A topical skin preparation containing 12-hydroxystearic acid and having a bicontinuous microemulsion structure.

Abstract

The purpose of the present invention is to provide a gel- or solid-form skin external agent that has sufficient viscosity or hardness and stability while retaining the cleansing power inherent to a bicontinuous microemulsion. The skin external agent according to the present invention is characterized by containing (A) water, (B) a water-soluble organic solvent, (C) a surfactant, (D) an oily component and (E) 12-hydroxystearic acid, having a bicontinuous microemulsion structure, and being in the form of a gel or solid.

Description

TECHNICAL FIELD

[0001] The present invention relates to an external skin preparation having a bicontinuous microemulsion structure. More specifically, by containing 12-hydroxystearic acid, the present invention relates to a gel-like or solid external skin preparation that has sufficient viscosity or hardness and stability while retaining the original detergency inherent to bicontinuous microemulsions, can prevent dripping, and has excellent handleability. BACKGROUND ART

[0002] Cleansing cosmetics are generally broadly classified into oily cleansing cosmetics and aqueous cleansing cosmetics. Oily cleansing cosmetics contain a large amount of oily components, so they blend well with makeup stains and exhibit excellent cleansing power, but they have a noticeable sticky sensation from the oily components and are inferior in feeling upon use. On the other hand, aqueous cleansing cosmetics have a refreshing feeling upon use due to the small blended amount of oily components, but tend to blend poorly with makeup stains and have inferior cleansing power.

[0003] Accordingly, as a technology combining these advantages, many cleansing cosmetics having a bicontinuous microemulsion structure (isotropic surfactant continuous phase) in which an oil phase and an aqueous phase form continuous phases have been proposed. For example, Patent Document 1 discloses a detergent composition containing an amphoteric surfactant and an anionic surfactant in a specific ratio, and further containing a liquid alcohol and / or a liquid fatty acid, and water, which is said to have excellent detergency by forming an isotropic surfactant continuous phase, that is, a bicontinuous phase. In addition, Patent Document 2 discloses a makeup remover containing a nonionic surfactant, a polar oil, a silicone oil, and water in specific blended amounts, and describes that since it has an isotropic surfactant continuous phase, it blends well with makeup and has a high makeup removing effect.

[0004] A bicontinuous microemulsion has a three-dimensionally interwoven structure in which layers of aqueous and oily components are bicontinuous, exhibiting optically isotropic and transparent single-liquid phase properties. By applying bicontinuous microemulsions to cleansing cosmetics, the interfacial tension between oil and water is reduced, resulting in better compatibility with makeup residue and high cleansing performance. Furthermore, because the continuous phase consists of oil and water, it has excellent makeup removal properties and provides a refreshing feeling. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2002-20791 [Patent Document 2] Japanese Patent Publication No. 2000-256132 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, topical skin preparations with a bicontinuous microemulsion structure have low viscosity and high fluidity like a liquid, which can lead to poor handling, such as dripping during application. Furthermore, depending on the ingredients, the aqueous and oil phases may separate if the temperature deviates from the appropriate level, resulting in poor stability.

[0007] This invention has been made in view of the above circumstances, and aims to provide a gel-like or solid topical skin preparation that has sufficient viscosity or hardness and stability while retaining the inherent cleansing power of a bicontinuous microemulsion. [Means for solving the problem]

[0008] The inventors conducted diligent research to solve the above problems and, as a result, discovered that by incorporating 12-hydroxystearic acid, sufficient viscosity or hardness and stability can be obtained while maintaining a bicontinuous microemulsion structure, thus completing the present invention.

[0009] In other words, the present invention is (A) Water, (B) Water-soluble organic solvent, (C) Surfactants, (D) Oils and (E)12-Hydroxystearic Acid The gist of this invention is a gel-like or solid topical skin preparation containing [ingredient name] and having a bicontinuous microemulsion structure. [Effects of the Invention]

[0010] The topical skin preparation according to the present invention, by having the above configuration, can realize a topical skin preparation having a bicontinuous microemulsion structure with sufficient viscosity or hardness and stability. This is thought to be because 12-hydroxystearic acid wedges itself into the bilayer of surfactants arranged between the oil layer and the water layer, physically supporting the structure. The topical skin preparation according to the present invention has a bicontinuous microemulsion structure, yet is in a gel or solid form, thus achieving excellent cleansing power and handling properties. [Modes for carrying out the invention]

[0011] The topical skin preparation of the present invention is (A) Water, (B) Water-soluble organic solvent, (C) Surfactants, (D) Oils and (E)12-Hydroxystearic Acid It contains [the following]. Details are provided below. In the following, polyoxyethylene may be abbreviated as "POE," polyoxypropylene as "POP," and polyethylene glycol as "PEG."

[0012] <(A) Water> The (A) water (hereinafter sometimes referred to as "component (A)") incorporated in the present invention is not particularly limited, and purified water, ion-exchanged water, distilled water, etc., can be used.

[0013] (A) The amount of water to be added is not particularly limited, but is preferably 10 to 70% by mass of the total amount of the topical skin preparation, and more preferably 20 to 50% by mass. If the amount is less than 10% by mass, a refreshing feeling may not be obtained, and if the amount exceeds 70% by mass, the stability and cleansing properties of the preparation may deteriorate.

[0014] <(B) Water-soluble organic solvent> The (B) water-soluble organic solvent (hereinafter sometimes referred to as "component (B)") incorporated in the present invention affects the association state of the (C) surfactant and can increase the amount of (D) oil and (E) 12-hydroxystearic acid solubilized into the hydrophobic portion of the (C) surfactant. As such (B) water-soluble organic solvents, it is preferable to use lower alcohols, polyhydric alcohols, or blocked alkylene oxide derivatives.

[0015] Examples of lower alcohols include ethanol, propanol, isopropyl alcohol, and butanol. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,2-pentanediol (pentylene glycol), 1,5-pentanediol, neopentyl glycol, 1,2-hexanediol, 1,6-hexanediol, 1,2-cyclohexanediol, heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, glycerin, pentaerythritol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, thiodiglycol, and the like. Further, examples of the block-type alkylene oxide derivative include dimethyl ethers of random or block copolymers of polyoxyethylene and polyoxypropylene such as POE(9)POP(2) dimethyl ether, POE(14)POP(7) dimethyl ether, POE(10)POP(10) dimethyl ether, POE(6)POP(14) dimethyl ether, POE(7)POP(14) dimethyl ether, and POE(17)POP(4) dimethyl ether (the numbers in parentheses after POE and POP represent the respective added mole numbers) (which may be simply referred to herein as "POE / POP dimethyl ether").

[0016] A particularly preferred (B) water-soluble organic solvent is one or more selected from the group consisting of dipropylene glycol, 1,3-butylene glycol, pentylene glycol, POE / POP dimethyl ether, polyethylene glycol, and glycerin. These may be used alone, or two or more of them may be used in combination.

[0017] The blending amount of the (B) water-soluble organic solvent is not particularly limited, but is preferably 3 to 60 mass% and more preferably 10 to 30 mass% relative to the total amount of the external skin preparation. If the blending amount is less than 3 mass%, a bicontinuous microemulsion structure may not be obtained, and if the blending amount exceeds 60 mass%, the stability and detergency of the preparation may deteriorate.

[0018] <(C) Surfactant> The (C) surfactant (hereinafter sometimes referred to as "component (C)") incorporated in the present invention is not particularly limited as long as it can form a bicontinuous microemulsion structure, and among them, hydrophilic nonionic surfactants are preferred. The (C) surfactant is preferably one or more selected from the group consisting of polyethylene glycol fatty acid esters, polyethylene glycol alkyl ethers, polyethylene glycol alkylphenyl ethers, polyethylene glycol castor oil derivatives, polyethylene glycol hydrogenated castor oil derivatives, and ethylene oxide derivatives of glycerin fatty acid esters.

[0019] Specific examples include polyethylene glycol distearate, polyethylene glycol monooleate, ethylene glycol distearate, polyethylene glycol lauryl ether, PEG-10 hydrogenated castor oil, PEG-8 glyceryl isostearate, palm oil fatty acid PEG-7 glyceryl, PEG-20 glyceryl triisostearate, and PEG-60 glyceryl isostearate. When a plurality of surfactants having different HLB values are blended as the (C) surfactant, the average HLB is preferably 8.5 to 14, and more preferably 9 to 12. As used herein, "average HLB" refers to a weighted average.

[0020] The blending amount of the (C) surfactant is not particularly limited, but is preferably 10 to 45% by mass, more preferably 20 to 40% by mass, relative to the total amount of the external skin preparation. If the blending amount is less than 10% by mass, the detergency may decrease, and if the blending amount exceeds 45% by mass, stickiness may occur during use.

[0021] <(D) Oil component> The (D) oil component (hereinafter sometimes referred to as "component (D)") incorporated in the present invention is not particularly limited, and various oil components widely used in topical skin preparations can be incorporated. In particular, it is preferable that it be one or more selected from the group consisting of liquid oils and fats, hydrocarbon oils, ester oils, and silicone oils. Specifically, liquid oils such as avocado oil, evening primrose oil, camellia oil, turtle oil, macadamia nut oil, sunflower oil, almond oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, peach kernel oil, wheat germ oil, sasanqua oil, castor oil, linseed oil, safflower oil, cottonseed oil, hen oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, cinnamon oil, Japanese tuni oil, jojoba oil, and germ oil; hydrocarbon oils such as isododecane, liquid paraffin, squalene, pristane, and polybutene; and palmitate. Cetyl, cetyl octanoate, cetyl 2-ethylhexanoate, hexyldecyl dimethyloctanoate, ethyl laurate, hexyl laurate, isopropyl myristate, 2-hexyldecyl myristate, myristyl myristate, octyldodecyl myristate, isopropyl palmitate, 2-ethylhexyl palmitate, 2-hexyldecyl palmitate, 2-heptylundecyl palmitate, butyl stearate, isocetyl stearate, isocetyl isostearate, olein Decyl acid, dodecyl oleate, oleyl oleate, myristyl lactate, cetyl lactate, diisostearyl malate, cholesteryl 12-hydroxystearylate, castor oil fatty acid methyl ester, 2-ethylhexyl succinate, diisobutyl adipate, 2-hexyldecyl adipate, di-2-heptylundecyl adipate, diisopropyl sebatate, di-2-ethylhexyl sebatate, ethylene glycol di-2-ethylhexanoate, neopentyl glycol dicaprate, dioctanoic acid Ester oils such as neopentyl glycol, acetoglyceride, glyceryl di-2-heptylundecanoate, glyceryl trioctanoate, glyceryl tri-2-ethylhexanoate, glyceryl trimyristate, glyceryl triisopalmitate, glyceryl tri-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetraoctanoate, and pentaerythritol tetra-2-ethylhexanoate;Examples of silicone oils include linear polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and diphenylpolysiloxane; cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexanesiloxane; and various modified polysiloxanes such as amino-modified polysiloxanes, polyether-modified polysiloxanes, alkyl-modified polysiloxanes, and fluorine-modified polysiloxanes.

[0022] (D) The amount of oil is not particularly limited, but is preferably 5 to 25% by mass of the total amount of the topical skin preparation, and more preferably 10 to 20% by mass. If the amount is less than 5% by mass, the cleansing effect may decrease, and if the amount exceeds 25% by mass, the stability of the preparation may deteriorate.

[0023] <Selection criteria for preferred combinations of components (B), (C), and (D)> The combination of (B) water-soluble organic solvent, (C) surfactant, and (D) oil incorporated into the topical skin preparation according to the present invention is subject to the following conditions (i) and (ii): (i) When a mixture consisting of (A) water, (B) water-soluble organic solvent, (C) surfactant, and (D) oil is prepared, it is either a single-phase system of either a liquid crystal phase formed by surfactant aggregates or an isotropic surfactant continuous phase, or a system of coexistence of either the liquid crystal phase or the isotropic surfactant continuous phase with the other phase. (ii) The viscosity of the mixture at 25°C is 250 mPa·s or less. It is preferable to select such that the following conditions are met.

[0024] <Condition (i)> Of the essential components incorporated into the topical skin preparation according to the present invention, it is preferable that the mixture consisting only of (A) water, (B) water-soluble organic solvent, (C) surfactant, and (D) oil, excluding (E) 12-hydroxystearic acid, forms a single-phase system of a liquid crystal phase or a continuous isotropic surfactant phase, or forms a system of coexistence of a liquid crystal phase and a continuous isotropic surfactant phase. Excellent cleansing effect can be obtained with any combination of (B) water-soluble organic solvent, (C) surfactant, and (D) oil that satisfies these conditions.

[0025] The mixing ratio of each component in this mixture is preferably the same as the mixing ratio of each component in a topical skin preparation. Specifically, it is preferable that the total amount of the mixture contains (A) 20-50% by mass of water, (B) 10-30% by mass of a water-soluble organic solvent, (C) 20-40% by mass of a surfactant, and (D) 10-20% by mass of oil.

[0026] Whether a mixture forms a liquid crystal phase and / or an isotropic surfactant continuous phase can typically be determined by known methods such as light transmission tests using polarizing plates, dispersion tests of aqueous and oily dyes, transmission electron microscopy observation, and electrical conductivity measurements, under temperature conditions of 25°C. Furthermore, since the liquid crystal phase is optically anisotropic, it can be distinguished from the isotropic surfactant continuous phase by light transmission testing using a polarizing plate.

[0027] <Condition (ii)> It is preferable that the mixture consisting of (A) water, (B) a water-soluble organic solvent, (C) a surfactant, and (D) an oil component has a viscosity of 250 mPa·s or less at 25°C. Good cleaning performance can be obtained with any combination of (B) a water-soluble organic solvent, (C) a surfactant, and (D) an oil component that satisfies this viscosity. The "viscosity" of this mixture was measured using a Type B viscometer after holding the mixture at 25°C for 30 minutes or more, under the conditions of rotor No. 2, rotation speed of 30 rpm, and 1 minute.

[0028] <(E)12-Hydroxystearic Acid> The (E)12-hydroxystearic acid (hereinafter sometimes referred to as "component (E)") incorporated in the present invention is obtained by hydrogenating ricinoleic acid and is a saturated fatty acid having an asymmetric hydroxyl group at the 12th carbon position. It can also be obtained by hydrolyzing hydrogenated castor oil obtained by hydrogenating castor oil, or by hydrogenating castor oil fatty acids obtained by hydrolyzing castor oil.

[0029] (E)12-hydroxystearic acid gels the topical skin preparation of the present invention, imparting sufficient viscosity or hardness and stability, but unlike general thickeners, it does not cause sliminess or stickiness. This is thought to be because (E)12-hydroxystearic acid wedges itself into the bilayer of surfactants arranged between the oil and water layers, physically supporting the bicontinuous microemulsion structure by linking the three-dimensionally intertwined water and oil layers.

[0030] (E) The amount of 12-hydroxystearic acid should be 0.5 to 10% by mass of the total amount of the topical skin preparation, with 1 to 5% by mass being more preferable. If the amount is less than 0.5% by mass, a sufficient gelling effect may not be obtained, and if it exceeds 10% by mass, it may become a hard solid, making it difficult to handle.

[0031] <Optional ingredients> In addition to the components (A) to (E) above, the topical skin preparation of the present invention may contain components commonly used in topical skin preparations, to the extent that they do not interfere with the effects of the present invention. For example, cleansing components such as anionic surfactants, chelating agents, preservatives, antioxidants, powders, fragrances, colorants, dyes, etc., may be added as needed.

[0032] <Bicontinuous microemulsion structure> The topical skin preparation of the present invention has a bicontinuous microemulsion structure. Whether or not it has a bicontinuous microemulsion structure can be determined by known methods such as light transmission tests using polarizing plates, dispersion tests of aqueous and oily dyes, and transmission electron microscopy observation of samples prepared by the freeze-fracture replica method.

[0033] The topical skin preparation of the present invention has a viscosity (B-type viscometer) of 400 mPa·s or more at 25°C, preferably 1000 to 100000 mPa·s, more preferably 2000 to 30000 mPa·s, or a hardness (rheometer) of 5 to 500 gf at 25°C, preferably 5 to 400 gf, more preferably 5 to 300 gf. Viscosity is an indicator when the topical skin preparation is in a liquid to gel state, and hardness is an indicator when the gelation of the topical skin preparation progresses further and exceeds the upper limit of viscosity measurement, i.e., when it is in a gel to solid state. By meeting these viscosity or hardness requirements, the topical skin preparation becomes a suitable gel or solid, exhibiting excellent handling properties that prevent dripping.

[0034] <Manufacturing method> In the manufacturing process for topical skin preparations having a bicontinuous microemulsion structure, the raw materials, which are solid at room temperature, are generally dissolved first, all components are uniformly mixed, and then cooled. However, if components (A) to (E) incorporated into the topical skin preparation of the present invention are simply heated, mixed, and cooled, crystals of (E) 12-hydroxystearic acid may precipitate and separate, making it impossible to obtain the appropriate viscosity or hardness.

[0035] To incorporate (E)12-hydroxystearic acid into a bilayer of surfactants arranged between the oil and water layers and form a bicontinuous microemulsion structure with appropriate viscosity or hardness and stability, it is necessary to first solubilize (E)12-hydroxystearic acid in the hydrophobic portion of the (C) surfactant, then mix it with water, and cool it. The specific manufacturing process involves the following steps (i) to (iii): (i) A step of preparing an intermediate composition by heating (B) a water-soluble organic solvent, (C) a surfactant, (D) an oil, and (E) 12-hydroxystearic acid to 60-90°C to dissolve them uniformly. (ii) A step of preparing a mixture by adding the intermediate composition obtained in step (i) to an aqueous medium containing water while stirring, or a step of preparing a mixture by adding the intermediate composition obtained in step (i) to an aqueous medium containing water while stirring, and (iii) A step of cooling the mixture obtained in step (ii) to room temperature. It is preferable that it includes.

[0036] <Application> The topical skin preparation of the present invention can be used primarily as a cleansing agent, and is particularly preferred for use as a facial cleanser. Furthermore, the topical skin preparation of the present invention can be impregnated into a base material such as a nonwoven fabric to form a sheet-like cleansing agent, which can then be used to wipe away makeup and sebum. [Examples]

[0037] The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, the amount of each component is expressed as a mass % of the system in which it is incorporated. Before describing each example in detail, the evaluation method used will be explained.

[0038] (1) Viscosity The viscosity of the prepared topical skin preparation was measured using a B-type viscometer after being held at 25°C for 30 minutes or more, under the conditions of rotor No. 3, rotation speed of 12 rpm, and 1 minute.

[0039] (2)Hardness The hardness of the prepared topical skin preparation after being held at 25°C for 30 minutes or more was measured using a rheometer (manufactured by Sun Science Co., Ltd.) with a load of 200g, a measuring terminal of 8mmφ, a needle insertion depth of 10mm, an ascent rate of 300mm / min, and a measurement temperature of 25°C.

[0040] (3) Stability The prepared topical skin preparations were stored at 50°C for one month, and then their condition was visually observed to evaluate their stability according to the following criteria. A: No crystal precipitation and / or phase separation was observed at all. B: Very slight crystal precipitation and / or phase separation were observed, but it was at a level that did not pose any problems for use. C: Crystal precipitation and / or phase separation were observed, making it unsuitable for use.

[0041] (4) Usability Twenty expert cosmetic evaluation panel members were asked to use the topical skin preparations of the examples and comparative examples. They evaluated the usability (non-dripping and ease of handling) on ​​a 5-point scale according to the following criteria, and the average score of all panel members was determined according to the following 3-point evaluation criteria. (Evaluation Criteria) Evaluation result: Score Very good: 5 points Good: 4 points Average: 3 points Slightly poor: 2 points Defective: 1 point (Judgment criteria) Judgment: Average score A: 4 or higher B: 3 or more but less than 4 C: Less than 3

[0042] <Examples 1-6 and Comparative Examples 1-2> Topical skin preparations having the compositions listed in Table 1 below were prepared, and their viscosity or hardness, stability, and usability were evaluated according to the evaluation method described above.

[0043] [Table 1]

[0044] As shown in Table 1 above, when the mixture contains (A) water, (B) water-soluble organic solvent, (C) surfactant, and (D) oil, and further contains (E) 12-hydroxystearic acid in the range of 0.5 to 10% by mass, a bicontinuous microemulsion structure is formed, and excellent stability and usability are obtained (Examples 1 to 6). On the other hand, when (E) 12-hydroxystearic acid is not included, dripping occurs and the usability is significantly poor (Comparative Example 1). Also, when the amount of (E) 12-hydroxystearic acid is too high, crystallinity becomes strong, resulting in insufficient stability and usability (Comparative Example 2). Note that in Comparative Example 2, crystal precipitation was observed without the formation of a bicontinuous microemulsion structure, so viscosity or hardness measurements were not performed.

[0045] <Examples 7-9 and Comparative Example 3> Topical skin preparations having the compositions listed in Table 2 below were prepared, and their viscosity, stability, and usability were evaluated according to the evaluation method described above.

[0046] [Table 2]

[0047] As shown in Table 2 above, even when the composition of (C) surfactant and (D) oil was changed, a bicontinuous microemulsion structure was formed, and sufficient stability and usability were obtained (Examples 7-9). On the other hand, when the amount of (C) surfactant was too small, phase separation occurred, resulting in poor stability and usability (Comparative Example 3). This is thought to be because the amount of (C) surfactant was too small, preventing sufficient solubilization of (E) 12-hydroxystearic acid and (D) oil. Note that in Comparative Example 3, phase separation occurred without forming a bicontinuous microemulsion structure, so viscosity was not measured.

[0048] <Examples 10-12 and Comparative Examples 4-5> Topical skin preparations having the compositions listed in Table 3 below were prepared, and their viscosity, stability, and usability were evaluated according to the evaluation method described above.

[0049] [Table 3]

[0050] As shown in Table 3 above, even when the composition of (C) surfactant was changed within the range of 8.5 to 14 in terms of average HLB, a bicontinuous microemulsion structure was formed, and sufficient stability and usability were obtained (Examples 10 to 12). On the other hand, when surfactants with average HLB of 8 and 16 were used, (E) 12-hydroxystearic acid and (D) oil could not be sufficiently solubilized, and phase separation occurred (Comparative Examples 4 and 5). Note that in Comparative Examples 4 and 5, phase separation occurred without the formation of a bicontinuous microemulsion structure, so viscosity measurements were not performed.

Claims

1. (A) Water, (B) Water-soluble organic solvent, (C) Surfactants, (D) Oils and (E) 12-hydroxystearic acid A gel-like or solid topical skin preparation containing and having a bicontinuous microemulsion structure.

2. (B) Water-soluble organic solvent, (C) surfactant, and (D) oil, under the following conditions (i) and (ii): (i) When a mixture consisting of (A) water, (B) water-soluble organic solvent, (C) surfactant, and (D) oil is prepared, it is either a one-phase system of either a liquid crystal phase formed by a surfactant aggregate or an isotropic surfactant continuous phase, or a system of coexistence of either the liquid crystal phase or the isotropic surfactant continuous phase with the other one phase. (ii) The viscosity of the mixture at 25°C is 250 mPa·s or less. A topical skin preparation according to claim 1, satisfying the requirements.

3. The topical skin preparation according to claim 1, wherein the amount of (E)12-hydroxystearic acid relative to the total amount of the topical skin preparation is 0.5 to 10% by mass.

4. (C) The topical skin preparation according to claim 1, wherein the surfactant is one or more nonionic surfactants selected from the group consisting of polyethylene glycol fatty acid esters, polyethylene glycol alkyl ethers, polyethylene glycol alkylphenyl ethers, polyethylene glycol castor oil derivatives, polyethylene glycol hydrogenated castor oil derivatives, and ethylene oxide derivatives of glycerin fatty acid esters.

5. The topical skin preparation according to claim 1, wherein the amount of surfactant (C) relative to the total amount of the topical skin preparation is 10 to 45% by mass, and the average HLB of surfactant (C) is 8.5 to 14.

6. (B) The topical skin preparation according to claim 1, wherein the water-soluble organic solvent is one or more selected from the group consisting of dipropylene glycol, 1,3-butylene glycol, pentylene glycol, POE / POP dimethyl ether, polyethylene glycol, and glycerin.

7. (D) The topical skin preparation according to claim 1, wherein the oil component is one or more selected from the group consisting of liquid oils and fats, hydrocarbon oils, ester oils, and silicone oils.

8. The topical skin preparation according to Claim 1, wherein the viscosity at 25°C is 1,000 to 100,000 mPa·S, or the hardness at 25°C is 5 to 500 gf.

9. A method for producing a topical skin preparation according to claim 1, comprising the following steps (i) to (iii): (i) A step of preparing an intermediate composition by heating (B) a water-soluble organic solvent, (C) a surfactant, (D) an oil, and (E) 12-hydroxystearic acid to 60 to 90°C to dissolve them uniformly. (ii) (A) A step of preparing a mixture by adding the intermediate composition obtained in step (i) to an aqueous medium containing water while stirring, or (A) A step of preparing a mixture by adding the intermediate composition obtained in step (i) to an aqueous medium containing water while stirring, and (iii) A step of cooling the mixture obtained in step (ii) to room temperature. A method for producing a topical skin preparation, including the above-mentioned preparation.

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