Topical composition containing ascorbic acid and / or salt thereof

Abstract

Provided is a topical composition having excellent stability.　In the present invention, a topical composition for skin is prepared, the topical composition comprising (A) at least one component selected from the group consisting of ascorbic acid and salts of ascorbic acid, (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, wherein the ratio of the amount of (A) in terms of part(s) by weight to the amount of (B) in terms of part(s) by weight, i.e., (A) / (B), is 1-1000 and the ratio of the amount of (A) in terms of part(s) by weight to the amount of (D) in terms of part(s) by weight, i.e., (A) / (D), is 0.01-5. This topical composition for skin can be prepared at ambient temperature and has good characteristic properties.

Description

Composition for external use containing ascorbic acid and / or its salt

[0001] The present invention relates to a topical composition containing ascorbic acid and / or a salt thereof.

[0002] Ascorbic acid is known to have various effects, such as anti-inflammatory effects, acne-reducing effects, whitening effects, anti-aging effects, antioxidant effects, cell activation effects by promoting the synthesis of biological components such as collagen, and effects of suppressing cell damage and DNA damage caused by ultraviolet rays in epidermal keratinocytes, and is widely used as an external skin agent in anticipation of these effects.

[0003] An aqueous external skin preparation containing ascorbic acid, a low molecular weight betaine, and a specific solvent has been proposed (for example, Patent Document 1).

[0004] Patent No. 7295809

[0005] An object of the present invention is to provide an ascorbic acid-containing topical composition that contains a high concentration of ascorbic acid and has good stability.

[0006] A topical composition containing ascorbic acid and / or a salt thereof is provided.

[0007] Compositions containing ascorbic acid and / or its salts have a whitening effect and are used in beauty serums and the like. However, to maintain the stability of the properties, it may be necessary to incorporate a low molecular weight betaine into the composition. Depending on the type of solvent used, the low molecular weight betaine may impart undesirable properties to the composition.

[0008] As a result of extensive research to solve the problem, the present inventors have found that an excellent topical composition for skin application that has good stability and is less likely to cause problems such as foundation smudging can be obtained by preparing a topical composition for skin application that contains (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid, (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, and that satisfies (A) / (B) of 1 to 1000 and (A) / (D) of 0.01 to 5, and thus have completed the present invention.

[0009] That is, the present invention provides the following topical composition for skin application: A topical composition for skin application containing (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid, (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, wherein (A) / (B) is 1-1000 and (A) / (D) is 0.01-5.

[0010] The present invention can provide a composition for external use on the skin that has excellent properties.

[0011] FIG. 1 is a photograph comparing the makeup state of an example composition and a comparative example composition applied to artificial leather followed by foundation.

[0012] In this specification, the unit of content "mass %" is synonymous with "g / 100 g".

[0013] [Composition for external use on skin] An embodiment of the present invention relates to a composition for external use on skin containing: (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid; (B) a low-molecular-weight betaine; (C) water; and (D) dimethyl isosorbide, wherein (A) / (B) is 1 to 1000 and (A) / (D) is 0.01 to 5.

[0014] The topical skin composition of this embodiment contains (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid, is stable even at low temperatures, and is less likely to cause problems such as makeup smudging and smudging.

[0015] ((A) At least one selected from the group consisting of ascorbic acid and salts of ascorbic acid) In this embodiment, ascorbic acid commercially available as a component of pharmaceuticals, quasi-drugs, or topical skin preparations in the field of cosmetics can be used, and these generally refer to the L-isomer.

[0016] Salts of ascorbic acid can also be used. Here, the salt of ascorbic acid refers to a pharmaceutically acceptable salt. Examples include, but are not limited to, salts with organic bases (e.g., salts with tertiary amines such as trimethylamine salt, triethylamine salt, monoethanolamine salt, triethanolamine salt, and pyridine salt; basic ammonium salts such as arginine); salts with inorganic bases (e.g., alkali metal salts such as ammonium salt, sodium salt, and potassium salt; alkaline earth metal salts such as calcium salt and magnesium salt; and aluminum salt). Particularly preferred salts of ascorbic acid are sodium salts and potassium salts. Specific examples include sodium ascorbate, sodium ascorbic acid monophosphate, sodium ascorbic acid diphosphate, sodium ascorbic acid triphosphate, and sodium ascorbic acid-2-sulfate.

[0017] In this embodiment, ascorbic acid or a salt thereof can be used alone or in combination of two or more kinds.

[0018] The total content of component (A) relative to the total amount of the topical composition is appropriately determined based on the balance with other components. The total content of component (A) relative to the total amount of the topical composition is not particularly limited, but is preferably 2% by mass or more, 3% by mass or more, more preferably 4% by mass or more, even more preferably 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, or 25% by mass or more. The total content of component (A) relative to the total amount of the topical composition is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. The total content of component (A) relative to the total amount of the topical composition is preferably 2 to 40% by mass, more preferably 3 to 40% by mass, more preferably 4 to 35% by mass, and even more preferably 5 to 30% by mass. From another perspective, the total content is preferably 10 to 40% by mass, more preferably 15 to 40% by mass, even more preferably 20 to 40% by mass, and particularly preferably 25 to 40% by mass.

[0019] (B) Low Molecular Weight Betaine) (Low Molecular Weight Betaine) In this embodiment, the low molecular weight betaine can be a compound that is commonly used as a component of topical skin preparations in the fields of pharmaceuticals, quasi-drugs, or cosmetics. In this embodiment, the low molecular weight betaine refers to a compound that forms a zwitterion in the molecule with a molecular weight of 500 or less, and specific examples include quaternary ammonium bases, quaternary phosphonium bases, and tertiary sulfonium bases, which hardly exhibit surfactant properties. Among these, compounds represented by the following chemical formula are preferred:

[0020] (wherein R1, R2 and R3 each independently represent an alkyl group having 1 to 6 carbon atoms, and n represents 1 to 6).

[0021] A wide variety of straight-chain or branched-chain alkyl groups having 1 to 6 carbon atoms can be used as R1 to R3. Examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, isohexyl, 3-methylpentyl, 2,2-dimethylbutyl, and 2,3-dimethylbutyl. R1 to R3 may be the same or different.

[0022] Specific examples include trimethylglycine, triethylglycine, tripropylglycine, and triisopropylglycine where n=1, trimethyl-β-alanine where n=2, and trimethyl-γ-aminobutyric acid where n=3, with trimethylglycine being preferred.

[0023] These low molecular weight betaines may be substituted, and specific examples thereof include N,N,N-trimethylalanine, N,N,N-triethylalanine, N,N,N-triisopropylalanine, N,N,N-trimethylmethylalanine, carnitine, and acetylcarnitine, with carnitine being preferred.

[0024] These can also be synthesized, or commercially available products can be used as they are.

[0025] These low molecular weight betaines can be used alone or in combination of two or more.

[0026] The total content of component (B) relative to the total amount of the topical composition is appropriately determined based on the balance with other components. The total content of component (B) relative to the total amount of the topical composition is not particularly limited, but is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and even more preferably 0.01% by mass or more. The total content of component (B) relative to the total amount of the topical composition is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. The total content of component (B) relative to the total amount of the topical composition is preferably 0.0001 to 30% by mass, more preferably 0.001 to 20% by mass, and even more preferably 0.01 to 10% by mass.

[0027] When the low molecular weight betaine is trimethylglycine, the content of trimethylglycine relative to the total amount of the topical composition is appropriately determined based on the balance with other ingredients. The content of trimethylglycine relative to the total amount of the topical composition is not particularly limited, but is preferably 0.0001% by weight or more, more preferably 0.001% by weight or more, even more preferably 0.01% by weight or more, even more preferably 0.1% by weight or more, particularly preferably 1% by weight or more, and most preferably 5% by weight or more. The content of trimethylglycine relative to the total amount of the topical composition is preferably 30% by weight or less, more preferably 25% by weight or less, even more preferably 20% by weight or less, even more preferably 15% by weight or less, and particularly preferably 10% by weight or less. The content of trimethylglycine relative to the total amount of the topical composition is preferably 0.0001 to 30% by mass, more preferably 0.001 to 25% by mass, even more preferably 0.01 to 20% by mass, even more preferably 0.1 to 15% by mass, particularly preferably 1 to 10% by mass, and most preferably 5 to 10% by mass.

[0028] In the topical composition of the present invention, the ratio of the amount of component (A) to component (B) is preferably 1 to 1,000 parts by mass, more preferably 1.25 to 500 parts by mass, even more preferably 2 to 100 parts by mass, and most preferably 2.5 to 100 parts by mass of the total content of component (A) per 1 part by mass of the total content of component (B).

[0029] In the topical composition of the present invention, the ratio of the amount of component (A) to trimethylglycine is preferably 1 to 1,000 parts by mass, more preferably 1.25 to 500 parts by mass, even more preferably 2 to 100 parts by mass, and most preferably 2.5 to 100 parts by mass of the total content of component (A) per 1 part by mass of trimethylglycine.

[0030] ((C) Water) The topical composition of this embodiment is a liquid composition containing water. The proportion of water is preferably 1% by mass or more, more preferably 5% by mass or more, and most preferably 10% by mass or more, based on the topical composition. The proportion of water is 40% by mass or less, preferably 30% by mass or less, and more preferably 25% by mass or less, based on the topical composition.

[0031] The total content of component (C) relative to the total amount of the topical composition of this embodiment is preferably 1 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 25% by mass.

[0032] In the topical composition of this embodiment, the ratio of the contents of component (A) and component (C) is not particularly limited, but the content of component (A) is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, per 1 part by mass of the total content of component (C).

[0033] In this embodiment, by making the composition contain a specific amount of water, it is possible to make a composition for external use that is excellent in stability and usability.

[0034] (D) Dimethyl isosorbide The topical composition of this embodiment is a liquid composition containing dimethyl isosorbide (isosorbide dimethyl ether). In this embodiment, dimethyl isosorbide that is commercially available as a component of topical skin preparations in the fields of pharmaceuticals, quasi-drugs, or cosmetics can be used.

[0035] This compound can be synthesized or a commercially available product can be used as is.

[0036] The content of component (D) relative to the total amount of the topical composition is appropriately determined based on the balance with other components. The content of component (D) relative to the total amount of the topical composition is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.1% by mass or more, even more preferably 1% by mass or more, and most preferably 4% by mass or more. The content of component (D) relative to the total amount of the topical composition is preferably 60% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 20% by mass or less. The content of component (D) relative to the total amount of the topical composition is preferably 0.001 to 60% by mass, more preferably 0.01 to 55% by mass, even more preferably 0.1 to 40% by mass, even more preferably 0.5 to 30% by mass, and most preferably 1 to 20% by mass, and can also be 1 to 15% by mass or 4 to 15% by mass.

[0037] In the topical composition of the present invention, the ratio of the contents of component (A) and component (D) is not particularly limited, but is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass of component (A) per 1 part by mass of component (D).

[0038] Furthermore, in the topical composition of the present invention, the ratio of the contents of component (B) and component (D) is not particularly limited, but is preferably 0.001 to 5 parts by mass, more preferably 0.001 to 3 parts by mass, and even more preferably 0.002 to 1 part by mass of component (B) per 1 part by mass of component (D).

[0039] (E) Diol Having 3 Carbon Atoms) From the viewpoint of improving the feel during use and improving stability, the topical composition of this embodiment may contain components other than the above-mentioned components (A), (B), (C), and (D), as long as the effects of the present invention are not impaired. The topical composition of the present invention may contain a diol having 3 carbon atoms. The diol having 3 carbon atoms is not particularly limited as long as it is used as a component of topical skin preparations in the fields of pharmaceuticals, quasi-drugs, or cosmetics. The diol having 3 carbon atoms is not limited, but is preferably 1,3-propanediol (CAS No.: 504-63-2, English name: 1,3-Dihydroxypropane or Trimethylene Glycol) or propylene glycol (CAS No.: 57-55-6, English name: 1,2-Dihydroxypropane, Japanese name: 1,2-propanediol). For example, either one or both of 1,3-propanediol and propylene glycol can be used as component (E). As such a diol having 3 carbon atoms, commercially available products can also be used as they are.

[0040] The content of component (E) relative to the total amount of the topical composition of this embodiment is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and even more preferably 25% by mass or more. The content of component (E) relative to the total amount of the topical composition is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. It is preferably 10 to 90% by mass, more preferably 15 to 85% by mass, even more preferably 18 to 80% by mass, and even more preferably 20 to 75% by mass.

[0041] In the topical composition of this embodiment, the ratio of the content of component (E) to component (A) is not particularly limited, but is preferably 0.25 to 30 parts by mass, more preferably 0.40 to 25 parts by mass, even more preferably 0.60 to 16 parts by mass, and even more preferably 0.65 to 10 parts by mass per part by mass of the total content of component (A).

[0042] ((F) Lower Alcohol) From the viewpoint of improving the feeling of use, facilitating stability and transdermal absorption, the topical composition of this embodiment may contain a lower alcohol in addition to the above-mentioned components (A), (B), (C) and (D), as long as it does not impair the effects of the present invention. The lower alcohol is not particularly limited as long as it is used as a component of topical skin preparations in the fields of pharmaceuticals, quasi-drugs or cosmetics. In this specification, the term "lower alcohol" does not mean C １ -C ６ Among them, C ２ -C ３ The following alcohols can be preferably used. Examples of such alcohols include ethanol, n-propanol, isopropanol, etc. Although not limited thereto, ethanol is particularly preferred.

[0043] The content of the lower alcohol in the topical composition of this embodiment is preferably 0.001 to 30% by mass, more preferably 0.01 to 25% by mass, even more preferably 0.1 to 20% by mass, and even more preferably 1 to 15% by mass.

[0044] [pH] From the viewpoints of the stability of component (A), low irritation to the skin and mucous membranes, and a pleasant feel on the skin, the pH of the topical composition of this embodiment is preferably adjusted to about 1 to 6. A pH of 4.5 or less is more preferred. The pH range can also be set to a range of 1.5 to 4.5 or 2 to 4.

[0045] [pH adjuster] The topical composition of this embodiment may contain a pH adjuster in addition to the above-mentioned components (A), (B), (C), and (D), from the viewpoint of improving the feel when used, promoting stability, and promoting transdermal absorption, as long as the effects of this embodiment are not impaired.

[0046] The pH adjuster used in this embodiment can be a compound commonly used as a component of topical skin preparations in the fields of pharmaceuticals, quasi-drugs, or cosmetics. Examples of pH adjusters include, but are not limited to, amine-containing pH adjusters (e.g., aspartic acid or a salt thereof, ε-aminocaproic acid or a salt thereof, glutamic acid or a salt thereof, aminoethylsulfonic acid or a salt thereof, monoethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, arginine, lysine, and L-carnitine), organic acid salts (e.g., sodium lactate, sodium acetate, sodium citrate, sodium succinate, sodium oxalate, calcium gluconate, and sodium pyrrolidonecarboxylate), inorganic acid salts (e.g., sodium pyrosulfite, potassium pyrosulfite, sodium phosphate, potassium nitrate, and sodium borate, preferably sodium pyrosulfite), and basic amino acids and salts thereof (arginine, lysine, or histidine and salts thereof).

[0047] (Other Ingredients) In addition to the above-mentioned components (A), (B), (C), and (D), the topical composition of the present invention may further contain one or more combinations of various ingredients, such as whitening ingredients, anti-inflammatory ingredients, antibacterial ingredients, cell activating ingredients, astringent ingredients, antioxidant ingredients, acne-reducing ingredients, anti-aging ingredients, ingredients promoting biocomponent synthesis such as collagen, blood circulation promoting ingredients, moisturizing ingredients, and anti-aging ingredients, in order to enhance or complement the various effects of ascorbic acid or to impart other useful effects. Preferred are one or more of the whitening ingredients, anti-inflammatory ingredients, antibacterial ingredients, cell activating ingredients, astringent ingredients, antioxidant ingredients, anti-aging ingredients, and moisturizing ingredients. Particularly preferred combinations of these ingredients include combinations with whitening ingredients, combinations of whitening ingredients and antioxidant ingredients, combinations with antioxidant ingredients, combinations with anti-aging ingredients, and combinations of whitening ingredients and anti-aging ingredients. These components are not particularly limited as long as they have been used in the past as components of topical skin preparations in the fields of pharmaceuticals, quasi-drugs, or cosmetics, or will be used in the future, and any component can be appropriately selected and used.

[0048] In addition to the above-mentioned components, the topical composition of the present invention may further contain a surfactant, a solubilizing component, oils and fats, sugars, or a transdermal absorption-promoting component. In particular, the inclusion of a surfactant, a solubilizing component, or an oil and fat can further improve the stability, efficacy, and usability of ascorbic acid in an aqueous solvent.

[0049] The topical composition of the present invention may contain, as needed, various ingredients commonly used as ingredients in topical preparations in the fields of pharmaceuticals, quasi-drugs, and cosmetics, such as amino acids, irritation-reducing agents, thickeners, preservatives, UV protection agents, colorants, dispersants, fragrances, etc., within quantitative and qualitative ranges that do not impair the qualities such as appearance stability and viscosity, or that do not impair the effects of the present invention. These ingredients may be used alone, or two or more may be used in combination.

[0050] The topical composition of this embodiment can be prepared in various desired forms such as paste, mousse, gel, liquid, emulsion, cream, sheet (supported by a substrate), aerosol, spray, etc. These can be produced by conventional methods in the art.

[0051] The topical composition of the present invention is particularly preferably a transparent or translucent composition in which ascorbic acid and / or a salt thereof has been solubilized. Here, "solubilized" is defined as follows: For example, it refers to a composition in which the transmittance at a wavelength of 700 nm measured using a spectrophotometer or a photoelectric photometer UV-2450 (Shimadzu Corporation) is 80 to 100%, preferably 85 to 100%, and more preferably 90 to 100% by ultraviolet-visible absorbance measurement. Here, the transmittance of water is defined as 100%. The solubilized composition of the present invention has a transparent or translucent appearance. The transmittance measurement method is more specifically in accordance with the method described in the 18th Edition of the Japanese Pharmacopoeia [B] General Test Methods, 2. Physical Test Methods, Spectroscopic Measurement Methods, 2.24, Ultraviolet-Visible Absorbance Measurement Method.

[0052] [Viscosity] The topical composition of the present invention can be prepared as a composition with a suitable viscosity, particularly that desired when used for application to the skin. The viscosity of the topical composition of the present invention is not particularly limited, but is typically about 1 to 300 mPa·s, preferably about 1 to 200 mPa·s, more preferably about 1 to 100 mPa·s, and most preferably about 1 to 50 mPa·s, when measured at 25°C using an E-type viscometer. The viscosity measurement method is more specifically based on the method described in the 18th Edition of the Japanese Pharmacopoeia [B] General Test Methods, Section 2. Physical Test Methods, Other Physical Test Methods, Section 2.53 Viscosity Measurement Methods, Section 2. Method 2, Rotational Viscometer Method, Section 2.1.3 Cone-Plate Rotational Viscometer. More specifically, the viscosity is measured at 25°C using a TV-100EL (manufactured by Toki Sangyo Co., Ltd.) under the conditions of a sample volume of 1 mL, a rotor diameter of 4.7 cm, a rotation speed of 5 rpm, and a range of "M".

[0053] [Uses] The topical composition of the present invention is particularly effective as a whitening agent, anti-inflammatory agent, and anti-aging agent, and has, for example, acne prevention and treatment and antioxidant effects. Furthermore, when applied to the skin, it may have the effects of increasing skin transparency, maintaining moisture, improving skin texture, and reducing roughness. Furthermore, it may have the effects of making pores less noticeable, conditioning skin, and moisturizing the skin, and can also be used to prevent and treat blemishes.

[0054] The topical composition of the present invention can be various skin compositions for external use that belong to the fields of cosmetics, topical pharmaceuticals, or topical quasi-drugs, such as skin care products such as serums, skin lotions, sunscreen creams, emulsions, creams, lotions, oils, and packs; cleansers such as face washes, cleansers, and body washes; and anti-armpit odor agents, athlete's foot treatments, antipruritics, wound healing agents, cleansing agents, cleansers, anti-inflammatory and analgesic agents, acne treatments, hemorrhoid treatments, germicides, disinfectants, whitening agents, and UV protection agents. Of these, the composition is particularly suitable for use as a skin care product.

[0055] (Container) The topical composition of the present invention can be stored and used in a container of a shape and material appropriately selected depending on the purpose and application. Specific examples of the container include spray type, bottle type, tube type, jar type, dropper type, dispenser type, dropping tube type, and sachet type.

[0056] Examples of materials for the container include polyethylene terephthalate, polypropylene, polyethylene (HDPE, LDPE, LLDPE, etc.), ABS resin, ethylene vinyl alcohol resin, polystyrene, glass, and metal (aluminum, etc.). These materials can be used as container materials by applying various coating treatments, combining these materials by mixing, or laminating them, taking into consideration strength, flexibility, weather resistance, component stability, etc. Among these, polyethylene (HDPE, LDPE, LLDPE, etc.) is preferred, with LLDPE being particularly preferred. For a container containing the composition of the present invention, it is preferred that at least a portion of the surface that comes into contact with the composition is made of glass.

[0057] The amount of the composition of the present invention filled into a container is preferably 1 to 50 mL, more preferably 3 to 40 mL, and particularly preferably 5 to 30 mL.

[0058] [Manufacturing Method] The manufacturing method of the topical composition of this embodiment is not particularly limited, but ascorbic acid or a salt thereof can be dissolved at room temperature, and all components can be mixed at room temperature to prepare the composition.

[0059] [Stabilization Method] Furthermore, the present invention provides a composition containing (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid, (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, where (A) / (B) is 1 to 1,000 and (A) / (D) is 0.01 to 5, thereby enabling the preparation to be stable even when a certain amount or more of ascorbic acid or a salt thereof is contained. Here, stability refers to, but is not limited to, maintaining the state of the preparation even at temperatures higher than room temperature or at low temperatures. Specifically, for example, stability refers to the suppression of precipitation of ascorbic acid or a salt thereof even when the composition is stored at a low temperature, such as -8°C, for at least one week. That is, the present invention also relates to a method for imparting low-temperature stability to a composition comprising at least one member selected from the group consisting of (A) ascorbic acid and salts of ascorbic acid, by adding (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, and adjusting (A) / (B) to 1-1000 and (A) / (D) to 0.01-5.

[0060] In the method of the present invention, the components and their ratios are the same as those used in the above-mentioned topical skin composition. Furthermore, the product obtained by this method can be used in a known or commonly used manner and dosage, from once to several times a day, depending on the intended use.

[0061] [Method for Improving Sensation of Use] Furthermore, the present invention provides a composition containing (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid, (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, where (A) / (B) is 1 to 1000 and (A) / (D) is 0.01 to 5, thereby enabling a formulation with excellent sensation of use even when containing a certain amount or more of ascorbic acid or a salt thereof. Therefore, the composition of the present invention is also preferably used for applying other cosmetics, including makeup cosmetics, on top of it. For example, in the process of applying cosmetics, it is common to apply cosmetics with various functions on top of each other, and the composition of the present invention can be used as any of these cosmetics, layered on top of other cosmetics. As used herein, "improved usability" includes, for example, when the composition of the present invention is applied to the skin as one of the basic cosmetics such as a serum or lotion, the subsequent application of other cosmetics (e.g., sunscreen or foundation) prevents the composition from mixing with the other cosmetics, resulting in an uneven appearance on the skin and problems such as makeup smudging. That is, the present invention also relates to a method for imparting an improved usability effect, such as prevention of makeup smudging, to a composition containing (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid, by adding (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, and adjusting (A) / (B) to 1 to 1,000 and (A) / (D) to 0.01 to 5. Makeup cosmetics or other cosmetics that can be combined with the composition of the present invention include, but are not limited to, foundations, eye shadows, blushes, makeup bases, sunscreen preparations, creams, or emulsions.

[0062] In the method of the present invention, the components and their ratios are the same as those used in the above-mentioned topical skin composition. Furthermore, the product obtained by this method can be used in a known or commonly used manner and dosage, from once to several times a day, depending on the intended use.

[0063] The present invention includes the following aspects. Item 1. A topical skin composition containing (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid, (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, wherein (A) / (B) is 1 to 1000 and (A) / (D) is 0.01 to 5. Item 2. The topical skin composition according to Item 1, wherein (A) / (C) is 0.1 to 50. Item 3. The topical skin composition according to Item 1 or 2, wherein (B) / (D) is 0.01 to 5. Item 4. The topical skin composition according to any one of Items 1 to 3, wherein the content of the component (A) is 2 to 40% by mass. Item 5. The topical skin composition according to any one of Items 1 to 4, wherein the component (B) is trimethylglycine. Item 6. Item 7. The topical skin composition according to any one of Items 1 to 5, wherein the content of component (D) is 1 to 15% by mass. Item 8. The topical skin composition according to any one of Items 1 to 6, further comprising 15% by mass or more of (E) a diol having 3 carbon atoms. Item 9. The topical skin composition according to any one of Items 1 to 7, wherein the pH is 4.5 or less. Item 10. The topical skin composition according to any one of Items 1 to 8, further comprising (F) a lower alcohol. Item 11. The topical skin composition according to any one of Items 1 to 9, wherein the viscosity is 1 to 300 mPa s. Item 12. Item 11. A method for imparting low temperature stability to a composition comprising at least one member selected from the group consisting of (A) ascorbic acid and salts of ascorbic acid by incorporating (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, and adjusting (A) / (B) to 1-1000 and (A) / (D) to 0.01-5. Item 12. A method for imparting an improved feel to a composition comprising at least one member selected from the group consisting of (A) ascorbic acid and salts of ascorbic acid by incorporating (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, and adjusting (A) / (B) to 1-1000 and (A) / (D) to 0.01-5.

[0064] EXAMPLES Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples. In the tables, the unit of the amount of each component is % by mass.

[0065] Compositions for external use were prepared with the compositions shown in Tables 1 to 4. These compositions were then subjected to tests according to the respective test items.

[0066] [Test for Inhibition of Ascorbic Acid Precipitation] The topical compositions of the Examples and Comparative Examples were visually evaluated for the presence or absence of ascorbic acid precipitation when stored at low temperatures. Specifically, ascorbic acid was added to a mixed solution of various components other than ascorbic acid according to the formulation (mass%) of each topical composition, and the mixture was mixed and dissolved at room temperature to prepare a composition. The prepared composition was filled into a 50 mL transparent glass bottle, and allowed to stand at -8°C under light-shielded conditions for 1 to 2 weeks. Each test solution was visually observed to determine the presence or absence of crystal precipitation.

[0067] <Evaluation criteria> ◯: No precipitates were visible to the naked eye. ×: Precipitates were visible to the naked eye.

[0068] [pH Measurement] Specifically, the pH was measured at 25°C.

[0069] [Usage Experience Test 1] 10 μL of each of the topical compositions in the Examples and Comparative Examples was placed on the surface of a 1.3 cm square piece of artificial leather (Sappare, manufactured by Idemitsu Technofine Co., Ltd.), and spread in a circular motion 10 times within a specific area (2 cm × 2 cm) on the surface (0.5 N, 10 rotations at 100 rpm). Immediately thereafter, 10 μL of each liquid foundation was placed on top and spread in the same manner under the above conditions. Thereafter, the state of the foundation was visually confirmed, and the brightness was confirmed using Imagej by histogram. Here, so-called "makeup smearing" is a phenomenon in which the applied foundation becomes uneven on the skin, so the degree of smearing was quantified by comparing the standard deviation of brightness, and a comparative evaluation was performed.

[0070] <Evaluation criteria> ○: Standard deviation of brightness is less than 25, high uniformity, and almost no makeup smearing is observed. △: Standard deviation of brightness is 25 to 35, and although there are uneven parts, no three-dimensional masses of the preparation are observed. ×: Standard deviation of brightness is more than 35, and three-dimensional masses of the preparation are observed, so much so that makeup smearing is observed.

[0071] [Usage Sensation Test 2] 10 μL of each of the topical compositions from the Examples and Comparative Examples was dropped onto a 3 cm x 3 cm frame on the inner skin of the forearm and rubbed in in a circular motion. Evaluation was made based on the number of rubs required for penetration.

[0072] <Evaluation criteria> ◎: 10 times or less ○: More than 10 times but 15 times or less △: More than 15 times but 20 times or less ×: More than 20 times

[0073] The results of each evaluation are also shown in the table.

[0074] The results in Table 1 show that the compositions of the Examples have good solubility when prepared at room temperature and do not precipitate at all at a low temperature of -8°C, whereas the compositions of the Comparative Examples are difficult to prepare at room temperature and precipitate was observed after storage at a low temperature of -8°C for two weeks.

[0075] The results in Table 2 show that when trimethylglycine is added to a composition, makeup may smudge depending on the combination with polyol, but the compositions of the examples did not smudge makeup and were in excellent condition (Figure 1). The compositions of the examples also had extremely good skin penetration.

[0076]

[0077] The results in Table 3 show that the compositions of the Examples have good solubility when prepared at room temperature and do not precipitate at a low temperature of -8°C, whereas the compositions of the Comparative Examples show precipitation after storage at a low temperature of -8°C for one week.

[0078] From the results in Table 4, it was found that the compositions of the examples had good solubility when prepared at room temperature and did not precipitate at a low temperature of -8°C.

[0079] [Formulation Examples] Formulation examples are shown in Table 5 below. The formulation examples can be suitably used for lotions, beauty serums, etc. The contents in the formulation examples are in mass %.

[0080]

Claims

1. A composition for external use on the skin, comprising (A) at least one selected from the group consisting of ascorbic acid and salts of ascorbic acid, (B) a low molecular weight betaine, (C) water, and (D) dimethyl isosorbide, wherein (A) / (B) is 1-1000 and (A) / (D) is 0.01-5.

2. The topical skin composition according to claim 1, wherein the content of component (A) is 2 to 40% by mass.

3. A topical skin composition according to claim 1 or 2, wherein component (B) is trimethylglycine.

4. A topical skin composition according to claim 1 or 2, wherein the content of component (D) is 1 to 15% by mass.

5. A topical skin composition according to claim 1 or 2, further comprising (E) 15% by mass or more of a diol having 3 carbon atoms.

6. A topical skin composition according to claim 1 or 2, having a pH of 4.5 or below.

7. A topical skin composition according to claim 1 or 2, further comprising (F) a lower alcohol.

8. A method for imparting low-temperature stability to a composition comprising at least one member selected from the group consisting of (A) ascorbic acid and salts of ascorbic acid, by adding (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, and by adjusting (A) / (B) to 1-1000 and (A) / (D) to 0.01-5.

9. A method for imparting an improved feeling to a composition containing at least one member selected from the group consisting of (A) ascorbic acid and salts of ascorbic acid, by adding (B) a low-molecular-weight betaine, (C) water, and (D) dimethyl isosorbide, and by adjusting (A) / (B) to 1-1000 and (A) / (D) to 0.01-5.

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