to the same temperature and the latter is gradually added to the former with uniform stirring, after which the mixture is emulsified to make a skin cream. Kojic acid and cyclodextrins or kojic acid incorporated into cyclodextrins may be added to said aqueous phase in the amounts mentioned above.

4 82887

The cosmetic agents according to the invention can also be used in the form of an emulsion or a milky cream. In this case, the cosmetics of the invention can be prepared according to the following method: a moisturizing ingredient such as glycerol, a pH adjusting agent such as acid and base, etc. are added to distilled water, and the resulting mixture is heated with stirring. Ethanol is then gradually added to the mixture to provide an aqueous phase. Oily additives such as preservatives and surfactants are then added to the oil, e.g. solid oils such as beeswax and paraffins; semi-solid oils such as petrolatum and lanolin; or liquid oils such as squalane, paraffin oils and edible oils made synthetically from glycerol and fatty acids; and the resulting mixture is heated to provide an oil phase. The oil phase is then added to the water phase and the mixture is preliminarily emulsified. Protective colloidal agents such as carboxyvinyl polymers and carboxymethylcellulose are added to the mixture thus formed, and the resulting mixture is uniformly emulsified using a homogenizing mixer to form the desired emulsion. The kojic acid and cyclodextrins or the kojic acid incorporated in the cyclodextrins may be added to the aqueous phase before said emulsification in the above-mentioned amount.

The cosmetics of the invention may also be formulated as a face mask, which may be prepared by any of the methods commonly used in the manufacture of face masks. For example, humectants such as glycerol, etc., film-forming agents such as polyvinyl alcohols and beeswax and other additives are added to distilled water. The resulting mixture is then allowed to swell. If desired, substances such as kaolin, talc and zinc oxide may also be added to the mixture as powders. Perfumes, preservatives, etc. are dissolved in ethanol. The ethanol solution is then mixed with the swollen product and the resulting mixture is wholly formed into a paste or cream. Kojic acid and cyclodextrins or kojic acid incorporated into cyclodextrins may be added at any of the above-described manufacturing steps in the above-mentioned amount.

Examples of the preparation of the active ingredient of the cosmetics according to the invention, which are cojic acid incorporated therein or kojic acid incorporated in cyclodextrins, are given below.

Illumination Example 0.5 to 4 parts by weight of β-cyclodextrin are added to 1.5 to 12 parts by weight of distilled water and mixed slowly. An additional 1 part by weight of kojic acid is then added and the resulting mixture is mixed thoroughly until a uniform dispersion is formed in which kojic acid is incorporated. The incorporated kojic acid thus formed can be dried by freezing.

Example 1: skin cream

Weight percent 20% incorporated kojic acid 5.0 beeswax 6.0 cetanol 5.8 hardened lanolin 8.0 squalane 30.0 glyceryl esters of fatty acids 4.0 oleophilic glyceryl monostearate 2.0 polyoxyethylene sorbitan monolaurate 2.0 propylene glycol 5.0 perfume required amount of preservative required amount required amount of distilled water 37.20 6 82887

Example 2: skin cream

Weight percent kojic acid 1.0 (b -cyclodextrin 4.0 beeswax 6.0 cetanol 5.8 hardened lanolin 8.0 squalane 30.0 glyceryl esters of fatty acids 4.0 oleophilic glyceryl monostearate 2.0 polyoxyethylene sorbitan monolaurate 2.0 perfume required amount of preservative required preservative required amount of distilled water 37.20

Example 3: milky skin cream

Weight percent 30% incorporated kojic acid 2.5 squalane 5.0 petrolatum 2.0 beeswax 0.5 sorbitan sesquioleate 0.8 polyoxyethylene oleyl ether 1.2 propylene glycol 5.0 ethanol 5.0 carboxyvinyl polymer (1% aqueous solution) 20.0 potassium hydroxide 0.1 perfume necessary amount of preservative and antioxidant necessary amount of distilled water 57.90 i 82887

Prerequisite 4: Milky cream

% By weight kojic acid 0.75 (i-cyclodextrin 1.75 squalane 5.0 petrolatum 2.0 beeswax 0.5 sorbitan sesquioleate 0.8 polyoxyethylene oleyl ether 1.2 propylene glycol 5.0 ethanol 5.0 carboxyvinyl polymer (1% aqueous solution) 20.0 potassium hydroxide 0.1 perfume necessary amount of preservative and antioxidant necessary amount of distilled water 57.90

Prerequisite 5: face mask

Percentage by weight 50% incorporated kojic acid 1.0 beeswax 5.0 squalane 2.0 propylene glycol 5.0 zinc oxide 10.0 kaolin 10.0 ethanol 5.0 perfume necessary amount of preservative necessary amount of distilled water 62.0 --- ---- -. .. 1—: 8 82887

Example 6: face mask

% By weight of kojic acid 0,5 / 3-cyclodextrin 0,5 beeswax 5,0 squalane 2,0 propylene glycol 5,0 zinc oxide 10,0 kaolin 10,0 ethanol 5,0 perfume necessary amount of preservative necessary amount of distilled water 62,0

Example 7: toner

40% by weight of incorporated kojic acid 2.0 citric acid 0.4 calcium carbonate 0.2 ethanol 5.0 propylene glycol 9.0 distilled water 82.4 perfume and preservative required

Example 8: toner

Percentage by weight of kojic acid 0,5 (b - cyclodextrin 1,5 citric acid 0,4 calcium carbonate 0,2 ethanol 5,0 propylene glycol 9,0 distilled water 82,4 perfume and preservative required 9 82887

Example 9

Testing of the anti-discoloration effect of the active ingredients according to the invention (1) Samples A: Ointment prepared according to Example 1 mixed with 5% by weight of 20% incorporated kojic acid (i.e. 1% by weight of kojic acid).

B: An ointment prepared according to Example 2 mixed with 1% by weight of kojic acid and 4% by weight of β-cyclodextrin.

C: Cream mixed with 1% by weight of kojic acid but not mixed with cyclodextrins.

(2) Test method Samples A, B and C were allowed to stand for 2 months at 45 ° C and their brightness (L), redness (a), yellowness (b) and E (color difference) were measured using a Color Difference Meter Z-1001 DP. manufactured by Nippon Denshoku Co., Ltd. and the values were compared to a control sample stored at 5 ° C for the same period of time.

(3) Test results

The results obtained are shown in Table 1.

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From the results shown in Table 1, it is apparent that Samples A and B or the cosmetics of the present invention have a clearly reduced coloring effect compared to Sample C to which only koji acid was added.

Example 10 Testing of the anti-staining effect on cultured dye-producing cells (1) Samples A: Kojic acid B: 20% incorporated kojic acid prepared according to the preparation example.

C: Kojic acid and fb-cyclodextrin D: fb-cyclodextrin (2) Test method

Mouse melanoma B16 cells were grown in Eagle's MEM medium containing 10% fetal bovine serum and: 1) 2.5 mM kojic acid (Test Area A) 2) 2.5 mM (calculated as kojic acid) 20% incorporated kojic acid (or kojodextrin-incorporated kojic acid) 20%) prepared according to Preparation Example (Experimental Area B); 3) Kojic acid and (b-cyclodextrin each in the same amount as used in Experiment Area B (Experiment Area C); nothing (test area E).

Samples were grown at 37 ° C for six days in a gas mixture of 5% CO 2 and 95% air, then trypsinized and centrifuged at 2000 rpm to prepare cell pellets. The darkness of the pellets thus prepared was compared with the naked eye.

i2 82887 (3) Test results

Experimental area A showed moderate whitening compared to experimental area E (control).

Experimental areas B and C clearly showed stronger whitening than experimental area A and the pellets obtained from these areas were white to light yellow in color.

Experimental area D showed no whitening.

From the above results, it is obvious that the active ingredients of this invention, namely incorporated kojic acid and the combination of kojic acid and cyclodextrins, have anti-melanin dye-forming effects as compared with the case where only kojic acid was used.

Claims (7)

1. Bleaching skin care agents, characterized in that it includes cosmetic base materials, kojic acid and cyclodextrins. 2. Bleaching skin conditioners according to claim 1, wherein said koji acid is included in said cyclodextrins. 3. Bleaching skin conditioners according to claim 1, characterized in that said kojic acid is included in said skin value agent in an amount of 0.01 ... 2% by weight based on the total weight of said skin value agent. 4. Bleaching skin conditioner according to claim 1, characterized in that it is a cosmetic skin cream. 5. Bleaching skin conditioner according to claim 1, characterized in that it is a cosmetic milk-like skin cream. 6. Bleaching skin conditioner according to claim 1, characterized in that it is a cosmetic face mask. 7. Bleaching skin conditioner according to claim 1, characterized in that it is cosmetic facial water.