KR0162643B1 - Skin whitening cosmetics - Google Patents

Abstract

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Description

Skin whitening cosmetics

The present invention relates to skin whitening cosmetics which contain certain fatty acids or derivatives thereof and which are effective in removing or preventing skin browning or pigmentation in the skin, such as spots or freckles caused by ultraviolet light.

Known cosmetics for beautifying facial skin include compositions containing ascorbic acid or derivatives thereof or tyrosinase inhibitors such as placental extracts and kojic acid or derivatives thereof. Although these conventional skin whitening cosmetics exhibited inhibitory activity against melanin synthesis in in vitro testing using tissue culture, they did not show sufficient effects in removing pigmentation when applied to the skin in practice.

As a result of extensive research on various components for their skin whitening effect, the present inventors have already applied for a patent for finding that an excellent skin whitening effect is obtained by incorporating certain fatty acids or salts or esters thereof into cosmetics. However, it has been found that such fatty acids or derivatives thereof, when combined with fats or oils that are commonly used in conventional cosmetics, in practical use, still do not have sufficient skin lightening effects.

Accordingly, it is an object of the present invention to provide a cosmetic which contains a specific fatty acid or salt or ester thereof, and which can sufficiently exhibit the skin whitening effect of the fatty acid or salt or ester thereof.

Other objects and effects of the present invention will be apparent from the following description.

The inventors have conducted extensive research and found that certain fatty acids, salts thereof, or combinations of these fatty acids with monohydric or dihydric alcohols and silicone oils unexpectedly exhibit excellent effects in the removal or prevention of skin pigmentation. To discover and complete the present invention.

That is, the present invention relates to (a) at least one compound selected from the group consisting of free fatty acids having 18 to 22 carbon atoms having at least two unsaturated bonds per molecule, salts thereof and esters of the fatty acids with monohydric or dihydric alcohols, and ( b) A cosmetic for skin whitening comprising at least one silicone oil selected from the group consisting of compounds of the general formulas (I), (II) and (III).

Wherein n ₁ is an integer from 4 to 6, n ₂ is an integer from 1 to 400, n ₃ and n ₄ each represent an integer and the sum of n ₃ and n ₄ is 1 to 400.

The present invention further relates to a cosmetic for skin whitening comprising (c) ethanol in addition to the components (a) and (b).

Fatty acids having 18 to 22 carbon atoms, such as linoleic acid and γ-linolenic acid, having two or more unsaturated bonds per molecule that can be used in the present invention are contained in vegetable and animal fats and oils. These fatty acids are rarely in free form but mostly in triglyceride form. Such triglycerides do not show a significant effect on the inhibition of pigmentation in animal experiments, as observed for free fatty acids or their alkyl esters. For example, saturated fatty acids such as palmitic acid and stearic acid do not promote melanin production, but in some cases saturated fatty acids also somewhat promote melanin production. Given that these saturated fatty acids are present in large amounts in vegetable and animal fats and oils, it is preferred to use purified unsaturated fatty acids in the preparation of the cosmetics of the invention.

Examples of free unsaturated fatty acids having 18 to 22 carbon atoms having two or more unsaturated bonds per molecule include linoleic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, eicosapentaenoic acid. And docosahexaenoic acid. These fatty acids may be used alone or in combination of two or more thereof.

These free unsaturated fatty acids are obtained by saponifying natural fats and oils. Examples of natural fats and oils are vegetable fats and oils, such as linseed oil, safflower oil, sunflower oil, soybean oil, radish seed oil, corn oil, sesame oil and grapeseed oil, and squid oil, sardine oil, saury oil and cod Marine animal oils such as liver oil.

Examples of salts of these free fatty acids that can be used in the present invention include metal salts such as sodium and potassium salts, amino acid salts such as arginine and lysine salts, and amine salts such as triethanolamine salts and monoethanolamine salts. It includes.

Examples of alkyl esters of fatty acids that can be used in the present invention include monohydric alcohols such as methanol, ethanol and isopropyl alcohol and dihydric alcohols such as ethylene glycol, propylene glycol and 1,3-butylene glycol. Esters.

Among the free unsaturated fatty acids and esters or salts of these fatty acids, linoleic acid, α-linolenic acid, γ-linolenic acid, arachidonic acid and sodium linoleate are preferably used in the present invention. In particular, linoleic acid and α-linolenic acid are more preferred.

Free fatty acids and salts or esters thereof are preferably used in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the total amount of the cosmetic of the present invention. If this amount is less than 0.1% by weight, the pigmentation inhibitory activity tends not to appear. If it exceeds 10% by weight, skin irritation may be caused.

The silicone oil used in combination with the above component (a) is selected from the compounds of the general formulas (I), (II) and (III).

Examples of silicone oils of general formula (I) include KF994 and KF995 (manufactured by Shin-Etsu Chemical Co., Ltd.) and SH244 and SH245 (manufactured by Toray Silicone Co., Ltd.). Examples of silicone oils of formula (II) are KF96 1cs and KF96 2cs (manufactured by Shin-Etsu Chemical Co., Ltd.) and SH200c / 1cs, SH 200c / 10cs, SH 200c / 100cs and SH200c / 500cs (Toray Silicone Co ., Ltd. products). Examples of the silicone oil of general formula (III) include SH556 (manufactured by Toray Silicone Co., Ltd.).

In said silicone oil, the compound of general formula (I) whose n <_1> is an integer of 4-6 and the compound of general formula (II) whose n <_2> is an integer of 1-10 are used preferably for this invention. In particular, the compound of general formula (I) whose n <_1> is an integer of 4 or 5 and the compound of general formula (II) whose n <_2> is an integer of 1-7 are more preferable.

The silicone oil is used in an amount of at least 1% by weight, more preferably at least 10% by weight, particularly preferably at least 50% by weight, based on the total amount of the cosmetic of the present invention.

The silicone oil used can be arbitrarily selected from the abovementioned compounds. Two or more of these silicone oils may be used in combination to improve the feeling at the time of application, the solubility of fatty acids and the freezing prevention properties at low temperatures.

For example, although octamethylcyclotetrasiloxane freezes at low temperatures (up to 10 ° C.), low temperature freezes can be prevented by adding decamethyl cyclopentasiloxane, methylphenylsiloxane or dimethylsiloxane, although linoleic acid, α-linolenic acid, etc. Although not soluble in this dimethylpolysiloxane, it is possible to improve the solubility by adding methylphenylsiloxane or octamethylcyclotetrasiloxane, although octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane have less lipophilic feeling when used, resulting in feeling when applying cosmetics Although not recommended, the appearance of cosmetics can be enhanced by adding dimethylsiloxane or methylphenylsiloxane.

For the same purpose, the cosmetic of the present invention may further contain ethanol. Ethanol is preferably used at 50.0% by weight or less, more preferably 1 to 40% by weight, particularly preferably 3 to 25% by weight, based on the total amount of cosmetics. If the amount of ethanol exceeds 50.0% by weight, the cosmetics are not only irritating to the skin, but also have a bad feeling upon application by causing a cold feeling upon application due to volatilization of ethanol.

Cosmetics of the present invention can be formulated with cosmetics, creams and the like by known methods.

If necessary, the cosmetic of the present invention may further contain other ingredients generally used in cosmetics, so long as the effects of the present invention are not impaired.

Conventional compositions and methods for their preparation and conventional ingredients added to cosmetic compositions are incorporated herein by reference in Keshohin-Gaku (Cosmetic Science), edited by T. Ikeda, published on May 20, 1979 by Nanzando , Japan], but the present invention should not be construed as being limited thereto.

In addition, if necessary, the cosmetics of the present invention may contain various conventional additives such as melanogenesis inhibitors (whitening agents) (such as vitamin C and placenta extract), anti-inflammatory agents and antioxidants so long as the effects of the present invention are not impaired. Can be.

Examples of conventional additives and their addition amount are shown in Table 1 below, but are not limited thereto. The amount added is expressed in weight percent based on the total amount of the cosmetic composition. (Except for Vitamin A).

Cosmetics of the present invention can be applied to the skin in a conventional manner. For example, a lotion containing 1% by weight of the compound of the present invention may be applied by hand one to several times a day, and one or two drops of the cosmetic oil containing 3% by weight of the compound may be applied to the site where pigmentation has occurred per day. The finger may be applied 1 to 3 times, the cream containing 5% by weight of the compound may be applied by hand 1 to several times a day, and the emulsion containing 2% by weight of the compound may be applied by hand 1 to 3 times a day. Once or twice a week, 5 to 10 g of the pack may be applied to the facial skin except for the eyes and nose and maintained for about 30 minutes before removing the pack.

The whitening effect according to the invention is tested as follows:

[Test Methods]

Ultraviolet rays (UVB intensity: 1 J / cm 2) are irradiated 4 times (twice / week) to shaved backs of British brown guinea pigs. One week after irradiation, the pigment is deposited.

To 6 cm 2 (2 cm 3 cm) of pigmented guinea pigs, 0.05 ml of linoleic acid solution in each substrate shown in Table 1 below is applied 20 times (once a day).

The degree of pigmentation is visually assessed and evaluated as follows, which is considered standard (0) with no test compound applied.

0: No reduction in pigmentation is observed.

-1: A slight decrease in pigmentation is observed.

-2: moderate reduction in pigmentation is observed.

-3: A significant decrease in pigmentation is observed.

The evaluation results are shown in Table 2 below.

Note: * 1 General formula (Ⅰ) (n = 4)

* 2 General formula (I) (n = 5)

As is apparent from the results in Table 2, pigmentation can be significantly reduced when linoleic acid is combined with silicone oil or mixtures thereof as a substrate. In addition, the skin lightening effect increases with increasing linoleic acid concentration. A satisfactory effect can be obtained with 0.1 to 10% by weight and preferably 0.1 to 5% by weight of linoleic acid. However, when used in high concentrations it is observed that linoleic acid does not dissolve in silicone oil bases, depending on the type of silicone oil.

The solubility of linoleic acid in silicone oils or mixed silicone oils is shown in Tables 3 and 4.

As is apparent from the results in Table 3, high concentrations of linoleic acid lack solubility in dimethylpolysiloxanes having a viscosity of 100 cs or more. In this case, the solubility of linoleic acid can be increased by adding an appropriate amount of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, methylphenylpolysiloxane, and the like as shown in Table 4.

Tables 5 and 6 show the low temperature stability of octamethylcyclotetrasiloxane. Although octamethylcyclotetrasiloxane freezes at low temperatures due to its high freezing point, an appropriate amount of decamethylcyclopentasiloxane, dimethylpolysiloxane, methylphenylpolysiloxane or ethanol can be used in combination to prevent freezing.

The present invention will be described in more detail with reference to the following examples, but the present invention should not be construed as being limited thereto. All percentages are by weight unless otherwise indicated.

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

In Examples 1 to 6, all the ingredients are uniformly mixed with each other and dissolved to obtain a cosmetic oil.

Example 7

In Examples 1 to 6 above, all the ingredients are uniformly mixed with each other and dissolved to obtain a cream.

The cosmetic according to the present invention, when applied to the skin, removes or prevents browning or pigmentation of the skin due to ultraviolet rays and exhibits an excellent skin whitening effect.

Although the present invention has been described in detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (4)

(a) at least one compound selected from the group consisting of free fatty acids having 18 to 22 carbon atoms, salts thereof, and esters of monohydric or dihydric alcohols with two or more unsaturated bonds per molecule, and (b) a general formula ( A cosmetic for skin whitening comprising at least one silicone oil selected from the group consisting of compounds of I), (II) and (III).

Wherein n ₁ is an integer from 4 to 6, n ₂ is an integer from 1 to 400, n ₃ and n ₄ each represent an integer and the sum of n ₃ and n ₄ is f1 to 400. The compound according to claim 1, wherein the compound selected from the group consisting of free fatty acids having 18 to 22 carbon atoms, salts and esters thereof containing two or more unsaturated bonds per molecule is present in an amount of 0.1 to 10% by weight, based on the weight of the cosmetic. Existing skin whitening cosmetics. The cosmetic for skin whitening according to claim 1, wherein the cosmetic further comprises ethanol. The skin whitening cosmetic according to claim 3, wherein the ethanol is present in an amount of 50.0% by weight or less based on the weight of the cosmetic.