Emulsion composition

Abstract

To provide a cubic liquid crystal emulsified composition having excellent separation stability.SOLUTION: An emulsified composition comprises (A) an ether-based nonionic surfactant and (B) a higher fatty acid. The composition is excellent in separation stability.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an emulsion composition. More specifically, the present invention relates to an emulsion composition having excellent separation stability. [Background technology]

[0002] Emulsion compositions are advantageous in terms of efficacy and usability, and are widely used as external compositions. Emulsion compositions include those that use liquid crystals such as lamellar liquid crystals, reverse hexagonal liquid crystals, and cubic liquid crystals, and each of these forms a unique emulsion system.

[0003] Cubic liquid crystals are known as highly viscous liquid crystals, and have begun to attract attention from the viewpoint of the penetration and absorption of active ingredients (Non-Patent Documents 1 and 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Patrick T. Spicer, et. al. (2001), “Novel Process for Producing Cubic Liquid Crystalline Nanoparticles (Cubosomes)”, Langmuir, 17, 5748-5756. [Non-patent document 2] Jun Wan, (2018), Phytantriol-based lyotropic liquid crystal as a transdermal delivery system. European Journal of Pharmaceutical Sciences, 125 : 93-101. Summary of the Invention [Problem to be solved by the invention]

[0005] However, techniques for improving the separation stability of cubic liquid crystal emulsion compositions have not been fully investigated.

[0006] Therefore, an object of the present invention is to provide a formulation technique that improves the separation stability of a cubic liquid crystal emulsion composition. [Means for solving the problem]

[0007] The present inventors have conducted extensive research and found that a cubic liquid crystal emulsion composition with excellent separation stability can be obtained by combining an ether-based nonionic surfactant with a higher fatty acid. Based on this finding, further research has led to the completion of the present invention.

[0008] That is, the present invention provides the following aspects. Item 1. An emulsion composition containing (A) an ether-based nonionic surfactant and (B) a higher fatty acid. Item 2. The emulsion composition according to Item 1, wherein the component (A) is a polyoxyalkylene alkyl ether, a polyoxyalkylene alkenyl ether, and / or a polyoxyalkylene steryl ether. Item 3. The emulsion composition according to Item 1 or 2, wherein the component (A) is a polyoxyalkylene alkyl ether and a polyoxyalkylene alkenyl ether. Item 4. The emulsion composition according to any one of Items 1 to 3, wherein the total HLB value of the component (A) is 11 to 18. Item 5. The emulsion composition according to any one of Items 1 to 4, wherein the content of the component (A) is 3 to 25% by weight. Item 6. The emulsion composition according to any one of Items 1 to 5, wherein the component (B) has 14 or more carbon atoms. Item 7. The emulsion composition according to any one of Items 1 to 6, wherein the content of the component (B) is 0.1 to 1 part by weight per 1 part by weight of the component (A). [Effects of the Invention]

[0009] According to the present invention, a cubic liquid crystal emulsion composition having excellent separation stability can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0010] The emulsion composition of the present invention is characterized by containing (A) an ether-based nonionic surfactant (hereinafter also referred to as "component (A)") and (B) a higher fatty acid (hereinafter also referred to as "component (B)"). The emulsion composition of the present invention will be described in detail below.

[0011] (A) Ether-based nonionic surfactants The emulsion composition of the present invention contains an ether-based nonionic surfactant as component (A). In the present invention, the ether-based nonionic surfactant refers to a nonionic surfactant having a structure in which a polyoxyalkylene group serving as a hydrophilic moiety and a hydrocarbon group serving as a hydrophobic moiety are ether-bonded.

[0012] Examples of the alkylene oxide in the polyoxyalkylene group include alkylene oxides having 2 to 5 carbon atoms, preferably 2 to 3 carbon atoms, such as ethylene oxide, propylene oxide, and butylene oxide. These alkylene oxides may be contained alone or in combination in the ether-based nonionic surfactant molecule. The number of moles of these alkylene oxides added is, for example, 5 to 40, more preferably 7 to 36.

[0013] Specific examples of ether-based nonionic surfactants include polyoxyalkylene alkyl ethers (nonionic surfactants having a structure in which a polyoxyalkylene group and an alkyl group are ether-bonded), polyoxyalkylene alkenyl ethers (nonionic surfactants having a structure in which a polyoxyalkylene group and an alkenyl group are ether-bonded), and polyoxyalkylene steryl ethers (nonionic surfactants having a structure in which a polyoxyalkylene group and a steryl group are ether-bonded).

[0014] The alkyl group in the polyoxyalkylene alkyl ether may be a linear or branched alkyl group having 10 to 24 carbon atoms. Specific examples of the alkyl group include a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl (cetyl) group, a heptadecyl group, an octadecyl (stearyl) group, a nonadecyl group, an eicosyl group, a docosyl group, a tetracosyl group, and a decyltetradecyl group. These polyoxyalkylene alkyl ethers may be used alone or in combination. Among these polyoxyalkylene alkyl ethers, from the viewpoint of further improving separation stability, preferred are linear alkyl groups having 12 to 22 carbon atoms (more preferably 14 to 20 carbon atoms, even more preferably 16 to 18 carbon atoms) and branched alkyl groups having 14 to 24 carbon atoms (more preferably 18 to 24 carbon atoms, even more preferably 22 to 24 carbon atoms). Preferred specific examples include a hexadecyl (cetyl) group, a heptadecyl group, an octadecyl (stearyl) group, and a decyltetradecyl group, and a more preferred example is an octadecyl (stearyl) group.

[0015] The alkenyl group in the polyoxyalkylene alkenyl ether may be a linear or branched alkenyl group having 10 to 24 carbon atoms, preferably 12 to 22 carbon atoms, and more preferably 14 to 20 carbon atoms. Specific examples of the alkenyl group include a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl (oleyl) group, a nonadecenyl group, an icosenyl group, a henicosenyl group, a docosenyl group, a tricosenyl group, and a tetracosenyl group. These alkenyl groups have a double bond at any position. These polyoxyalkylene alkenyl ethers may be used alone or in combination. Among these polyoxyalkylene alkenyl ethers, from the viewpoint of further improving separation stability, a linear alkenyl group having preferably 12 to 22 carbon atoms, more preferably 16 to 20 carbon atoms, is used. Preferred specific examples include a hexadecenyl group, a heptadecenyl group, an octadecenyl (oleyl) group, a nonadecenyl group, and an icosenyl group, and a more preferred example is an octadecenyl (oleyl) group.

[0016] Examples of the steryl group in the polyoxyalkylene steryl ether include a cholesteryl group (cholesterol residue), a cholestaryl group (cholestanol residue), a stigmasteryl group (stigmasterol residue), a β-sitosteryl group (β-sitosterol residue), a lanosteryl group (lanosterol residue), an ergosteryl group (ergosterol residue), a phytosteryl group (phytosterol residue), and hydrogenated groups thereof. These polyoxyalkylene steryl ethers may be used alone or in combination. Among these polyoxyalkylene steryl ethers, a phytosteryl group (phytosterol residue) is preferred from the viewpoint of further improving separation stability.

[0017] In the present invention, the component (A) may be one of the above polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, and polyoxyalkylene steryl ethers, or a combination of two or more of them. Among the above polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, and polyoxyalkylene steryl ethers, a combination of polyoxyalkylene alkyl ethers and polyoxyalkylene alkenyl ethers is preferred.

[0018] In the present invention, the total HLB value of component (A) is not particularly limited, but may be, for example, 11 to 18. Here, the HLB value generally indicates the affinity of a surfactant to water and oil, and in the present invention, the HLB value determined by the Griffin method is used. The total HLB value refers to the sum of the individual HLB values ​​of all compounds used in component (A), multiplied by the weight proportion of each compound when the total weight of component (A) is 1. For example, when component (A) contains only compound a, which has an HLB value of 15, the total HLB value is 15 (= 15 × 1). When component (A) contains compound a1, which has an HLB value of 10, and compound a2, which has an HLB value of 18, in a weight ratio of a1:a2 = 4:6, the total HLB value is 14.8 (= 10 × 0.4 + 18 × 0.6). From the viewpoint of further improving separation stability, the total HLB value of component (A) is preferably 12 to 16, more preferably 13 to 15, and even more preferably 13.8 to 14.5.

[0019] Particularly preferred examples of component (A) include polyoxyethylene (20) polyoxypropylene (6) decyltetradecyl ether, polyoxyethylene (30) polyoxypropylene (6) decyltetradecyl ether, polyoxyethylene (20) polyoxypropylene (4) cetyl ether, polyoxyethylene (20) stearyl ether, polyoxyethylene (20) oleyl ether, and polyoxyethylene (30) phytosterol, more preferably polyoxyethylene (30) polyoxypropylene (6) decyltetradecyl ether, polyoxyethylene (20) polyoxypropylene (4) cetyl ether, polyoxyethylene (20) stearyl ether, and polyoxyethylene (20) oleyl ether, and even more preferably polyoxyethylene (20) stearyl ether and polyoxyethylene (20) oleyl ether.

[0020] In the emulsion composition of the present invention, the content of component (A) is not particularly limited, but may be, for example, 3 to 25% by weight. From the viewpoint of further improving separation stability, the content of (A) is preferably 9 to 25% by weight, more preferably 10 to 22% by weight, and even more preferably 12 to 15% by weight.

[0021] (B) Higher fatty acids The emulsion composition of the present invention contains a higher fatty acid as component (B). In the present invention, a higher fatty acid is a fatty acid having 12 or more carbon atoms.

[0022] The higher fatty acid may be either a straight-chain fatty acid or a branched fatty acid, and may be either a saturated fatty acid or an unsaturated fatty acid. Specific examples of component (B) include lauric acid, myristic acid, pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, arachidic acid, mead acid, arachidonic acid, behenic acid, isopalmitic acid, isostearic acid, and isoarachidic acid, with preferred specific examples being isopalmitic acid, isostearic acid, and isoarachidic acid.

[0023] These higher fatty acids may be used alone or in combination of two or more.

[0024] Among the above higher fatty acids, from the viewpoint of further improving separation stability, higher fatty acids having a carbon number of preferably 14 or more, more preferably 16 or more, and even more preferably 18 or more are used. The upper limit of the carbon number of component (B) is, for example, 22 or less, preferably 20 or less, and more preferably 19 or less.

[0025] Among the above higher fatty acids, from the viewpoint of further improving separation stability, branched fatty acids and / or saturated fatty acids are preferred, and branched saturated fatty acids are more preferred.

[0026] Of the above higher fatty acids, preferred specific examples of the component (B) used in the present invention include isostearic acid and isoarachic acid, and a particularly preferred specific example is isostearic acid.

[0027] In the emulsion composition of the present invention, the content of component (B) is not particularly limited, but may be, for example, 2 to 10% by weight. From the viewpoint of further improving separation stability, the content of (B) is preferably 3 to 8% by weight, more preferably 4 to 6% by weight.

[0028] In the emulsion composition of the present invention, the content ratio of the (B) component to 1 part by weight of the (A) component is determined by the above-mentioned contents of each component. From the viewpoint of further improving separation stability, the content ratio of the (B) component to 1 part by weight of the (A) component is preferably 0.05 to 1 part by weight, more preferably 0.15 to 0.7 parts by weight, and even more preferably 0.3 to 0.5 parts by weight.

[0029] water The emulsion composition of the present invention contains water as a base. The water content in the emulsion composition of the present invention is not particularly limited, but may be, for example, 41% by weight or more, preferably 42 to 85% by weight, more preferably 43 to 60% by weight, and even more preferably 44 to 55% by weight.

[0030] oily base The emulsion composition of the present invention contains an oily base. As the oily base, any oily base that is used in emulsion compositions can be used without any particular limitation, but from the viewpoint of further improving separation stability, liquid oil is preferably used. Examples of liquid oils include liquid hydrocarbon oils such as liquid paraffin, squalene, and squalane; silicone oils such as dimethylpolysiloxane and methylphenylpolysiloxane; medium-chain fatty acid triglycerides such as triglycerides of fatty acids having 6 to 12 carbon atoms (for example, vegetable oils such as camellia oil, soybean oil, cottonseed oil, sesame oil, safflower oil, corn oil, coconut oil, perilla oil, and castor oil; and synthetic oils such as 2-linoleoyl-1,3-dioctanoylglycerol); and ester oils such as cetyl ethylhexanoate, octyldodecyl myristate, glyceryl tri-2-ethylhexanoate (glycerin triisooctanoate), isopropyl myristate, and glyceryl divalamethoxycinnamate-monoethylhexanoate.

[0031] These liquid oils may be used alone or in combination of two or more. Among these liquid oils, from the viewpoint of further improving separation stability, liquid hydrocarbon oils and ester oils are preferred.

[0032] The content of the oily base in the emulsion composition of the present invention is not particularly limited, but may be, for example, 5 to 20% by weight, and more preferably 10 to 15% by weight.

[0033] Other ingredients The emulsion composition of the present invention may contain, as necessary, other components in addition to the above components, to the extent that the effects of the present invention are not impaired, such as other surfactants (anionic surfactants, cationic surfactants, zwitterionic surfactants), thickeners, other aqueous bases (lower monohydric alcohols such as ethanol and isopropanol; polyhydric alcohols, etc.), buffers, chelating agents, antioxidants, stabilizers, preservatives, fragrances, freshening agents, dispersants, wetting agents, etc. Among these other components, anionic surfactants and polyhydric alcohols are preferred from the viewpoint of further improving separation stability.

[0034] The anionic surfactant may be an anionic surfactant having a phosphate group, a carboxyl group, or a sulfate group, and one or more of these may be used. Among these anionic surfactants, an anionic surfactant having a phosphate group is preferred from the viewpoint of further improving separation stability.

[0035] Examples of anionic surfactants having a phosphate group include polyoxyethylene (POE) alkyl ether phosphates or salts thereof, and monoalkyl phosphates or salts thereof. Examples of POE alkyl ether phosphates or salts thereof include POE lauryl ether phosphate, sodium POE oleyl ether phosphate, and sodium POE cetyl ether phosphate. Examples of monoalkyl phosphates or salts thereof include lauryl phosphate. These anionic surfactants having a phosphate group may be used alone or in combination of two or more.

[0036] When the emulsion composition of the present invention contains an anionic surfactant, the content of the anionic surfactant is, for example, 1 to 10% by weight, preferably 2 to 8% by weight, and more preferably 3 to 6% by weight.

[0037] Examples of polyhydric alcohols include glycerin, propylene glycol, 1,3-butylene glycol, etc., and one or more of these may be used. Among these polyhydric alcohols, glycerin and 1,3-butylene glycol are preferred from the viewpoint of further improving separation stability.

[0038] When the emulsion composition of the present invention contains a polyhydric alcohol, the content of the polyhydric alcohol is, for example, 4 to 20% by weight. From the viewpoint of further improving separation stability, the content of the polyhydric alcohol is preferably 6 to 15% by weight, more preferably 8 to 12% by weight.

[0039] Formulation The state of the emulsion composition of the present invention is not particularly limited, and examples thereof include liquid, semi-solid (gel, paste), and solid forms. From the viewpoint of further enhancing the effect of improving the feeling of use, the formulation form is more preferably a gel or paste form.

[0040] The emulsion composition of the present invention forms cubic liquid crystals, which can be confirmed by a small-angle X-ray scattering device.

[0041] The emulsion type of the emulsion composition of the present invention may be either an oil-in-water emulsion or a water-in-oil emulsion, but is preferably an oil-in-water emulsion.

[0042] The emulsion composition of the present invention can be used as an external preparation such as a cosmetic, an external quasi-drug, an external pharmaceutical, etc. The product form of the external composition of the present invention is not particularly limited, and examples thereof include lotions, creams, ointments, emulsions, gels, oils, liniments, aerosols, etc.

[0043] Purpose The emulsion composition of the present invention can usually be used externally. When used externally, the application site of the emulsion composition of the present invention is not particularly limited. However, due to the bioadhesiveness based on the high viscosity unique to cubic liquid crystals, it can be preferably applied to skin areas requiring protection and / or areas that come into contact with clothing and other wearable articles. Specific areas to which the emulsion composition of the present invention can be applied include, for example, the face, neck, chest, back, arms, elbows, hands, axillae, abdomen, vulva, buttocks, anus, legs, fingers, toes, and soles, preferably the vulva, buttocks, anus, etc., and particularly preferably the vulva.

[0044] The target populations for the emulsion composition of the present invention are not particularly limited, but preferred examples include newborns (up to 28 days after birth) who are prone to diaper rash; infants (28 days after birth and younger than 1 year old); young children (1 year old to preschool age); women who are prone to rashes caused by menstrual blood and / or vaginal secretions; and middle-aged people (ages 45 to 55) and elderly people (ages 55 and older) who are prone to rashes caused by urine, menstrual blood, and / or vaginal secretions. Among these, particularly preferred target populations include middle-aged and elderly people (ages 45 and older) whose skin (particularly the vulva) is prone to physical and / or chemical irritation due to contact with clothing and other articles of clothing, menstrual blood, vaginal secretions, sweat, etc.

[0045] Method for producing emulsion composition The emulsion composition of the present invention can be prepared by mixing the above-mentioned components (A) and (B), and other components that are blended as needed, in the usual order in the desired amounts, in accordance with a conventional method for manufacturing an emulsion composition. [Example]

[0046] The present invention will be explained in more detail below by showing examples, but the present invention is not limited to these examples.

[0047] The emulsion compositions shown in Tables 1 and 2 were prepared. First, predetermined amounts of oily bases (liquid paraffin, glycerin triisooctanoate, and sodium POE oleyl ether phosphate) were mixed, and then components (A) and (B) were added and mixed at 80°C to prepare an oily composition. Separately, predetermined amounts of aqueous bases (purified water, 1,3-butylene glycol, and glycerin) were mixed at 80°C to prepare an aqueous composition. These oily composition and aqueous composition were mixed at 80°C and emulsified to prepare an emulsion composition. The resulting emulsion compositions were evaluated as follows.

[0048] <Confirmation of cubic liquid crystal formation> The formation of cubic liquid crystals in each emulsion composition was confirmed using a small-angle X-ray scattering device. Specifically, each emulsion composition was irradiated with X-rays, and the scattered X-rays emitted from the emulsion were detected to obtain a peak chart. The obtained peak pattern was then compared with a peak pattern characteristic of cubic liquid crystals to confirm the formation of cubic liquid crystals in each emulsion composition.

[0049] <Separation stability> 100 g of each emulsion composition was filled into a mayonnaise bottle (140 mL) and stored in a dark place at 25°C for 6 months. After storage, the appearance of each emulsion composition was observed, and the degree of separation stability was scored on a 10-point scale using a visual analog scale (VAS), with 10 points representing a clear state with no separation observed (Example 1) and 1 point representing a state in which severe separation was observed and the composition could not be made uniform even after shaking (Comparative Example 1). A score of 5 or higher was considered to have the desired separation stability. The results are shown in Tables 1 and 2.

[0050] [Table 1]

[0051] [Table 2]

[0052] As is clear from Tables 1 and 2, it was found that by blending components (A) and (B), cubic liquid crystals with excellent separation stability were formed. Formulation Examples

[0053] Each emulsion composition shown in Tables 3 and 4 was prepared, and the formation of cubic liquid crystals, separation stability, and usability were evaluated using the same methods as in the Examples.Cubic liquid crystals were formed in all emulsion compositions of Formulation Examples 1 to 15, and the desired separation stability was observed.

[0054] [Table 3]

[0055] [Table 4]

Claims

1. (A) an ether-based nonionic surfactant, (B) a higher fatty acid, and (C) a polyhydric alcohol, An emulsion composition, wherein the total HLB value of the component (A) is 13 to 14.5, and the content of the component (C) is 4 to 12 wt %.

2. The emulsion composition according to claim 1, wherein the component (A) is a polyoxyalkylene alkyl ether, a polyoxyalkylene alkenyl ether, and / or a polyoxyalkylene steryl ether.

3. The emulsion composition according to claim 1 or 2, wherein the component (A) is a polyoxyalkylene alkyl ether and a polyoxyalkylene alkenyl ether.

4. The emulsion composition according to any one of claims 1 to 3, wherein the content of the component (A) is 3 to 25 wt%.

5. The emulsion composition according to any one of claims 1 to 4, wherein the component (B) has 14 or more carbon atoms.

6. 6. The emulsion composition according to claim 1, wherein the content of the component (B) is 0.1 to 1 part by weight per 1 part by weight of the component (A).

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