JPH0733633A - External preparation for skin - Google Patents

Abstract

PURPOSE:To provide an external preparation for skin which can increase moisture retention in the corneal layer, improve skin roughening and exhibits high storage stability. CONSTITUTION:The external preparation for skin comprises (A) one or more selected from ceramides of the formula I (R<1>, R<2> are straight-chain or branched- chain, saturated or unsaturated hydrocarbon group of 8 to 26 carbon atoms where one or more OH may be substituted) and ceramide-like substances of the formula II (R<3> is straight-chain or branched-chain, saturated or unsaturated hydrocarbon of 10 to 26 carbon atoms; R<4> is straight-chain or branched-chain, saturated or unsaturated hydrocarbon of 9 to 25 carbon atoms), for example, N-(2-hydroxy-3-hexadecyloxypropyl)-N-2-hydroxyethy-hexadecanamide and (B) a compound of the formula III [R<5> is the residue of cholesterol except OH proton, the formula IV (R<6> is straight or branched chain alkylene of 10 to 20 carbon atoms; R<7>, R<8> are straight or branched chain alkyl of 10 to 26 carbon atoms to which polyoxyalkylene may be added); n is 5<=n<40], preferably at an A/B ratio of 70/30 to 20/80.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skin external preparation, and more particularly to a skin external preparation capable of enhancing the water-retaining power of the stratum corneum and improving rough skin.

[0002]

2. Description of the Related Art Conventionally, it has been known that the water content of the stratum corneum is important for moisturizing and softening the skin. The retention of the water is said to be due to a water-soluble component contained in the stratum corneum, that is, a free amino acid, an organic acid, urea or an inorganic ion, and these substances are used alone or in combination, and a medicated skin external preparation. Alternatively, it is used in cosmetics for the purpose of improving or preventing skin roughness.

Apart from this, many moisturizing substances having a high affinity with water have been developed and used for the same purpose.

Furthermore, in recent years, it has been found that lipids existing between keratinocytes have a high moisturizing ability, and the artificial intercellular lipids composed of the structurally similar substances of the interkeratinocyte lipid component moisturize the skin. Is given and is made flexible, and a relatively high effect is obtained.

[0005]

However, when a moisturizing substance such as a water-soluble component present in the stratum corneum is applied to the skin, its action is to provide water to the stratum corneum and supply water to the stratum corneum. However, the effect was temporary, and it was not intended to fundamentally improve the water-retaining ability of the stratum corneum and essentially prevent or cure the rough skin.

When artificial intercellular lipids are applied to the skin, the water-retaining ability of the stratum corneum can be fundamentally improved, and the effect of preventing or healing skin roughening can be obtained to some extent, but it is completely effective in living organisms. It has not reached the level equal to and was not yet satisfactory.

[0007] Therefore, it is possible to fundamentally improve the water-retaining ability of the stratum corneum and restore the function of the rough stratum corneum to a level equivalent to that of a healthy body, and to give the skin a feeling of moisture and flexibility. Development of an external preparation has been desired.

[0008]

Under these circumstances, the present inventors have conducted diligent research focusing on the interaction between lipid molecules between keratinocytes in order to solve the above-mentioned problems. A ceramide and / or a ceramide-like structure containing a ceramide represented by 1) and / or a ceramide-like structural substance represented by the following general formula (2) in combination with a compound represented by the following general formula (3) The present invention has been completed by finding that a substance can be aligned in a liquid crystal state and that a stable external preparation for skin can be obtained.

That is, the present invention provides the following components (A) and (B): (A) General formula (1)

[0010]

[Chemical 4]

(Wherein R ¹ and R ² represent a linear or branched, saturated or unsaturated hydrocarbon group having 8 to 26 carbon atoms, which may be substituted by one or more hydroxyl groups). Ceramide and general formula (2)

[0012]

[Chemical 5]

(In the formula, R ³ represents a straight chain or branched chain saturated or unsaturated hydrocarbon group having 10 to 26 carbon atoms, and R ⁴ represents a straight chain or branched chain saturated or unsaturated group having 9 to 25 carbon atoms. 1 or more selected from the group consisting of ceramide-like structural substances represented by (representing an unsaturated hydrocarbon group) (B) General formula (3) R ^5- (OCH ₂ CH ₂ ) _n -OH (3 [Wherein R ⁵ is a residue excluding hydroxyl group protons of cholesterols or the following formula (4)

[0014]

[Chemical 6]

(In the formula, R ⁶ represents a linear or branched alkylene group having 10 to 26 carbon atoms, and R ⁷ and R ⁸ each have 10 carbon atoms to which polyoxyethylene may be added.
The group represented by the formula (1) to (26 represents a straight chain or branched chain alkyl group), and n represents an integer of 5 to 40].

Of the components (A) used in the present invention, ceramide is represented by the above general formula (1), which is a known compound. In the formula (1), examples of the linear or branched saturated or unsaturated hydrocarbon group having 8 to 26 carbon atoms represented by R ¹ and R ² include octyl, nonyl, decyl, dodecyl, undecyl, tridecyl, Tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, hexacosyl, nonenyl, decenyl, dodecenyl, undecenyl,
Tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, nonadecenyl, eicosenyl, heneicosenyl, docosenyl, tricocenyl, tetracocenyl, pentacocenyl,
Hexacosenyl, nonadienyl, decadienyl, dodecadienyl, undecadienyl, tridecadienyl, tetradecadienyl, pentadecadienyl, hexadecadienyl, heptadecadienyl, octadecadienyl, nonadecadienyl, henecosadienyl, heneicocosadienyl, heneicocosadienyl, heneicosacenyl, Tetracosadienyl, pentacosadienyl, hexacosadienyl, 2
—Hexyldecyl, 2-octylundecyl, 2-decyltetradecyl group and the like. One or more hydroxyl groups may be substituted on these hydrocarbon groups.

Of the component (A), the ceramide-like structural material represented by the general formula (2) can be prepared by a known method [for example, Polish Journal of Chemistry (Pol. J. Chem.) 52 , 1059 (19
78); ibid. 52 , 1283 (1978); JP-A-54-
No. 117421, No. 54-144308, No. 54-147937, No. 62-228048, No. 63-216852]. That is, according to the reaction formula shown below,
It can be produced by reacting a compound (5) obtained from glycidyl ether and ethanolamine with a fatty acid methyl ester.

[0018]

[Chemical 7]

(Wherein R ³ and R ⁴ have the same meanings as described above) (2) In the formula, a linear or branched saturated or unsaturated hydrocarbon having 10 to 26 carbon atoms represented by R ³ Examples of the group include those having 10 to 26 carbon atoms in the above R ¹ and R ² , and as a linear or branched saturated or unsaturated hydrocarbon group having 9 to 25 carbon atoms represented by R ^4. Are those having 9 to 25 carbon atoms in the above R ¹ and R ² .

These ceramides of the component (A) and substances having a similar structure to ceramides can be used alone or in combination of two or more kinds.

The compound of the component (B) used in the present invention is represented by the above general formula (3).
Among the compounds represented by R ⁵ in the formula (3), examples of cholesterols include cholesterol, stigmasterol, β-sitosterol, lanosterol, ergosterol and the like. Further, in the group represented by the formula (4), the number of carbon atoms represented by R ⁷ and R ⁸ is 10 to 26.
Examples of the straight chain or branched chain alkyl group include those mentioned above among these, and 1 to 30 mol of polyoxyethylene may be added to these alkyl groups. Further, in the formula (3), n represents an integer of 5 or more and less than 40.

These components (B) can be used alone or in combination of two or more.

The blending ratio of the component (A) and the component (B) to the external preparation for skin of the present invention is preferably 95: 5 to 5:95 by weight, and particularly preferably 70:30 to 20:80. In order to mix these, it is preferable to mix the both in the above proportions, once heat and dissolve, and then cool to form a paste, which is added to the other components.

The amount of the mixture of the components (A) and (B) to be added to the external preparation for skin of the present invention is not particularly limited, but in the case of an emulsified external preparation for skin, 0.01 to 60 of the total composition is usually used. Weight% (hereinafter simply expressed as%), particularly 0.1 to 30% is preferable, and 1 to 90%, particularly 5 to 50 in the case of oily external preparation for skin based on liquid hydrocarbon such as squalane. %
Is preferred.

Further, it is preferable that the external preparation for skin of the present invention further contains glycerin because the liquid crystal can be maintained more stably. When blending glycerin, the blending ratio of glycerin and the mixture of component (A) and component (B) is
The weight ratio is preferably 50:50 to 95: 5.

The external preparation for skin of the present invention is roughly classified into a medical external preparation for skin and a cosmetic in its use form.

Examples of the external medicated skin agent include various ointments containing medicinal components. The ointment may be either an oil-based base, an oil / water, or a water / oil-type emulsion base. The oily base is not particularly limited, and examples thereof include vegetable oil, animal oil, synthetic oil, fatty acid, and natural or synthetic glyceride. In addition, the medicinal component is not particularly limited, and for example, an analgesic / anti-inflammatory agent, an antipruritic agent, a bactericidal disinfectant, an astringent agent, an emollient agent, a hormone agent and the like can be appropriately used as necessary.

When used as a cosmetic, in addition to the essential ingredients, oils, moisturizers, ultraviolet absorbers, alcohols, chelating agents, pH adjusters, preservatives, and additives commonly used as cosmetic ingredients are used. A sticky agent, a pigment, a fragrance, etc. can be arbitrarily combined and blended.

As the cosmetics, various forms such as water /
Can be used as skin cosmetics such as oils, oil / water emulsion cosmetics, creams, lotions, lotions, oily cosmetics, lipsticks, foundations, skin cleansers, hair tonics, hair conditioners, hair nourishing agents, hair restorers, etc. .

[0030]

The action mechanism of the mixture of the component (A) and the component (B) in the external preparation for skin of the present invention has not been completely clarified, but the combination of the component (A) and the component (B) is easy. Since a multi-layered lamella structure is constructed in the body and a lot of bound water is contained in the structure, it is considered that this is exerted as a water retaining function of the stratum corneum.

[0031]

Since the external preparation for skin of the present invention contains a mixture of the component (A) and the component (B) having such an action, it exerts an excellent effect of improving and preventing skin roughness. The storage stability as an external preparation is extremely good.

[0032]

The present invention will be further described with reference to examples, but the present invention is not limited thereto. In this Example, the compound (2a) means N- (2-hydroxy-3-hexadecyloxypropyl) -N produced according to the method described in Reference Example 1 of JP-A-63-192703. 2-hydroxyethylhexadecanamide [in the formula (2), R ³ = C ₁₆ H ₃₃ , R ⁴ =
C ₁₅ H ₃₁ ] is shown.

Example 1 Preparation of Mixture of Component (A) and Component (B): Compound (2
Sample bottle with a glass screw cap so that 50% by weight of a) and 50% by weight of polyoxyethylene cholesteryl ether [in the formula (3), R ⁵ = residue of cholesterol except hydroxyl protons, n = 15]. Weigh to
Use a heating block to heat the sample bottle to 80 ℃
Heat so that When heated and completely dissolved, the same amount of the aqueous phase is added to the total weight, stirred, and allowed to cool in the air to obtain a mixture in a paste state.

Example 2 A skin external preparation having the composition shown in Table 2 was produced and evaluated for storage stability, skin conductance and skin roughness score.
The results are shown in Table 3. (Evaluation method) (1) Storage stability The external preparation for skin was stored at -5 ° C, 5 ° C, room temperature and 40 ° C for 1 month, and then evaluated according to the following criteria. ◯: No phase separation was observed and there was no change in appearance. Δ: Although there is no change in appearance, phase separation or change in viscosity is observed. X: Phase separation occurs and the viscosity changes significantly.

(2) Skin Conductance Ten females aged 20 to 50 who have rough skin on the cheeks in winter are used as test subjects, and different samples are applied to the left and right cheeks once a day for 2 weeks. The day after 2 weeks of application, 3
After washing the face with warm water of 7 ° C. and resting in a room at a temperature of 20 ° C. and a humidity of 40% for 20 minutes, the water content of the stratum corneum was measured with a skin conductance meter (manufactured by IBS). The smaller the conductance value is, the rougher the skin is, and when the conductance value is 5 or less, the skin is severely rough. On the other hand, if this value is 20 or more, almost no skin roughness is observed.

(3) Skin Roughness Score Similar to the case of skin conductance, the sample was applied for 2 weeks, and then the skin roughness was observed with the naked eye and judged according to the following criteria. The score was shown by the average value +/- standard deviation.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

Example 3 An external preparation for the skin having the composition shown in Table 4 was prepared and subjected to 1 in a dry environment.
The amount of water contained in the external preparation for skin after left standing for a day was quantified. The results are shown in Table 4. (Evaluation method) A skin external preparation is evenly applied to the petri dish surface,
The desiccant was left to stand in a desiccator which was dried. One day later, the amount of water remaining in the external preparation for skin was quantified by Karl Fischer (Hiranuma automatic water content measuring device AQV-5).

[0041]

[Table 4]

Claims (3)

[Claims] 1. The following components (A) and (B): (A) General formula (1) (In the formula, R ¹ and R ² represent a linear or branched saturated or unsaturated hydrocarbon group having 8 to 26 carbon atoms in which one or more hydroxyl groups may be substituted) and general ceramides Formula (2) (In the formula, R ³ represents a linear or branched saturated or unsaturated hydrocarbon group having 10 to 26 carbon atoms, and R ⁴ represents a linear or branched saturated or unsaturated hydrocarbon group having 9 to 25 carbon atoms. A hydrocarbon group) or one or more selected from the group consisting of ceramide-like structural substances (B) General formula (3) R ^5- (OCH ₂ CH ₂ ) _n -OH (3) [Formula In the formula, R ⁵ is a residue excluding the hydroxyl group proton of cholesterol or the following formula (4): (In the formula, R ⁶ represents a linear or branched alkylene group having 10 to 26 carbon atoms, and R ⁷ and R ⁸ each represent a linear or branched C 10 to 26 carbon atom to which polyoxyethylene may be added. Represents a group represented by a branched chain alkyl group), and n represents an integer of 5 ≦ n <40]. 2. The weight ratio of component (A) to component (B) is 9
The external preparation for skin according to claim 1, which is 5: 5 to 5:95. 3. The external preparation for skin according to claim 1, further comprising glycerin.