JPH08113525A - Beautifying and whitening skin preparation for external use - Google Patents

Abstract

PURPOSE: To obtain a readily usable beautifying and whitening skin preparation for external use, excellent in preservation stability, readily soluble in water, etc., and capable of preventing the skin from blackening and erythemas from producing, rapidly lightening colors of blackened skin, dermal stains or ephelides. CONSTITUTION: This beautifying and whitening skin preparation for external use contains (a) L-ascorbic acid and its derivative, (b) cyclodextrin, (c) a polyhydric alcohol-soluble physiologically active ingredient permissible as a cosmetic raw material and (d) the polyhydric alcohol.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has excellent storage stability and usability, prevents skin blackening and erythema due to the influence of ultraviolet rays, etc., and quickly darkens blackened skin, spots and freckles. The present invention relates to a whitening skin external preparation suitable as a cosmetic or medicinal aqueous and non-aqueous external preparation.

[0002]

2. Description of the Related Art Skin tissue that protects the internal organs of the living body develops erythema when exposed to excessive ultraviolet light, and tyrosine is oxidatively polymerized at melanocytes to produce a blackened melanin pigment. When this melanin pigment is released into the epidermal cells, the skin becomes darkened, so-called tanned skin. If the pigment is not dispersed in the skin tissue and stays in the dermis layer for some reason, it becomes spots or freckles. In particular, recently, it has been pointed out that UV exposure is associated with not only acceleration of skin aging but also increase in skin cancer, and skin care cosmetics for protecting UV rays and recovering adverse effects of excessive exposure at an early stage. Etc., the demand is increasing.

Conventionally, in order to prevent or treat darkening of the skin and abnormal deposition of pigments such as spots and freckles, reduction is carried out for the purpose of suppressing the production of melanin pigments or lightening the produced melanin pigments. The use of a component having a bleaching action or a component that inhibits the activity of tyrosinase involved in the process of conversion from tyrosine to melanin and suppresses melanin production has been investigated. For example, L-ascorbic acid and its derivatives, hydroquinone derivatives such as hydroquinone monobenzyl ether, etc., as a whitening component for preventing melanin generation and oxidative color development, and kojic acid derivatives, licorice derivatives as components having a tyrosinase activity inhibitory action. Oil-soluble components, plant-derived components of tyrosinase such as mulberry bark, etc. are known.

However, these whitening ingredients and the like have various problems as the ingredients of the external preparation for skin as described below. For example, a hydroquinone derivative is recognized as having a whitening effect on excessive pigment deposition, but has a problem in safety for living bodies. Although the effects of kojic acid derivatives and plant extracts have been confirmed in vitro,
When actually applied to the skin, the transdermal absorbability is poor due to the influence of the compounding concentration, the size of the molecular weight, etc., and the whitening effect is not sufficient.

Among the above-mentioned whitening ingredients, ascorbic acid or salts thereof are the most easy-to-use whitening ingredients because they are confirmed to be safe and are widely used as cosmetics, food and pharmaceutical ingredients. However, ascorbic acid or its salts are easily decomposed by light, heat, oxidation, etc.,
Especially in the presence of water, it is extremely easily decomposed. Therefore, it is usually in the form of powder or granules, and it is unavoidable to dissolve it in water or the like for use, and in that case, there is a problem in terms of usability such that it is difficult to dissolve.

In order to improve such problems, a method of increasing the stability of ascorbic acid in the aqueous solution as a phosphoric acid magnesium salt or a sulfuric acid metal salt (Japanese Patent Laid-Open No. 1-283208), stearic acid, palmitic acid. It is a known fact that a higher fatty acid ester such as the above is dissolved in a lipophilic organic solvent, for example, alcohol or vegetable oil, and is a known fact.
It is also listed in P611 to P613, published by Yakuji Nippo Ltd. for 4 years. However, external preparations for skin obtained by these methods have insufficient stability and solubility over time, problems such as cloudiness during storage at low temperatures, precipitation of crystals, remarkable coloring during storage at high temperatures, and content due to decomposition of ascorbic acid. There is a problem such as a decrease in

[0007]

The present invention solves the above problems, improves the storage stability and usability of an external preparation for skin containing ascorbic acid or a derivative thereof, and can maintain a stable whitening effect for a long period of time. Another object of the present invention is to provide an external preparation for whitening skin, which has excellent solubility in water and the like during use.

[0008]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventor has found that inclusion of ascorbic acid or a derivative thereof in cyclodextrin can improve stability, and polyhydric alcohol as a solvent. As a result, they have found that the liquid form can be easily used without impairing the stability, and have completed the present invention.

The present invention comprises (a) L-ascorbic acid and its derivatives, (b) cyclodextrin, (c) polyhydric alcohol-soluble physiologically active ingredient acceptable as a cosmetic raw material, and (d) polyhydric alcohol. An external preparation for whitening skin is provided.

As the L-ascorbic acid and its derivative as the component (a) used in the present invention, those generally used as raw materials for cosmetics can be used as they are.
Further, as a derivative, even if it does not have reducing power itself, when it is applied to the skin, it is percutaneously absorbed,
A substance that is hydrolyzed in the skin by the action of an enzyme or the like to produce L-ascorbic acid can also be used. Such derivatives include higher fatty acid esters of L-ascorbic acid, such as ascorbic acid monostearate,
Mention may be made of ascorbic acid monopalmitate or ascorbic acid dipalmitate.

As the component (a) of the present invention, it is preferable to use ascorbic acid alone or to use ascorbic acid and the higher fatty acid ester which is a derivative thereof in combination. Ascorbic acid penetrates the skin in the presence of moisture,
Although it rapidly exhibits a reducing action, the higher fatty acid ester of ascorbic acid is absorbed into the skin by using a sebum component as a medium and gradually hydrolyzed to produce ascorbic acid, which exhibits a reducing action. Therefore, by combining both components, the component (a) can be made into a component capable of exhibiting an immediate effect and a prolonged effect.

The content of the component (a) in the whitening skin external preparation is preferably 0.1 to 10.0% by weight, particularly preferably 0.5 to 2.0% by weight. This compounded amount is 0.1
If it is less than 10% by weight, the whitening effect will be insufficient and 10.0
If it exceeds the weight%, insoluble matter may precipitate,
It is not preferable because the effect corresponding to the compounding amount cannot be obtained only by increasing the manufacturing cost.

When the component (a) is a mixture of ascorbic acid and a higher fatty acid ester of ascorbic acid, the compounding ratio can be appropriately set in consideration of the properties of both components depending on the type of cosmetic product. . Usually, higher fatty acid ester is added in an amount of 0 to 70 relative to 100 parts by weight of ascorbic acid.
Although it can be used in parts by weight, it is particularly preferably 20 to 50 parts by weight.

The cyclodextrin of the component (b) used in the present invention is light-inclusion in the external preparation by encapsulating the component (a).
It is a component that protects from heat and oxidation and enhances stability. Further, it is a component that not only imparts moisturizing properties to the skin but also enhances the emulsion stability when the external preparation of the present invention is incorporated into an emulsion system such as cream or emulsion. Such (b)
As the component cyclodextrin, in addition to α, β or γ-cyclodextrin, those containing δ or ε-cyclodextrin having a higher polymerization degree than them can also be used.

The blending amount of the component (b) in the external whitening agent for skin whitening is preferably 0.1 to 5.0% by weight, and particularly preferably 0.1.
5 to 1.5% by weight is preferred. When the content is less than 0.1% by weight, the above-mentioned various effects cannot be sufficiently exhibited, and when it exceeds 5.0% by weight, the viscosity of the external preparation increases, which is not preferable.

The physiologically active ingredient of the component (c) used in the present invention, which is acceptable as a polyhydric alcohol-soluble cosmetic raw material, is a component which promotes the whitening effect of the component (a) and improves various physiological functions of the skin. . Examples of the polyhydric alcohol here include the same as the following component (d).

Examples of the component (c) include inorganic salts such as sodium chloride for controlling the water retention of the skin, lactates such as sodium lactate for improving the skin moisturizing property, or polysaccharides such as sodium hyaluronate, Examples thereof include glycolic acid and salts thereof which enhance the physiological function of skin, glabridin which is a hydrophobic licorice extract component having a tyrosinase inhibitory action, β-glycyrrhetinic acid and a derivative thereof which have an anti-inflammatory action.

The amount of the component (c) in the external whitening agent for skin whitening is preferably 0.1 to 3.0% by weight, more preferably 0.
5 to 1.5% by weight is preferred. If the blending amount is less than 0.1% by weight, the effect of adding various components cannot be obtained and 3.0
If it exceeds the weight%, insoluble matter may precipitate,
It is not preferable because the effect corresponding to the compounding amount cannot be obtained only by increasing the manufacturing cost.

The polyhydric alcohol as the component (d) used in the present invention dissolves the components (a), (b) and (c), and when added to water or the like, the components are uniformly and rapidly added. It is a component to be dissolved in. Examples of such polyhydric alcohols include glycerin, propylene glycol, dipropylene glycol, butylene glycol, and polyethylene glycol of low polymerization degree, and among these, glycerin and propylene glycol are preferable.

The amount of the component (d) in the external whitening agent for skin whitening may be 27.0 to 98.2% by weight, preferably 62.0 to 87.5% by weight. When the blending amount is less than 27.0% by weight, (a), (b)
And, if the component (c) cannot be dissolved and exceeds 98.2% by weight, the higher fatty acid ester of ascorbic acid cannot be dissolved and gelled to make it difficult to be absorbed into the skin, which is not preferable.

In the present invention, in addition to the component (d), an alcohol can be further added as a dissolution aid. This alcohol is preferably added when the component (d) alone is difficult to dissolve, for example, when a higher fatty acid ester of ascorbic acid is used as the component (a). Examples of the alcohol include ethanol, propanol, isopropanol and the like, and among them, anhydrous ethanol is preferable.

The content of alcohol in the whitening skin external preparation is preferably 1.0 to 50.0% by weight, and particularly 1
0.0 to 30.0% by weight is preferable. This compounded amount is 1.
If it is less than 0% by weight, the action as a dissolution aid is insufficient, and if it exceeds 50.0% by weight, an alcohol odor is produced, which is not preferable. Further, the compounding ratio to the component (d) is 1 part by weight of alcohol to 100 parts by weight of the component (d).
1.0 to 50.0 parts by weight is preferable.

When the external preparation of the present invention is used as a preparatory type for mixing with cosmetics containing water such as lotion and emulsion, a water molecule cluster regulator may be further added. This water molecule cluster regulator is a component that acts to make the water molecule clusters smaller,
More specifically, it is a component in which the measured value of the full width at half maximum of the resonance frequency of the nuclear magnetic resonance spectrum of the treated water becomes narrow.
By blending this cluster modifier, the stability of the component (a) over time can be increased and the transdermal absorbability of each component including the component (a) can be increased.

Examples of such a cluster adjusting agent include divalent and trivalent complex iron compounds described in JP-A-5-245482. Examples of the complex iron compound include hydrochlorides, inorganic salts such as sulfates and citrates, organic salts such as acetates, complex salts and the like, which show intermediate properties between divalent iron salts and trivalent iron salts. Particularly preferred is an aqua complex in which a spinel structure type compound is constituted by divalent and trivalent iron ions, and more specifically, a natural product name PWS bulk powder (made of salt Body)
Can be mentioned. The PWS bulk powder has a function of making clusters of water molecules small by the weak electromagnetic energy of the divalent and trivalent iron compound having a spinel structure.

The compounding amount of the cluster modifier in the whitening skin external preparation is preferably 0.5 to 5.0% by weight, particularly preferably 1.0 to 3.0% by weight. This blending amount is 0.
If it is less than 5% by weight, the cluster adjusting action becomes insufficient, and if it exceeds 5.0% by weight, for example, the carrier component may be precipitated, which is not preferable.

In addition to the above-mentioned components, the external preparation for whitening skin of the present invention contains, if necessary, various components usually incorporated in cosmetics, such as preservatives, antioxidants, pigments, and fragrances. be able to.

The whitening skin external preparation of the present invention can be used as it is as a non-aqueous cosmetic or medicinal external preparation. Further, when used, it can be used as an external preparation of a preparation type that is mixed with water, lotion, emulsified cosmetics and non-aqueous cosmetics. Thus, when used as an external preparation of the preparation type, the amount used is preferably 0.1 to 1.0% by weight, particularly 0.1 to 0.5% by weight relative to about 1 ml of water or cosmetics.
Weight percent is preferred. If the amount used is within this range,
Due to the heat of dilution of the component (d) and the alcohol blended as necessary, the temperature of water or cosmetics rises by 2 to 3 ° C, so that the transdermal absorbability is improved and the reducing whitening effect of the component (a) is enhanced. Therefore, it is preferable.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 A whitening skin external preparation comprising the components of the following composition was produced by the following method. Further, the stability and the whitening effect of the obtained whitening skin external preparation were tested by the following methods.

(Composition) (% by weight) L-ascorbic acid 0.8 cyclodextrin (trade name Ringdex B; manufactured by Mercian) 1.5 sodium lactate 0.3 PWS bulk powder 1.0 anhydrous ethanol 20.0 glycerin 76.4

(Manufacturing Method) Each of the above-mentioned components was dissolved at a temperature of 45 ° C. or lower with stirring so as to obtain a whitening skin external preparation. This whitening skin external preparation was stored in a light-shielding container.

(Test method) (1) Storage stability at low temperature The above external whitening skin preparation was tested for white turbidity or crystal precipitation when stored in a refrigerator at 3 ° C for 3 months. As a result, no change in properties was observed. (2) High-temperature storage stability The above-mentioned whitening skin external preparation was added at 40 ° C in a constant temperature bath at 6 ° C for 6 days.
Changes in color tone and changes in L-ascorbic acid content when stored for a month were measured. The content of L-ascorbic acid was quantified by the iodometry method. as a result,
The color tone was slightly yellowish and almost colorless when dissolved in water or the like. Also, the L-ascorbic acid content was only 2.2% lower, and had no effect on the whitening effect. (3) Usability (convenience), feeling of use and whitening effect 30 females with sunburn skin from 20 to 50 years old who have experience of using the above-mentioned external whitening skin preparation as a powder or granule product containing L-ascorbic acid. I asked them to use it for sensory evaluation of each item. In addition, the test is applied once a day before going to bed, to which 1.0 ml of water for external use for whitening skin is added / dissolved in an amount of 0.1% by weight and applied to the face, and it is continued for 1 month. I went by. As a result, regarding the usability, it was evaluated that all were easier to dissolve in water and easier to use than powder or granule products. Regarding the feeling of use, it was evaluated that all of them did not feel any irritation or discomfort to the skin. Furthermore, with continuous use for 1 week, 2
It was evaluated by 5 women that the blackening of sunburn skin was recovered faster than that of powder or granule products. From this, it was confirmed that the transdermal absorbability into the skin was excellent. In addition, 16 women evaluated that the spots became thin after continuous use for 1 month.

Example 2 A whitening skin external preparation comprising the components of the following composition was prepared according to Example 1
It was manufactured in the same manner as.

(Composition) (% by weight) L-ascorbic acid 0.8 Ascorbic acid monostearate 0.4 Cyclodextrin (trade name Ringdex B; manufactured by Mercian) 1.5 β-glycyrrhetinic acid 0.2 PWS raw material Powder 1.0 Absolute ethanol 30.0 Glycerin 66.0

Using this external preparation for whitening skin, the same test as in Example 1 was carried out. As a result, the same result as in Example 1 was obtained. Further, when used before going to bed for sunburn skin immediately after bathing in the sea, almost no erythema or inflammation due to sunburn was observed, and it was apparently possible to prevent excessive production and deposition of melanin pigment.

[0036]

The whitening skin external preparation of the present invention comprises (a),
The components (b) and (c) are dissolved in the polyhydric alcohol of the component (d). Therefore, even when it is used as a topical preparation type external preparation, it can be rapidly and uniformly dissolved in water or the like at the time of use and is excellent in usability. In addition, it has excellent storage stability at low and high temperatures, and can maintain the quality during manufacture as it is for a long period of time. Further, it has an excellent whitening effect such that it is possible to prevent blackening and erythema of the skin due to the influence of ultraviolet rays and to quickly lighten the blackened skin, spots and freckles.

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Claims (6)

[Claims] 1. It contains (a) L-ascorbic acid and its derivative, (b) cyclodextrin, (c) polyhydric alcohol-soluble physiologically active ingredient acceptable as a cosmetic raw material, and (d) polyhydric alcohol. An external preparation for whitening skin characterized by: 2. The external whitening skin preparation according to claim 1, wherein the component (a) is a mixture of L-ascorbic acid and a higher fatty acid ester of ascorbic acid. 3. The whitening skin external preparation according to claim 2, wherein the higher fatty acid ester of ascorbic acid is ascorbic acid monostearate, ascorbic acid monopalmitate or ascorbic acid dipalmitate. 4. The whitening skin external preparation according to claim 1, which further contains alcohol. 5. The external preparation for whitening skin according to claim 4, wherein the alcohol is ethanol, propanol or isopropanol. 6. The whitening skin external preparation according to claim 1, which further contains a cluster modifier for water molecules.