Skin composition

Abstract

Provided is a benzoyl peroxide-containing composition that has smaller change in viscosity over time and can be easily removed from the skin. This skin composition comprises: (A) benzoyl peroxide; (B) an acrylamide-(sodium acryloyldimethyltaurate) copolymer; (C) a surfactant comprising at least one selected from the group consisting of (c1) a combination of sodium lauroyl sarcosinate and at least one anionic surfactant and / or nonionic surfactant, (c2) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl ether sulfates, and sodium lauroyl glutamate, and (c3) a combination of sodium oleate and at least one anionic surfactant and / or nonionic surfactant; and (D) at least one water-based solvent selected from among water and a water-soluble solvent. The skin composition is used by being applied to an affected area of the skin, left to stand for a predetermined time, and subsequently removed from the affected area.

Description

Composition for skin

[0001] The present invention relates to a topical composition for the skin that is useful for preventing and treating acne vulgaris. More specifically, the present invention relates to a composition for the skin (particularly a gel) containing benzoyl peroxide that has antibacterial effects, which is to be applied to the affected area of ​​the skin for a predetermined period of time and then removed.

[0002] Acne vulgaris, commonly known as "pimples," is a skin disease that frequently occurs on the face, and self-care is commonly performed by applying topical preparations. Benzoyl peroxide is used in many countries for the prevention and treatment of acne vulgaris, and for example, Patent Documents 1 to 5 disclose topical skin preparations containing benzoyl peroxide as an active ingredient.

[0003] Japanese Patent Publication No. 2018-538365 Japanese Patent Publication No. 2017-508770 Japanese Patent Publication No. 2005-513146 Japanese Patent Application Laid-Open No. 2010-513428 WO2017 / 109761

[0004] Patent Document 1 discloses a skin-friendly, stable composition that does not contain irritating surfactants, more specifically, a topical pharmaceutical composition or cosmetic cleanser composition containing an alkyl glucoside derivative surfactant. Patent Document 2 discloses a benzoyl peroxide-containing composition provided in the form of a foam intended for topical rinsing application, more specifically, a composition containing little or no foaming surfactants. Patent Document 3 discloses a composition containing a retinoid and benzoyl peroxide, more specifically, the use of a specific pH-independent gelling agent to suppress viscosity loss over time and maintain good chemical stability of the two active ingredients. Patent Document 4 discloses a composition containing a retinoid and benzoyl peroxide, more specifically, the provision of the composition in a cream-gel form without the use of an emulsifier. Patent Document 5 discloses that a composition containing benzoyl peroxide, a silicone compound (such as siloxane), and a zinc compound is provided that can effectively treat acne and simultaneously prevent the formation of acne scars and other scars.

[0005] None of the above patent documents discloses a gel-type benzoyl peroxide-containing formulation that is used to treat acne by contacting the affected area for a predetermined period of time (e.g., 1 to 30 minutes) and then removing the formulation (e.g., rinsing it off). Since dry skin at the application site has been reported as a side effect of benzoyl peroxide-containing formulations, a formulation that is removed after contacting the affected area is preferable in terms of reducing such side effects. Furthermore, because benzoyl peroxide is insoluble in water, it exists in a suspended state in the formulation. Gel-type formulations have a moderate viscosity, making them suitable for uniformly dispersing benzoyl peroxide within the formulation. To commercialize such gel-type formulations, it is important to suppress viscosity fluctuations during storage, which can prevent changes in appearance and provide formulations with stable quality.

[0006] Therefore, an object of the present invention is to provide a benzoyl peroxide-containing skin composition (particularly a gel) that is less likely to change in viscosity over time and is easy to remove from the skin.

[0007] As a result of extensive research into solving the above problems, the present inventors have succeeded in developing a skin composition (particularly a gel) that is less likely to change in viscosity over time and is easy to remove after application, by using a specific thickener to impart viscosity to a benzoyl peroxide-containing composition and by further using a specific surfactant.

[0008] The composition of the present invention, which can solve the above-mentioned problems, has the following configuration: [1] A skin composition containing: (A) benzoyl peroxide, (B) an acrylamide-sodium acryloyldimethyltaurate copolymer, (C) a surfactant containing at least one selected from the group consisting of (c1), (c2), and (c3) below: (c1) a combination of sodium lauroyl sarcosinate and at least one anionic surfactant and / or nonionic surfactant, (c2) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl ether sulfate, and sodium lauroyl glutamate, (c3) a combination of sodium oleate and at least one anionic surfactant and / or nonionic surfactant, and (D) at least one aqueous solvent selected from water and water-soluble solvents, and used by applying the composition to an affected area of ​​skin, leaving it for a predetermined period of time, and then removing it from the affected area. [2] The composition according to [1], wherein the at least one anionic surfactant and / or nonionic surfactant according to (c1) is at least one surfactant selected from the group consisting of sodium salts of sulfate esters of higher aliphatic alcohols, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl ether sulfates, sodium salts of long-chain fatty acids, polyoxyethylene polyoxypropylene glycols, fatty acid alkanolamides, polyglycerin fatty acid esters, and polyoxyethylene alkyl ethers. [3] The composition according to [1] or [2], wherein the surfactant (C) includes (c1).[4] The composition according to any one of [1] to [3], wherein the surfactant (C) contains 2.0% by weight or less of sodium lauroyl sarcosinate, and 2.0% by weight or less of at least one anionic surfactant and / or nonionic surfactant selected from the following (I) and (II): (I) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, polyoxyethylene oleyl ether sodium phosphate, polyoxyethylene lauryl ether sodium phosphate, polyoxyethylene cetyl ether sodium phosphate, polyoxyethylene lauryl ether sodium sulfate, sodium stearate, and sodium oleate; (II) at least one nonionic surfactant selected from the group consisting of polyoxyethylene polyoxypropylene glycol, lauric acid diethanolamide, decaglyceryl laurate, polyoxyethylene behenyl ether, and coconut oil fatty acid diethanolamide. [5] The composition according to any one of [1] to [3], wherein the surfactant (C) comprises 1.0% by weight or less of sodium lauroyl sarcosinate, and 1.0% by weight or less of at least one anionic surfactant selected from the following (I): (I) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, polyoxyethylene oleyl ether sodium phosphate, polyoxyethylene lauryl ether sodium phosphate, polyoxyethylene cetyl ether sodium phosphate, polyoxyethylene lauryl ether sodium sulfate, sodium stearate, and sodium oleate. [6] The composition according to [1], wherein the surfactant (C) comprises (c2). [7] The composition according to [1], wherein the surfactant (C) comprises (c3).[8] The composition according to [1] or [7], wherein the surfactant (C) comprises 2.0% by weight or less of sodium oleate, and 2.0% by weight or less of at least one anionic surfactant and / or nonionic surfactant selected from the following (I) and (II): (I) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, polyoxyethylene oleyl ether sodium phosphate, polyoxyethylene lauryl ether sodium phosphate, polyoxyethylene cetyl ether sodium phosphate, polyoxyethylene lauryl ether sodium sulfate, sodium stearate, and sodium lauroyl sarcosinate; (II) at least one nonionic surfactant selected from the group consisting of polyoxyethylene polyoxypropylene glycol, lauric acid diethanolamide, decaglyceryl laurate, polyoxyethylene behenyl ether, and coconut oil fatty acid diethanolamide. [9] The composition according to [1] or [7], wherein the surfactant (C) comprises 1.0% by weight or less of sodium oleate and 1.0% by weight or less of at least one anionic surfactant selected from the following (I): (I) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, polyoxyethylene oleyl ether sodium phosphate, polyoxyethylene lauryl ether sodium sulfate, and sodium lauroyl sarcosinate.

[10] The composition according to any one of [1] to [9], which contains only benzoyl peroxide as an active ingredient.

[11] The composition according to any one of [1] to

[10] , which is in the form of a gel.

[12] The composition according to any one of [1] to

[11] , which is applied to an affected area of ​​skin, left for 1 to 30 minutes, and then removed from the affected area.

[13] The composition according to any one of [1] to

[12] , wherein the copolymer (B) comprises at least one selected from the group consisting of Sepino P600 (Seppic), SIMULGEL 600 (Seppic), and Acrylamide / sodium acryloyldimethyltaurate copolymer (Alfa Chemistry).

[0009] The present invention can provide a benzoyl peroxide-containing skin composition (particularly a gel) that exhibits little change in viscosity over time and is easy to remove from the skin.

[0010] A gel generally refers to a gel-like topical preparation to be applied to the skin, which has a moderate viscosity and in which the active ingredient is dissolved or uniformly dispersed in an aqueous or oily base. The skin composition of the present invention is primarily a suspension gel in which benzoyl peroxide is uniformly dispersed in an aqueous base.

[0011] The composition contains benzoyl peroxide (A) as an active ingredient. Benzoyl peroxide can be prepared by adding hydrogen peroxide to sodium hydroxide solution to obtain a sodium peroxide solution, and then adding benzoyl chloride to the sodium peroxide solution. It is also commercially available. Benzoyl peroxide may be coated with a metal oxide layer or the like, but uncoated benzoyl peroxide is preferred. The benzoyl peroxide content is preferably 1.0 to 20 wt %, more preferably 1.5 to 15 wt %, particularly preferably 2.0 to 12 wt %, and even more preferably 2.5 to 11 wt % or 5.0 to 10 wt %. Because the composition is removed from the skin after a predetermined time has elapsed after application, even if it contains a high concentration of benzoyl peroxide, side effects due to benzoyl peroxide are unlikely to occur.

[0012] In this specification, the terms "wt %," "content," and "concentration" refer to the weight ratio of each component when the total weight of the composition is taken as 100%.

[0013] The composition preferably contains only benzoyl peroxide as an active ingredient (an ingredient for preventing and treating acne). For example, a combination drug containing a retinoid such as adapalene and benzoyl peroxide as active ingredients is known as an acne treatment agent, but the composition of the present invention preferably does not contain a retinoid compound such as adapalene (or a naphthoic acid compound).

[0014] Carboxyvinyl polymer and acrylamide / sodium acryloyldimethyltaurate copolymer were examined as potential thickeners for maintaining benzoyl peroxide in a dispersed state. As a result, it was confirmed that acrylamide / sodium acryloyldimethyltaurate copolymer is preferable as the thickener of the present invention, taking into consideration the amount of stratum corneum peeling, especially in the case of short-term contact. Therefore, the composition of the present invention contains acrylamide / sodium acryloyldimethyltaurate copolymer (Acrylamide / Sodium Acryloyldimethyltaurate Copolymer; (C3H5NO.C7H 13 NO4S.Na)x) (B). The weight-average molecular weight of copolymer (B) is preferably 2 million to 30 million, more preferably 4 million to 20 million, more preferably 6 million to 14 million, and even more preferably 8 million to 12 million. Copolymer (B) is commercially available. For example, products containing this copolymer are sold by Seppic under the trade names Sepineo P600 and SIMULGEL 600, or by Alfa Chemistry under the trade name "Acrylamide / sodium acryloyldimethyltaurate copolymer." Sepineo P600 and Acrylamide / sodium acryloyldimethyltaurate copolymer are more preferred. These products may be used alone or in combination, but are preferably used alone.

[0015] In order to impart an appropriate viscosity to the composition, the content of copolymer (B) is preferably 0.5 to 4.0 wt%, more preferably 0.7 to 3.5 wt%, and particularly preferably 1.0 to 3.0 wt%. Even if the amount of copolymer (B) is small, viscosity fluctuations of the composition can be suppressed by using it in combination with a specific surfactant, so considering cost, the content of copolymer (B) is preferably 0.5 to 2.5 wt%, more preferably 1.0 to 2.0 wt%, and particularly preferably 1.3 to 1.7 wt%.

[0016] When the composition contains at least one product selected from the group consisting of Sepineo P600 (Seppic), SIMULGEL 600 (Seppic), and Acrylamide / sodium acryloyldimethyltaurate copolymer (Alfa Chemistry), the total content is preferably 1.5 to 10 wt%, more preferably 2 to 9 wt%, and particularly preferably 3 to 8 wt%. Considering cost, the total content of the product is preferably 1.5 to 6.5 wt%, more preferably 2 to 6 wt%, particularly preferably 3 to 5 wt%, and even more preferably 3.5 to 4.5 wt%. Preferred compositions include those containing one of the products in the above wt% range.

[0017] The composition contains a specific surfactant (C). As described above, the copolymer (B) can impart an appropriate viscosity to the benzoyl peroxide-containing composition, but this viscosity significantly decreases over time, resulting in the inability to maintain the quality of the formulation. Furthermore, if the viscosity decreases too much, precipitation of benzoyl peroxide may occur. In contrast, the use of a specific surfactant can suppress changes in viscosity over time. Furthermore, the action of the surfactant can provide a composition that is easy to wash off from the skin.

[0018] The total content of the surfactant (C) in the composition is preferably 0.2 to 10% by weight, more preferably 0.3 to 8.0% by weight, still more preferably 0.4 to 6.0% by weight, particularly preferably 0.5 to 5.0% by weight, still more preferably 0.7 to 4.0% by weight, and most preferably 1.0 to 2.0% by weight.

[0019] The surfactant (C) includes at least one selected from the group consisting of the following (c1), (c2), and (c3): (c1) a combination of sodium lauroyl sarcosinate and at least one anionic surfactant and / or nonionic surfactant; (c2) at least one anionic surfactant selected from sodium lauryl sulfate, polyoxyethylene (POE) alkyl ether phosphate (wherein the alkyl preferably has 10 to 24 carbon atoms, such as sodium POE oleyl ether phosphate, sodium POE lauryl ether phosphate, and sodium POE cetyl ether phosphate), polyoxyethylene (POE) alkyl ether sulfate (wherein the alkyl preferably has 10 to 24 carbon atoms, such as sodium POE lauryl ether sulfate), and sodium lauroyl glutamate (sodium N-lauroyl-L-glutamate) (wherein the average POE number of the POE-containing surfactant is preferably 2 to 10); (c3) A combination of sodium oleate and at least one anionic surfactant and / or nonionic surfactant.

[0020] Examples of anionic surfactants and / or nonionic surfactants that can be used in combination with (c1) sodium lauroyl sarcosinate or (c3) sodium oleate include the following: Examples of anionic surfactants: sodium salts of sulfate esters of higher aliphatic alcohols (alcohols having 6 or more carbon atoms, preferably alcohols having 8 to 24 carbon atoms) (e.g., sodium lauryl sulfate, sodium cetyl sulfate, etc.), POE alkyl ether phosphates (wherein the alkyl group preferably has 10 to 24 carbon atoms, e.g., sodium POE oleyl ether phosphate, sodium POE lauryl ether phosphate, sodium POE cetyl ether phosphate, etc.), and POE alkyl ether sulfates (wherein the alkyl group preferably has 10 to 24 carbon atoms, e.g., sodium POE lauryl ether sulfate), and sodium salts of long-chain fatty acids (fatty acids having 12 or more carbon atoms, preferably 14 to 24 carbon atoms) (e.g., sodium stearate, etc.) (wherein the average POE number of the POE-containing surfactant is preferably 2 to 10). Examples of nonionic surfactants include polyoxyethylene polyoxypropylene (POE / POP) glycols (wherein the average POE number is preferably 2 to 200, 4 to 100, 8 to 50, or 10 to 30, and the average POP number is preferably 2 to 100, 4 to 70, 5 to 50, or 10 to 30), fatty acid alkanolamides (wherein the fatty acid preferably has 6 to 22 carbon atoms and the alkanol preferably has 2 to 10 carbon atoms, such as lauric acid diethanolamide and coconut oil fatty acid diethanolamide), polyglycerin fatty acid esters (wherein the fatty acid preferably has 10 to 24 carbon atoms, such as decaglyceryl laurate), and polyoxyethylene alkyl ethers (wherein the alkyl preferably has 10 to 24 carbon atoms and the average POE number is preferably 2 to 30 or 10 to 20, such as POE behenyl ether).

[0021] The surfactant (C) may satisfy both (c1) and (c2) at the same time, i.e., the surfactant (C) may contain a combination of sodium lauroyl sarcosinate and the anionic surfactant described in (c2).

[0022] The surfactant (C) may satisfy both (c2) and (c3) at the same time, i.e., the surfactant (C) may contain a combination of sodium oleate and the anionic surfactant described in (c2).

[0023] The surfactant (C) may satisfy both (c1) and (c3) at the same time, i.e., the surfactant (C) may include a combination of sodium lauroyl sarcosinate and sodium oleate.

[0024] The surfactant (C) may satisfy only one of (c1) to (c3). For example, the surfactant (C) may satisfy only (c1). That is, the surfactant (C) may include: a combination of sodium lauroyl sarcosinate and a nonionic surfactant (preferably POE-POP glycol, lauric acid diethanolamide, decaglyceryl laurate, POE behenyl ether, or coconut oil fatty acid diethanolamide), or a combination of sodium lauroyl sarcosinate and "an anionic surfactant that does not fall into either the anionic surfactant (c2) or the sodium oleate (c3)."

[0025] The surfactant (C) may satisfy only (c2). That is, the surfactant (C) may contain an anionic surfactant selected from (c2) but may not contain sodium lauroyl sarcosinate and sodium oleate. The total content of the anionic surfactant (c2) is preferably 0.2 to 6.0 wt%, more preferably 0.3 to 5.0 wt%, more preferably 0.5 to 4.0 wt%, more preferably 0.5 to 3.0 wt%, and most preferably 0.5 to 2.0 wt%.

[0026] The surfactant (C) may satisfy only (c3). That is, the surfactant (C) may include: a combination of sodium oleate and a nonionic surfactant (preferably POE-POP glycol, lauric acid diethanolamide, decaglyceryl laurate, POE behenyl ether, or coconut oil fatty acid diethanolamide), or a combination of sodium oleate and "an anionic surfactant that does not fall into either the anionic surfactant of (c2) or the sodium lauroyl sarcosinate of (c1)."

[0027] Although (c1) sodium lauroyl sarcosinate and (c3) sodium oleate cannot sufficiently maintain the viscosity of the composition alone, when combined with other anionic or nonionic surfactants, they exhibit a high viscosity fluctuation suppression effect (for example, the viscosity of the composition after storage at 40°C for 3 months can be maintained within a range of 50% or more, preferably 55 to 140%, more preferably 80 to 120%, and particularly preferably 90 to 110% of the initial viscosity). More specifically, the following effects were confirmed: - Even if another anionic or nonionic surfactant cannot maintain an appropriate viscosity by itself, it can maintain an appropriate viscosity by combining it with sodium lauroyl sarcosinate or sodium oleate; - Even if another anionic or nonionic surfactant can maintain an appropriate viscosity at high concentrations but not at low concentrations, it can maintain an appropriate viscosity even at low concentrations by combining it with sodium lauroyl sarcosinate or sodium oleate; - Even if another anionic or nonionic surfactant can maintain an appropriate viscosity by itself and at low concentrations, it can be more effective in suppressing viscosity fluctuations by combining it with sodium lauroyl sarcosinate or sodium oleate;

[0028] When the surfactant (C) satisfies (c1), the content of sodium lauroyl sarcosinate is preferably 0.2 to 3.0 wt%, for example, 0.2 to 2.0 wt% (more preferably 0.2 to 1.5 wt%, particularly preferably 0.3 to 1.2 wt%, and even more preferably 0.4 to 1.0 wt%), and the total content of the anionic surfactant and / or nonionic surfactant is preferably 0.1 to 3.0 wt% (more preferably 0.1 to 2.0 wt%, particularly preferably 0.3 to 1.5 wt%, and even more preferably 0.4 to 1.5 wt%, 0.4 to 1.0 wt%, or 0.4 to 0.7 wt%). Here, the anionic surfactant may or may not fall under (c2).

[0029] Preferred examples of surfactant (C) that satisfy at least (c1) and optionally (c2) include: sodium lauroyl sarcosinate, and at least one anionic surfactant and / or nonionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, POE oleyl ether sodium phosphate, POE lauryl ether sodium phosphate, POE cetyl ether sodium phosphate, POE lauryl ether sodium sulfate, sodium stearate, lauric acid diethanolamide, decaglyceryl laurate, and POE behenyl ether (it has been confirmed that the viscosity change can be maintained in the range of 65 to 130% when combined with sodium lauroyl sarcosinate), more preferably at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, POE oleyl ether sodium phosphate, and POE lauryl ether sodium sulfate, and particularly preferably at least one anionic surfactant selected from sodium lauryl sulfate and sodium cetyl sulfate.

[0030] When the surfactant (C) satisfies (c3), the content of sodium oleate is preferably 0.2 to 2.0% by weight, for example, 0.2 to 1.5% by weight (more preferably 0.3 to 1.2% by weight, particularly preferably 0.4 to 1.0% by weight), and the total content of the anionic surfactant and / or nonionic surfactant is preferably 0.1 to 2.0% by weight (more preferably 0.3 to 1.5% by weight, particularly preferably 0.4 to 1.2% by weight, 0.4 to 1.0% by weight, or 0.4 to 0.7% by weight). Here, the anionic surfactant may or may not fall under (c2).

[0031] Preferred examples of the surfactant (C) that satisfies at least (c3) and optionally (c2) include a combination of: sodium oleate, and at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, POE oleyl ether sodium phosphate, and POE lauryl ether sodium sulfate.

[0032] In particular, it has been observed that when sodium lauroyl sarcosinate (c1) or sodium oleate (c3) is used in combination with an anionic surfactant, the viscosity fluctuation of the composition tends to be effectively suppressed. Therefore, a preferred example of a composition that satisfies (c1) or (c3) is a combination of sodium lauroyl sarcosinate or sodium oleate with an anionic surfactant.

[0033] In particular, sodium lauroyl sarcosinate is expected to improve the skin permeability of benzoyl peroxide based on the results of an in vitro hairless mouse skin permeation test. Furthermore, sodium lauroyl sarcosinate is also compatible with copolymer (B). Therefore, a preferred example of surfactant (C) of the present invention is a combination of sodium lauroyl sarcosinate and an anionic surfactant.

[0034] The composition contains at least one aqueous solvent (D) selected from water and water-soluble solvents. Preferred examples of aqueous solvents include water (preferably purified water) and polyhydric alcohols. Examples of polyhydric alcohols include polyhydric alcohols having 3 to 6 carbon atoms. Polyhydric alcohols selected from glycerin, propylene glycol, and 1,3-butylene glycol are more preferred. Any of the above aqueous solvents can be used alone or in combination.

[0035] The content of the aqueous solvent (D) is preferably 70% by weight or more, more preferably 80% by weight or more, and particularly preferably 85% by weight or more. The upper limit of the aqueous solvent (D) is preferably 95% by weight or less, more preferably 94% by weight or less. The appropriate range of the content of the aqueous solvent (D) is 70 to 95% by weight, more preferably 80 to 95% by weight, and particularly preferably 85 to 94% by weight.

[0036] The composition may contain both (d1) a polyhydric alcohol and (d2) water (preferably purified water) as the aqueous solvent (D). For example, the composition may contain 1 to 20 wt% of a polyhydric alcohol and 60 wt% or more of water, 2 to 10 wt% of a polyhydric alcohol and 70 wt% or more of water, or 3 to 7 wt% of a polyhydric alcohol and 75 wt% or 80 wt% or more of water. The weight percentages of (d1) and (d2) above do not refer to the total amount of the aqueous solvent (D), but rather refer to weight percentages when the total amount of the composition is taken as 100 wt%.

[0037] Although a lower monohydric alcohol (a monohydric alcohol having 1 to 3 carbon atoms, such as ethanol or isopropanol) may be used as the aqueous solvent (D), it is preferable that the composition of the present invention essentially does not contain a lower monohydric alcohol because lower monohydric alcohols are irritating to the skin. In this specification, "essentially does not contain a lower monohydric alcohol" means that a lower monohydric alcohol is not intentionally added during preparation of the composition, and therefore the content of the lower monohydric alcohol in the composition is usually less than 1.0 wt%, more preferably less than 0.5 wt%, and particularly preferably 0 wt%.

[0038] To reduce the side effects of benzoyl peroxide, the composition is applied by contacting the affected skin area with the composition for a predetermined time (e.g., about 1 to 30 minutes, 2 to 20 minutes, 3 to 15 minutes, or 5 to 10 minutes) and then removing the composition from the affected skin area (e.g., by rinsing or wiping). Therefore, the composition is preferably substantially free of oily components so that it can be quickly and easily removed from the affected skin area. As used herein, "substantially free of oily components" means that the proportion of oily components in the total amount of the composition is 4.0% by weight or less, preferably 3.0% by weight or less, and more preferably 2.0% by weight or less.

[0039] The pH value of the composition is preferably 3 to 7. A pH below 3 may cause irritation to the skin, while a pH above 7 may result in poor stability of benzoyl peroxide. A more preferred pH value is 3 to 6, and a particularly preferred pH value is 3 to 4.5. Examples of pH adjusters include diisopropanolamine, triisopropanolamine, triethanolamine, potassium hydroxide, sodium hydroxide, citric acid hydrate, sodium citrate hydrate, phosphoric acid, potassium dihydrogen phosphate, sodium dihydrogen phosphate, tartaric acid, dl-malic acid, and glacial acetic acid. Any of the above pH adjusters may be used alone or in combination.

[0040] The viscosity of the composition is not particularly limited as long as it can maintain benzoyl peroxide in a dispersed state, but is preferably 200 mPa·s or more or 400 mPa·s or more, more preferably 500 mPa·s or more, even more preferably 1,000 mPa·s or more, and particularly preferably 1,300 mPa·s or more. In consideration of ease of spreading on the skin, the upper limit of the viscosity is preferably 10,000 mPa·s or less, more preferably 7,000 mPa·s or less or 6,000 mPa·s or less, and particularly preferably 4,000 mPa·s or less or 3,000 mPa·s or less. Examples of appropriate viscosity ranges include 500 to 7,000 mPa·s, 800 to 5,000 mPa·s, 900 to 4,000 mPa·s, and 1,000 to 3,000 mPa·s. In this specification, viscosity refers to the viscosity measured 30 seconds after the start of rotation using a cone-plate viscometer (modular compact rheometer) at a measurement temperature of 25°C, cone plate No. 50-1, and a rotation speed of 10 rpm.

[0041] The composition may contain other additives commonly used in topical skin preparations. Examples of other additives include antioxidants (such as ascorbic acid, dibutylhydroxytoluene, dibutylhydroxyanisole, α-tocopherol, tocopherol acetate, propyl gallate, sodium bisulfite, sodium sulfite, sodium metabisulfite, and erythorbic acid), stabilizers (such as sodium edetate hydrate and 1-menthol), preservatives (such as parahydroxybenzoates and phenoxyethanol), colorants (such as titanium oxide), humectants, buffers, solubilizers, and any combination thereof. The total content of the other additives is preferably 5% by weight or less, more preferably 3% by weight or less, and particularly preferably 2% by weight or less.

[0042] The composition may be free of silicone compounds (such as siloxanes) and / or zinc compounds. The composition may be free of a hydrophobic phase. The composition may be free of malonic acid and / or benzoic acid aryl esters. The composition may be free of amphoteric surfactants. The composition may be free of cannabinoids, terpenes, and / or flavonoids. The composition may achieve the desired effect even without these ingredients.

[0043] A particularly preferred example of the composition includes: (A) benzoyl peroxide; (B) acrylamide-sodium acryloyldimethyltaurate copolymer; (C) a combination of sodium lauroyl sarcosinate and at least one anionic surfactant selected from the group consisting of sodium salts of sulfate esters of higher aliphatic alcohols, POE alkyl ether phosphates, POE alkyl ether sulfates, and sodium salts of long-chain fatty acids (more preferably at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, POE oleyl ether sodium phosphate, POE lauryl ether sodium phosphate, POE cetyl ether sodium phosphate, POE lauryl ether sodium sulfate, and sodium stearate; particularly preferably at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, POE oleyl ether sodium phosphate, and POE lauryl ether sodium sulfate; and even more preferably at least one anionic surfactant selected from sodium lauryl sulfate and sodium cetyl sulfate); and (D) an aqueous solvent consisting of a polyhydric alcohol and water. In particular, a composition (particularly a gel) in which the total content of (A) to (D) is 95% by weight or more, 97% by weight or more, or 98% by weight or more is preferred. In the particularly preferred example, the content of (A) is preferably 1.0 to 20% by weight (more preferably 1.5 to 15% by weight, particularly preferably 2.0 to 12% by weight, even more preferably 2.5 to 11% by weight or 5.0 to 10% by weight), the content of (B) is preferably 0.5 to 4.0% by weight (more preferably 0.7 to 3.5% by weight, 1.0 to 3.0% by weight, 1.0 to 2.5% by weight, or 1.0 to 2.0% by weight, particularly preferably 1.3 to 1.7% by weight), the contents of sodium lauroyl sarcosinate and anionic surfactant in (C) are each preferably 0.2 to 1.5% by weight (more preferably 0.3 to 1.2% by weight, particularly preferably 0.4 to 1.0% by weight), and the content of (D) is preferably 70 to 95% by weight (more preferably 80 to 94% by weight, particularly preferably 85 to 93% by weight).In one particularly preferred example, the copolymer (B) may be at least one selected from the group consisting of Sepineo P600 (Seppic), SIMULGEL 600 (Seppic), and Acrylamide / sodium acryloyldimethyltaurate copolymer (Alfa Chemistry), which are commercially available products containing this copolymer. When the composition contains such a commercially available product, its total content is preferably 2 to 10 wt% (more preferably 2 to 9 wt%, 3 to 8 wt%, 3 to 6 wt%, or 3 to 5 wt%, and particularly preferably 3.5 to 4.5 wt%). For example, the composition may contain one of the commercially available products in the above weight percentages.

[0044] The composition can be used for the prevention and treatment of acne. Examples of acne include, but are not limited to, acne vulgaris, acne comedonal or polymorphous acne, acne rosacea, nodular cystic acne, acne congregata, senile acne or secondary acne (e.g., actinic acne), drug-induced acne, and occupational acne. The application amount and frequency can be adjusted appropriately depending on the severity of the symptoms, the concentration of benzoyl peroxide in the composition, and other factors. For example, when used on the face, the composition is applied to the affected skin once or twice daily in an amount sufficient to cover the affected area. The composition is then left in contact with the affected area for a predetermined period of time (e.g., 1 to 30 minutes, 2 to 20 minutes, 3 to 15 minutes, or 5 to 10 minutes) after application, and then removed from the affected area (e.g., by rinsing or wiping).

[0045] In the preceding paragraphs, preferred compound names of the essential and optional components used in the composition of the present invention have been described, but the composition of the present invention also includes compositions obtained by any combination of these and any combination of the contents of each component. Numerical ranges for viscosity, pH, content, etc. can also be arbitrarily combined, and when multiple numerical ranges are described, the upper and lower limits of each numerical range can also be arbitrarily combined.

[0046] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0047] Example 1: Preparation of Formulations A commercially available thickening agent (Sepineo P600; Seppic) containing acrylamide-sodium acryloyldimethyltaurate copolymer was used. Sepineo P600 is a raw material mixture containing acrylamide-sodium acryloyldimethyltaurate copolymer, isohexadecane, polysorbate 80, sorbitan oleate, and water. Various surfactants and pH adjusters were added to an aqueous solvent (mainly purified water) and dissolved by stirring until homogeneous. Sepineo P600 was added to the resulting solution and stirred until homogeneous to prepare an aqueous phase. Benzoyl peroxide was added to this aqueous phase and stirred until homogeneous to prepare a formulation (suspended gel) with the composition shown in Table 1.

[0048] Viscosity Measurement An appropriate amount of each formulation was taken and its viscosity was measured using a modular compact rheometer under the following measurement conditions (n=3). The initial viscosity and the viscosity after storage at 50°C for 2 weeks to 1 month or at 40°C for 1 to 3 months were measured, and the ratio of the viscosity after storage to the initial viscosity was calculated. Jig: CP50-1 Rotation speed: 10 rpm Measurement temperature: 25.0°C±0.1°C Measurement time: 30 seconds

[0049] The results are shown in Table 1. The values ​​for each component shown in Table 1 are in weight percent. The "trace amount" for the pH adjuster in the table refers to the amount necessary to adjust the pH to about 4, which is less than 1 weight percent. The aqueous solvents in the table are purified water and polyhydric alcohol (almost all purified water), and "appropriate amount" means an amount that makes the total amount of the formulation 100 weight percent. The ratio to the initial viscosity was calculated by dividing the viscosity after storage by the initial viscosity and multiplying the result by 100 (the same applies to other tables).

[0050]

[0051] As can be seen from Table 1, when benzoyl peroxide-containing formulations were thickened with Sepineo P600 (a product containing acrylamide / sodium acryloyldimethyltaurate copolymer), they were gel-like immediately after preparation, but the viscosity significantly decreased over time, changing from gel to liquid (see Formulation 1). While the viscosity after 3 months of storage at 40°C is preferably within the range of 50% to 140% of the initial viscosity, the viscosity of Formulation 1 after 3 months at 40°C was only 5% of the initial viscosity, indicating that the thickening effect of the copolymer was almost completely eliminated. In contrast, the inventors have found that the addition of surfactants listed in Table 1 significantly suppresses the decrease in viscosity of the gel (see Formulations 2-15). The effect of suppressing viscosity decrease tended to increase with increasing surfactant content.

[0052] [Example 2] Furthermore, the present inventors discovered that the decrease in viscosity of a gel can be more effectively suppressed by using sodium lauroyl sarcosinate, an anionic surfactant, in combination with another anionic or nonionic surfactant. This result was unexpected because sodium lauroyl sarcosinate alone was not able to sufficiently suppress the decrease in viscosity of the gel.

[0053] The type of surfactant used in combination with sodium lauroyl sarcosinate and the ratio of viscosity after storage to the initial viscosity are shown in Tables 2 and 3. In the column for ratio to initial viscosity in Table 3, "Unpreparable" indicates that when the aqueous solvent containing the surfactant and the copolymer was stirred, it did not become homogeneous, so preparation of the formulation was abandoned without adding benzoyl peroxide. In the same column, "-" indicates that no measurement was performed and no data are available (the same applies to other tables).

[0054]

[0055]

[0056] As shown in Tables 2 and 3, when sodium lauroyl sarcosinate was added alone in an amount of 0.5 wt %, the viscosity after 3 months of storage at 40°C decreased to 35% of the initial viscosity, and the initial feel during use could not be maintained (Formulation 16). However, when sodium lauroyl sarcosinate was used in combination with other anionic / nonionic surfactants, viscosity fluctuations were significantly suppressed even when the concentrations of both surfactants were low. This effect was observed with both anionic and nonionic surfactants, but was particularly pronounced when used in combination with an anionic surfactant.

[0057] For example, the viscosity of Formulation 8 (POE cetyl ether sodium phosphate concentration = 1.0 wt%) after 3 months at 40°C was 63% of the initial viscosity, while that of Formulation 32 (total concentration of sodium lauroyl sarcosinate + POE cetyl ether sodium phosphate = 1.0 wt%) was 84%. Also, the viscosity of Formulation 12 (POE lauryl ether sodium sulfate concentration = 1.0 wt%) after 3 months at 40°C was 78% of the initial viscosity, while that of Formulation 34 (total concentration of sodium lauroyl sarcosinate + POE lauryl ether sodium sulfate = 0.625 wt%) was 105%. Furthermore, sodium cetyl sulfate was unable to sufficiently suppress viscosity changes at any of the concentrations of 0.5, 2.0, 4.0, and 10 wt% (at any concentration, the viscosity after 3 months at 40°C was less than 50% of the initial viscosity; data not shown), whereas formulation 23 (total concentration of sodium lauroyl sarcosinate + sodium cetyl sulfate = 1.0 wt%) achieved 90%. These results suggest that the combined use of sodium lauroyl sarcosinate and anionic or nonionic surfactants can more efficiently suppress viscosity changes with a smaller total amount of surfactant than the use of anionic or nonionic surfactants alone.

[0058] [Example 3] Furthermore, the present inventors discovered that the decrease in viscosity of the gel can be more effectively suppressed by using sodium oleate, an anionic surfactant, in combination with another surfactant. This result was unexpected because sodium oleate alone could not even make the aqueous solvent containing the copolymer homogeneous.

[0059] Table 4 shows the types of surfactants used in combination with sodium oleate and the ratio of viscosity after storage to the initial viscosity.

[0060] As shown in Table 4, when sodium oleate was used alone at an amount of 0.5 wt %, it was not possible to prepare a formulation (Formulation 47). However, by using sodium oleate in combination with other surfactants, it was possible to significantly suppress viscosity fluctuations. Furthermore, the use of other surfactants in combination with sodium oleate was more effective in suppressing viscosity fluctuations than the use of the other surfactants alone.

[0061] [Example 4] Preparations (suspension gels) containing different amounts of benzoyl peroxide were prepared, and the ratio of the viscosity after storage to the initial viscosity was investigated. The results are shown in Table 5.

[0062] As shown in Table 5, even when the concentration of benzoyl peroxide was changed, a gel with little change in viscosity was obtained with a small amount of surfactant.

[0063] As shown in the above examples, the use of a specific surfactant allows the thickening effect of copolymer (B) on the composition to be maintained over time. It was also confirmed that each composition is easily removed from the skin after being applied to the skin and left for 1 to 30 minutes. Therefore, the composition of the present invention is suitable for use by applying it to an affected area of ​​skin, leaving it for a predetermined period of time, and then removing it from the affected area.

[0064] Example 5 A formulation (suspension gel) was prepared in the same manner as in Example 1 using a commercially available product other than Sepineo P600 (trade name "Acrylamide / sodium acryloyldimethyltaurate copolymer" manufactured by Alfa Chemistry; hereinafter referred to as "Alfa product"), and a similar experiment was conducted. The Alfa product contains 35-40 wt% acrylamide / sodium acryloyldimethyltaurate copolymer, 20-25 wt% isohexadecane, 5-10 wt% polysorbate 80, 0-5 wt% sorbitan oleate, and water. The results are shown in Table 6. In Table 6, the value in parentheses in the Alfa product column indicates the weight percent of acrylamide / sodium acryloyldimethyltaurate copolymer contained in the Alfa product.

[0065]

[0066] As shown in Table 6, the use of Alfa products also yielded results similar to those of Sepineo P600. Specifically, benzoyl peroxide-containing products thickened with Alfa products were gel-like immediately after preparation, but their viscosity significantly decreased over time. After 1 month at 50°C and 3 months at 40°C, the thickening effect almost disappeared and the product turned liquid (see Formulation 59). Furthermore, when sodium lauroyl sarcosinate alone was added (Formulation 60), viscosity fluctuations were not sufficiently suppressed, and the initial feel was not maintained. When sodium oleate alone was added (Formulation 63), benzoyl peroxide could not be uniformly dispersed, and even formulation preparation was unsuccessful. In contrast, the combination of sodium lauroyl sarcosinate or sodium oleate with sodium lauryl sulfate or lauric acid diethanolamide significantly suppressed viscosity fluctuations and was easily removed from the skin after application and leaving on.

[0067] [Example 6] Preparations (suspended gels) were prepared with varying amounts of Sepineo P600 or Alfa product, and the ratio of viscosity after storage to the initial viscosity was investigated. The results are shown in Table 7 (the number in parentheses in the Alfa product column is the weight percentage of acrylamide-sodium acryloyldimethyltaurate copolymer contained in the Alfa product).

[0068] As shown in Table 7, both Sepineo P600 and Alfa products could be combined with specific surfactants to provide gels with minimal viscosity fluctuations, regardless of the amount. In particular, gels containing a combination of sodium lauroyl sarcosinate and an anionic surfactant exhibited minimal viscosity fluctuations.

Claims

1. A skin composition containing: (A) benzoyl peroxide; (B) a copolymer of acrylamide and sodium acryloyldimethyltaurate; (C) a surfactant selected from at least one of the following groups (c1), (c2), and (c3): (c1) a combination of sodium lauroyl sarcosinate and at least one anionic surfactant and / or nonionic surfactant; (c2) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl ether sulfate, and sodium lauroyl glutamate; (c3) a combination of sodium oleate and at least one anionic surfactant and / or nonionic surfactant; (D) at least one aqueous solvent selected from water and water-soluble solvents, which is used by applying it to the affected area of the skin, leaving it for a predetermined time, and then removing it from the affected area.

2. The composition according to claim 1, wherein at least one of the anionic surfactant and / or nonionic surfactant described in (c1) is a sodium salt of a sulfate ester of a higher aliphatic alcohol; polyoxyethylene alkyl ether phosphate; polyoxyethylene alkyl ether sulfate; sodium salt of a long-chain fatty acid; polyoxyethylene polyoxypropylene glycol; fatty acid alkanolamide; polyglycerin fatty acid ester; and at least one surfactant selected from the group consisting of polyoxyethylene alkyl ether.

3. The composition according to claim 1, wherein the surfactant (C) contains (c1).

4. The composition according to claim 1, wherein the surfactant (C) contains 2.0% by weight or less of sodium lauroyl sarcosinate and at least one anionic surfactant and / or nonionic surfactant selected from the following (I) and (II) in an amount of 2.0% by weight or less: (I) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, sodium polyoxyethylene oleyl ether phosphate, sodium polyoxyethylene lauryl ether phosphate, sodium polyoxyethylene cetyl ether phosphate, sodium polyoxyethylene lauryl ether sulfate, sodium stearate, and sodium oleate; (II) at least one nonionic surfactant selected from the group consisting of polyoxyethylene polyoxypropylene glycol, diethanolamine laurate, decaglyceryl laurate, polyoxyethylene behenyl ether, and coconut oil fatty acid diethanolamide.

5. The composition according to claim 1, wherein the surfactant (C) contains 1.0% by weight or less of sodium lauroyl sarcosinate and at least one anionic surfactant selected from the following (I) in an amount of 1.0% by weight or less: (I) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, sodium polyoxyethylene oleyl ether phosphate, sodium polyoxyethylene lauryl ether phosphate, sodium polyoxyethylene cetyl ether phosphate, sodium polyoxyethylene lauryl ether sulfate, sodium stearate, and sodium oleate.

6. The composition according to claim 1, wherein the surfactant (C) contains (c2).

7. The composition according to claim 1, wherein the surfactant (C) contains (c3).

8. The composition according to claim 1, wherein the surfactant (C) contains sodium oleate at 2.0% by weight or less and at least one anionic surfactant and / or nonionic surfactant selected from the following (I) and (II) at 2.0% by weight or less: (I) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, sodium polyoxyethylene oleyl ether phosphate, sodium polyoxyethylene lauryl ether phosphate, sodium polyoxyethylene cetyl ether phosphate, sodium polyoxyethylene lauryl ether sulfate, sodium stearate, and sodium lauroyl sarcosinate; (II) at least one nonionic surfactant selected from the group consisting of polyoxyethylene polyoxypropylene glycol, diethanolamine laurate, decaglyceryl laurate, polyoxyethylene behenyl ether, and coconut oil fatty acid diethanolamide.

9. The composition according to claim 1, wherein the surfactant (C) contains sodium oleate at 1.0% by weight or less and at least one anionic surfactant selected from the following (I) at 1.0% by weight or less: (I) at least one anionic surfactant selected from the group consisting of sodium lauryl sulfate, sodium cetyl sulfate, sodium polyoxyethylene oleyl ether phosphate, sodium polyoxyethylene lauryl ether sulfate, and sodium lauroyl sarcosinate.

10. The composition according to any one of claims 1 to 9, which contains only benzoyl peroxide as an active ingredient.

11. The composition according to any one of claims 1 to 9, wherein the composition is a gel.

12. The composition according to any one of claims 1 to 9, which is applied to the affected area of the skin, left for 1 to 30 minutes, and then removed from the affected area.

13. The composition according to any one of claims 1 to 9, wherein the copolymer (B) contains at least one selected from the group consisting of Sepineo P600 (Seppic), SIMULGEL 600 (Seppic), and Acrylamide / sodium acryloyldimethyltaurate copolymer (Alfa Chemistry).

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