JP4152301B2 - Oil-in-water emulsion composition - Google Patents

Description

The present invention relates to oil-in-water emulsified composition for use as a skin Hadagaiyo agent. More particularly, the present invention relates to an oil-in-water emulsion composition that is excellent in whitening effect and has good temporal stability and usability.

  “Whitening”, which means white and beautiful skin, is one of the most important themes in external preparations for skin, especially cosmetics.

  In cosmetics intended for this “whitening”, as a whitening component, for example, vitamin C, its derivatives, arbutin and the like are blended. Searches for whitening components have become increasingly popular in recent years, and as one of the results, alkoxysalicylic acids have been proposed as components having an excellent whitening effect (Patent Document 1).

  However, when alkoxysalicylic acids are blended in an oil-in-water emulsion composition, there is a problem that storage stability, particularly temperature (high temperature / low temperature) stability, is poor, and separation or separation tends to occur over time.

  In addition, an oil-in-water emulsion composition having improved usability and high-temperature stability by including α-gel in the outer phase has been proposed by the present applicant (Patent Document 2), but it contains alkoxysalicylic acids. There has been no consideration or research on the stability of these cases.

Japanese Patent Laid-Open No. 6-40886 JP 2001-348325 A

  The present invention has been made in order to solve the above-mentioned problems of the prior art, and its purpose is to provide an oil-in-water solution having good emulsification stability with time and excellent usability in a system containing alkoxysalicylic acids. It is in providing a type | mold emulsion composition.

  In order to achieve the above object, the present invention provides an oil-in-water emulsion composition comprising the following components (A) to (E) and satisfying the following conditions (i) to (iv).

  Component (A): Alkoxysalicylic acid represented by the following general formula (I) or a salt thereof.

(In the formula (I), R represents a lower alkyl group having 1 to 6 carbon atoms ).

  (B) Component: Long chain acyl sulfonate type anionic surfactant represented by the following general formula (II).

_{R 1 CO-a- (CH 2} ) n SO 3 M 1 (II)

(In the formula (II), R ₁ CO— represents a saturated or unsaturated fatty acid residue (acyl group) having an average carbon number of 10 to 22; a represents —O— or —NR ₂ — (where R ₂ Represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms); M ₁ represents a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic amine; n represents 1 to 3 Indicates an integer).

(C) component: The following (C ₁ ) component and (C ₂ ) component.
Component (C ₁ ): stearyl alcohol and / or behenyl alcohol.
(C ₂₎ component: with a straight or branched alkyl chain, higher aliphatic carbon atoms 12 to 22

  (D) Component: Water.

  (E) component: Oil content.

Condition (i): (B) forming a component and gel in the (C ₁₎ component and the (D) component transition temperature of the gel formed is 60 ° C. or higher.

  Condition (ii): The blending amount of the component (B) forming the gel is 0.1% by mass or more and less than 1.0% by mass with respect to the total amount of the oil-in-water emulsion composition.

Condition (iii): The molar ratio of the blending amount of the component (B) and the component (C ₁ ) forming the gel is 1: 3.

Condition (iv): I do not want to participate in the formation of the gel (C ₂₎ containing components or amphiphile, from 0.98745 to 3.50841 weight amount thereof is against the oil-in-water emulsion total amount of the skin treatment composition %.

  The present invention also provides the oil-in-water emulsion composition, which is a creamy or milky skin external preparation.

The present invention, while taking excellent whitening effect by Arco key Shisarichiru acid or a salt thereof, good oil-in-water emulsion composition of the stability and usability is provided.

  The alkoxysalicylic acid of component (A) used in the present invention is represented by the following general formula (I), and the hydrogen atom at the 3-position, 4-position or 5-position of salicylic acid is substituted with an alkoxy group (—OR). Is a salicylic acid compound.

In the general formula (I), the alkyl group constituting the alkoxy group (-OR) (R) is a lower alkyl group carbon atom number of 1-6. Both straight and branched chains are included. Specifically, a methyl group (corresponding alkoxy group-OR: methoxy group), ethyl group (same: ethoxy group), propyl group (same: propoxy group), isopropyl group (same: isopropoxy group), butyl group ( I.e., butoxy group) and isobutyl group (i.e., isobutoxy group), but are not limited thereto.

  Specific examples of the alkoxysalicylic acid represented by the general formula (I) include 3-methoxysalicylic acid (2-hydroxy-3-methoxybenzoic acid), 3-ethoxysalicylic acid (2-hydroxy-3-ethoxybenzoic acid), 4-Methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid), 4-Ethoxysalicylic acid (2-hydroxy-4-ethoxybenzoic acid), 4-Propoxysalicylic acid (2-hydroxy-4-propoxybenzoic acid), 4-Isoproxysalicylic acid (2-hydroxy-4-isopropoxybenzoic acid), 4-butoxyproxysalicylic acid (2-hydroxy-4-buthoxybenzoic acid), 5-methoxysalicylic acid (2-hydroxy-5-methoxybenzoic acid), 5-ethoxysalicylic acid (2-hydroxy) -5-ethoxybenzoic acid), 5-propoxysalicylic acid (2-hydroxy-5-propoxybenzoic acid) and the like.

  Alkoxysalicylic acid is a known substance. For example, 5-methoxysalicylic acid can be easily synthesized by the methods described in “Beil” and 10227, and 4-methoxysalicylic acid in “Beil” and 10379, respectively. Further, it is commercially available as a reagent from Aldrich (Germany) and the like, and it is also possible to use it.

  Alkoxysalicylic acid that can be blended in the emulsion composition of the present invention includes a salt thereof. The type of the salt is not particularly limited as long as it is a pharmaceutically acceptable salt, for example, alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt, Examples include salts such as ammonium salts and amino acid salts.

  (A) A component can mix | blend 1 type (s) or 2 or more types. The blending amount of the component (A) should be appropriately selected according to the specific dosage form of the external preparation for skin and other blending components, and is not particularly limited. Is preferably 0.001 to 20.0% by mass, particularly preferably 0.01 to 10.0% by mass, based on the whole agent. If the amount is less than 0.001% by mass, it is difficult to sufficiently exert the whitening effect. On the other hand, even if the amount exceeds 20.0% by mass, the improvement of the whitening effect commensurate with the increase in the amount is hardly recognized. On the contrary, it tends to promote the generation of a sticky feeling of use, which is not preferable.

  The long-chain acyl sulfonate type anionic surfactant as the component (B) in the present invention is represented by the following general formula (II).

_{R 1 CO-a- (CH 2} ) n SO 3 M 1 (II)

In the general formula (II), R ₁ CO- represents a saturated or unsaturated fatty acid residue having an average carbon number from 10 to 22 (an acyl group). As R ₁ CO, C ₁₁ H ₂₃ CO, C ₁₂ H ₂₅ CO, C ₁₃ H ₂₇ CO, C ₁₄ H ₂₉ CO, C ₁₅ H ₃₁ CO, C ₁₆ H ₃₃ CO, C ₁₇ H ₃₅ CO, coconut fatty acid residue Groups, palm palm fatty acid residues and the like. R ₁ CO is more preferably one having an average carbon atom number of 12 to 22 from the viewpoint of safety and the like.

a represents —O— or —NR ₂ — (wherein R ₂ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms). These are electron donating groups. a is preferably —O—, —NH—, or —N (CH ₃ ) —.

M ₁ represents a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic amine. Examples of M ₁ include lithium, potassium, sodium, calcium, magnesium, ammonium, monoethanolamine, diethanolamine, triethanolamine, sodium taurine, sodium N-methyltaurine, and the like.

  n represents an integer of 1 to 3.

  As the component (B), a compound in which a represents —O— in the above general formula (II), that is, as a long-chain acyl isethionate type anionic surfactant, cocoyl isethionate, stearoyl isethionate , Lauryl isethionate, myristoyl isethionate and the like.

  In the general formula (II), a compound in which a represents —NH—, that is, a long-chain acyl taurine salt type anionic surfactant includes N-lauroyl taurine salt, N-cocoyl-N-ethanol taurine salt, N -Myristoyl taurine salt, N-stearoyl taurine salt and the like are exemplified.

In the above general formula (II), a compound in which a represents —N (CH ₃ ) —, ie, a long-chain acylmethyl taurine salt type anionic surfactant, includes N-lauroyl-N-methyl taurate, N— Examples include palmitoyl-N-methyltaurine salt, N-stearoyl-N-methyltaurine salt, N-cocoyl-N-methyltaurine salt and the like.

  Among these, N-stearoyl-N-methyltaurine salt is particularly preferable as the component (B). (B) component can use 1 type (s) or 2 or more types.

The component (C) is composed of a component (C ₁ ) and a component (C ₂ ). The component (C ₁ ) is stearyl alcohol and / or behenyl alcohol. Higher aliphatic alcohols as (C ₂₎ component has a straight or branched alkyl chain, an aliphatic alcohol having a carbon number of 12 to 22. Examples of the component (C) include linear alcohols such as lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetostearyl alcohol, hardened rapeseed oil alcohol, jojoba alcohol, and monostearyl glycerol ether (batyl alcohol). ), 2-decyltetradecinol, lanolin alcohol, cholesterol, phytosterol, hexyldodecanol, isostearyl alcohol, octyldodecanol and other branched chain alcohols. In the present invention, a linear alcohol is preferred. (C ₂₎ component Ru can be used either alone or in combination.

  (C) A component is mix | blended so that it may be sufficient quantity to form the gel mentioned later and a surplus may be contained in a specific quantity system.

  Water as the component (D) used in the present invention forms an outer phase. Although the compounding quantity of (D) component mix | blended with this invention is suitably determined according to a product, 40-95 mass% is preferable with respect to this invention oil-in-water emulsion composition whole quantity.

In the present invention, a gel is formed with the component (B), the component (C) and the component (D). It is necessary that the gel has a transition temperature of 60 ° C. or higher, more preferably a transition temperature of 65 ° C. or higher. When the gel transition temperature is less than 60 ° C., the temperature stability of the system is lowered, and creaming may occur at a high temperature, which is not preferable. In the gel formation, stearyl alcohol and / or behenyl alcohol are involved as the (C ₁ ) component.

  This gel is composed of α-gel. An α-gel is an aggregate formed in water by a higher aliphatic alcohol and a hydrophilic surfactant. The α-structure (Shoji Fukushima, “Physical Chemistry of Cetyl Alcohol”, Fragrance Journal, 1992) Means a gel to take.

  The blending amount of the component (B) that forms the gel needs to be 0.1% by mass or more and less than 1.0% by mass with respect to the total amount of the oil-in-water emulsion composition. If it is less than 0.1% by mass, the temperature stability of the system may be lowered and creaming may occur. On the other hand, if it is 1.0% by mass or more, the feeling during use is heavy and satisfactory usability is obtained. Absent.

  Moreover, in the said gel, the compounding ratio of (B) component which forms a gel, and (C) component is 1: 3 by molar ratio.

  In the present invention, the gel means an aggregate comprising a lamellar structure of the component (B) and the component (C) formed in the aqueous phase. It can be confirmed by DSC (differential scanning calorimeter) that the component (B) and the component (C) form an aggregate. That is, the endothermic peak of the sample in which both the component (B) and the component (C) are mixed and dispersed in water is the endothermic peak obtained in the sample in which the components (B) and (C) are each dissolved or dispersed in water alone. A single endothermic peak is shown on the higher temperature side than the peak, but when the component ratio of component (C) is low (component (C) is insufficient), the temperature of the endothermic peak of the aggregate is low, and the temperature is After the composition ratio of the component (C) increases and the aggregate structure is completed, when the component (C) becomes excessive, it becomes constant and an excessive peak of the component (C) appears.

Here, when the aggregate is formed by a hydrophilic surfactant having a single alkyl chain and a higher alcohol having a single alkyl chain, the composition with which the aggregate structure is completed is hydrophilic surfactant 1 It is known that there are 3 moles of higher alcohol per mole. In the present invention, it further contains an excess (C) component (hereinafter also referred to as “(C ₂ ) component”) that is not involved in the formation of the gel, or an amphiphile, and the content thereof is an oil-in-water type. It is 0.5-10 mass% with respect to the emulsion composition whole quantity.

Description of involved such have (C ₂₎ component in the formation of the gel is involved in the formation of the gel component (C) (hereinafter, also referred to as "(C ₁₎ component") is the same as described. Usually, the same C ₂ component as the C ₁ component is added in excess. That is, since the blending molar ratio of the component (B) and the component (C ₁ ) forming the gel is 1: 3, the content of the component (C ₁ ) involved in α-gel formation is the amount of the component (B). It is a value obtained by multiplying the number obtained by multiplying the number of moles by 3 by the average molecular weight of the component (C ₁ ). Therefore, this is greater than the value excess (C ₂₎ component is blended, excess must be 0.5 to 10 mass% relative to oil-in-water emulsion composition the total amount. In the present invention, the excess is particularly set to 0.98745 to 3.50841% by mass.

An amphiphilic substance other than the component (C ₂ ) may be blended, preferably an amphiphilic substance having a melting point of 55 ° C. or higher, more preferably 60 ° C. or higher. When this melting point is less than 55 ° C., the temperature stability of the system is lowered depending on the formulation, and creaming may occur.

In the present invention, the amphiphilic substance is a substance other than the component (C) and has a surface activity, but itself has a strong hydrophobicity and does not have a surface activity as a general surfactant. Examples include higher fatty acids, monoglycerides, glycerol monoalkyl ethers, monoalkylamines, and sterols. Specific examples include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, 12-hydroxystearic acid, undecylenic acid, tolic acid, isostearic acid, linoleic acid, linolenic acid, eicosapentaenoic acid. (EPA), higher fatty acids such as docosahexaenoic acid (DHA); sterols such as cholesterol and phytosterol; monoglyceride, glycerol monoalkyl ether, monoalkylamine and the like, but are not limited to these examples. When both the (C ₂ ) component and the amphiphilic substance not involved in gel formation are blended, the total blended amount of both is 0.5 to 10% by mass with respect to the total amount of the oil-in-water emulsion composition. Like that. In the present invention, the blending amount is particularly 0.98745 to 3.50841% by mass.

If the blending amount of the (C ₂ ) component not involved in gel formation (the total blending amount of both components when blending an amphiphilic substance other than the (C ₂ ) component) is less than 0.5% by mass, excessive (C ₂ ) The amount of crystals of the component or amphiphile is small, and sufficient high temperature stability cannot be maintained. On the other hand, if the blending amount is more than 10% by mass, the hardness becomes too high depending on the composition, and the feeling in use becomes worse.

  In the present invention, in addition to the essential component (B) that forms a gel, a new oily nonionic surfactant, a cationic surfactant, an anionic surfactant, or an amphoteric surfactant is added. As long as the effects of the invention are not impaired, they can be blended. In addition, the (B) component which does not participate in formation of a gel may exist.

  The oil as the component (E) blended in the oil-in-water emulsion composition of the present invention can be selected from those generally used in cosmetics within a range not impairing stability.

  Desirable oils are preferably nonpolar oils such as hydrocarbon oils or silicone oils. Nonpolar oil means that the molecular structure does not contain hydratable functional groups such as ether bonds, ester bonds, amide bonds, hydroxyl groups, and carboxyl groups.

  As the hydrocarbon oil, liquid paraffin, squalane, squalene, paraffin, isoparaffin, ceresin and the like can be used.

  Examples of the silicone oil include chain silicones such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylhydrogenpolysiloxane; cyclic silicones such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane; Examples thereof include silicone resin and silicone rubber forming a network structure.

  About a polar oil component, a small amount can be mix | blended in the range which does not impair stability. Polar oils include liquid oils and ester oils.

  Liquid oils include linseed oil, camellia oil, macadamia nut oil, corn oil, mink oil, olive oil, avocado oil, sasanqua oil, castor oil, safflower oil, jojoba oil, sunflower oil, almond oil, rapeseed oil, sesame oil, large There are bean oil, peanut oil, triglycerin, glycerin trioctanoate, glycerin triisopalmitate and the like.

  Ester oils include cetyl octanoate, hexyl laurate, isopropyl myristate, octyl palmitate, isocetyl stearate, isopropyl isostearate, octyl isopalmitate, isodecyl oleate, glyceryl tri-2-ethylhexanoate, tetra-2-ethyl There are pentaerythritol hexanoate, 2-ethylhexyl succinate, diethyl sebacate and the like.

  (E) Although the compounding quantity of a component is suitably determined according to a product, it is preferable that it is 3-50 mass% with respect to the oil-in-water type emulsion composition whole quantity. In the present invention, the component (E) does not include the component (C) which is an essential component and an amphiphilic substance.

  In the oil-in-water emulsion composition, the present invention containing the essential components forms a gel composed of (B) component- (C) component- (D) component. Since it is less than 1% by mass with respect to the total amount of the emulsified composition, the amount of gel formation is small, and it has a refreshing and light usability compared to conventional emulsions or creams. In addition, since an excessively high melting point (C) component crystal coexists with the gel, it is possible to sufficiently thicken and solidify and prevent creaming even though the gel is small. According to the present invention, it is possible to provide an oil-in-water emulsion composition having good stability over time and good usability despite a small amount of surfactant to be blended.

  The oil-in-water emulsified composition of the present invention can produce oil-in-water emulsified compositions mainly used as a skin external preparation for cosmetics, pharmaceuticals, quasi-drugs and the like by a conventional method. It is preferably used as an external preparation for skin which takes the form of an oil-in-water cream form to be formed in principle. In the external preparation for skin, general medicinal components and drug components can be blended depending on the specific purpose as long as the intended effects of the present invention are not impaired.

  As the medicinal component, for example, when the skin external preparation of the present invention is used as a suncare product, a benzoic acid-based ultraviolet absorber such as paraminobenzoic acid; an anthranilic acid-based ultraviolet absorber such as methyl anthranilate; , Salicylic acid UV absorbers such as homomenthyl salicylate; isopropyl paramethoxycinnamate, octyl paramethoxycinnamate, 2-ethylhexyl paramethoxycinnamate, glyceryl mono-2-ethylhexanoate diparamethoxycinnamate, [4-bis (trimethylsiloxane) methylsilyl-3-methylbutyl] -cinnamic acid-based UV absorbers such as 3,4,5-trimethoxycinnamic acid ester; 2,4-dihydroxybenzophenone, 2-hydroxy-4- Methoxybenzophenone, 2-hydroxy- Benzophenone ultraviolet absorbers such as methoxybenzophenone-5-sulfonic acid, sodium 2-hydroxy-4-methoxybenzophenone-5-sulfonate; urocanic acid, ethyl urocanate, 2-phenyl-5-methylbenzoxazole, 2- Ultraviolet absorbers such as (2′-hydroxy-5′-methylphenyl) benzotriazole and 4-tert-butyl-4′-methoxydibenzoylmethane can be blended in the skin external preparation of the present invention.

  In order to impart a moisturizing effect to the skin external preparation of the present invention, polyethylene glycol, propylene glycol, dipropylene glycol, glycerin, diglycerin, 1,3-butylene glycol, hexylene glycol, xylitol, sorbitol, maltitol, maltose, D-mannit, water candy, glucose, fructose, lactose, sodium chondroitin sulfate, sodium hyaluronate, sodium adenosine phosphate, sodium lactate, bile salt, pyrrolidone carboxylic acid, glucosamine, cyclodextrin, etc. Can do.

  Further, as medicinal ingredients, vitamins having uses other than oil-soluble antioxidants; hormones such as estradiol and ethinyl estradiol; amino acids such as arginine, aspartic acid, cystine, cysteine, methionine, serine, leucine, and tryptophan; allantoin, Anti-inflammatory agents such as azulene and glycyrrhetinic acid; whitening agents such as arbutin; astringents such as zinc oxide and tannic acid; refreshing agents such as L-menthol and camphor; combined with sulfur, lysozyme chloride, pyridoxine hydrochloride, γ-oryzanol can do.

  Furthermore, various extracts having various medicinal effects can be blended. In other words, Dokudami Extract, Oat Extract, Merilot Extract, Oyster Extract, Licorice Extract, Peonies Extract, Soap Extract, Loofah Extract, Kina Extract, Yukinoshita Extract, Clara Extract, Licorice Extract, Fennel Extract, Primrose Extract, Rose Extract, Giant Extract, Lemon Extract , Sicon extract, aloe extract, ginger root extract, eucalyptus extract, horsetail extract, sage extract, thyme extract, tea extract, seaweed extract, cucumber extract, clove extract, raspberry extract, melissa extract, carrot extract, maroni extract, peach extract, peach leaf extract , Mulberry extract, cornflower extract, clam extract, placenta extract, thymus extract, silk extract, etc. can be blended in the skin external preparation of the present invention. .

  In addition, the medicinal component which can be mix | blended with the skin external preparation of this invention is not limited to these medicinal components. Moreover, the above-mentioned medicinal ingredients can be blended as appropriate in combination with two or more kinds of the medicinal ingredients, depending on the purpose, in addition to blending alone with the skin external preparation of the present invention.

  As the base component of the present invention, in addition to the above essential components, a known base component can be blended in a range not impairing the effects of the present invention, depending on the specifically desired form.

  For example, lower alcohols such as ethanol, propanol, and isopropanol; and sterols such as cholesterol, sitosterol, phytosterol, and lanosterol can be blended in the skin external preparation of the present invention.

  In addition, plant-based water solutions such as arabia gum, tragacanth gum, galactan, guar gum, carob gum, caraya gum, carrageenan, pectin, agar, quince seed (malmello), alge colloid (gypsum extract), starch (rice, corn, potato, wheat), glycyrrhizic acid, etc. Water-soluble polymers such as xanthan gum, dextran, succinoglucan, and bullulan; animal-based water-soluble polymers such as collagen, casein, albumin, and gelatin; starches such as carboxymethyl starch and methylhydroxypropyl starch Water-soluble polymer: methylcellulose, nitrocellulose, ethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, sodium cellulose sulfate, hydroxypropy Cellulose-based water-soluble polymers such as cellulose, sodium carboxymethyl cellulose (CMC), crystalline cellulose, cellulose powder; alginic acid-based water-soluble polymers such as sodium alginate and propylene glycol alginate; polyvinyl alcohol, polyvinyl methyl ether, polyvinyl pyrrolidone, carboxy Vinyl-based water-soluble polymers such as vinyl polymers (Carbopol); Polyoxyethylene-based water-soluble polymers such as polyethylene glycol 20,000, 4,000,000, and 600,000; Polyoxyethylene polyoxypropylene Copolymer water-soluble polymers such as polymers; water-soluble acrylic polymers such as sodium polyacrylate, polyethyl acrylate, polyacrylamide, polyethyleneimine, cationic polymers Etc. are exemplified. In addition, inorganic water-soluble polymers such as bentonite, silicate AlMg (beegum), laponite, hectorite, and silicic anhydride are also included.

  Furthermore, sequestering agents such as alanine, sodium edetate, sodium polyphosphate, sodium metaphosphate, phosphoric acid; 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1,3- Neutralizing agents such as propanediol, potassium hydroxide, sodium hydroxide, L-arginine, L-lysine, triethanolamine, sodium carbonate; lactic acid, citric acid, glycolic acid, succinic acid, tartaric acid, dl-malic acid, carbonic acid Antioxidants such as potassium, sodium hydrogen carbonate, ammonium hydrogen carbonate and other pH adjusters can be blended in the skin external preparation of the present invention.

  In addition, antibacterial agents such as benzoic acid, salicylic acid, coalic acid, paraoxybenzoic acid ester, parachloromethcresol, hexachlorophene, benzalkonium chloride, chlorhexidine chloride, trichlorocarbanide, photosensitizer, phenoxyethanol, paraben, etc. It can mix | blend in an agent.

  Moreover, a suitable fragrance | flavor, pigment | dye, etc. can be mix | blended with this invention skin external preparation in the range which does not impair the effect of this invention as needed.

  In addition, said base component is an illustration and the base component which can be mix | blended with these base components in this invention external preparation is not limited.

  These base components can be appropriately combined and blended in the skin external preparation of the present invention according to a prescription according to a desired form.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Unless otherwise specified, the blending amount is expressed in mass% with respect to the system in which the component is blended.

(Examples 1-4, Comparative Examples 1-4)
The oil-in-water emulsion compositions having the compositions of Examples and Comparative Examples shown in the following Table 1 were prepared, and the stability with time and usability were evaluated according to the following evaluation criteria using this as a sample. The results are also shown in Table 1.

(Examples 5-7, Comparative Examples 5-7)
An oil-in-water emulsion composition having the compositions of Examples and Comparative Examples shown in Table 2 below was prepared, and the stability over time and usability were evaluated according to the following evaluation criteria using this as a sample. The results are also shown in Table 2.

(Manufacturing method)
In Tables 1 and 2, the water phase component and the oil phase component in the formulation were mixed, and the oil phase heated to 80 ° C was added to the 80 ° C aqueous phase, and the mixture was uniformly emulsified with a homomixer and dissolved in water. The drug component was added and stirred, and cooled to room temperature to prepare an oil-in-water emulsion composition.

In Tables 1 and 2, “(C) component mole number ^{(* 1)} ” and “(B) component or surfactant mole number ^{(* 1)} ” are all in 100 g of the oil-in-water emulsion composition. The number of moles contained in is shown.

  The component (C) (% by mass) involved in the gel is represented by the number of moles of the component (B) ((other) surfactant in the comparative example) × 3 × (C) average molecular weight. In the case of the component (C) having a single straight chain alkyl chain and the component (B) of a single straight chain alkyl chain ((other) surfactant in the comparative example), 3 parts per mole of the surfactant Since it is known that the mole (C) component associates to form a gel, the amount of the (C) component not involved in the gel can be determined by calculation.

  Component (C) not involved in gel = blending amount of component (C)-blending amount of component (C) involved in gel.

[Low temperature and high temperature stability]
The state after each sample was stored at −20 ° C. and 50 ° C. for 1 month was visually observed and evaluated according to the following criteria.
(Evaluation criteria)
○: No change in state △: Slight separation of aqueous phase is observed ×: Aqueous phase is considerably separated

[Usability]
Each material was evaluated according to the following criteria.
(Evaluation criteria)
○: Light use feeling △: Somewhat heavy use feeling ×: Heavy use feeling

(Manufacturing method)
Mix the water phase component and oil phase component in the formulation, add the oil phase heated to 80 ° C to the 80 ° C water phase, uniformly emulsify with a homomixer, and then add the drug component dissolved in water. The mixture was stirred and cooled to room temperature to prepare an oil-in-water emulsion composition.

  In Table 1, Examples 1 to 4 and Comparative Examples 1 to 4 are examples in which the blending amounts of the component (B) and the component (C) were examined. In Examples 1 to 4, in which the blending amounts of the component (B) and the component (C) satisfy the requirements of the present invention, the low-temperature and high-temperature stability and usability were good, but excessive (not involved in gel formation) Comparative Example 1 in which the blending amount of component C) is less than 0.5% by mass is inferior in high-temperature stability, and Comparative Example 2 in which the blending amount of component (B) is less than 0.1% by mass is low temperature and Comparative Example 3 in which the compounding amount of the excess component (C) is inferior to high-temperature stability and does not participate in gel formation exceeds 10% by mass, and the compounding amount of component (B) is 1.0% by mass or more. 4 was inferior in usability.

  In Table 2, Examples 5 to 7 according to the present invention were able to obtain the effects of the present invention in any of low temperature stability, high temperature stability, and usability. Comparative Example 5 is an example in which N-stearoyl-L-glutamate monosodium is used as a surfactant instead of the component (B), and Comparative Example 6 is a nonionic surfactant instead of the component (B). In this example, the surfactant POE (20) stearyl ether was used, but in all cases, the low-temperature stability was poor. Comparative Example 7 is an example in which a blending formulation of (B) component- (C) component- (D) component was set so that the gel transition temperature was less than 60 ° C., and the high-temperature stability was poor.

The oil-in-water emulsified composition according to the present invention is applied to use as a skin external preparation having excellent whitening effect and good stability over time and usability.

Claims (2)

An oil-in-water emulsified skin external preparation containing the following components (A) to (E) and satisfying the following conditions (i) to (iv).
Component (A): Alkoxysalicylic acid represented by the following general formula (I) or a salt thereof.

(In the formula (I), R represents a lower alkyl group having 1 to 6 carbon atoms).
(B) Component: Long chain acyl sulfonate type anionic surfactant represented by the following general formula (II).
_{R 1 CO-a- (CH 2} ) n SO 3 M 1 (II)
(In the formula (II), R ₁ CO— represents a saturated or unsaturated fatty acid residue (acyl group) having an average carbon number of 10 to 22; a represents —O— or —NR ₂ — (where R ₂ Represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms); M ₁ represents a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic amine; n represents 1 to 3 Indicates an integer).
(C) component: The following (C ₁ ) component and (C ₂ ) component.
Component (C ₁ ): stearyl alcohol and / or behenyl alcohol.
(C ₂₎ component: with a straight or branched alkyl chain, higher aliphatic alcohols carbon atoms 12 to 22.
(D) Component: Water.
(E) component: Oil content.
Condition (i): (B) forming a component and gel in the (C ₁₎ component and the (D) component transition temperature of the gel formed is 60 ° C. or higher.
Condition (ii): The blending amount of the component (B) forming the gel is 0.1% by mass or more and less than 1.0% by mass with respect to the total amount of the oil-in-water emulsified skin external preparation.
Condition (iii): The molar ratio of the blending amount of the component (B) and the component (C ₁ ) forming the gel is 1: 3.
Condition (iv): I do not want to participate in the formation of the gel (C ₂₎ containing components or amphiphile, from 0.98745 to 3.50841 weight amount thereof is against the oil-in-water emulsion total amount of the skin treatment composition %.   The oil-in-water emulsified skin external preparation according to claim 1, which is a creamy or milky external preparation for skin.