Oil-in-water emulsion skin cosmetic composition

Abstract

To provide an oil-in-water emulsion skin cosmetic composition that exhibits excellent skin penetration and storage stability of water-soluble active ingredients. [Solution] An oil-in-water emulsion skin cosmetic composition comprising (A) a water-soluble active ingredient having a molecular weight of 700 Da or less, (B) an oil that is solid at 25°C, (C) one or more nonionic surfactants selected from polyglycerin fatty acid esters and polyoxyethylene alkyl ethers, (D) water, and (E) a higher alcohol having 18 to 22 carbon atoms, wherein the HLB value of one of the (C) components or a mixture of two or more of the (C) components is 8 to 12, and the ratio of the content of the (C) component to the content of the (E) component {(C) / (E)} is 0.4 to 1.3.

Description

Technical Field

[0001] The present invention relates to a water-in-oil emulsified skin cosmetic composition.

Background Art

[0002] Since human skin has a hydrophobic barrier function due to the stratum corneum, there has been a problem with the permeability of water-soluble active ingredients contained in cosmetic compositions such as skin care cosmetics (see, for example, Non-Patent Document 1).

[0003] Conventionally, methods for promoting the skin penetration of water-soluble active ingredients using physical promotion methods such as iontophoresis, electroporation, and sonophoresis, and chemical promotion methods such as microemulsion and microcapsule technology have been proposed. However, there are problems such as the need for dedicated equipment and the difficulty of maintaining the storage stability of cosmetic compositions, and there is room for improvement.

[0004] Therefore, there is a demand for a cosmetic composition that is excellent in the skin permeability and storage stability of water-soluble active ingredients.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to solve the above-described conventional problems and achieve the following object. That is, an object of the present invention is to provide a water-in-oil emulsified skin cosmetic composition that is excellent in the skin permeability and storage stability of water-soluble active ingredients. [Means for solving the problem]

[0007] The oil-in-water emulsion skin cosmetic composition of the present invention contains (A) a water-soluble active ingredient with a molecular weight of 700 Da or less, (B) an oil that is solid at 25°C, (C) one or more nonionic surfactants selected from polyglycerin fatty acid esters and polyoxyethylene alkyl ethers, (D) water, and (E) a higher alcohol having 18 to 22 carbon atoms, wherein the HLB value of one of the (C) components or a mixture of two or more of the (C) components is 8 to 12, and the ratio of the content of the (C) component to the content of the (E) component {(C) / (E)} is 0.4 to 1.3.

[0008] The present invention is based on the inventors' findings, and the means for solving the above-mentioned problems are as follows. <1> (A) A water-soluble active ingredient with a molecular weight of 700 Da or less, (B) Oil that is solid at 25℃, (C) One or more nonionic surfactants selected from polyglycerin fatty acid esters and polyoxyethylene alkyl ethers, (D) Water and, (E) A higher alcohol having 18 or more carbon atoms and 22 or less carbon atoms, comprising an oil-in-water emulsion skin cosmetic composition, The HLB value of one of the aforementioned (C) components, or a mixture consisting of two or more of the aforementioned (C) components, is 8 or more and 12 or less. The oil-in-water emulsion skin cosmetic composition is characterized in that the ratio of the content of component (C) to the content of component (E) {(C) / (E)} is 0.4 or more and 1.3 or less. <2> The content of component (A) is 2% by mass or more and 30% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The content of component (B) is 1.2% by mass or more and 6% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The content of component (C) is 1.5% by mass or more and 4.5% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The content of component (E) is 1% by mass or more and 8% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. <1> This is an oil-in-water emulsion skin cosmetic composition as described above. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an oil-in-water emulsion skin cosmetic composition that is excellent in skin penetration and storage stability of water-soluble active ingredients. [Modes for carrying out the invention]

[0010] (Oil-in-water emulsion skin cosmetic composition) The oil-in-water emulsion skin cosmetic composition of the present invention contains (A) a water-soluble active ingredient with a molecular weight of 700 Da or less, (B) an oil that is solid at 25°C, (C) one or more nonionic surfactants selected from polyglycerin fatty acid esters and polyoxyethylene alkyl ethers, (D) water, and (E) a higher alcohol having 18 to 22 carbon atoms, and may optionally contain other components. In this specification, "(A) a water-soluble active ingredient with a molecular weight of 700 Da or less" may be referred to as "(A)" or "component (A)", "(B) an oil that is solid at 25°C" may be referred to as "(B)" or "component (B)", "(C) one or more nonionic surfactants selected from polyglycerin fatty acid esters and polyoxyethylene alkyl ethers" may be referred to as "(C)" or "component (C)", "(D) water" may be referred to as "(D)" or "component (D)", and "(E) a higher alcohol having 18 to 22 carbon atoms" may be referred to as "(E)" or "component (E)".

[0011] <(A) Water-soluble active ingredients> In this specification, "water-soluble" means that 3.33 g or more dissolves in 100 g of water at 25°C.

[0012] The component (A) is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include vitamins B and C, oligosaccharides, polyhydric alcohols, amide alcohols, and the like. These may be used alone or in combination of two or more.

[0013] Specific examples of the vitamins B and C include niacinamide, pyridoxine hydrochloride, biotin, ascorbic acid, and the like.

[0014] Specific examples of the oligosaccharides include maltotetraose, maltose, maltotriose, glucose, sucrose, lactose, trehalose, raffinose, panose, and the like.

[0015] Specific examples of the polyhydric alcohols include BG (1,3-butylene glycol), DPG (dipropylene glycol), glycerin, sorbitol, pentylene glycol, and the like.

[0016] Specific examples of the amide alcohol include panthenol and the like.

[0017] Among these, maltotetraose, niacinamide, BG, DPG, glycerin, sorbitol, maltotriose, maltose, glucose, and pentylene glycol are preferred. Maltotetraose is preferred from the viewpoints of moisturizing effect and itching inhibitory effect, and niacinamide is preferred from the viewpoints of moisturizing effect, whitening effect, and improvement effect of skin barrier function.

[0018] For the component (A), those synthesized as appropriate may be used, or commercially available products may be used. Examples of commercially available products of the component (A) include, for example, under the trade names Niacinamide USP PC (niacinamide, manufactured by Arcsada Japan Co., Ltd.), Leogard MT (hydrolyzed corn starch, manufactured by Lion Specialty Chemicals Co., Ltd.), and the like.

[0019] The molecular weight of the component (A) is 700 Da or less from the viewpoint of ease of penetration into the skin stratum corneum structure, and preferably 50 Da or more and 700 Da or less. The method for measuring the molecular weight of the component (A) is not particularly limited and can be appropriately selected according to the purpose. For example, it can be measured by the static light scattering method (SLS method). The SLS method is a method for measuring the absolute molecular weight by measuring the scattered light intensity based on the relationship between the intensity of light scattered by molecules and the molecular weight and size of the molecules.

[0020] The content of the component (A) is preferably 2% by mass or more and 35% by mass or less, and more preferably 2% by mass or more and 30% by mass or less based on the total amount of the oil-in-water type emulsified skin cosmetic composition.

[0021] <Oil solid at 25°C (B)> The oil solid at 25°C imparts good skin permeability to the oil-in-water type emulsified skin cosmetic composition.

[0022] As the component (B), as long as it is solid at 25°C, there is no particular limitation and it can be appropriately selected according to the purpose. From the viewpoint of improving skin permeability, fats and oils, waxes, ester oils, and hydrocarbon oils are preferred. These may be used alone or in combination of two or more.

[0023] Specific examples of the fats and oils include coconut oil, horse oil, etc.

[0024] Specific examples of the waxes include beeswax, jojoba seed oil, candelilla wax, etc.

[0025] Specific examples of the ester oils include phytosteryl sunflower seed oil fatty acid, hydrogenated castor oil isostearate, dimer dilinoleic acid (phytosteryl / isostearyl / cetyl / stearyl / behenyl), jojoba ester, etc.

[0026] Specific examples of the hydrocarbon oils include petrolatum, etc.

[0027] Among these, sunflower seed oil fatty acid phytosteryl / oleate phytosteryl is more preferred from the viewpoint of improving skin penetration.

[0028] The aforementioned component (B) may be synthesized as appropriate, or a commercially available product may be used. Examples of commercially available products of component (B) include Plandool Sun (phytosteryl sunflower seed oil fatty acid / phytosteryl oleate, manufactured by Nippon Seika Co., Ltd.) under the trade name.

[0029] From the viewpoint of improving skin penetration and storage stability, the content of component (B) is preferably 1.2% by mass or more and 7.8% by mass or less, and more preferably 1.2% by mass or more and 6% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition. When the content of component (B) is 1.2% by mass or more relative to the total amount of the oil-in-water emulsion skin cosmetic composition, the skin penetration is good. When the content of component (B) is 7.8% by mass or less relative to the total amount of the oil-in-water emulsion skin cosmetic composition, the storage stability is good.

[0030] <(C) One or more nonionic surfactants selected from polyglycerin fatty acid esters and polyoxyethylene alkyl ethers> The (C) nonionic surfactant selected from polyglycerin fatty acid esters and polyoxyethylene alkyl ethers imparts good skin penetration and storage stability to the oil-in-water emulsion skin cosmetic composition.

[0031] The HLB value of one of the aforementioned (C) components, or a mixture of two or more of the aforementioned (C) components, is preferably 8 to 12, and more preferably 10 to 12, from the viewpoint of improving skin permeability and storage stability. Here, the HLB value in this specification is an index indicating the hydrophilic-lipophilic balance, and can be calculated by (Σ inorganic value / Σ organic value) × 10. Here, "HLB value of one (C) component or a mixture of two or more (C) components" refers to the HLB value of the one (C) component if the oil-in-water emulsion skin cosmetic composition contains only one (C) component, and the HLB value of the mixture of those (C) components if the oil-in-water emulsion skin cosmetic composition contains two or more (C) components. When the HLB value is 8 or higher, skin permeability and storage stability are good. When the HLB value is 12 or less, skin permeability and storage stability are good.

[0032] The HLB value (HLB) of a mixture consisting of two or more of the above-mentioned (C) components AB There are no particular restrictions on the measurement method for each component, and it can be selected as appropriate depending on the purpose. For example, the HLB value of each component can be measured separately. A and HLB B Assuming that the mass ratios of each component to the total amount of the mixture are a mass% and b mass%, respectively, the HLB value can be calculated using the following formula. Similarly, the HLB value of a mixture consisting of three or more of the aforementioned (C) components can also be calculated in the same manner.

[0033]

number

[0034] As for component (C), from the viewpoint of improving skin penetration, polyglycerin fatty acid esters having 12 to 22 carbon atoms derived from fatty acids and an average degree of polymerization of glycerin of 1 to 10 are preferred, polyoxyethylene alkyl ethers having 12 to 22 carbon atoms in the alkyl group and an average number of added moles of ethylene oxide of 5 to 30 are preferred, and polyglycerin fatty acid esters having 17 to 20 carbon atoms derived from fatty acids and an average degree of polymerization of glycerin of 1 to 10 are more preferred. These may be used individually or in combination of two or more types.

[0035] Specific examples of polyglycerin fatty acid esters having 12 to 22 carbon atoms derived from the aforementioned fatty acids and an average degree of polymerization of glycerin of 1 to 10 include: glyceryl stearate, polyglyceryl-2 stearate (average degree of polymerization of glycerin: 2), polyglyceryl-4 stearate (average degree of polymerization of glycerin: 4), polyglyceryl-5 stearate (average degree of polymerization of glycerin: 5), polyglyceryl-6 stearate (average degree of polymerization of glycerin: 6), polyglyceryl-10 stearate (average degree of polymerization of glycerin: 10), polyglyceryl-10 laurate (average degree of polymerization of glycerin: 10), polyglyceryl-6 laurate (average degree of polymerization of glycerin: 6), and polyglyceryl-3 laurate. Examples include polyglyceryl-10 myristate (average degree of polymerization of glycerin: 3), polyglyceryl-6 myristate (average degree of polymerization of glycerin: 6), polyglyceryl-5 myristate (average degree of polymerization of glycerin: 5), polyglyceryl-10 palmitate (average degree of polymerization of glycerin: 10), polyglyceryl-6 palmitate (average degree of polymerization of glycerin: 6), polyglyceryl-3 palmitate (average degree of polymerization of glycerin: 3), glyceryl behenate, polyglyceryl-10 behenate (average degree of polymerization of glycerin: 10), polyglyceryl-6 behenate (average degree of polymerization of glycerin: 6), and polyglyceryl-3 behenate (average degree of polymerization of glycerin: 3).

[0036] Specific examples of polyoxyethylene alkyl ethers in which the alkyl group has 12 to 22 carbon atoms and the average number of moles of ethylene oxide added is 5 to 30 include polyoxyethylene stearyl ether (average number of moles of ethylene oxide added: 3), polyoxyethylene stearyl ether (average number of moles of ethylene oxide added: 5), polyoxyethylene stearyl ether (average number of moles of ethylene oxide added: 8), polyoxyethylene stearyl ether (average number of moles of ethylene oxide added: 10), polyoxyethylene stearyl ether (average number of moles of ethylene oxide added: 15), polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene myristyl ether, and polyoxyethylene behenyl ether.

[0037] Specific examples of polyglycerin fatty acid esters derived from the aforementioned fatty acids, having 17 to 20 carbon atoms and an average degree of polymerization of glycerin of 1 to 10, include glyceryl stearate, polyglyceryl-2 stearate (average degree of polymerization of glycerin: 2), polyglyceryl-4 stearate (average degree of polymerization of glycerin: 4), polyglyceryl-5 stearate (average degree of polymerization of glycerin: 5), polyglyceryl-6 stearate (average degree of polymerization of glycerin: 6), and polyglyceryl-10 stearate (average degree of polymerization of glycerin: 10).

[0038] The aforementioned component (C) may be synthesized as appropriate, or a commercially available product may be used. Examples of commercially available products containing component (C) include, by trade name, NIKKOL MGS-ASEV (glyceryl stearate (average degree of polymerization of glycerin: 1), manufactured by Nikko Chemicals Co., Ltd.), NIKKOL Decaglyn 1-SV (polyglyceryl stearate (average degree of polymerization of glycerin: 10), manufactured by Nikko Chemicals Co., Ltd.), NIKKOL HEXAGLYN 1-SV (polyglyceryl stearate (average degree of polymerization of glycerin: 6), manufactured by Nikko Chemicals Co., Ltd.), EMALEX 603 (steareth (average number of moles of ethylene oxide added: 3), manufactured by Nippon Emulsion Co., Ltd.), EMALEX 608 (steareth (average number of moles of ethylene oxide added: 8), manufactured by Nippon Emulsion Co., Ltd.), and EMALEX 615 (steareth (average number of moles of ethylene oxide added: 15), manufactured by Nippon Emulsion Co., Ltd.).

[0039] From the viewpoint of improving skin penetration and storage stability, the content of component (C) is preferably 1.0% by mass or more and 5% by mass or less, and more preferably 1.5% by mass or more and 4.5% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition. When the content of component (C) is 1.0% by mass or more relative to the total amount of the oil-in-water emulsion skin cosmetic composition, the skin penetration and storage stability are good. When the content of component (C) is 5% by mass or less relative to the total amount of the oil-in-water emulsion skin cosmetic composition, the storage stability is good.

[0040] <(D)Water> There are no particular restrictions on the water (D) mentioned above, and it can be selected as appropriate depending on the purpose.

[0041] There are no particular restrictions on the content of component (D), and it can be set appropriately depending on the content of the other components, but it is preferably 40% by mass or more and 60% by mass or less.

[0042] <(E) Higher alcohols with 18 to 22 carbon atoms> The aforementioned (E) higher alcohol having 18 to 22 carbon atoms imparts good emulsion stability to the oil-in-water emulsion skin cosmetic composition.

[0043] The aforementioned component (E) is not particularly limited as long as it has 18 to 22 carbon atoms, and can be appropriately selected according to the purpose. However, from the viewpoint of improving storage stability, hydrogenated rapeseed alcohol, stearyl alcohol, arachidyl alcohol, and behenyl alcohol are preferred. Among these, a mixture of hydrogenated rapeseed alcohol, stearyl alcohol, arachidyl alcohol, and behenyl alcohol is more preferable from the viewpoint of improving storage stability. These may be used individually or in combination of two or more types.

[0044] The aforementioned component (E) may be synthesized as appropriate, or a commercially available product may be used. Examples of commercially available products of component (E) include Alcohol No. 20B (hydrogenated rapeseed alcohol, manufactured by AGC SI-TEC Co., Ltd.) under the trade name.

[0045] From the viewpoint of improving storage stability, the content of component (E) is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1.0% by mass or more and 8.0% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition. If the content of component (E) is 0.5% by mass or more relative to the total amount of the oil-in-water emulsion skin cosmetic composition, the storage stability will be good. When the content of component (E) is 10% by mass or less relative to the total amount of the oil-in-water emulsion skin cosmetic composition, the storage stability is good.

[0046] <Mass ratio {(C) / (E)}> There are no particular restrictions on the ratio {(C) / (E)} of the content of component (C) to the content of component (E), and it can be appropriately selected depending on the purpose. However, from the viewpoint of improving skin permeability and storage stability, a ratio of 0.4 to 1.3 is preferred, and a ratio of 0.45 to 1.25 is more preferred. When the ratio of the content {(C) / (E)} is 0.4 or higher, skin permeability and storage stability are good. When the ratio of the content {(C) / (E)} is 1.3 or less, skin permeability and storage stability are good. The oil-in-water emulsion skin cosmetic composition of the present invention satisfies the aforementioned ratio of (C) / (E), and when the oil-in-water emulsion skin cosmetic composition is applied to the skin, the water in the composition is localized on the skin side and less likely to volatilize, thus improving skin penetration.

[0047] <Other ingredients> In addition to the components (A), (B), (C), (D), and (E) of the present invention, other components may be added to the oil-in-water emulsion skin cosmetic composition as needed, provided that the effects of the present invention are not impaired. Examples of the other components mentioned above include water-soluble active ingredients other than component (A), oils other than component (B), surfactants other than component (C), pH adjusters, thickeners, emulsifying stabilizers, polymer emulsifiers, texture enhancers, preservatives, anti-inflammatory agents, and antioxidants. These may be used individually or in combination of two or more types. The other components may be synthesized as appropriate, or commercially available products may be used.

[0048] Other than component (A) mentioned above, there are no particular restrictions on the water-soluble active ingredients, and they can be appropriately selected depending on the purpose. For example, dipotassium glycyrrhizinate (molecular weight: 899 Da) is one example. The content of water-soluble active ingredients other than component (A) is preferably 0.001% by mass or more and 0.5% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0049] Other oils besides component (B) are not particularly limited and can be appropriately selected depending on the purpose. Examples include liquid isoparaffin, tocopherol, isohexadecane, sugar squalane, glyceryl tri-2ethylhexanoate, phytosterols, and ceramides. The content of the liquid isoparaffin is preferably 0.001% by mass or more and 20.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The tocopherol content is preferably 0.001% by mass or more and 5.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The isohexadecane content is preferably 0.001% by mass or more and 20.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The sugar squalane content is preferably 0.001% by mass or more and 20.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The content of glyceryl tri-2-ethylhexanoate is preferably 0.001% by mass or more and 20.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The phytosterols content is preferably 0.0000005% by mass or more and 5.0% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition. The ceramide content is preferably 0.0000005% by mass or more and 0.1% by mass or less, relative to the total amount of the oil-in-water emulsion skin cosmetic composition.

[0050] Other surfactants besides component (C) are not particularly limited and can be appropriately selected depending on the purpose. Examples include polysorbate 80 (polyoxyethylene sorbitan monooleate (average number of moles of ethylene oxide added: 20)) and hydrogenated lecithin. The content of the polysorbate 80 is preferably 0.0000005% by mass or more and 10.0% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition. The hydrogenated lecithin content is preferably 0.0000005% by mass or more and 5.0% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0051] There are no particular restrictions on the pH adjusting agent, and it can be appropriately selected depending on the purpose. Examples include citric acid, citrates, and hydroxides. There are no particular restrictions on the amount of the pH adjuster, and it can be set appropriately depending on the amount of other components.

[0052] The aforementioned thickening agent is not particularly limited and can be appropriately selected depending on the purpose. Examples include carboxyvinyl polymer and gellan gum. The content of the carboxyvinyl polymer is preferably 0.001% by mass or more and 15.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The gellan gum content is preferably 0.01% by mass or more and 1.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0053] The emulsifying stabilizer is not particularly limited and can be appropriately selected depending on the purpose; for example, stearic acid can be used. The content of the emulsifying stabilizer is preferably 0.001% by mass or more and 20.0% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0054] The polymer emulsifier is not particularly limited and can be appropriately selected depending on the purpose. Examples include (sodium acrylate / sodium acryloyldimethyl taurate) copolymer. The content of the polymer emulsifier is preferably 0.001% by mass or more and 3.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0055] The tactile agent is not particularly limited and can be appropriately selected depending on the purpose; examples include dimethicone and silica. The dimethicone content is preferably 0.001% by mass or more and 20.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The silica content is preferably 0.001% by mass or more and 20.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0056] There are no particular restrictions on the preservatives mentioned above, and they can be appropriately selected depending on the purpose. Examples include phenoxyethanol and sodium benzoate. The phenoxyethanol content is preferably 0.001% by mass or more and 1.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The sodium benzoate content is preferably 0.001% by mass or more and 1.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0057] There are no particular restrictions on the anti-inflammatory agent, and it can be appropriately selected depending on the purpose. Examples include Rosa rugosa extract and hydroxyphenylpropamide benzoic acid. The content of the aforementioned Rosa rugosa extract is preferably 0.0000005% by mass or more and 2.0% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition. The content of hydroxyphenylpropamide benzoic acid is preferably 0.00001% by mass or more and 2.0% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0058] The aforementioned antioxidant is not particularly limited and can be appropriately selected depending on the purpose; for example, ascorbyl palmitate is one such example. The content of the antioxidant is preferably 0.000001% by mass or more and 2% by mass or less, based on the total amount of the oil-in-water emulsion skin cosmetic composition.

[0059] -pH- The pH of the oil-in-water emulsion skin cosmetic composition at 30°C is not particularly limited and can be appropriately selected depending on the purpose, but a pH of 5.0 or higher and 6.0 or lower is preferred. The aforementioned pH can be measured, for example, using a glass electrode color hydrogen ion concentration indicator HM-41X (electrode type GST-5821C, manufactured by Toa DKK Co., Ltd.).

[0060] -viscosity- The viscosity of the oil-in-water emulsion skin cosmetic composition at 30°C is not particularly limited and can be appropriately selected depending on the purpose, but a viscosity of 30.0 Pa·s or more and 150 Pa·s or less is preferred. There are no particular restrictions on the method for measuring the viscosity, but one example is to use a Brookfield viscometer BHII type (manufactured by Toki Sangyo Co., Ltd.) and measure the viscosity after 1 minute with a sample temperature of 25°C, a rotation speed of 10 rpm, and rotor No. 7.

[0061] -Manufacturing method- There are no particular limitations on the method for producing the oil-in-water emulsion skin cosmetic composition of the present invention, and can be appropriately selected depending on the purpose. It can be obtained by mixing component (A), component (B), component (C), component (D), and component (E), and optionally the other components. Specific examples are as follows. The aqueous phase and the oil phase (with the activator dispersed in the oil phase) are heated to over 80°C and stirred until homogeneous. The oil phase is slowly added to the aqueous phase while stirring to induce initial emulsification. Using a homomixer, mechanical emulsification is performed at 6,000 to 10,000 rpm for 1 to 5 minutes, and then cooled to 40°C. After cooling, preservatives and active ingredients are added and stirred uniformly to prepare an oil-in-water emulsion skin cosmetic composition.

[0062] The oil-in-water emulsion skin cosmetic composition may be prepared using an apparatus. The apparatus is not particularly limited and can be appropriately selected depending on the purpose. Examples include a stirring device equipped with stirring blades that have shearing force and can mix the entire mixture. There are no particular restrictions on the stirring blades, and they can be appropriately selected according to the purpose. Examples include propellers, turbines, dispersers, homomixers, etc.

[0063] -Applications- There are no particular restrictions on the area or method of use of the oil-in-water emulsion skin cosmetic composition, and they can be appropriately selected according to the purpose. For example, it can be used on the whole body, face, hands, etc., in the usual manner.

[0064] There are no particular limitations on the uses of the aforementioned oil-in-water emulsion skin cosmetic composition, and it can be appropriately selected according to the purpose. Examples include skin barrier function enhancers, itch suppressants, acne preventatives, whitening agents, and moisturizers. [Examples]

[0065] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited in any way to these examples. The content of each component described in the examples and comparative examples is shown in "mass%", the total amount is 100 mass%, and all values ​​are calculated on a pure content basis.

[0066] (Examples 1-18 and Comparative Examples 1-8) Each oil-in-water emulsion skin cosmetic composition was obtained by mixing the compositions and contents shown in Examples 1-18 and Comparative Examples 1-8. A 5L vacuum emulsifier (PVT-5, 11505, manufactured by Mizuho Industries Ltd.) was used for the mixing process.

[0067] For each oil-in-water emulsion skin cosmetic composition, "skin penetration" and "storage stability" were evaluated and determined as follows. The results are shown in Tables 1 to 5 below.

[0068] <Evaluation of skin permeability> Skin penetration was evaluated using a Strat-M® membrane (25 mm) for transdermal diffusion testing. A Strat-M membrane was attached to a Franz cell, and 0.5 g of a cream-type oil-in-water emulsion skin cosmetic composition was uniformly applied. PBS solution (pH=7.4) was used as the receptor solution. The cells were allowed to penetrate for 4 hours under conditions of 32°C ± 0.5°C and 50% humidity. The concentration of niacinamide that penetrated into the receptor solution was measured by HPLC and evaluated based on the following criteria. -HPLC measurement conditions- • Detector: UV absorption photometer (measurement wavelength: 230nm) • Column: Inertsil ODS-3 (5μm, 4.6mm x 150mm) Column temperature: 40°C ·Flow rate: 1.0mL / min ·Injection volume: 20μL Mobile phase: 5 mM 1-Sodium hexanesulfonate 0.1% CH3COOH (acetic acid):Methanol = 93:7 (v / v) -Judgment criteria- ◎: Permeation exceeds 0.2 ppm ○: Permeation amount is between 0.1 ppm and 0.2 ppm. ×: Permeation amount less than 0.1 ppm

[0069] <Evaluation of storage stability> Each oil-in-water emulsion skin cosmetic composition was filled into SV-50 vials at a concentration of 50°C at a constant temperature of 1 month. After storage, each oil-in-water emulsion skin cosmetic composition was visually inspected and evaluated based on the following criteria. -Judgment criteria- ◎: No changes in appearance, color, or scent after storage. ○: After storage, there may be slight changes in appearance, color, or scent, but this does not affect the quality. ×: Separation or precipitation may occur after storage.

[0070] [Table 1]

[0071] [Table 2]

[0072] [Table 3]

[0073] [Table 4]

[0074] [Table 5]

[0075] Details of each component used in Examples 1-18 and Comparative Examples 1-8 are shown in Table 6 below.

[0076] [Table 6]

[0077] (Prescription examples 1-6) Cosmetics with the composition and content shown in Table 7 below were prepared in the same manner as in Example 1.

[0078] [Table 7]

[0079] Details of each ingredient used in prescription examples 1-6 are shown in Table 8 below.

[0080] [Table 8] [Industrial applicability]

[0081] The aforementioned oil-in-water emulsion skin cosmetic composition has excellent skin penetration and storage stability of water-soluble active ingredients, and can therefore be suitably used as, for example, a skin barrier function enhancer, an anti-itch agent, an acne preventative, a whitening agent, and a moisturizer.

Claims

1. (A) A water-soluble active ingredient having a molecular weight of 700 Da or less, (B) Oil that is solid at 25°C, (C) One or more nonionic surfactants selected from polyglycerin fatty acid esters and polyoxyethylene alkyl ethers, (D) Water and, (E) A higher alcohol having 18 or more carbon atoms and 22 or less carbon atoms, comprising an oil-in-water emulsion skin cosmetic composition, The HLB value of one of the aforementioned (C) components, or a mixture consisting of two or more of the aforementioned (C) components, is 8 or more and 12 or less. An oil-in-water emulsion skin cosmetic composition characterized in that the ratio of the content of component (C) to the content of component (E) {(C) / (E)} is 0.4 or more and 1.3 or less.

2. The content of component (A) is 2% by mass or more and 30% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The content of component (B) is 1.2% by mass or more and 6% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The content of component (C) is 1.5% by mass or more and 4.5% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition. The oil-in-water emulsion skin cosmetic composition according to claim 1, wherein the content of component (E) is 1% by mass or more and 8% by mass or less based on the total amount of the oil-in-water emulsion skin cosmetic composition.

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