KR102463131B1 - Composition containing aha, urea, and niacinamide for softening and whitening stratum corneum - Google Patents

Abstract

The present invention relates to a cosmetic composition for keratin softening and whitening comprising AHA, urea, and niacinamide, and more specifically, AHA (alpha hydroxy acids), an alkali metal salt of AHA, and urea as active ingredients It relates to a composition for external application for keratin softening in which formulation stability is maintained by including, and to a composition for external application for skin having a whitening effect by further including niacinamide.
The composition according to the present invention and cosmetics made therefrom have excellent keratin softening and skin whitening effects, and are particularly effective for keratin in the elbow or heel region, and the pH of the formulation is maintained within the range of 4.0 to 8.0 suitable as a cosmetic, so that the active ingredient in the composition It can be stably maintained without being decomposed within it.

Description

A cosmetic composition for keratin softening and whitening comprising AHA, urea, and niacinamide

The present invention relates to a cosmetic composition for keratin softening and whitening comprising AHA, urea, and niacinamide, and more specifically, AHA (alpha hydroxy acids), an alkali metal salt of AHA, and urea as active ingredients It relates to a composition for external application for keratin softening in which formulation stability is maintained by including, and to a composition for external application for skin having a whitening effect by further including niacinamide.

The stratum corneum (horney layer) of the skin refers to the outermost layer of the skin composed of dead cells. Healthy skin undergoes a so-called turnover action in which the aged keratin is removed and a new cell layer is created every 28 days. Repeat. However, when the turnover function of the skin is slowed due to internal and external factors such as aging, stress, ultraviolet rays and pollution, unnecessary dead skin cells are not removed but accumulated, and the skin becomes rough and thick. resulting in blackening.

In particular, since the skin of the heel or elbow is frequently exposed to pressure or friction among body parts, it is easily deprived of moisture and becomes dry, and hyperkeratinization is more likely to occur than the skin in other parts of the body. Due to the proliferation and differentiation of abnormal keratinocytes in which hyperkeratinization occurs, the surface becomes rough and the skin loses its luster and appears dull and black.

Alpha hydroxy acids (hereinafter referred to as AHA) used in the present invention is one of the ingredients commonly used to soften or remove hyperkeratinized skin layers. It has also been shown to be effective, and many products containing it have recently been launched in the cosmetic and pharmaceutical industries. In addition, in whitening products, it is used to remove the already generated melanin together with a melanin production inhibitor for the purpose of increasing the effect. As a type of AHA, glycolic acid (MW=76.05) obtained from sugar cane has the smallest molecular weight among alpha hydroxy acids, so it penetrates quickly into the skin and is effective. There is a problem, such as a balanced peeling (Peeling) is not made. In addition, the keratin softening effect appears due to the low pH of AHA, and when it is formulated as a cosmetic, the low pH acts as a cause of lowering the stability of the formulation.

Urea used in the present invention is safe for the skin and promotes skin penetration effect and moisture retention and moisture retention ability of the stratum corneum, normalization of increased cell activation, antibacterial effect to suppress chronic eczema, and is applied to the skin together It has been used in many functional cosmetic formulations as a substance having an action such as promoting the penetration of other moisturizing ingredients. In addition, as it is known that it is non-toxic to the human body as it is distributed in each organ and body fluid of the human body, it is attracting attention in the pharmaceutical world. However, when contained in formulated cosmetics, urea changes to basic ammonia over time, which also changes the pH of the formulation, causing the formulation to become unstable.

Accordingly, the present inventors have made intensive efforts to find a method that can maintain formulation stability while containing AHA and urea effective for softening the hyperstratum corneum. As a result, the alkali metal salt of AHA, which is an acidity regulator, was specified for specific amounts of AHA and urea. It was found that the stability of the formulation is improved when the composition is formulated by adding more in a proportion, and the present invention has been completed.

An object of the present invention is to provide a composition for external application for keratin softening comprising AHA (alpha hydroxy acids) and urea as active ingredients, wherein the composition further contains an alkali metal salt of AHA as an acidity regulator to maintain stability of the formulation. To provide a composition for external application to the skin, characterized in that.

In order to achieve the above object, the present invention provides a composition for external application for keratin softening comprising AHA (alpha hydroxy acids) and urea as active ingredients, wherein the composition further comprises an alkali metal salt of AHA as an acidity regulator. It provides a composition for external application to the skin, characterized in that.

In addition, the present invention provides a cosmetic for keratin softening of a solubilizing formulation made from the composition for external application to the skin.

In addition, the present invention provides a cosmetic for keratin softening in a cream formulation made from the composition for external application to the skin.

The composition according to the present invention and cosmetics made therefrom have excellent keratin softening and skin whitening effects, and are particularly effective for keratin in the elbow or heel region, and the pH of the formulation is maintained within the range of 4.0 to 8.0 suitable as a cosmetic, so that the active ingredient in the composition It can be stably maintained without being decomposed within it.

1 is a graph showing the pH change according to the mixing ratio of lactic acid (LA; Lactic Acid) and sodium lactate (SL; Sodium Lactate) mixture.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is those well known and commonly used in the art.

In Examples and Test Examples of the present invention, 5% by weight of AHA mixed with 2% by weight of glycolic acid and 3% by weight of lactic acid with respect to the total weight of the composition and 6% by weight of sodium lactate were mixed to adjust the pH to 4.0-5.0 Then, as a result of formulating by adding 4% by weight of urea, it was confirmed that the active ingredient was not decomposed and stably maintained while the pH of the formulated composition was maintained at 4.0 to 8.0 as well as an excellent keratin softening effect when used. could In addition, as a result of adding 2% by weight of niacinamide to the composition, it was confirmed that not only the keratin softening effect but also the whitening effect was excellent.

Accordingly, in one aspect, the present invention provides a composition for external application for keratin softening comprising AHA (alpha hydroxy acids) and urea as active ingredients, the composition further comprising an alkali metal salt of AHA as an acidity regulator It relates to a composition for external application to the skin.

In the present invention, the AHA may be characterized in that glycol acid (glycolic acid), lactic acid (lactic acid), or a mixture of glycolic acid and lactic acid.

Alpha hydroxy acid (AHA) of the present invention AHA is a generic term for compounds in which the α carbon of a carboxylic acid is substituted with a hydroxyl group, and is the most representative chemical exfoliating component. It helps to remove the link between the dead skin cells in the stratum corneum by the action of acid, and it has the effect of softening the dead skin cells. AHA usable in the present invention is glycolic acid contained in sugar cane, lactic acid contained in spoiled milk or tomato juice, malic acid contained in apples, and contained in tangerines and oranges. Citric acid (citric acid), tartaric acid (tartaric acid) contained in wine, etc., but among them, it is most preferable to use glycolic acid and lactic acid in particular. This is because the molecular weight of glycolic acid (MW=76.05) and lactic acid (MW=90.08) among AHAs are small, so it penetrates quickly into the skin and is effective.

Further, in the present invention, the AHA may be contained in an amount of 3 to 10% by weight, preferably 4 to 6% by weight, based on the total weight of the composition. When AHA is contained in an amount of less than 3% by weight, the keratin softening effect is weak, and when it is contained in an amount exceeding 10% by weight, the acidity becomes excessively high, irritating to the skin, and there is difficulty in stabilizing the formulation.

The alkali metal salt of AHA contained together with AHA in the composition of the present invention may be preferably sodium lactate or sodium glycolate, but the cation binding to lactic acid or glycolic acid is potassium, zinc, and zinc in addition to sodium. , calcium, magnesium, zinc, copper, manganese, boron, or ammonium can be substituted. In addition, it may be characterized in that it is contained so that the weight ratio of the AHA to the alkali metal salt of the AHA is 0.01 to 1.

For example, if AHA is 5 wt% based on the total weight of the composition, it is preferable to add the alkali metal salt of AHA so as to be 6 wt%, and at this time, it is suitable because AHA/AHA alkali metal salt = 0.83. As a more specific example, when the AHA is a mixture of 2% by weight of glycolic acid and 3% by weight of lactic acid (total 5% by weight), it is preferable to add sodium lactate, an alkali metal salt of lactic acid, so that 6% by weight, at this time, lactic acid It is suitable because /sodium lactate = 0.5.

The alkali metal salt of AHA of the present invention is added as an acidity control agent to neutralize the low acidity (pH 2-3) of AHA to a level of pH 4-5. In one test example of the present invention, as a result of measuring the pH of lactic acid, which is one of the AHAs, by concentration, it was confirmed that the pH was changed within the range of 2.0 to 3.0, and sodium lactate was specified in the lactic acid having a pH of 2.0 to 3.0. When added in a ratio, it was confirmed that the pH was maintained at 4.0 to 5.0, particularly when the mixture was mixed so that the ratio of lactic acid to sodium lactate was 0.01 to 1, that is, lactic acid/sodium lactate.

In the present invention, the urea may be characterized in that it is contained in an amount of 4 wt% or more, preferably 4-10 wt%, based on the total weight of the composition.

Urea is a kind of Natural Moisturing Factor (NMF) present in the skin, and it binds with moisture and inhibits the drying of moisture in the skin. Urea is non-toxic, non-allergenic, colorless and odorless. When urea is contained in a cosmetic formulation, it is decomposed over time due to contact with moisture or a change in temperature and is changed to ammonia. However, even if the mixture of AHA and alkali metal salt of AHA of the present invention maintains the pH of the formulation at 4.0 to 5.0, and the urea changes to ammonia over time and the pH rises, the pH of the formulation does not deviate from the range of 4.0 to 8.0. , to maintain an appropriate pH as a cosmetic product.

When the content of urea contained in the composition of the present invention exceeds 10% by weight, it is difficult to use as a cosmetic due to the base odor of the raw material itself, and it is irritating to the skin by generating odor and gas due to ammonia generated during the decomposition of the raw material. In addition, when the content of urea is less than 4% by weight, there is a problem in that the keratin softening and moisturizing effects are not sufficiently exhibited.

In addition, in the present invention, the mixture of the AHA and the alkali metal salt of AHA may be characterized in that it is contained in an amount effective to maintain the pH of the composition at 4.0 to 8.0. As described above, the pH of only the mixture of AHA and the alkali metal salt of AHA is 4.0 to 5.0, and when ammonia derived from urea is added to this, the pH increases. Even if the pH increases, the alkali metal salt of AHA and AHA pH can be maintained at 4.0~8.0 suitable for cosmetics due to the mixture of

In addition, in the present invention, the composition further comprises niacinamide as a whitening agent, and the niacinamide is contained in an amount of 1 to 10% by weight, preferably 1 to 5% by weight, based on the total weight of the composition. can be done with When niacinamide is contained in an amount of less than 1% by weight, it is difficult to expect a whitening effect, and when it is contained in an amount exceeding 5% by weight, skin irritation may appear. Additionally, the composition may be characterized in that it further comprises a polyol as a water-soluble moisturizer.

Niacinamide, which may be contained in the composition of the present invention, is a physiologically active amide of vitamin B3, also known as nicotinamide and pyridine-3-carboxylic acid. known to interfere. Accordingly, the skin pigmentation is reduced to increase the whitening action. In addition, niacinamide also increases the synthesis of collagen and intercellular lipids, thereby having a beneficial effect on skin moisturizing and the like. Niacinamide contained in the composition of the present invention has an effect of whitening the darkening of the elbow or heel. As a whitening agent, in addition to niacinamide, arbutin, thymol trimethoxycinnamate, etc. may be used, but the present invention is not limited thereto.

In addition, the polyol that may be contained in the composition of the present invention means an aliphatic compound having two or more hydroxyl groups (-OH). (glycerin). As the polyol used in the present invention, dihydric alcohols such as butylene glycol as well as glycerin may be used, and a mixture of monohydric to trihydric alcohols may be used. The polyol improves the feeling of use of cosmetics by supplying moisture to the keratin and softening the skin.

In another aspect, the present invention relates to a cosmetic for softening keratin in a solubilizing formulation made from a composition for external application for emollient skin comprising the AHA, an alkali metal salt of AHA, and urea as active ingredients. In addition, the solubilization formulation may be characterized in that it is any one formulation selected from the group consisting of a softening lotion, a nutrient lotion, an essence, and a mist of a spray type.

The composition for external application for skin of the present invention may be formulated in a cream formulation, but a surfactant is used for emulsification and stabilization of the cream formulation, and a thickener is also added to stabilize the cream formulation, and a thickener (polyethylene glycol (PEG), etc.) ) is weak to acid, and when it is contained together with the AHA and urea of the present invention, which exhibit low pH, the activity of the thickener may decrease, resulting in instability of the formulation. Therefore, it is advantageous to formulate the composition of the present invention in a solubilizing formulation containing a small amount of surfactant and thickening agent rather than a cream formulation. The solubilization formulation may include, but is not limited to, softening lotion, nutrient lotion, essence, mist, and the like.

In another aspect, the present invention relates to a cosmetic for softening keratin in the form of a cream made from a composition for external application for emollient skin comprising the AHA, an alkali metal salt of AHA, and urea as active ingredients. However, as described above, the thickener added to the cream formulation does not sufficiently exhibit the thickening effect at low pH. It is desirable to maintain the thickening effect with only and fatty alcohol. It can be formulated as a liquid crystal formulation capable of stabilizing high hardness without containing such a thickener, but is not necessarily limited thereto.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not to be construed as being limited by these examples. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

[Test Example 1] Measurement of an appropriate mixing ratio of AHA and alkali metal salt of AHA contained in the composition of the present invention

First, as a result of measuring the pH of the aqueous solution containing lactic acid alone, which is most suitable as the AHA of the present invention, as shown in Table 1 below, the pH varies within the range of 2.0 to 3.0 depending on the concentration of the aqueous lactic acid solution, was found to represent

Concentration of lactic acid aqueous solution (g/l) pH One 2.91 2 2.76 3 2.67 4 2.6 5 2.56 6 2.52 7 2.48 8 2.45 9 2.43 10 2.41 11 2.38

Accordingly, an appropriate mixing ratio of lactic acid and sodium lactate was searched so that the pH could be maintained at 4.0 to 5.0 by appropriately adding sodium lactate, an alkali metal salt of lactic acid, to lactic acid as an acidity control agent. As a result, as shown in FIG. 1, when the ratio of lactic acid/sodium lactate is between 0 and 1, the pH of the composition containing lactic acid and sodium lactate is maintained at 4.0 to 5.0, and when the ratio exceeds 1, In this case, it was found that the pH was gradually lowered to 4 or less, which was not appropriate as the pH of the cosmetic formulation.

[Formulation Example 1] Preparation of a solubilization formulation containing the composition of the present invention

In order to examine the stabilizing effect in solubilizing formulations such as skins, a transparent gel skin containing AHA (lactic acid), an alkali metal salt of AHA (sodium lactate), and urea of the present invention was prepared with the composition shown in Table 2 below. did. At this time, by setting the pH of the skin to 4.2, the ratio of lactic acid/sodium lactate was 0.5 to maintain the final pH in the range of 4.0 to 8.0 even if the pH of the skin changes over time. The viscosity of the formulation was about 4,000 cps as measured at 30° C. 12 rpm using Brookfield (LVDVII+).

ingredient Content (wt%) glycerin 5 propylene glycol 4 lactic acid 3 sodium lactate 6 glycolic acid 2 urea 4 Niacinamide 2 ethanol 10 Sodium polyacrylate 0.5 antiseptic appropriate amount Purified water to 100

[Comparative Formulation Example 1]

As a comparative formulation example with respect to Formulation Example 1, a skin in the form of a transparent gel was prepared with the composition shown in Table 3 below. Unlike Formulation Example 1, the ratio of lactic acid and sodium lactate was set and mixed so that the pH of the skin was 2.6. The viscosity of the formulation was about 4,000 cps as in Formulation Example 1 as a result of measurement at 30° C. 12 rpm using Brookfield (LVDVII+).

ingredient Content (wt%) glycerin 5 propylene glycol 4 lactic acid 6 sodium lactate 3 glycolic acid 2 urea 4 Niacinamide 2 ethanol 10 Sodium polyacrylate 0.5 antiseptic appropriate amount Purified water to 100

[Test Example 2] Formulation stability measurement of Formulation Example 1 and Comparative Formulation Example 1

In order to confirm the stability of the active ingredient in the skin prepared according to the composition of Formulation Example 1 and Comparative Formulation Example 1, the prepared sample was stored in an oven at 40 ° C. was measured. The results are shown in Table 4 below.

formulation
Initial concentration retention rate (%) immediately after manufacturing 1 week later 2 weeks later after 3 weeks after 4 weeks Formulation Example 1
(pH 4.2) 100 100 100 100 100 Comparative Formulation Example 1
(pH 2.6) 100 91 81

As shown in Table 4, in the case of Formulation Example 1 in which the initial pH of the formulation is 4.2, the concentration of the active ingredient is maintained as it is over time, whereas in Comparative Formulation Example 1 in which the initial pH of the formulation is 2.6, as time passes As the active ingredient was decomposed, it was found that the concentration of the active ingredient decreased. Therefore, as in Formulation Example 1, it was confirmed that the stability of the formulation was maintained when the ratio of AHA/AHA alkali metal salt was less than 1.

[Test Example 3] Measurement of keratin softening effect and whitening effect of Formulation Example 1

In order to examine the skin keratin softening effect of Formulation Example 1, the keratin exfoliation promoting effect of Formulation Example 1 was measured for 30 healthy adult males and females between 20-40 years of age.

Before sample application, the color of the elbow of the test subject was measured with a chromameter (CR300, Minolta, Japan), and then, about 0.4 ml of dihydroxyacetone (DHA) with a concentration of 10 wt% was added to the Hill Top chamber (manufactured by The Hill Top). and attached to the elbow for 6 hours. After 24 hours, the color of the area colored brown by DHA was measured to compare the color difference from before application of the sample. Thereafter, while the sample of Formulation Example 1 was applied twice a day, the degree of daily discoloration was measured with a chromameter to measure the time it takes to return to the original skin color. The keratin exfoliation rate was calculated by Equation 1 below. The results are shown in Table 5 below.

*Untreated group: After staining with DHA, no sample was applied type of sample Turnover Time (days) Exfoliation rate (%) untreated group 18.4 - Formulation Example 1 13.5±3.5 20.55 Comparative Formulation Example 1 16.4±3.2 15.10

As shown in Table 5, in Formulation Example 1 containing active ingredients such as AHA, alkali metal salt of AHA, urea, and niacinamide, Turnover Time, which is the time required for the existing stratum corneum to be replaced with a new stratum corneum, was the untreated group or Compared to Comparative Formulation Example 1, it was shorter and exhibited an excellent keratin exfoliation effect. In addition, it was confirmed that the skin tone of the elbow, which was dark and dull, was brightened by exfoliation of dead skin and whitening ingredients.

On the other hand, in the case of Comparative Formulation Example 1, as shown in Test Example 2, the stability of the formulation was not maintained and the active ingredient was decomposed and the content of the active ingredient was reduced. It was confirmed that the formulation was lower than that of Formulation Example 1.

As described above in detail a specific part of the content of the present invention, for those of ordinary skill in the art, it is clear that this specific description is only a preferred embodiment, and the scope of the present invention is not limited thereby. something to do. Accordingly, it is intended that the substantial scope of the present invention be defined by the appended claims and their equivalents.

Claims (14)

A composition for external application for keratin softening comprising AHA (alpha hydroxy acids), an alkali metal salt of AHA, and urea as active ingredients,
The AHA is contained in an amount of 3 to 10% by weight based on the total weight of the composition,
The alkali metal salt of the AHA is contained so that the weight ratio of the AHA to the alkali metal salt of the AHA is 0.01 to 1,
The urea is contained in an amount of 4 to 10% by weight based on the total weight of the composition,
The composition for external application for skin, characterized in that the pH of the composition is 4.0 to 8.0. The composition for external application for skin according to claim 1, wherein the AHA is glycolic acid, lactic acid, or a mixture of glycolic acid and lactic acid. The composition for external application for skin according to claim 1, wherein the alkali metal salt of AHA is sodium lactate or sodium glycolate. The composition for external application for skin according to claim 1, wherein the composition further comprises niacinamide as a whitening agent. The composition for external application for skin according to claim 4, wherein the niacinamide is contained in an amount of 1 to 10% by weight based on the total weight of the composition. The composition for external application for skin according to claim 1, wherein the composition further comprises a polyol as a water-soluble moisturizer. A cosmetic for keratin softening in a solubilizing formulation made from the composition for external application for skin according to any one of claims 1 to 6. The cosmetic according to claim 7, wherein the solubilizing formulation is any one formulation selected from the group consisting of softening lotion, nutrient lotion, essence, and spray type mist. A cosmetic for softening keratin in a cream form made from the composition for external application for skin according to any one of claims 1 to 6. delete delete delete delete delete

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