JPH06345633A - External preparation for skin - Google Patents

Abstract

PURPOSE:To obtain an external preparation for skin comprising an amphiphatic lipid orientated in a liquid crystal state, having stability and high skin care effect. CONSTITUTION:An external preparation for skin comprises (A) an amphiphatic lipid such as higher alcohol, fatty acid, ceramide, glycoceramide, phospholipid, glycolipid, cholesterol, cholesterol fatty acid ester, especially an amide derivative of the formula (R<1> is 10-26C saturated or unsaturated hydrocarbon group; R<2> is 9-25C saturated or unsaturated hydrocarbon group), (B) a nonionic surfactant, preferably a polyoxyethylene hardened castor oil or a polyoxyethylene alkyl ether having preferably 8-20 HLB value, (C) an ionic surfactant, (D) an oil agent such as hydrocarbons or animal or vegetable fats and oils and (E) an aqueous medium such as water or a combination of water and a water-soluble alcohol at a ratio of A+B+C=1-90wt.%, preferably 2-40wt.%, A:(B+C)=1:20-10:1, preferably 1:3-4:1, (A+B+C):D=1:1-50:1, preferably 3:2-12:1.

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 for orienting amphipathic lipids in a liquid crystal form, which is stable and has a high skin care effect.

[0002]

2. Description of the Related Art It is said that the water content of the stratum corneum is reduced in rough skin, dry skin, aged skin, etc., and the purpose is to improve the appearance and feel of these skins. Therefore, cosmetics in which various oils and water-soluble moisturizing ingredients are emulsified with a surfactant are used. These emulsion-type cosmetics inevitably have a problem that the emulsified particles coagulate with time. Therefore, development of a stable formulation having a skin care effect has been desired.

In particular, in recent years, amphipathic lipids, particularly keratinocyte lipids, have been extracted from the skin or the like and used in place of oil or water-soluble moisturizing components (Japanese Patent Laid-Open Nos. 62-29508 and 62-62).
-120308), and its chemical structural analogs have been proposed to be synthesized and used (JP-A-62-228048). Keratinocyte intercellular lipid is a substance that is found between cells of the horny cell, forms a layered structure, and is said to contribute to keratinocyte adhesion and hydration of the horny layer. These amphipathic lipids, including keratinocyte lipids, are at room temperature (25 ° C)
However, it is difficult to obtain an extremely stable emulsion because it is a solid and it must be added in a small amount to stably mix it with an external preparation, or the viscosity of the entire system must be increased to delay the separation of the emulsion. Met.

Therefore, a skin external preparation having a stable dosage form and a high skin care effect has been desired.

[0005]

Under the circumstances, as a result of intensive studies by the present inventors, as a result, the amphipathic lipid, the nonionic surfactant, the ionic surfactant and the oil agent were mixed in a specific ratio. The present invention has been completed by discovering that, when used, an amphipathic lipid can be aligned in a liquid crystal form, and a stable external preparation for skin can be obtained.

That is, the present invention provides the following components (A) to
(E): (A) Amphipathic lipid (B) Nonionic surfactant (C) Ionic surfactant (D) Oil agent (E) Aqueous medium is contained, (A) + (B) + ( C) = 1 to 90% by weight,
(A): [(B) + (C)] = 1:20 to 10: 1, and [(A) + (B) + (C)] :( D) = 1: 1 to 5
The present invention provides a skin external preparation having a ratio of 0: 1.

The amphipathic lipid as the component (A) used in the present invention is a substance which has both a hydrophilic part and a hydrophobic part and is insoluble in water but solid at room temperature (25 ° C.) which tends to disperse. There are, for example, higher alcohols, fatty acids, ceramides, sugar ceramides, phospholipids, glycolipids, cholesterol, cholesterol fatty acid esters and structural analogs thereof. Particularly preferred amphipathic lipids include, for example, amide derivatives represented by the following general formula (1).

[0008]

[Chemical 1]

[0009] (wherein, R ¹ is a linear or branched, saturated or unsaturated hydrocarbon group of 10-26 carbon atoms, R ² is a saturated straight chain or branched chain of 9 to 25 carbon atoms or an Indicates a saturated hydrocarbon group.)

The above amide derivative (1) can be obtained, for example, from JP-A-62-128048 and JP-A-63-216852.
It can be manufactured according to the publication. These amphipathic lipids can be used alone or in combination of two or more, and it is particularly preferable to use the amide derivative (1) alone or in combination with other amphipathic lipids. preferable. When the amide derivative (1) is used in combination with another amphipathic lipid, the ratio of the two is 100/1 to 1
/ 100, particularly preferably in the range of 10/1 to 1/10.

The amount of the amphipathic lipid as the component (A) is 0.1 to 30% by weight (hereinafter simply referred to as%) in the total composition, and particularly 1 to
It is preferable to add 20%.

Examples of the nonionic surfactant as the component (B) include polyoxyethylene hydrogenated castor oil; polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tetraoleate, and other polyoxyethylene sorbitan fatty acid esters; poly. Polyoxyethylene glyceryl fatty acid esters such as oxyethylene glyceryl monoisostearate and polyoxyethylene glyceryl triisostearate; Polyethylene glycol fatty acid esters such as polyethylene glycol monoisostearate; Polyoxyethylene hexyl decyl ether, polyoxyethylene octyl Dodecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxy Other than polyoxyethylene addition type surfactants such as polyoxyethylene alkyl ethers such as tylene oleyl ether and polyoxyethylene nonyl phenyl ether, polyglycerin alkyl ethers, polyglycerin fatty acid esters, sucrose fatty acid esters and the like, Among them, polyoxyethylene hydrogenated castor oil or polyoxyethylene alkyl ether,
An HLB value of 8 to 20, particularly 10 to 16 is preferable.

These nonionic surfactants may be used alone or in combination of two or more so as to obtain a preferable HLB value. 0.05 to 30% in the total composition,
It is particularly preferable to add 0.1 to 10%.

The ionic surfactant as the component (C) may be any of an anionic surfactant, an amphoteric surfactant and a cationic surfactant. Examples of the anionic surfactant include polyoxyethylene lauryl. Polyoxyethylene alkyl sulfates such as sodium ether sulfate and polyoxyethylene lauryl ether sulfate triethanolamine; N-acyl amino acid salts such as sodium lauroyl sarcosine and sodium lauroyl methylalanine; sodium polyoxyethylene lauryl ether phosphate, poly Sodium oxyethylene cetyl ether phosphate, dipolyoxyethylene alkyl ether phosphoric acid, tripolyoxyethylene alkyl ether phosphoric acid, dipolyoxyethylene nonylphenyl ether phosphoric acid, polyoxyethylene Polyoxyethylene alkyl ether phosphates such as sodium lauryl ether phosphate, sodium dipolyoxyethylene lauryl ether phosphate, etc .: Examples of the amphoteric surfactant include alkyl betaine, alkylamido betaine, alkyl sulfobetaine, etc .: Examples of the cationic surfactant include di long-chain alkyl quaternary ammonium salt, mono long-chain alkyl quaternary ammonium salt, di long-chain alkyl polyoxyethylene quaternary ammonium salt, mono long-chain alkyl polyoxyethylene quaternary ammonium salt. , Bis (hydroxyalkyl) quaternary ammonium salts, quaternary ammonium salts having an amide / ester bond, and the like.

These ionic surfactants alone are
Or it can be used in combination of two or more,
It is preferable to add 1 to 50%, especially 2 to 30% of the component (B).

As the oil agent of the component (D), room temperature (25
Those which are liquid at (° C.) are preferred, for example squalane,
Hydrocarbons such as liquid paraffin, animal and vegetable oils and fats such as olive oil and jojoba oil, and higher alcohol higher fatty acid esters such as octyl oxystearate. These oil agents can be used alone or in combination of two or more kinds, and are 0.1 to 30%, particularly 0.5 to 30% in the total composition.
It is preferable to mix it up to 20%.

As the aqueous medium of the component (E), water or water and ethanol, glycerin, sorbitol, propylene glycol, dipropylene glycol, 1,3-
Examples include combinations with water-soluble alcohols such as butanediol. The total amount of the component (E) is 40 to 9 in the entire composition.
It is preferable to add 9%, particularly 70 to 90%.

In the present invention, the total content of the components (A), (B) and (C) is 1 to 90%, preferably 2%.
It is necessary to be ˜40%. Also, (A):
[(B) + (C)] = 1:20 to 10: 1, preferably 1: 3 to 4: 1.

Further, [(A) + (B) + (C)]:
(D) = 1: 1 to 50: 1, preferably 3: 2 to 12:
Must be 1.

In the external preparation for skin of the present invention, in addition to the above-mentioned essential components, other components to be added to ordinary external preparations for skin, such as polyols, water-soluble polymers, ultraviolet absorbers, preservatives, fragrances, ethanol and inorganics. Alternatively, an organic powder, a bactericidal agent, a pigment, etc. can be appropriately added within a range that does not impair the effects of the present invention.

The external preparation for skin of the present invention comprises, for example, an amphipathic lipid as a component (A), a surfactant as a component (B) and a component (C), and an oil agent as a component (D) at high temperature (60 to 95 ° C.). It can be manufactured by dissolving, dropping an aqueous phase separately mixed therein, and cooling it to room temperature. Here, when a polyol such as glycerin is added to the lipid / activator / oil phase, liquid crystal can be formed more effectively.

The skin external preparation of the present invention thus obtained has a structure in which the lipid is in a liquid crystal state and a water layer is sandwiched between the layers. Such a liquid crystal structure can be confirmed for its layered structure by microscopic observation under polarized light, and also by X-ray analysis.

Further, the external preparation for skin of the present invention can be obtained as one having a transparent appearance by appropriately selecting the contents of essential components and the like, and a turbidity agent such as latex may be added to this to make it opaque or ethylene. It can be used in various appearances by blending glycol ester or the like into pearls, adding solids that are not dissolved in a composition such as powder and dispersing them in a geometric pattern, or adding a dye.

[0024]

EXAMPLES Next, the present invention will be further described with reference to examples, but the present invention is not limited to these examples.

Example 1 External skin preparations having the compositions shown in Tables 1 to 3 were produced. That is, components other than water were mixed and dissolved at 85 to 90 ° C., water heated to the same temperature was added dropwise thereto, and the mixture was cooled to room temperature to obtain a cream. All of these creams were liquid crystals having optical anisotropy.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

Example 2 A skin external preparation having the composition shown in Table 5 was produced and its performance was evaluated. The results are shown in Table 6. (Production method) Components other than water are mixed and dissolved at 85 to 90 ° C,
Water heated to the same temperature was added dropwise to this, and cooled to room temperature to obtain a cream.

(Evaluation method) (1) Confirmation of liquid crystal structure: A skin external preparation was thinly spread on a glass plate and observed with a polarizing microscope. A birefringent image is recognized in the liquid crystal form. The one in which the birefringence image was observed is indicated by ◯, and the one in which it was not observed was indicated by x. (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 the application for 2 weeks, after washing the face with warm water of 37 ° C and resting for 20 minutes in a room at a temperature of 20 ° C and a humidity of 40%,
The water content of the stratum corneum is measured by the skin conductance meter (I
(Manufactured by BS). The smaller the conductance value is, the rougher the skin is, and when it 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: After applying the sample for 2 weeks as in the case of skin conductance, the skin roughness was visually observed and judged according to the following criteria. Scores are shown as mean value ± standard deviation.

[0031]

[Table 4]

(4) Persistence on the skin surface: Ten women in their 20s to 50s were used as test subjects, and after washing the face, the same amount of the external preparation for skin was applied to the same position and the same area on the left and right cheeks. After spending daily life for 8 hours, the area of the external preparation for skin spread on the applied part was copied, and the ratio of the expanded area to the applied area was calculated.

[0033]

[Table 5]

[0034]

[Table 6]

[0035]

The external preparation for skin of the present invention is a stable one-phase system. Further, since the lipid is in a liquid crystal state and has a structure in which an aqueous layer is sandwiched between the layers, water evaporation from the composition is suppressed and the water content is higher than that of an emulsion or the like. Therefore, the moisturizing property is high, the skin can be efficiently replenished with water, and the skin can be softened. Further, since there is no continuous phase of an aqueous phase or an oil phase like a conventional emulsion, aggregation of the emulsion does not occur and a stable structure can be maintained, so that water such as sweat and oil such as sebum can be maintained. In contrast, it has high persistence on the skin. Furthermore, since the lamellar structure of the composition is the same aggregate structure as the lamellar structure of interkeratinous lipids, it has excellent skin absorbability of amphipathic lipids.

Claims (1)

[Claims] 1. The following components (A) to (E): (A) amphipathic lipid (B) nonionic surfactant (C) ionic surfactant (D) oil agent (E) aqueous medium Contains, (A) + (B) + (C) = 1 to 90% by weight,
(A): [(B) + (C)] = 1:20 to 10: 1, and [(A) + (B) + (C)] :( D) = 1: 1 to 5
The skin external preparation is 0: 1.