Oil-in-water emulsion composition

Abstract

The purpose of the present invention is to provide an oil-in-water emulsion composition for use on skin, the oil-in-water emulsion composition having excellent feeling of use, storage stability, and low irritation. The oil-in-water emulsion composition is characterized by containing components (A) to (D): (A) 2-60 mass% of an oil phase; (B) 3-30 mass% of cyclodextrin; (C) a water-soluble polysaccharide; and (D) a liquid polyhydric alcohol.

Description

Oil-in-water type emulsion composition

[0001] The present invention relates to an oil-in-water type emulsion composition characterized by containing an oil phase, cyclodextrin, a water-soluble polysaccharide, and a liquid polyhydric alcohol.

[0002] Compositions used by applying them to the skin, such as cosmetics and external skin preparations (including quasi-drugs unless otherwise specified in this specification), are required to have characteristics such as enhanced effects and high persistence of the active ingredients contained, a fresh and non-greasy feeling of use, and low irritation. In particular, a composition having an enhancing effect that can obtain a higher effect with the same content of the active ingredient is desirable from the viewpoint of preventing a decrease in the feeling of use and skin irritation derived from the active ingredient. Also, in an emulsified composition, it is also desirable not to use a surfactant from the viewpoints of low irritation and persistence. In order to meet these requirements, various techniques have been conventionally proposed in this field.

[0003] For example, Patent Document 1 (WO2018 / 062469) describes that a skin external composition having a high ability to enhance the ultraviolet absorption spectrum can be obtained by using an alkyl-modified silicone and / or an alkyl-modified silicone resin and an ultraviolet absorption (scattering) agent (

[0007] ). However, in order to blend these silicone waxes and resins, it is necessary to blend an oil agent for dissolving them, so there is a problem of a greasy feeling of use.

[0004] Patent Document 2 (WO2022 / 064997) describes that a skin emulsified composition containing water, fats and oils, cyclodextrin, and a specific water-soluble gelling agent has high stability and a good feeling of use without using a synthetic surfactant. However, this skin emulsified composition has a sudden stopping feeling when dried and is difficult to stretch when spreading it on the skin, so it has been difficult to use it daily as a cosmetic from the viewpoint of the feeling of use. Also, regarding using an ultraviolet absorber as an oil agent, neither the description nor the suggestion is given as to whether an enhancing effect of the ultraviolet protection ability can be obtained when using the ultraviolet absorber.

[0005] Table 1 of Patent Document 3 (EPA3037083) describes a composition containing α-cyclodextrin, an ultraviolet absorber, xanthan gum, and ethanol. However, because the α-cyclodextrin content is 0.500-2.000% by mass, the level of enhancement of ultraviolet protection ability and stability was not sufficient.

[0006] Japanese Patent Publication No. 2016-11290, WO2022 / 064907, EPA 3037083

[0007] The present invention aims to provide an oil-in-water emulsion composition for use applied to the skin that is excellent in terms of feel, storage stability, and low irritation. The present invention also aims to provide an oil-in-water emulsion composition for use applied to the skin that is excellent in enhancing and prolonging the effects of the active ingredient. The present invention also aims to provide an oil-in-water emulsion composition that is excellent in terms of enhancing UV protection, prolonging sunburn prevention effect, feel, storage stability, and low irritation.

[0008] As a result of diligent research to solve the above problems, the present inventors have found that by emulsifying and dispersing the oil phase in an aqueous phase containing water-soluble polysaccharides and liquid polyhydric alcohols using a specific amount of cyclodexlin without using a surfactant, it is possible to obtain an oil-in-water emulsion composition with excellent usability, storage stability, and low irritation. Furthermore, they have found that by including an active ingredient such as an ultraviolet absorber in the oil phase of this oil-in-water emulsion composition, it is possible to enhance the effect of the active ingredient or improve the duration of its effect.

[0009] The present invention is based on these novel findings and encompasses the following inventions: [1] An oil-in-water emulsion composition characterized by containing the following components (A) to (D): (A) Oil phase 2 to 60% by mass (B) Cyclodextrin 3 to 30% by mass (C) Water-soluble polysaccharide (D) Liquid polyhydric alcohol [2] The oil-in-water emulsion composition of [1], wherein the mass ratio (B) / (A) of component (B) to component (A) is 1 / 10 to 20 / 10. [3] The oil-in-water emulsion composition of [1] or [2], wherein the oil phase contains an oil-soluble active ingredient. [4] The oil-in-water emulsion composition of [3], wherein the oil-soluble active ingredient is an oil-soluble ultraviolet absorber. [5] An oil-in-water emulsion composition according to [3], wherein the oil-soluble active ingredient is an oil-soluble ultraviolet absorber, oil-soluble vitamins, anti-inflammatory ingredients, cooling agents, warming agents, ceramides, carotenoids, flavonoids, coenzyme Q10, insect repellents, drugs, plant extracts, pigments, dyes, fragrances, skincare ingredients, dullness / pigmentation care ingredients, moisturizing ingredients, hair growth / hair restoration ingredients, steroids, antiperspirant ingredients, deodorant ingredients, antibacterial ingredients, or anti-inflammatory analgesics. [6] An oil-in-water emulsion composition according to any of [3] to [5], wherein the oil-soluble active ingredient content is 0.01 to 30% by mass. [7] An oil-in-water emulsion composition according to any of [1] to [6], substantially free of surfactants. [8] An oil-in-water emulsion composition according to any of [1] to [7], substantially free of solid oils with a melting point of 40°C or higher. [9] An oil-in-water emulsion composition according to any of [3] to [8], which is a cosmetic.

[10] An oil-in-water emulsion composition according to any of [3] to [8], which is a topical skin preparation. This specification includes the contents described in the specification of Japanese Patent Application No. 2024-231719, filed on 27 December 2024, which is the basis of the priority claim of this application. All publications, patents and patent applications cited herein are incorporated herein by reference in their entirety.

[0010] The present invention provides an oil-in-water emulsion composition for use applied to the skin that is excellent in terms of feel, storage stability, and low irritation. Furthermore, the present invention provides an oil-in-water emulsion composition for use applied to the skin that is excellent in enhancing and prolonging the effects of the active ingredient. Furthermore, the present invention provides an oil-in-water emulsion composition that is excellent in terms of enhancing UV protection, prolonging sunburn prevention effect, feel, storage stability, and low irritation.

[0011] Figure 1 is a photographic diagram showing the results of applying the sunscreen lotions of Example 19 and Comparative Example 11 to urethane artificial skin, allowing them to dry completely, then placing oil-blotting paper on top and evaluating the amount of oil adhering to the oil-blotting paper (secondary adhesion). Compared to Comparative Example 11, the sunscreen lotion of Example 19 shows less oil adhering to the oil-blotting paper, indicating superior resistance to secondary adhesion.

[0012] The oil-in-water emulsion composition of the present invention contains (A) an oil phase, (B) cyclodextrin, (C) a water-soluble polysaccharide, and (D) a liquid polyhydric alcohol. Each component will be described in detail below.

[0013] (A: Oil Phase) The oil phase of the oil-in-water emulsion composition of the present invention may contain liquid oil and / or solid oil. Here, "liquid oil" means oil that is fluid at room temperature (25°C) and semi-solid oil with a melting point of less than 40°C, and "solid oil" means solid oil with a melting point of 40°C or higher. The melting point is the value measured by the second method of melting point measurement, which is a general test method of the Quasi-Drug Raw Material Standards.

[0014] Liquid oils are not particularly limited as long as they are those commonly used in cosmetics and topical skin preparations, and may be animal oils, vegetable oils, or synthetic oils. Specific examples of liquid oils include triethylhexanoin, caprylic / capric triglyceride, neopentyl glycol dicaprate, isononyl isononanoate, isotridecyl isononanoate, ethylhexyl palmitate, isopropyl myristate, isopropyl palmitate, octyldodecyl myristate, diisostearyl malate, oligomer esters of dimer acid and dimerol, pentaerythritol tetraisostearate, diglyceryl tetraisostearate, cetyl isooctanoate, dicaprylyl carbonate, alkyl benzoate, cholesterol fatty acid esters, esters such as jojoba oil; volatile isoparaffins, polybutene, polyisobutylene, heavy liquid isoparaffins, liquid paraffin Examples of suitable ingredients include hydrocarbons such as rhaffin, α-olefin oligomers, and squalane; oils and fats such as olive oil, castor oil, mink oil, and macadamia nut oil; fatty acids such as isostearic acid and oleic acid; higher alcohols such as oleyl alcohol and isostearyl alcohol; silicone oils such as low-molecular-weight dimethylpolysiloxane, cyclic silicone, high-molecular-weight dimethylpolysiloxane, methylphenylpolysiloxane, methyl trimethicone, caprylyl trimethicone, cross-linked organopolysiloxane, and fluorine-modified polysiloxane; fluorinated oils such as perfluoropolyethers; and lanolin derivatives such as lanolin, lanolin acetate, isopropyl lanolin fatty acid, and lanolin alcohol. However, the ingredients are not limited to these. Among these, esters are preferred from the viewpoint of solubility when oil-soluble active ingredients are included.

[0015] The solid oils used are not particularly limited as long as they are those commonly used in cosmetics and topical skin preparations, and animal waxes, vegetable waxes, mineral waxes, silicone waxes, synthetic waxes, etc., can be used. Specific examples of solid oils include, but are not limited to, beeswax, bleached beeswax, carnauba wax, candelilla wax, whale wax, montan wax, rice bran wax, lanolin, Japanese wax, hexyl laurate, reduced lanolin, hydrogenated jojoba oil, hard lanolin, shellac wax, microcrystalline wax, paraffin wax, polyethylene wax, Fischer-Tropsch wax, hydrogenated oil, hydrogenated castor oil, petrolatum, alkyl silicones, jojoba esters, stearyl alcohol, and behenyl alcohol. When the oil phase contains solid oil, it is necessary to heat the oil phase when mixing and emulsifying the oil phase and the aqueous phase to obtain an oil-in-water emulsion. However, in the present invention, if the emulsion is heated to 50°C or higher, it becomes difficult to obtain a uniform and stable emulsion. Therefore, the solid oil content is preferably less than 2% by mass, and more preferably less than 1% by mass, of the total amount of the oil-in-water emulsion composition. Particularly preferable is that the composition is substantially free of solid oil. In the present invention, "substantially free of solid oil" means that the oil-in-water emulsion composition of the present invention does not contain solid oil in a manner that affects its physical properties, and does not mean that it contains no solid oil at all. In the present invention, it is particularly preferable that the composition contains no solid oil at all.

[0016] In the oil-in-water emulsion composition of the present invention, the content of (A) the oil phase is 2 to 60% by mass of the total amount of the oil-in-water emulsion composition. Preferably, it is 3 to 50% by mass, and more preferably 5 to 45% by mass. If the oil phase content is excessively high, stickiness will occur and the feel of use will decrease. On the other hand, if it is excessively low, when an oil-soluble active ingredient is included, it may not be possible to include a large amount, and the effect of the oil-soluble active ingredient may not be fully obtained.

[0017] (B: Cyclodextrin) The cyclodextrin component (B) contained in the oil-in-water emulsion composition of the present invention refers to a cyclic, unreduced maltooligosaccharide with glucose as a constituent unit, and includes α-cyclodextrin with six glucose units, β-cyclodextrin with seven units, and γ-cyclodextrin with eight units. In the present invention, α-, β-, and γ-cyclodextrins, their derivatives, and any combination thereof can be used. Examples of cyclodextrin derivatives include, but are not limited to, ethyl cyclodextrin, methyl cyclodextrin, hydroxyethyl cyclodextrin, hydroxypropyl cyclodextrin, methylaminocyclodextrin, aminocyclodextrin, carboxyethyl cyclodextrin, carboxymethyl cyclodextrin, sulfoxyethyl cyclodextrin, sulfoxyl cyclodextrin, acetyl cyclodextrin, branched cyclodextrin, cyclodextrin fatty acid esters, glucosyl cyclodextrin, and maltosyl cyclodextrin. α-cyclodextrin is preferably used. α-cyclodextrin has high solubility in water, allowing for the creation of stable oil-in-water emulsion compositions.

[0018] In the oil-in-water emulsion composition of the present invention, the mechanism by which a stable oil-in-water emulsion composition can be obtained without the use of surfactants is not entirely clear. However, it is conceivable that cyclodextrin dissolved in the aqueous phase and oil molecules in the oil phase form inclusion compounds at the oil-water interface, and that these compounds, along with (C) water-soluble polysaccharides, stabilize the oil-water interface. Furthermore, since inclusion compounds are generally known to be poorly soluble, it is thought that when the oil-in-water emulsion composition of the present invention is applied to the skin and the water evaporates, a mixture of solid inclusion compounds and liquid oil forms a semi-solid film on the skin. This semi-solid film can accumulate on the skin with greater thickness compared to the film formed by liquid oil obtained with conventional oil-in-water emulsion compositions. Therefore, if the oil-in-water emulsion composition of the present invention contains an oil-soluble active ingredient, a larger amount of the oil-soluble active ingredient can be retained on the skin, resulting in a higher efficacy. Furthermore, the semi-solid film formed on the skin is non-sticky due to its semi-solid nature, providing a pleasant user experience. It is also less likely to adhere to clothing, hands, handkerchiefs, etc. (referred to as secondary adhesion in this specification), resulting in excellent sustained effectiveness of the oil-soluble active ingredient. For example, when the oil-soluble active ingredient is an ultraviolet absorber, including it in the oil-in-water emulsion composition of the present invention makes it possible to obtain a higher ultraviolet protection effect and a more sustained effect even with the same amount of ultraviolet absorber.

[0019] In the oil-in-water emulsion composition of the present invention, the content of (B) cyclodextrin is 3 to 30% by mass of the total amount of the oil-in-water emulsion composition. Preferably, it is 4 to 25% by mass, and more preferably, 5 to 20% by mass. If the cyclodextrin content is too low, the emulsification will be unstable, and if the oil-in-water emulsion composition of the present invention contains an oil-soluble active ingredient, the effect of the oil-soluble active ingredient may not be fully obtained. On the other hand, if the cyclodextrin content is too high, the viscosity of the emulsion will become too high, making it difficult to apply.

[0020] In the oil-in-water emulsion composition of the present invention, in order to obtain a stable emulsion, the mass ratio (B) / (A) of the content of component (B) to component (A) is preferably 1 / 10 to 20 / 10, more preferably 2 / 10 to 18 / 10, and particularly preferably 3 / 10 to 15 / 10. If this ratio is too small, a stable emulsion cannot be obtained, and if it is too large, the ease of spreading when applied to the skin decreases.

[0021] (C: Water-soluble polysaccharide) The water-soluble polysaccharide included as component (C) of the present invention, together with cyclodextrin, imparts emulsification stability to the oil-in-water emulsion. The water-soluble polysaccharide may be a naturally derived substance or a substance obtained by chemical synthesis.

[0022] Examples of water-soluble polysaccharides include anionic water-soluble polysaccharides such as xanthan gum, carrageenan, sodium carboxymethyl dextran, quince seed extract, gellan gum, sodium alginate, pectin, carboxymethylcellulose, sodium chondroitin sulfate, tuberose polysaccharide, and hyaluronic acid; and nonionic water-soluble polysaccharides such as hydroxyethylcellulose, hydroxypropylcellulose, guar gum, agarose, pullulan, locust bean gum, galactan, gum arabic, tara gum, tamarind seed gum, sclerotium gum, and agar. Of these, from the viewpoint of stability, one or more selected from xanthan gum, carrageenan, sodium carboxymethyl dextran, gellan gum, sodium alginate, carboxymethylcellulose, guar gum, and hydroxyethylcellulose are preferably used. The use of xanthan gum is particularly preferred.

[0023] Xanthan gum is produced by Xanthomonas bacteria through fermentation using hydrocarbons as a carbon source, and its constituent sugars include glucose, mannose, and glucuronic acid. Examples of commercially available products include KELTROL CG, KELTROL CG-T, KELTROL CG-SFT (manufactured by CPKelco), Monart Gum 80N, Echo Gum T, Keldent SFT (manufactured by MP Gokyo Food & Chemical Co.), Nomcoat ZZ (manufactured by Nisshin Oillio Co., Ltd.), and Echo Gum T (manufactured by Dainippon Sumitomo Pharma Co., Ltd.).

[0024] In the oil-in-water cosmetic composition of the present invention, the content of (C) water-soluble polysaccharides is preferably 0.01 to 2% by mass of the total amount of the oil-in-water emulsion composition. More preferably, it is 0.05 to 1% by mass. If the content of (C) water-soluble polysaccharides is excessively low, it is difficult to maintain emulsion stability, and if it is excessively high, stickiness occurs.

[0025] (D: Liquid polyhydric alcohol) In the oil-in-water emulsion composition of the present invention, (D) a liquid polyhydric alcohol is used for the purpose of improving ease of application to the skin. The liquid polyhydric alcohol can be any polyhydric alcohol that is liquid at room temperature (20°C), and those commonly used in cosmetics and topical skin preparations can be used.

[0026] Examples include BG (1,3-butylene glycol), propylene glycol, propanediol (1,3-propanediol), glycerin, diglycerin, isoprene glycol, dipropylene glycol, PEG-8 (polyethylene glycol 400), pentylene glycol, hexanediol, and caprylyl glycol. These liquid polyhydric alcohols can be used individually or in combination of two or more. BG, propanediol, and diglycerin are preferred because they alleviate the abrupt stopping sensation when spreading on the skin and provide a good user experience.

[0027] The content of component (D) is 0.1 to 30% by mass, preferably 0.5 to 25% by mass, and more preferably 1 to 20% by mass, of the total amount of the oil-in-water emulsion composition. If the content of component (D) is excessively low, it will be difficult to spread on the skin, and the feel and UV protection enhancement effect will be reduced. If the content of component (D) is excessively high, it will not be possible to form a thick film, and if the oil-in-water emulsion composition of the present invention contains an oil-soluble active ingredient, the enhancement effect of the oil-soluble active ingredient may not be sufficiently obtained.

[0028] (Aqueous Phase Components) In the oil-in-water emulsion composition of the present invention, the aqueous phase may include, in addition to water and components (B), (C), and (D) of the present invention, water-soluble components and water-dispersible components commonly used in cosmetics and topical skin preparations. Examples of water-soluble or water-dispersible components that can be incorporated include, but are not limited to, water-soluble polymers other than component (B), hydrophilic surfactants, pH adjusters, lower alcohols, solid polyhydric alcohols, water-soluble ultraviolet absorbers, water-soluble vitamins and water-soluble plant and animal extracts and other water-soluble active ingredients, chelating agents, water-soluble antioxidants, water-soluble antibacterial agents, etc.

[0029] Examples of water-soluble polymers other than component (B) include, but are not limited to, acrylic acid-based water-soluble polymers such as sodium polyacrylate, carboxyvinyl polymer, alkyl acrylate methacrylate copolymer, copolymer or crosspolymer containing 2-acrylamido-2-methylpropanesulfonic acid or its salt as constituent units, and hydrophobic modified polyether urethane.

[0030] Examples of hydrophilic surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants with an HLB value of 8 or higher. However, from the viewpoint of water resistance and low irritation of the film formed on the skin, if a hydrophilic surfactant is included, it is preferably 3% by mass or less, and more preferably 1% by mass or less, of the total amount of the oil-in-water emulsion composition. Particularly preferable is that the composition is substantially free of hydrophilic surfactants. In the present invention, "substantially free of hydrophilic surfactants" means that the oil-in-water emulsion composition of the present invention does not contain hydrophilic surfactants in a manner that exhibits surfactant or emulsifying effects, and does not mean that it contains no hydrophilic surfactants at all. In the present invention, it is particularly preferable that the composition contains no hydrophilic surfactants at all.

[0031] The pH adjuster is not particularly limited as long as it can be used in cosmetics and topical skin preparations, but examples include (but is not limited to) acidic substances such as citric acid, succinic acid, phosphoric acid, glycolic acid, tartaric acid, lactic acid, aspartic acid, glutamic acid, phosphoric acid, and carbonic acid, their sodium or potassium salts, and basic substances such as sodium hydroxide, potassium hydroxide, lysine, and arginine. Citric acid, succinic acid, phosphoric acid, tartaric acid, lactic acid, and their alkali metal salts are preferably used. From the viewpoint of low irritation and stability, the pH of the oil-in-water emulsion composition of the present invention is preferably 4 to 9, more preferably 5 to 8, and particularly preferably 5 to 7. When the pH is alkaline, stability tends to deteriorate, so it is preferable that it be weakly acidic (5 or more and less than 7).

[0032] Examples of lower alcohols include, but are not limited to, ethanol and isopropyl alcohol. Examples of solid polyhydric alcohols include, but are not limited to, sorbitol, xylitol, and polyethylene glycol with a molecular weight of 1000 or more.

[0033] (Powder) In the oil-in-water emulsion composition of the present invention, powder can be contained in the aqueous or oil phase. The powder is not particularly limited as long as it can be used in cosmetics and topical skin preparations, and examples include fine particle metal oxides such as fine particle titanium dioxide and fine particle zinc oxide, pigment-grade titanium dioxide, iron oxide, talc, mica and other inorganic powders; polymer powders, metal soaps and other organic powders; tar-based dyes and other dye powders, metal powders, composite powders, etc., and the surface of the powder may be hydrophobic or lipophilic. However, when the oil-in-water emulsion composition of the present invention contains powder, when applied to the skin, it may cause eraser-like clumping (wrinkling) when it dries, so the amount of powder is preferably 5% by mass or less, and more preferably 1% by mass or less, of the total amount of the oil-in-water emulsion composition (100% by mass). It is particularly preferable that the powder is substantially free of content. In the present invention, "substantially free of powder" means that in the oil-in-water emulsion composition of the present invention, powder is not included in a manner that exhibits the effects of a pigment or ultraviolet scattering agent, and does not mean that no powder is included at all. In the present invention, it is particularly preferable that the composition contains no powder at all.

[0034] In the oil-in-water emulsion composition of the present invention, the content of the aqueous phase is preferably 40 to 98% by mass, more preferably 50 to 97% by mass, and even more preferably 55 to 95% by mass, of the total amount of the oil-in-water emulsion composition. If the aqueous phase content is excessively low, the amount of oil phase becomes high, resulting in stickiness and a decrease in usability. If the aqueous phase content is excessively high, when the oil-in-water emulsion composition of the present invention contains an oil-soluble active ingredient, it may not be possible to include a large amount, and the effect of the oil-soluble active ingredient may not be fully obtained.

[0035] The oil-in-water emulsion composition of the present invention can be prepared according to conventional methods. For example, an aqueous phase containing components (B) to (D) and an oil phase containing component (A) can be prepared separately, and the emulsion can be prepared by adding the oil phase to the aqueous phase or the aqueous phase to the oil phase while stirring. Adding the oil phase to the aqueous phase tends to yield an emulsion with better storage stability compared to the reverse method. Furthermore, the emulsification process is preferably carried out at a temperature of 40°C or lower. When emulsifying at high temperatures, it is difficult to obtain a stable emulsion.

[0036] The oil-in-water emulsion composition of the present invention may be in any form, such as cream, gel, emulsion, liquid (dilute emulsion), or two-layer emulsion (lotion). A two-layer emulsion (lotion) is a form in which, when left standing, the lower layer is a cloudy layer in which emulsion particles consisting of an oil phase and an inclusion compound formed by at least a portion of (B) cyclodextrin and oil molecules are dispersed in the aqueous phase, and the upper layer is a clear aqueous phase that does not contain the oil phase. When using, it should be shaken gently. Because the oil-water interface of the oil-in-water emulsion composition of the present invention is stabilized by the inclusion compound, even if it separates into two layers, the emulsion particles do not coalesce, and a uniform emulsion composition can be formed again by light penetration. The two-layer emulsion (lotion) is a preferred form because it does not require a large amount of water-soluble thickener, and therefore provides a fresh and non-sticky feel.

[0037] The oil-in-water emulsion composition of the present invention can be used as a base for cosmetics and topical skin preparations, and may contain active ingredients for cosmetics and topical skin preparations. In the present invention, the active ingredients are included in the (A) oil phase of the oil-in-water emulsion composition. When the oil-in-water emulsion composition of the present invention is applied to the skin, after the water evaporates, the mixture of the solid inclusion compound containing the active ingredients dispersed in the oil phase and the liquid oil is thought to form a semi-solid film on the skin. This film can accumulate on the skin with thickness, allowing more active ingredients to be retained on the skin and resulting in a high efficacy. Furthermore, because the semi-solid film formed on the skin is semi-solid, it is not sticky, providing a good feel, and is less prone to secondary adhesion. Therefore, the effects of the oil-soluble active ingredients can be sustained.

[0038] In the present invention, the active ingredient can be any active ingredient that can be dissolved or dispersed in the oil phase (i.e., an oil-soluble active ingredient), and can be appropriately selected from those commonly used as active ingredients in cosmetics and topical skin preparations, depending on the desired purpose. Examples of such oil-soluble active ingredients include, but are not limited to, oil-soluble UV absorbers, oil-soluble vitamins, anti-inflammatory ingredients, cooling agents, warming agents, ceramides, carotenoids, flavonoids, coenzyme Q10, insect repellents, drugs, plant extracts, pigments, dyes, fragrances, skincare ingredients, dullness / pigmentation care ingredients, moisturizing ingredients, hair growth / hair restoration ingredients, steroids, antiperspirant ingredients, deodorant ingredients, antibacterial ingredients, anti-inflammatory analgesics, etc. Oil-soluble active ingredients can be used alone or in combination of two or more. Specific examples of oil-soluble vitamins include oil-soluble derivatives of vitamin C such as ascorbyl monostearate, ascorbyl monopalmitate, ascorbyl dipalmitate, ascorbyl triisopalmitate, ascorbyl tetraisopalmitate, and ascorbyl tetrahexyldecanoate; vitamin E and its derivatives such as tocopherol and tocopherol acetate; vitamin A and its derivatives such as retinol, retinal, retinoic acid, and retinyl palmitate; and vitamin D and its derivatives such as ergocalciferol and cholecalciferol. Specific examples of anti-inflammatory components include stearyl glycyrrhetinate. Specific examples of cooling agents include menthol, menthyl lactate, 3-l-mentoxypropane-1,2-diol, borneol, camphor, and thymol. Specific examples of warming agents include capsicum tincture, capsaicin, capsinoids, vanillyl butyl ether, and vanillyl nonanoate. Specific examples of carotenoids include astaxanthin, canthaxanthin, α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, zeaxanthin, and fucoxanthin.

[0039] In the present invention, the amount of oil-soluble active ingredient can be appropriately determined according to the desired effect derived from the oil-soluble active ingredient, provided that the content of the oil phase (A), including the oil-soluble active ingredient, is within the above-mentioned range and does not interfere with the above-mentioned properties of the oil-in-water emulsion composition of the present invention. For example, the amount of oil-soluble active ingredient in the oil-in-water emulsion composition of the present invention is preferably 0.01 to 30% by mass, more preferably 0.05 to 25% by mass, and even more preferably 0.1 to 22% by mass, of 100% by mass of the total amount of the oil-in-water emulsion composition. If it is less than 0.01% by mass, the effect is poor, and if it exceeds 30% by mass, the feel of the oil-in-water emulsion composition of the present invention may decrease, and skin irritation may also be a concern.

[0040] Typical oil-soluble active ingredients usable in the present invention include oil-soluble ultraviolet absorbers. Oil-soluble ultraviolet absorbers are not particularly limited as long as they are commonly used in cosmetics and topical skin preparations; for example, the following are examples. Oil-soluble ultraviolet absorbers can be used alone or in combination of two or more. Cinnamic acid-based UV absorbers such as benzyl paramethoxycinnamate, ethylhexyl methoxycinnamate (2-ethylhexyl paramethoxycinnamate), and glyceryl mono-2-ethylhexanoate diparamethoxycinnamate; benzophenone-based UV absorbers such as hydroxymethoxybenzophenone, dihydroxymethoxybenzophenone, dihydroxybenzophenone, and tetrahydroxybenzophenone; benzoic acid ester-based UV absorbers such as paraaminobenzoic acid, ethyl paraaminobenzoate, glyceryl paraaminobenzoate, amyl paradimethylaminobenzoate, dimethyl PABA ethylhexyl (2-ethylhexyl dimethylparaaminobenzoate), ethyl 4-[N,N-di(2-hydroxypropyl)amino]benzoate, and diethylaminohydroxybenzoyl hexyl benzoate; Salicylic acid-based UV absorbers such as ethylene glycol salicylate, phenyl salicylate, ethylhexyl salicylate, benzyl salicylate, para-tert-butylphenyl salicylate, homosalate (homomenthyl salicylate); triazine-based UV absorbers such as ethylhexyl triazone (2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]1,3,5-triazine) and bis-ethylhexyloxyphenol methoxyphenyl triazine; and other UV absorbers such as t-methoxydibenzoylmethane, menthyl anthranilate, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidinepropionate, octocrylene, and dimethicone diethylbenzalmalonate.

[0041] Among these, when selecting ultraviolet absorbers such as ethylhexyl methoxycinnamate, ethylhexyl salicylate, homosalate, bis-ethylhexyloxyphenol methoxyphenyl triazine, ethylhexyl triazone, octocrylene, t-methoxydibenzoylmethane, and hexyl diethylaminohydroxybenzoyl benzoate, a particularly high ultraviolet protection effect can be obtained.

[0042] For example, the blending amount of the oil-soluble ultraviolet absorber in the oil-in-water type emulsion composition of the present invention is preferably 1 to 30% by mass, more preferably 2 to 25% by mass, and still more preferably 4 to 22% by mass, based on 100% by mass of the total amount of the oil-in-water type emulsion composition. If it is less than 1% by mass, the sunburn prevention effect is poor, and if it exceeds 30% by mass, the feel of use of the oil-in-water type emulsion composition of the present invention may decrease, or skin irritation may be a concern.

[0043] The oil-in-water type emulsion composition of the present invention containing an oil-soluble ultraviolet absorber as an active ingredient in the (A) oil phase can be used not only as a sunscreen cosmetic but also as other cosmetics imparted with an ultraviolet shielding effect. Specific examples of other cosmetics include foundations, base cosmetics, skin care cosmetics such as emulsions, creams, beauty essences, BB creams, CC creams, and hair cosmetics. Among them, it is suitable for base cosmetics because there is little stickiness due to oil.

[0044] Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited by these examples. In addition, the blending amounts in the formulations in the following description are mass % with respect to the total amount unless otherwise specified.

[0045] Also, the evaluation methods of the oil-in-water type emulsion compositions in the following examples and comparative examples are as follows.

[0046] (Evaluation method: Emulsion stability) After preparing aqueous emulsified compositions of the examples and comparative examples containing an oil-soluble ultraviolet absorber as an active ingredient, the state immediately after preparation and the state after storage at 50°C for one week were observed and judged according to the following evaluation criteria. (Evaluation criteria) A: After storage at 50°C, the whole is uniformly turbid, or it separates into two layers, a transparent aqueous phase in the upper layer and a turbid emulsified layer in the lower layer, and by gently shaking and mixing, the whole becomes uniformly turbid. B: After storage at 50°C, it separates into two layers, a transparent aqueous phase in the upper layer and a turbid emulsified layer in the lower layer, and by gently shaking and mixing, the whole becomes uniformly turbid, but there is slight turbidity in the transparent aqueous phase in the upper layer. C: After storage at 50°C, oil droplets separate at the top. D: A uniform oil-in-water type emulsified composition cannot be obtained immediately after preparation.

[0047] (Evaluation item: Feeling of use) Regarding the feeling of use (non-stickiness), 10 evaluators applied each sample to the inner forearm of the face and conducted a four-level sensory evaluation based on the following scoring criteria (scores). (Scores) 5 points: Extremely excellent. 4 points: Excellent. 3 points: Ordinary. 2 points: Inferior. 1 point: Extremely inferior. (Evaluation criteria) A: Average score value is 4.0 points or more. B: Average score value is 3.5 points or more and less than 4.0 points. C: Average score value is 2.5 points or more and less than 3.5 points. D: Average score value is less than 2.5 points.

[0048] (Evaluation method: Water resistance) Each sample was applied to the inner part of the forearm of a male at a thickness of 5 mg / cm

[0049] , ,

[0048] , ２ , , ２ , After thoroughly drying, 20 μL of purified water was dropped, the water droplet was photographed from the side, the contact angle was determined by the θ / 2 method, and judged according to the following evaluation criteria. (Evaluation criteria) A: Contact angle; 90° or more. B: Contact angle; 60° or more and less than 90°. C: Contact angle; 30° or more and less than 60°. D: No water droplet is formed and it wets and spreads.

[0049] (Evaluation method: In vitro SPF) The ultraviolet protection effect was measured as the SPF value (in vitro SPF) using a SPF Analyzer UV-1000S manufactured by Labsphere. The sample application plate used was SPFMASTER-PA01 manufactured by Shiseido Medical and Chemical Technology Co., Ltd. Each sample was applied at 2 mg / cm ２ and used for measurement.

[0050] (Evaluation method: Resistance to secondary adhesion) The sample was placed on a urethane artificial skin (BioSkin Plate P001-001 manufactured by Viewlux Corporation) at a concentration of 4 mg / cm². ２ Apply to a thickness of 800 g / cm², and after it has dried completely, place oil-blotting paper (Daiso's 3-color oil-blotting paper) on top. ２ After applying the load for one minute, the oil adhering to the oil-absorbing paper was visually observed and judged according to the following evaluation criteria. Photographs of the oil-absorbing paper after the test are shown in Figure 1 (Example 19 and Comparative Example 11). (Evaluation Criteria) A: The entire oil-absorbing paper remains white, with only a very small area showing oil. B: The area of ​​the oil-absorbing paper that is wet with oil is less than 10%. C: The area of ​​the oil-absorbing paper that is wet with oil is 10% or more but less than 50%. D: The area of ​​the oil-absorbing paper that is wet with oil is 50% or more.

[0051] The method for producing the oil-in-water emulsion composition in the following examples and comparative examples is as follows: (Manufacturing procedure) (1) Mix the aqueous phase component and the oil phase component uniformly. (2) Add the aqueous phase to the oil phase while stirring and mix thoroughly to obtain the emulsion composition.

[0052] Example 1 and Comparative Examples 1-2 <Two-Layer Sunscreen Lotion> The sunscreen lotions shown in Table 1 were prepared according to the above manufacturing procedure and evaluated using the above evaluation method. The results are also shown in Table 1.

[0053]

[0054] As is clear from the results in Table 1, the oil-in-water emulsion composition of the present invention was superior in terms of emulsion stability, feel, water resistance, sun protection effect (SPF), and resistance to secondary adhesion (Example 1). In particular, a clearly higher SPF value was obtained compared to compositions using nonionic surfactants (Comparative Example 1) and anionic surfactants (Comparative Example 2), which are commonly used as emulsifiers for oil-in-water emulsion compositions. Comparative Example 1, which used a nonionic surfactant (lauryl glucoside) as an emulsifier, and Comparative Example 2, which used fatty acid soap produced from isostearic acid and potassium hydroxide, were excellent in emulsion stability, but were inferior in SPF value, feel, water resistance, and resistance to secondary adhesion.

[0055] Examples 2-4 and Comparative Examples 3-4 <Two-Layer Sunscreen Lotion> The sunscreen lotions shown in Table 2 were prepared according to the above manufacturing procedure and evaluated using the above evaluation method. The results are also shown in Table 2.

[0056]

[0057] As is clear from the results in Table 2, the oil-in-water emulsion compositions of the present invention were superior in terms of emulsion stability, feel, water resistance, sun protection effect (SPF), and resistance to secondary adhesion (Examples 2-4). In contrast, the composition of Comparative Example 3, which did not contain water-soluble polysaccharides, could not uniformly emulsify the oil phase into the aqueous phase. The composition of Comparative Example 4, which used a general-purpose water-soluble thickener, (acrylates / alkyl acrylate (C10-30)) crosspolymer, instead of water-soluble polysaccharides, was inferior in terms of emulsion stability, feel, water resistance, sun protection effect (SPF), and resistance to secondary adhesion.

[0058] Examples 5-10 <Two-layer type sunscreen lotion> The sunscreen lotions shown in Table 3 were prepared according to the above manufacturing procedure and evaluated using the above evaluation method. The results are also shown in Table 3.

[0059]

[0060] As is clear from the results in Table 3, the oil-in-water emulsion composition of the present invention was superior in terms of emulsion stability, feel, water resistance, sun protection effect (SPF), and resistance to secondary adhesion. When the mass ratio of component (B) to component (A), (B) / (A), was small, there was a tendency for the SPF value to decrease.

[0061] Examples 11-14 and Comparative Examples 5-6 <Two-Layer Sunscreen Lotion> The sunscreen lotions shown in Table 4 were prepared according to the above manufacturing procedure and evaluated using the above evaluation method. The results are also shown in Table 4.

[0062]

[0063] As is clear from the results in Table 4, the oil-in-water emulsion compositions of the present invention were superior in terms of emulsion stability, feel, water resistance, sun protection effect (SPF), and resistance to secondary adhesion (Examples 11-14). In contrast, the compositions of Comparative Examples 5 and 6, which had a low content of (A) cyclodextrin, were inferior in emulsion stability, feel, and resistance to secondary adhesion.

[0064] Examples 15-18 and Comparative Examples 7-10 <Two-Layer Sunscreen Lotion> The sunscreen lotions shown in Table 5 were prepared according to the above manufacturing procedure and evaluated using the above evaluation method. The results are also shown in Table 5.

[0065]

[0066] As is clear from the results in Table 5, the oil-in-water emulsion compositions of the present invention were superior in terms of emulsion stability, feel, water resistance, sun protection effect (SPF), and resistance to secondary adhesion (Examples 15-18). In contrast, the composition of Comparative Example 7, which did not contain polyhydric alcohol, had significantly inferior feel. Compositions using monohydric alcohol (Comparative Example 8) or solid polyhydric alcohol (Comparative Examples 9 and 10) instead of liquid polyhydric alcohol showed reduced feel.

[0067] Examples 19-21 and Comparative Examples 11-13 <Two-Layer Sunscreen Lotion> The sunscreen lotions shown in Table 6 were prepared according to the above manufacturing procedure and evaluated using the above evaluation method. The results are also shown in Table 6.

[0068]

[0069] As is clear from the results in Table 6, the oil-in-water emulsion composition of the present invention was superior in terms of emulsion stability, feel, water resistance, sun protection effect (SPF), and resistance to secondary adhesion (Examples 19-21). Comparing Example 19 with Comparative Example 11, it can be seen that despite containing the same amount of UV absorber, conventional emulsification using fatty acid soap obtained by neutralizing isostearic acid does not yield a high SPF value. Similarly, comparing Examples 20 and 21 with Comparative Examples 12 and 13, it can be seen that when a general-purpose nonionic surfactant (lauryl glucoside) is used, a high SPF value cannot be obtained.

[0070] The present invention provides an oil-in-water emulsion composition for use applied to the skin that is excellent in terms of feel, storage stability, and low irritation. Furthermore, the present invention provides an oil-in-water emulsion composition for use applied to the skin that is excellent in enhancing and prolonging the effects of the active ingredient. Furthermore, the present invention provides an oil-in-water emulsion composition suitable as a sunscreen cosmetic, which is excellent in terms of emulsification stability, feel, water resistance, sun protection effect, and resistance to secondary adhesion.

Claims

1. An oil-in-water emulsion composition characterized by containing the following components (A) to (D): (A) Oil phase 2 to 60% by mass (B) Cyclodextrin 3 to 30% by mass (C) Water-soluble polysaccharides (D) Liquid polyhydric alcohol 2. The oil-in-water emulsion composition according to claim 1, wherein the mass ratio (B) / (A) of component (B) to component (A) is 1 / 10 to 20 / 10.

3. The oil-in-water emulsion composition according to claim 1, wherein the oil phase contains an oil-soluble active ingredient.

4. The oil-in-water emulsion composition according to claim 3, wherein the oil-soluble active ingredient is an oil-soluble ultraviolet absorber.

5. The oil-in-water emulsion composition according to claim 3 or 4, wherein the content of the oil-soluble active ingredient is 0.01 to 30% by mass.

6. The oil-in-water emulsion composition according to claim 1 or 2, which is substantially free of surfactants.

7. The oil-in-water emulsion composition according to claim 1 or 2, which substantially does not contain solid oil with a melting point of 40°C or higher.

8. The oil-in-water emulsion composition according to claim 3, which is a cosmetic.

9. The oil-in-water emulsion composition according to claim 3, which is a topical skin preparation.

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