Water-based components

Abstract

A new technology is provided for stably incorporating cholesterol at high concentrations into aqueous compositions. The aqueous composition contains component (A): cholesterol and component (B): an anionic surfactant, and a liquid ordered (Lo) phase is formed.

Description

[Technical Field]

[0001] The present invention relates to an aqueous composition. [Background technology]

[0002] Techniques for incorporating cholesterol and a surfactant into a composition include those described in Patent Document 1 (JP-T-2002-528481A) and Patent Document 2 (JP-A-2013-227293A). Patent Document 1 describes a shampoo composition comprising an active ingredient and multilamellar vesicles, the multilamellar vesicles essentially consisting of an anionic surfactant and a sterol (Claim 1), and states that the multilamellar vesicles are storage stable and can be used to encapsulate the active ingredient in the shampoo, thereby enhancing the performance of the active ingredient and promoting its release from the shampoo (Paragraph 0012).

[0003] Furthermore, Patent Document 2 describes a solubilized composition containing a nonionic surfactant with an HLB of 11 to 16, diglyceryl monoisostearate and / or diglyceryl monooleate, an anionic surfactant, cholesterol and / or phytosterol, and ethanol (Claim 1), and describes that the solubilized composition has a transparent or translucent appearance and is a so-called micelle or microemulsion (Paragraph 0026). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2002-528481 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-227293 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a new technique for stably incorporating cholesterol at a high concentration into an aqueous composition. [Means for solving the problem]

[0006] According to the present invention, the following aqueous composition and method for producing a skin cosmetic are provided. [1] An aqueous composition comprising the following components (A) and (B), in which a liquid ordered (Lo) phase is formed: (A) Cholesterol (B) Anionic surfactant [2] The aqueous composition according to [1], wherein when heated from 0°C to 70°C at a rate of 5°C / min in differential scanning calorimetry, the aqueous composition has an endothermic enthalpy of 3.0 mJ / mg or less, with a peak at 40°C to 55°C. [3] The aqueous composition according to [1] or [2], wherein when the aqueous composition is observed under a polarizing microscope at 20°C and a magnification of 100 times, no light emission originating from crystals is observed. [4] The aqueous composition according to any one of [1] to [3], wherein the component (B) is an amino acid-based anionic surfactant. [5] The aqueous composition according to any one of [1] to [4], wherein the molar ratio ((A) / ((A)+(B))) of the content of component (A) to the total content of components (A) and (B) in the aqueous composition is 0.4 or more and 0.65 or less. [6] The aqueous composition according to any one of [1] to [5], which is for use as a skin cosmetic. [7] A method for producing a skin cosmetic, comprising blending and diluting the aqueous composition described in any one of [1] to [6].

[0007] Furthermore, according to this embodiment, for example, a skin cosmetic containing the aqueous composition of the present invention can also be provided.

[0008] The present invention can also provide an aqueous composition containing, for example, at least one selected from the group consisting of cholesterol and phytosterols and an anionic surfactant, in which a liquid ordered (Lo) phase is formed. [Effects of the Invention]

[0009] According to the present invention, cholesterol can be stably incorporated into an aqueous composition at a high concentration. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows a DSC chart of an aqueous composition in an example. [Figure 2] FIG. 1 shows a DSC chart of an aqueous composition in an example. [Figure 3] FIG. 1 shows a DSC chart of an aqueous composition in an example. [Figure 4] FIG. 1 shows a DSC chart of an aqueous composition in an example. [Figure 5] FIG. 2 is a DSC chart of an aqueous composition in a comparative example. [Figure 6] FIG. 2 is a DSC chart of an aqueous composition in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described. In this embodiment, the composition may contain each component either alone or in combination of two or more. In this specification, the symbol "to" indicating a numerical range means "greater than or equal to" or "less than or equal to," and both of the numerical values ​​at both ends are included.

[0012] (aqueous composition) In this embodiment, the aqueous composition contains at least one selected from the group consisting of cholesterol and phytosterol, and an anionic surfactant, and a liquid ordered (Lo) phase is formed. More specifically, in this embodiment, the aqueous composition contains the following components (A) and (B), and a liquid ordered (Lo) phase is formed. (A) Cholesterol (B) Anionic surfactant Hereinafter, the aqueous composition in this embodiment may also be simply referred to as a composition.

[0013] In this embodiment, the aqueous composition contains component (B) in combination with component (A), and the Lo phase is formed, so that excellent storage stability can be achieved even when the poorly water-soluble component (A) is blended at a high concentration. Furthermore, this embodiment also makes it possible to obtain an aqueous composition that exhibits excellent storage stability at high temperatures, for example, 70°C or higher. Furthermore, this embodiment also makes it possible to obtain a water-soluble composition that exhibits excellent storage stability by containing component (A) at a high concentration of, for example, 1% by mass or higher, preferably more than 3% by mass. Furthermore, according to the present embodiment, it is possible to obtain an aqueous composition in which deterioration such as phase separation and crystal precipitation due to stimuli such as vibration is suitably suppressed, and thereby it is also possible to suppress deterioration of the aqueous composition during movement such as transportation.

[0014] The Lo phase is a lipid bilayer membrane phase that exhibits intermediate properties between the liquid crystal phase and the gel phase. The gel-liquid crystal phase transition does not occur in the Lo phase, and the gel-liquid crystal phase transition disappears in compositions in which the entire bilayer membrane of the composition is in the Lo phase. The aqueous composition may be partially or entirely in the Lo phase, and preferably entirely in the Lo phase. Specifically, the Lo phase contains components (A) and (B), and is, for example, made up of components (A) and (B). Also, the aqueous composition preferably does not have multilamellar vesicles.

[0015] Furthermore, whether or not a Lo phase is formed in the aqueous composition can be confirmed by, for example, a combination of differential scanning calorimetry (DSC), X-ray small-angle / wide-angle scattering, polarizing microscope observation, transmittance measurement, viscosity measurement, and the like. For example, when measuring by small-angle and wide-angle X-ray scattering, if the Lo phase is formed, it is confirmed that the layered lamellar structure is aligned with a lattice spacing of 1 to 10 nm in the small-angle region, and in the wide-angle region, a specific sharp peak due to the hexagonal structure appears at q = 12 to 15 nm. -1 It is observed near the . If the Lo phase is formed, for example, cross-shaped or linear emission will be observed when observing with a polarized microscope. On the other hand, when measuring with small-angle and wide-angle X-ray scattering, if no layered lamellar structure is observed in the small-angle region or if no sharp peak is observed in the wide-angle region, the Lo phase is not formed.

[0016] In differential scanning calorimetry (DSC), the amount of heat absorbed due to a temperature change is measured as a peak, and the area of ​​that peak is calculated as the enthalpy. In this embodiment, this enthalpy can also be used as an index of heat resistance. Another feature of the aqueous composition of this embodiment is that the area of ​​the endothermic peak measured by DSC is small. When the temperature is increased from 0°C to 70°C at a rate of 5°C / min in differential scanning calorimetry, the endothermic enthalpy having a peak between 40°C and 55°C is, for example, 3.0 mJ / mg or less, preferably 2.0 mJ / mg or less, more preferably 1.0 mJ / mg or less, and even more preferably 0.5 mJ / mg or less. This makes it possible to more stably obtain an aqueous composition in which component (A) is stably blended at a high concentration even after heated storage. There is no lower limit to the enthalpy, and it may be, for example, 0 mJ / mg or more. Furthermore, the aqueous composition preferably does not have an endothermic peak between 40°C and 55°C in differential scanning calorimetry. This makes it possible to obtain an aqueous composition with excellent storage stability in a more stable manner. Here, "not having an endothermic peak" specifically means that the aqueous composition does not have an endothermic peak of greater than 0.1 mJ / mg between 40°C and 55°C. The measurement temperature for differential scanning calorimetry is from 0°C to 70°C, and the temperature rise rate is 5°C / min.

[0017] Preferably, when the aqueous composition is stored at 70°C for 4 hours, cooled to 20°C, and then held at -80°C by differential scanning calorimetry, the composition does not exhibit an endothermic peak between 40°C and 55°C when heated from 0°C to 70°C at a rate of 5°C / min. This can further improve the storage stability of the aqueous composition at high temperatures.

[0018] Furthermore, since a Lo phase is formed in the aqueous composition, when observed under a polarizing microscope at 20°C and a magnification of 100x, preferably at least one of cross-shaped luminescence and linear luminescence is observed, and more preferably both cross-shaped luminescence and linear luminescence are observed.

[0019] Furthermore, when the aqueous composition is observed under a polarizing microscope at 20°C and a magnification of 100 times, preferably no light emission derived from crystals is observed, which can further improve the storage stability of the aqueous composition at high temperatures.

[0020] For the same reason, when the aqueous composition is heated to 70° C. and observed under a polarizing microscope, preferably cross-shaped luminescence is observed, and luminescence derived from crystals is not confirmed. Here, the light emitted from the crystal observed under a polarizing microscope specifically refers to light emitted from the entire angular mass.

[0021] In this embodiment, the criteria for determining whether or not a Lo phase has been formed can be, for example, a comprehensive evaluation of the results of appearance observation, DSC measurement, and polarizing microscope observation. More specifically, if the appearance of the composition at room temperature (20°C) is uniform, there is no peak with an endothermic amount exceeding 3.0 mJ / mg between 40°C and 55°C in the DSC measurement chart, and cross-shaped or linear emission is observed in polarizing microscope observation, but emission derived from crystals is not, the composition can be determined to have a Lo phase.

[0022] The aqueous composition is preferably uniformly opaque to the naked eye, which allows for more stable formulation of component (A) at a high concentration. From the same viewpoint, the transmittance at 600 nm of an aqueous composition diluted 400 times is preferably 70% or less, more preferably 60% or less, and even more preferably 55% or less. The transmittance of the water-soluble composition may be, for example, 5% or more, 10% or more, or 15% or more. Here, the measurement conditions for the transmittance of the aqueous composition are specifically as follows: dilution solvent: water, 20° C., and optical path length: 1 cm.

[0023] The water-soluble composition is also preferably uniformly fluid. The viscosity of the aqueous composition measured with a Brookfield viscometer at 20°C is preferably 10 mPa·s or more, more preferably 25 mPa·s or more, and even more preferably 50 mPa·s or more, which allows for more stable blending of component (A) at a high concentration. In addition, from the viewpoint of improving stirring efficiency, the viscosity of the aqueous composition measured by a Brookfield viscometer at 20°C is preferably 5 x 10 5 mPa·s or less, and more preferably 2×10 5 mPa·s or less, more preferably 1×10 5 mPa·s or less.

[0024] Here, the viscosity of the aqueous composition may be measured at 20°C using a Brookfield viscometer (for example, TVB-25L manufactured by Toki Sangyo Co., Ltd.) in accordance with the instruction manual for the Brookfield viscometer (the instruction manual for using the TVB-25L manufactured by Toki Sangyo Co., Ltd. is TKV-M0184B: August 2011), for example, under the following conditions: rotor used: No. 1, measurement speed: 30 rpm, 1.0 M range, and measurement time: 60 seconds.

[0025] Next, the components of the aqueous composition will be described. (Component (A)) Component (A) is cholesterol. The aqueous composition contains component (A), and thus can impart effects such as anti-inflammatory action, skin moisturizing, and barrier function recovery to skin cosmetics obtained by blending the aqueous composition. Component (A) can be produced by known methods, or commercially available products can be used.

[0026] The content of component (A) in the aqueous composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.25% by mass or more, even more preferably 0.5% by mass or more, even more preferably more than 0.5% by mass, even more preferably 1% by mass or more, even more preferably 2% by mass or more, even more preferably more than 3% by mass, and even more preferably 6% by mass or more, based on the total amount of the aqueous composition. This allows component (A) to be blended at a high concentration. On the other hand, in order to more reliably suppress crystallization and precipitation of component (A), the content of component (A) in the aqueous composition is preferably 20 mass% or less, more preferably 12 mass% or less, and even more preferably 10 mass% or less, and also preferably 5 mass% or less or 2.5 mass% or less, based on the total amount of the aqueous composition.

[0027] In the aqueous composition, the enthalpy change of component (A) at 40 to 55°C when heated from 0 to 70°C at a rate of 5°C / min as measured by differential scanning calorimetry is preferably 3.0 mJ / mg or less, more preferably 2.0 mJ / mg or less, even more preferably 1.0 mJ / mg or less, and still more preferably 0 mJ / mg, allowing component (A) to be blended at a high concentration and more stably. The enthalpy change of the component (A) may be, for example, 0 mJ / mg or more or 0.5 mJ / mg or more.

[0028] (Component (B)) Component (B) is an anionic surfactant. In this embodiment, the aqueous composition contains component (B) in combination with component (A) and has a configuration in which a Lo phase is formed, so that component (A), which has low water solubility, can be stably blended in the aqueous composition at a high concentration.

[0029] Component (B) preferably contains an amino acid-based anionic surfactant, more preferably an amino acid-based anionic surfactant, even more preferably an N-acylamino acid salt, and even more preferably an N-acylglutamate, which allows for more stable incorporation of component (A) at a high concentration.

[0030] The amino acid-based anionic surfactant is at least one selected from the group consisting of N-acyl acidic amino acid salts such as N-acyl glutamate, N-acylaspartate, N-acylmethylalanine salt, N-acylglycine salt, and N-acylmethylalanine salt; and acylmethyltaurine salt, i.e., salts of condensates of N-methyltaurine and fatty acids.

[0031] In these amino acid-based anionic surfactants, the acyl group is preferably derived from a fatty acid having 8 or more carbon atoms, and preferably from a fatty acid having 24 or fewer carbon atoms, more preferably from a fatty acid having 22 or fewer carbon atoms, even more preferably from a fatty acid having 20 or fewer carbon atoms, and even more preferably from a fatty acid having 18 or fewer carbon atoms. This allows the Lo phase to be more stably formed in the aqueous composition. The fatty acid may include at least one of a saturated fatty acid and an unsaturated fatty acid. The fatty acid may also include at least one of a straight-chain fatty acid and a branched fatty acid. The fatty acid is, for example, one or more selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, beef tallow fatty acid, coconut oil fatty acid, and palm kernel oil fatty acid, and is preferably lauric acid, myristic acid, or coconut oil fatty acid. The acyl group preferably contains one or more groups selected from the group consisting of a lauroyl group, a myristoyl group, a stearoyl group and a cocoyl group, and more preferably a lauroyl group or a myristoyl group.

[0032] The salt of the amino acid surfactant is, for example, one or more selected from the group consisting of alkali metal salts such as lithium salt, sodium salt, potassium salt, etc.; alkaline earth metal salts such as calcium salt, magnesium salt, etc.; alkanolamine salts such as monoethanolamine salt, diethanolamine salt, triethanolamine (TEA) salt, etc.; ammonium salt; and basic organic salts, preferably at least one selected from the group consisting of alkali metal salts and alkanolamine salts, more preferably one or more selected from the group consisting of sodium salt, potassium salt, and TEA salt.This can improve the availability of amino acid surfactants. Furthermore, in terms of improving the ease of handling of the amino acid-derived surfactant, the salt in the amino acid-derived surfactant is preferably an alkali metal salt, and more preferably at least one selected from the group consisting of sodium salts and potassium salts. Furthermore, the N-acyl acidic amino acid salt specifically includes at least one of a mono-salt and a di-salt, preferably includes one or more selected from the group consisting of a monosodium salt, a disodium salt, a monopotassium salt, a dipotassium salt, and a triethanolamine (TEA) salt, and more preferably includes at least one of a monosodium salt, a disodium salt, and a potassium salt.

[0033] Examples of amino acid surfactants include disodium myristoyl glutamate, sodium myristoyl glutamate, dipotassium myristoyl glutamate, potassium myristoyl glutamate, TEA myristoyl glutamate, sodium lauroyl glutamate, potassium lauroyl glutamate, TEA lauroyl glutamate, sodium cocoyl glutamate, disodium cocoyl glutamate, potassium cocoyl glutamate, TEA cocoyl glutamate, sodium stearoyl glutamate, disodium stearoyl glutamate, potassium stearoyl glutamate, sodium methyl cocoyl taurate, and sodium methyl cocoyl taurate. The compound is one or more compounds selected from the group consisting of disodium myristoyl glutamate, sodium myristoyl glutamate, potassium myristoyl glutamate, TEA myristoyl glutamate, sodium lauroyl glutamate, potassium lauroyl glutamate, TEA lauroyl glutamate, sodium cocoyl glutamate, disodium cocoyl glutamate, and TEA cocoyl glutamate, and more preferably one or more compounds selected from the group consisting of sodium myristoyl glutamate, sodium lauroyl glutamate, and sodium cocoyl glutamate.

[0034] The content of component (B) in the aqueous composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and even more preferably 4% by mass or more, based on the total amount of the aqueous composition, which allows for the component (A) to be blended at a high concentration and more stably. In addition, in order to suppress irritation to the skin, the content of component (B) in the aqueous composition is preferably 15% by mass or less, more preferably 12% by mass or less, and even more preferably 10% by mass or less, based on the total amount of the aqueous composition.

[0035] In the aqueous composition, the enthalpy change of component (B) at 40 to 55°C when heated from 0 to 70°C at a rate of 5°C / min as measured by differential scanning calorimetry is preferably 3.0 mJ / mg or less, more preferably 2.0 mJ / mg or less, even more preferably 1.0 mJ / mg or less, and still more preferably 0 mJ / mg, allowing component (A) to be blended at a high concentration and more stably. The enthalpy change of the component (B) may be, for example, 0 mJ / mg or more or 0.5 mJ / mg or more.

[0036] The molar ratio ((A) / ((A)+(B))) of the content of component (A) to the total content of components (A) and (B) in the aqueous composition is preferably 0.4 or more, more preferably 0.45 or more, even more preferably 0.5 or more, still more preferably 0.52 or more, and even more preferably 0.55 or more. This more reliably suppresses phase separation of component (B). Furthermore, in order to more reliably suppress precipitation due to crystallization or the like of component (A), the molar ratio ((A) / ((A)+(B))) is preferably 0.8 or less, more preferably 0.75 or less, even more preferably 0.7 or less, even more preferably 0.65 or less, and even more preferably 0.62 or less. Furthermore, when ((A) / ((A)+(B))) is within the above-mentioned range, the content of component (A) in the aqueous composition is preferably 0.5 mass% or more, and more preferably more than 0.5 mass%, based on the total amount of the aqueous composition.

[0037] (water) Aqueous compositions specifically comprise water. The content of water in the aqueous composition can be, for example, the remainder after excluding components other than water in the aqueous composition. The water content in the aqueous composition is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and is preferably 99% by mass or less, more preferably 95% by mass or less, even more preferably 80% by mass or less, and even more preferably 75% by mass or less, based on the total weight of the aqueous composition. This allows for a composition with a refreshing feel when used.

[0038] The aqueous composition may further contain components other than the components (A), (B) and water. A specific example of such a component is component (C): a polyhydric alcohol.

[0039] (Component (C)) Component (C) is a polyhydric alcohol. By further including component (C) in the composition, a composition with even more excellent moisturizing power can be obtained. Specific examples of the component (C) include glycerins such as glycerin, diglycerin, and polyglycerin; sugar alcohols such as sorbitol, erythritol, and xylitol; Examples of the glycol include one or more selected from the group consisting of glycols such as isoprene glycol, 1,2-propylene glycol (PG), dipropylene glycol (DPG), polyethylene glycol (PEG), ethoxydiglycol, 1,3-butylene glycol (BG), diethylene glycol monoethyl ether, and pentylene glycol.

[0040] Component (C) is preferably a polyhydric alcohol having a molecular weight of 150 or less, and more preferably one or more compounds selected from the group consisting of BG, glycerin, DPG, PG, and pentylene glycol, which allows for a composition that is moisturizing and less sticky.

[0041] The content of component (C) in the composition is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total mass of the aqueous composition, which can impart moisturizing power to the composition. In addition, in order to achieve a less sticky feel when used, the content of component (C) in the aqueous composition is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on the total mass of the composition.

[0042] The composition may further comprise ingredients other than those mentioned above. Next, a method for producing the aqueous composition will be described. The aqueous composition can be produced, for example, by blending components (A), (B), water, and optionally other components to obtain a mixture. During the production process, the components or the mixture may be heated. Here, in order to obtain an aqueous composition in which a Lo phase is formed, it is important to appropriately select the type of component (B), the amounts and ratios of components (A) and (B), as well as the manufacturing process for the aqueous composition. For example, it is preferable that the component (B) contained in the water-soluble composition contains an amino acid-derived surfactant, and that the types, amounts and ratios of the components (A) and (B) are appropriately designed. In addition, in the process for producing the aqueous composition, it is also preferable to prepare component (B) as an aqueous solution in advance and then mix it, to repeatedly perform the heating step and the stirring step, or to prepare it with a lid on to prevent water evaporation.

[0043] The aqueous composition obtained in this embodiment has excellent storage stability even when the concentration of component (A) is high, and therefore can be suitably used as a raw material for producing cosmetics containing component (A), such as skin cosmetics. That is, the aqueous composition is preferably used for skin cosmetics. In this embodiment, a method for producing a skin cosmetic product includes blending and diluting the aqueous composition of this embodiment. By using the aqueous composition in a skin cosmetic product, it is possible to obtain a preparation that is stable over time and also contributes to moisturizing the skin and restoring the barrier function.

[0044] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. [Example]

[0045] The present embodiment will be specifically described below with reference to examples, but the present embodiment is not limited to these examples.

[0046] (Examples 1 to 4, Comparative Examples 1 to 4) In this example, an aqueous composition containing cholesterol was prepared and the properties of the resulting composition were confirmed. The formulation and results are shown in Table 1.

[0047] (Method for preparing aqueous composition) (Preparation Procedure) An appropriate amount of surfactant was weighed and dissolved in water to prepare a 20% aqueous solution. The surfactant aqueous solution, cholesterol powder (Cholesterol JSQI, manufactured by Nippon Fine Chemical Co., Ltd.), and water were weighed into a vial for sample preparation, sealed, and heated to 70°C. After standing at 70°C for about 5 minutes, the mixture was stirred in a vortex mixer for about 1 minute and centrifuged at 4000 rpm for 1 minute. If cholesterol crystals remain, they will form precipitates in the sample after centrifugation. The above steps were repeated until no cholesterol crystals remained visible or the amount of remaining cholesterol crystals remained unchanged, to obtain the compositions of each example.

[0048] (External observation) The appearance of the composition obtained in each example was visually inspected at 20°C after standing at room temperature.

[0049] (transmittance) In some examples, the obtained compositions were diluted 400 times with purified water, and the transmittance was measured using a ratio beam spectrophotometer U-5100 (manufactured by Hitachi) at 20°C, a measurement wavelength of 600 nm, and an optical path length of 1 cm.

[0050] (enthalpy) For the examples other than Comparative Examples 2 and 4, in which crystals were observed by visual observation, approximately 15 μg of each sample was measured by differential scanning calorimetry (differential scanning calorimeter DSC7000X (manufactured by Hitachi)) by raising the temperature from 0°C to 70°C at a rate of 5°C / min, and the endothermic enthalpy having a peak between 40°C and 55°C was measured. Representative examples of DSC charts are shown in Figures 1 to 6. Figures 1 to 6 show DSC charts for Examples 1 to 4, Comparative Example 1, and Comparative Example 3, respectively. It is presumed that the endothermic peak near 30 to 35°C in Figure 1 is not related to the presence or absence of the formation of a Lo phase.

[0051] (Polarizing microscope observation) The composition obtained in each example was examined under a polarizing microscope (ECLIPSE Si LS (manufactured by NIKON)) at room temperature (20° C.) and a magnification of 100 times. In addition, for examples in which cross-shaped or linear luminescence was confirmed at room temperature, the polarizing microscope images were further checked at each stage: after heating at 70°C for 1 minute, and after leaving the sample to stand at room temperature immediately after heating at 70°C for 1 minute and then cooling.

[0052] (Formation of Lo phase) Based on these results, the composition was evaluated as having a Lo phase if it had a uniform appearance, a DSC endothermic value of 3.0 mJ / mg or less, and cross-shaped or linear luminescence was observed under a polarized microscope, but no luminescence derived from crystals was observed.

[0053] (evaluation) The storage stability of the compositions at room temperature was evaluated by leaving the compositions obtained in each example at 20°C for one month, and then visually inspecting their appearance.

[0054] [Table 1]

[0055] As can be seen from Table 1, in each example, component (A) was uniformly blended in the composition, a Lo phase was formed, and the composition had appropriate fluidity. Furthermore, the compositions of each example had excellent storage stability. Therefore, the compositions of the examples have excellent stability during storage and transportation, and can be used as they are or as raw materials for skin cosmetics and the like.

Claims

1. An aqueous composition comprising the following components (A) and (B), in which a liquid ordered (Lo) phase is formed: (A) Cholesterol (B) Anionic surfactant

2. 2. The aqueous composition according to claim 1, wherein, when heated from 0°C to 70°C at a rate of 5°C / min in differential scanning calorimetry, the aqueous composition has an endothermic enthalpy of 3.0 mJ / mg or less, having a peak at 40°C to 55°C.

3. 3. The aqueous composition according to claim 1, wherein when the aqueous composition is observed under a polarizing microscope at 20°C and a magnification of 100 times, no light emission derived from crystals is observed.

4. 3. The aqueous composition according to claim 1, wherein the component (B) is an amino acid-based anionic surfactant.

5. 3. The aqueous composition according to claim 1, wherein the molar ratio ((A) / ((A)+(B))) of the content of component (A) to the total content of components (A) and (B) in the aqueous composition is 0.4 or more and 0.65 or less.

6. 3. The aqueous composition according to claim 1, which is used as a skin cosmetic.

7. A method for producing a skin cosmetic, comprising blending and diluting the aqueous composition according to claim 1 or 2.

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