JP2007070329A - Microemulsion composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microemulsion composition achieving at a high level both of safety and low and high temperature stability, and to provide a method for producing the composition. <P>SOLUTION: The microemulsion composition is obtained by compounding at ≤55°C (d) a basic amino acid in a microemulsion containing (a) a nonionic surfactant, (b) an oily component and (c) a polyol as essential components. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a microemulsion composition and a method for producing the same. Specifically, the present invention relates to a microemulsion composition that can be used in the fields of pharmaceuticals, cosmetics, foods, and the like, and a method for producing the same.

  Conventionally, emulsion formulations have been used very often in fields such as pharmaceuticals, cosmetics and foods. Among them, microemulsions in which dispersed particles are very finer than general emulsions are transparent or translucent in appearance, have excellent permeability due to the fineness of the particles, are thermodynamically stable, etc. Therefore, it is regarded as an important technique in the above field.

  By the way, as the surfactant used in the microemulsion composition, a nonionic surfactant is often used from the viewpoint of safety.

  On the other hand, microemulsion preparations used in the fields of pharmaceuticals, cosmetics, foods and the like need to maintain their quality over a long period of time in various environments. There is a demand for microemulsions that do not easily change state such as aggregation.

  Therefore, for the purpose of obtaining a microemulsion with high temperature stability using a nonionic surfactant, for example, a hydrophilic nonionic surfactant, a certain range of carbon number, and inorganic on the organic conceptual diagram There has been proposed a microemulsion composition comprising one or more kinds of oils having a property value and water in a specific weight ratio (see, for example, Patent Document 1).

Japanese Patent Publication No. 6-61454

  However, recently, interest in safety such as low irritation and low toxicity has been increasing, and even if it is the microemulsion composition described in Patent Document 1 described below, it is desired to achieve a higher level of safety. For this reason, the temperature stability is not necessarily sufficient.

  That is, according to the study by the present inventors, in the microemulsion composition described in Patent Document 1, in order to sufficiently reduce skin irritation and ocular mucosal irritation and the like, it is less irritating as a nonionic surfactant. It has been found that if a non-ionic surfactant is used or if the amount of the nonionic surfactant is reduced, sufficient stability is not exhibited at low and high temperatures.

  The present invention has been made in view of the above-described problems of the prior art, and provides a microemulsion composition that can achieve both safety and stability at low and high temperatures at a high level and a method for producing the same. With the goal.

  In order to solve the above-mentioned problems, the present inventors have intensively studied. As a result, a basic amino acid is blended in a microemulsion comprising a nonionic surfactant, an oil component, a polyol and water at a specific temperature or lower. As a result, it was found that the stability of the obtained microemulsion was improved, and the present invention was completed.

  That is, the microemulsion composition of the present invention comprises a microemulsion comprising (a) a nonionic surfactant, (b) an oily component and (c) a polyol as essential components. It is obtained by blending a sex amino acid.

  In the present invention, “microemulsion” refers to an emulsion particle having an average particle diameter of 300 nm or less. Moreover, the value obtained by a dynamic light scattering method is employ | adopted for this average particle diameter.

  According to the microemulsion composition of the present invention, the stability of the microemulsion having the above configuration is drastically improved by blending the basic amino acid under the above conditions. Even when selecting the active agent and setting the blending amount, it is possible to sufficiently ensure the stability of the microemulsion preparation at low and high temperatures. Therefore, according to the microemulsion composition of the present invention, a microemulsion formulation having a high level of safety and sufficiently excellent stability can be realized.

  In addition, according to the microemulsion composition of the present invention, the effect of improving the stability of the prepared microemulsion preparation against shearing force can be obtained, and the state change after the process of applying the shearing force can be sufficiently suppressed. it can. As a result, it is possible to sufficiently prevent quality deterioration due to filling or the like.

  Furthermore, according to the microemulsion composition of the present invention, sufficient storage stability can be ensured even if the prepared microemulsion formulation has a low viscosity. Therefore, this invention can provide the microemulsion composition characterized by the viscosity in 25 degreeC being 1000 mPa * s or less. Such a microemulsion composition can be applied to low-viscosity products such as emulsions and lotions, and can achieve safety and stability at a high level.

  Moreover, according to the microemulsion composition of the present invention, an unexpected effect that the moisture retention of the microemulsion preparation can be improved can be obtained.

  The microemulsion composition of the present invention preferably contains a polyglycerin fatty acid ester as the nonionic surfactant.

  Polyglycerin fatty acid esters are known as highly safe nonionic surfactants, but because of their weak emulsifying ability, it has been difficult to obtain microemulsions that are particularly stable at low and high temperatures. On the other hand, according to the present invention, sufficient stability can be ensured in a wide temperature range even when a polyglycerin fatty acid ester is used by blending basic amino acids. Therefore, according to the microemulsion composition of the present invention containing a polyglycerin fatty acid ester, it is possible to realize a microemulsion preparation that is sufficiently excellent in stability at low and high temperatures and has higher safety.

  Furthermore, the microemulsion composition of the present invention preferably contains a compound having a hydrophobic group having 11 to 28 carbon atoms and a hydroxyl group or a carboxyl group in the molecule as the oil component. By containing such a higher fatty acid or higher alcohol, the amount of the nonionic surfactant to be used can be further reduced, and a microemulsion preparation with even higher safety can be realized.

  The microemulsion composition of the present invention preferably contains at least one compound selected from the group consisting of arginine, lysine and histidine as the basic amino acid. By using such a basic amino acid, the effect of improving the stability of the microemulsion described above can be obtained more reliably.

  Moreover, in said microemulsion composition, content of the said (a) component is 0.1-10 mass% on the basis of the total mass of a microemulsion composition, and content of the said (b) component is 0.00. It is preferable that 1-20 mass%, content of the said (c) component is 1.0-30 mass%, and content of the said (d) component is 0.01-2.0 mass%.

  Moreover, content of the said (b) component is 1-10 mass parts with respect to 1 mass part of said (a) component, and content of the said (c) component is 1 mass of said (a) component It is preferable that it is 1-20 mass parts with respect to a part.

  The present invention also provides a microemulsion preparation step for preparing a microemulsion comprising (a) a nonionic surfactant, (b) an oil component, (c) a polyol, and water, and a microemulsion preparation step. And (d) a basic amino acid mixing step of mixing the basic amino acid and the microemulsion at a temperature of 55 ° C. or lower.

  According to such a method for producing a microemulsion composition, the microemulsion composition of the present invention that can achieve both safety and stability at low and high temperatures at a high level can be obtained more reliably. The reason why such an effect can be obtained is that the step of blending the basic amino acid has the above-described configuration, so that even if the microemulsion contains a component capable of forming a salt with the basic amino acid, This is presumably because basic amino acids can be blended in the microemulsion composition while preventing formation of basic amino acid salts. Moreover, according to the manufacturing method of the microemulsion composition of this invention, the freedom degree of design of a microemulsion composition can further be raised from said reason.

  Furthermore, the present invention provides an oil phase preparation step for preparing an oil phase comprising (a) a nonionic surfactant, (b) an oil component, and a first polyol, a second polyol, and water. And an aqueous phase preparation step for preparing an aqueous phase comprising a microemulsion preparation step for preparing a microemulsion comprising the oil phase and the aqueous phase, and a temperature of 55 ° C. or less after the microemulsion preparation step (d And a basic amino acid mixing step of mixing the basic amino acid and the microemulsion. A method for producing a microemulsion composition is provided.

  The “first polyol” and the “second polyol” may be the same polyol or different polyols. Further, such a polyol may be one kind or a mixture of two or more kinds.

  According to such a method for producing a microemulsion composition, a microemulsion having an average particle diameter of 300 nm or less can be efficiently prepared by providing the oil phase preparation step and the water phase preparation step, and Even if a component that can form a salt with a basic amino acid is included in the emulsion, the basic amino acid is mixed with the basic amino acid in the microemulsion composition while the basic amino acid mixing step is prevented. it can. Therefore, according to the manufacturing method of said microemulsion composition, while the freedom degree of design of a microemulsion composition can be raised, the microemulsion composition of this invention can be manufactured with outstanding productivity.

  Moreover, in the manufacturing method of said microemulsion composition, the compounding quantity of said (a) component, said (b) component, said (c) component, and said (d) component is each finally obtained. Based on the total mass of the microemulsion composition, 0.1 to 10 mass%, 0.1 to 20 mass%, 1.0 to 30 mass%, and 0.01 to 2.0 mass% It is preferable to set.

  ADVANTAGE OF THE INVENTION According to this invention, the microemulsion composition which can achieve both safety | security and stability at low temperature and high temperature at a high level and its manufacturing method can be provided.

  Hereinafter, embodiments of the present invention will be described.

  Examples of the (a) nonionic surfactant used in the present invention include polyglyceryl fatty acid ester, sorbitan fatty acid ester, polyoxyethylene (POE) fatty acid ester, POE hydrogenated castor oil, and sucrose fatty acid ester. .

  The nonionic surfactant preferably has an HLB value of 7 to 16, and preferably has a large molecular weight.

  In the present invention, from the viewpoint of further improving safety such as low skin irritation and low eye mucous membrane irritation, it is particularly preferable to use polyglyceryl fatty acid ester among the above nonionic surfactants.

  Moreover, the polyglyceryl fatty acid ester used in the present invention preferably has an HLB value of 7 to 16, and preferably has a large molecular weight. Specifically, for example, hexaglyceryl monolaurate, hexaglyceryl monomyristate, hexaglyceryl monopalmitate, decaglyceryl monolaurate, decaglyceryl monomyristate, decaglyceryl monostearate, decaglyceryl mono Examples thereof include polyglyceryl fatty acid esters such as isostearic acid ester, decaglyceryl monooleic acid ester, decaglyceryl monolinoleic acid ester, decaglyceryl distearic acid ester, decaglyceryl dioleic acid ester and decaglyceryl diisostearic acid ester. These can be used alone or in combination of two or more.

  Examples of the oil component (b) used in the present invention include avocado oil, almond oil, olive oil, macadamia nut oil, castor oil, camellia oil, jojoba oil, sesame oil, safflower oil, soybean oil, persic oil, cottonseed oil, Sunflower oil, linseed oil, cacao butter, coconut butter, molasses, carnauba wax, candelilla wax and other vegetable oils, egg yolk oil, turtle oil, mink oil, cod liver oil, shark liver oil, orange luffy oil, beef tallow, pork fat, Animal fats such as sheep fat, beeswax, whale wax, lanolin, hardened oils, hydrocarbons such as liquid paraffin, petrolatum, isoparaffin, ceresin, squalane, squalene, paraffin, microcrystalline wax, lauric acid, myristic acid, Stearic acid, oleic acid, behenic acid, undecylenic acid, lanolin fatty acid, isostere Fatty acids such as phosphoric acid, linoleic acid, linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, higher alcohols such as lauryl alcohol, cetanol, stearyl alcohol, oleyl alcohol, lanolin alcohol, hydrogenated lanolin alcohol, hexyl decanol, octyldodecanol, Isopropyl myristate, isopropyl palmitate, butyl stearate, decyl oleate, myristyl myristate, octyldodecyl myristate, hexyl laurate, propylene glycol dioleate, propylene glycol monostearate, ethylene glycol monostearate, glyceryl trimyristate , Lanolin acetate, cetyl lactate, myristyl lactate, hexyldecyl dimethyloctanoate, isostearyl malate Esters, dimethyl polysiloxane and silicone oil such as methyl phenyl polysiloxane. These can be used alone or in combination of two or more.

  Further, from the viewpoint of reducing the blending amount of the nonionic surfactant, it is preferable to use a higher alcohol or a higher fatty acid as the oil component, and a hydrophobic group having 11 to 28 carbon atoms and a hydroxyl group or a carboxyl group in the molecule. It is more preferable to use a compound having

  Examples of such compounds include higher alcohols such as stearyl alcohol, oleyl alcohol, hexyl decanol, octyldodecanol, behenyl alcohol, and myristyl alcohol, and stearic acid, oleic acid, behenic acid, isostearic acid, lauric acid, myristic acid, and the like. And higher fatty acids.

  The (c) polyol used in the present invention is a compound having two or more hydroxyl groups in the molecule. For example, propylene glycol, dipropylene glycol, ethylene glycol, diethylene glycol, polyethylene glycol, isoprene glycol, 1,3-butane. Diol (1,3-butylene glycol), 2,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 1,5-pentanediol, glycerin, diglycerin, triglycerin, poly Examples include glycerin, trimethylolpropane, erythritol, pentaerythritol, sorbitol, mabit, maltitol, lactose, fructose, maltose, sorbitan, glucose, arabitol, xylitol, mannitol and the like. These can be used alone or in combination of two or more.

  Examples of the basic amino acid (d) used in the present invention include arginine, lysine, histidine and the like. These can be used alone or in combination of two or more.

  In the microemulsion composition according to the present invention containing (a) a nonionic surfactant, (b) an oily component, (c) a polyol, and (d) a basic amino acid as essential components, the microemulsion Based on the total mass of the composition, the content of component (a) is 0.1 to 10% by mass, the content of component (b) is 0.1 to 20% by mass, and the content of component (c) is 1. It is preferable that the content of the component (d) is 0.01 to 2.0% by mass.

  When the content of the component (a) is less than 0.1% by mass, it becomes difficult to sufficiently emulsify when the content of the oil component is large, and a microemulsion excellent in stability tends to be unable to be formed. On the other hand, when the content exceeds 10% by mass, skin irritation and the like may increase, and it tends to be difficult to maintain high safety.

  When the content of the component (b) is less than 0.1% by mass, the effect of adding the oil component tends to be difficult to obtain. On the other hand, when the content exceeds 20% by mass, it tends to be difficult to form a microemulsion excellent in stability.

  When the content of the component (c) is less than 1.0% by mass, the moisturizing power tends to be insufficient. On the other hand, when the content exceeds 30% by mass, the feeling of use tends to be sticky.

  When the content of the component (d) is less than 0.01% by mass, the stability of the microemulsion composition at low and high temperatures tends to be insufficient. On the other hand, when the content exceeds 2.0% by mass, the pH may become too high, resulting in a problem of skin irritation.

  Furthermore, content of (b) component is 1-10 mass parts with respect to 1 mass part of content of (a) component, and content of (c) component is content of (a) component It is preferable that it is 1-20 mass parts with respect to 1 mass part. By containing the component (a), the component (b) and the component (c) in the above proportions, a microemulsion excellent in balance satisfying all of safety, storage stability, feeling of use and moisturizing power is obtained. Can do.

  The microemulsion composition according to the present invention may further contain a surfactant other than the nonionic surfactant as long as the effects of the present invention are not impaired. From the viewpoint of safety, the microemulsion composition is substantially nonionic. It is preferable to contain only a surfactant as a surfactant.

  In the microemulsion composition according to the present invention, an oil-soluble additive component such as an antioxidant such as tocopherol acetate and an ultraviolet absorber can be further added to the oil phase, and an ascorbic acid derivative such as an ascorbic acid derivative can also be added to the aqueous phase. Moisturizing agents such as water-soluble vitamins, amino acids, polyhydric alcohols, mucopolysaccharides and collagen, preservatives and the like can be added.

  The microemulsion composition according to the present invention is used in the form of a base in pharmaceutical preparations such as emulsions and emulsion-type ointments, cosmetics such as emulsions and creams, and food emulsions. In particular, it is suitable for a liquid or paste-like preparation having a low viscosity.

(Method for producing microemulsion composition)
Next, a preferred embodiment of the method for producing a microemulsion composition according to the present invention will be described.

  One embodiment of the method for producing a microemulsion composition according to the present invention is a micro comprising the above (a) nonionic surfactant, the above (b) oil component, the above (c) polyol, and water. A microemulsion preparation step of preparing an emulsion, and a basic amino acid mixing step of mixing the basic amino acid and the microemulsion at a temperature of 55 ° C. or lower after the microemulsion preparation step.

  As a specific example of such a production method, (i) (a) component, (b) component, (c) component, water, and other additives as necessary are added to a vacuum emulsifier, for example, at 80 ° C. (Ii) (a) A method in which a microemulsion is prepared by emulsifying, and subsequently stirring and cooling to lower the temperature in the system to 55 ° C. or less, and then (d) adding and mixing a basic amino acid. A microemulsion is prepared from a mixture of the component, the component (b), the component (c), water, and other additives as necessary, for example, using a high-pressure homogenizer, an ultrasonic emulsifier, a colloid mill, etc. For example, after the microemulsion is transferred to an open kettle, (d) a basic amino acid is added and mixed at a temperature of 55 ° C. or lower. In this embodiment, the temperature at which the microemulsion and (d) the basic amino acid are mixed is preferably in the range of room temperature to 50 ° C.

  Another embodiment of the method for producing a microemulsion composition according to the present invention is an oil phase comprising (a) a nonionic surfactant, (b) an oily component, and a first polyol. An oil phase preparation step for preparing a water phase, a water phase preparation step for preparing an aqueous phase containing a second polyol and water, a microemulsion preparation step for preparing a microemulsion containing an oil phase and an aqueous phase, After the microemulsion preparation step, a basic amino acid mixing step of mixing the above basic amino acid (d) with the microemulsion obtained in the microemulsion preparation step at a temperature of 55 ° C. or less. Here, the 1st polyol and the 2nd polyol can use the same thing as the above-mentioned (c) polyol, and each may be the same polyol or a different polyol. Moreover, the 1st polyol and the 2nd polyol may be 1 type, or 2 or more types of mixtures may be sufficient as them.

  In the oil phase preparation step, the oil phase is prepared by stirring and mixing a predetermined amount of the component (a), the component (b) and the first polyol, and other additives as necessary. The stirring and mixing may be performed as long as the oil phase is uniformly dissolved. For example, it is preferably performed at room temperature to 90 ° C. for about 1 to 30 minutes.

  In the aqueous phase preparation step, the aqueous phase is prepared by stirring and mixing a predetermined amount of the second polyol and water, and if necessary, other additives. The stirring and mixing may be performed as long as the aqueous phase is uniformly dissolved.

  In this embodiment, the blending amount of the component (a) is set so that the content of the component (a) is 0.1 to 10% by mass based on the total mass of the finally obtained microemulsion composition. It is preferable to do. Moreover, the compounding quantity of the said (b) component can be set so that content of (b) component may be 0.1-20 mass% on the basis of the total mass of the microemulsion composition finally obtained. preferable. The blending amount of the first polyol and the second polyol is such that the total content of the first polyol and the second polyol is 1.0 to 30% by mass based on the total mass of the finally obtained microemulsion composition. It is preferable to set so that.

  The blending amounts of the first polyol and the second polyol are set so that [the blending amount of the first polyol]: [the blending amount of the second polyol] = 1: 10 to 10: 1. Is preferred.

  In the microemulsion preparation step, for example, the water phase obtained in the water phase preparation step is added to the oil phase obtained in the oil phase preparation step, and the mixture is pre-emulsified by mixing at 70 ° C. or higher. A microemulsion is prepared by emulsification using a homomixer, a high-pressure homogenizer, an ultrasonic emulsifier or a colloid mill.

  In the basic amino acid mixing step, for example, the microemulsion obtained in the microemulsion preparation step is cooled to a temperature of 55 ° C. or lower and a solution of (d) 55 ° C. or lower containing the basic amino acid is added and mixed. . By setting the mixing temperature to 55 ° C. or lower in this way, it is possible to prevent the higher fatty acid and the basic amino acid from forming soap, particularly when the higher fatty acid is blended as the (b) oil component. The basic emulsion can be surely contained in the microemulsion composition, and the effect of adding higher fatty acids can be prevented from being impaired. Therefore, according to the above method, it is possible to easily reduce the blending amount of the surfactant and obtain a microemulsion composition having a higher level of safety.

  In this embodiment, the temperature at which the microemulsion and (d) the basic amino acid are mixed is preferably in the range of room temperature to 50 ° C.

  The solution containing the basic amino acid (d) at a temperature of 55 ° C. or lower is preferably prepared in advance by mixing (d) the basic amino acid, purified water, and other additives as required.

  The blending amount of the component (d) may be set so that the content of the component (d) is 0.01 to 2.0% by mass based on the total mass of the finally obtained microemulsion composition. preferable.

  Mixing of the microemulsion and the solution containing (d) a basic amino acid can be performed, for example, in an emulsification pot, an open kettle, or the like, and can be set as appropriate according to the apparatus in which the microemulsion is prepared.

  Through the basic amino acid mixing step, the microemulsion composition according to the present invention is obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

(Example 1) Moisturizing liquid (1) Squalane 7.8 (mass%)
(2) Refined jojoba oil 0.1
(3) Beeswax 0.2
(4) Stearic acid 0.5
(5) Hydrogenated palm oil 0.8
(6) Behenyl alcohol 1.2
(7) Lipophilic glyceryl monostearate 0.6
(8) Pentaglycerin monostearate 2.2
(9) d-δ-tocophenol 0.03
(10) Tri-fatty acid (D-20) glyceryl 0.1
(11) 1,3-butylene glycol 10.0
(12) 1,3-butylene glycol 6.0
(13) Purified water 24.0
(14) Purified water 30.97
(15) L-arginine (10% by mass aqueous solution) 0.2
(16) Phenoxyethanol 0.2
(17) Native ethanol 5.0
(18) Purified water 10.0
(19) Dimethylpolysiloxane (viscosity: 10 mPa · s) 0.1

Production method: First, components (1) to (11) were mixed to prepare an oil phase and heated to 80 ° C. On the other hand, components (12) and (13) were mixed to prepare an aqueous phase and heated to 80 ° C. Next, the aqueous phase was added to the oil phase, emulsified using a homomixer, and then purified water (14) at 80 ° C. was added. Next, after stirring and cooling until the temperature of the emulsion becomes 50 ° C. or lower, a solution (temperature 50 ° C.) in which the components (15) to (19) are mixed is added to this emulsion and stirred and mixed. A moisturizing liquid was obtained.

(Comparative Example 1) Moisturizing liquid A moisturizing liquid of Comparative Example 1 was obtained in the same manner as in Example 1 except that L-arginine (15) was not used and purified water (14) was 31.17% by mass. .

(Comparative example 2) Moisturizing liquid Oil phase using sodium lauryl sulfate (blending amount: 2.9% by mass) instead of lipophilic glyceryl monostearate, pentaglyceryl monostearate and trifatty acid (D-20) glyceryl A moisturizing liquid of Comparative Example 2 was obtained in the same manner as in Example 1 except that was prepared.

  Measurement of average particle diameter, pH and viscosity, storage stability test (5 ° C, 25 ° C, 40 ° C, 50 ° C, cycle), freeze-thaw test, shear test for moisturizing liquids of Example 1 and Comparative Examples 1 and 2 The sensory evaluation of the feeling of use and the skin irritation evaluation were performed based on the following methods. The results obtained are shown in Tables 3 and 4.

<Measurement of average particle diameter, pH and viscosity>
The average particle diameter was measured at a temperature of 25 ° C. by a dynamic scattering method. The pH was measured at a temperature of 25 ° C. The viscosity (mPa · s) was measured at a temperature of 25 ° C. using a B-type viscometer (rotor No. 4).

<Storage stability test>
The state of the emulsion after storage for 1 month at each temperature (5 ° C., 25 ° C., 40 ° C., 50 ° C.) was visually confirmed and evaluated based on the following criteria.
“◯”: Emulsion coalescence is not recognized.
“×”: Emulsion coalescence is recognized.

  Also, 24 hours at −5 ° C. and 24 hours at 30 ° C. are regarded as one cycle, and the number of cycles until the change in the state of the emulsion starts to be recognized is evaluated. "△", 1 cycle or less was taken as "x".

<Freeze-thaw test>
After freezing at −20 ° C. and then thawing at room temperature five times, the state of the emulsion was visually confirmed and evaluated based on the following criteria.
“◯”: Emulsion coalescence is not recognized.
“×”: Emulsion coalescence is recognized.

<Shear test>
The operation of putting a sample in a 100 mL glass syringe with a diameter of 1 mm and discharging it was set as one time, and the state of the emulsion after repeating this operation 10 times was visually confirmed and evaluated based on the following criteria.
“◯”: Emulsion coalescence is not recognized.
“×”: Emulsion coalescence is recognized.

<Sensory evaluation>
Usability was evaluated according to the evaluation items shown in Table 1 as a group of 10 female panels, and the average score was calculated.

<Evaluation of skin irritation>
A 48-hour occlusion sticking test was conducted by 20 male panelists, and the results were determined according to the criteria shown in Table 2 and indicated by the average value of the skin irritation index of 20 people.

  As shown in Tables 3 and 4, in Example 1, a moisturizing liquid that is a microemulsion having an average particle diameter of 300 nm or less is obtained, and the moisturizing liquid is excellent in stability at low and high temperatures and has skin irritation. It turned out that it was excellent in safety. Moreover, it was confirmed that the moisturizing agent of Example 1 is superior in moisturizing property as compared with the moisturizing agent of Comparative Example 1 that does not contain L-arginine. Furthermore, it was found that the humectant of Example 1 can stably maintain the state of the microemulsion even when a shearing force is applied. On the other hand, the moisturizing liquid of Comparative Example 1 was confirmed to have insufficient microemulsion stability. Moreover, it was confirmed that the moisturizing liquid of Comparative Example 2 using an anionic surfactant has a high skin irritation index and is insufficient in safety.

(Production method comparison example 1)
First, components (1) to (11) were mixed to prepare an oil phase and heated to 80 ° C. On the other hand, the component (12), purified water (13) and L-arginine (15) were mixed to prepare an aqueous phase and heated to 80 ° C. Next, the aqueous phase was added to the oil phase, emulsified using a homomixer, and then purified water (14) at 80 ° C. was added. Next, after stirring and cooling until the temperature of the emulsion was 50 ° C. or lower, a solution (temperature 50 ° C.) in which the components (16) to (19) were mixed was added to this emulsion and stirred and mixed. The emulsion was creamy (average particle size: 1 μm or more), and a microemulsion could not be obtained.

(Production method comparison example 2)
First, components (1) to (11) were mixed to prepare an oil phase and heated to 80 ° C. On the other hand, an aqueous phase was prepared by mixing component (12) and purified water (13), and heated to 80 ° C. Next, the water phase was added to the oil phase, emulsified using a homomixer, and then a mixed solution of purified water (14) and L-arginine (15) (temperature 80 ° C.) was added. Next, after stirring and cooling until the temperature of the emulsion was 50 ° C. or lower, a solution (temperature 50 ° C.) in which the components (15) to (19) were mixed was added to the emulsion and stirred and mixed. The emulsion was creamy (average particle size: 1 μm or more), and a microemulsion could not be obtained.

(Example 2) Moisturizing liquid (1) Decaglyceryl monolaurate 2.0 (mass%)
(2) Squalane 8.0
(3) Isostearyl alcohol 5.0
(4) 1,3-butylene glycol 7.0
(5) 1,3-butylene glycol 5.0
(6) Purified water 30.9
(7) Purified water 30.9
(8) Sodium pyrrolidonecarboxylate solution 0.5
(9) Methyl paraoxybenzoate 0.2
(10) Lysine (10% by mass aqueous solution) 0.5
(11) Purified water 10.0

Production method: First, components (1) to (4) were mixed to prepare an oil phase and heated to 80 ° C. On the other hand, components (5) and (6) were mixed to prepare an aqueous phase and heated to 80 ° C. Next, the water phase was added to the oil phase, emulsified using a homomixer, and then purified water (7) at 80 ° C. was added. Next, after stirring and cooling until the temperature of the emulsion becomes 50 ° C. or less, a solution (temperature 50 ° C.) in which the components (8) to (11) are mixed is added to this emulsion and stirred and mixed. A moisturizing liquid was obtained.

  The average particle diameter of the obtained moisturizing liquid was 180 nm. In addition, with respect to the obtained moisturizing liquid, the storage stability test (5 ° C., 25 ° C., 40 ° C., 50 ° C., cycle), freeze-thaw test, shear test, sensory evaluation of feeling of use, and skin irritation evaluation are described above. The results of the storage stability test (5 ° C., 25 ° C., 40 ° C., 50 ° C., cycle), the freeze-thaw test, and the shear test are all “◯”. The results of sex evaluation were “4.10” and “0”, respectively.

(Example 3) Emulsion (1) Decaglyceryl distearate 3.0 (mass%)
(2) Liquid paraffin 10.0
(3) Isostearic acid 5.0
(4) Glycerin 3.5
(5) Glycerin 3.5
(6) Purified water 32.2
(7) Purified water 32.3
(8) Methyl paraoxybenzoate 0.2
(9) L-arginine (10 mass% aqueous solution) 0.3
(10) Purified water 10.0

Production method: First, components (1) to (4) were mixed to prepare an oil phase and heated to 80 ° C. On the other hand, components (5) and (6) were mixed to prepare an aqueous phase and heated to 80 ° C. Next, the water phase was added to the oil phase, emulsified using a homomixer, and then purified water (7) at 80 ° C. was added. Next, after stirring and cooling until the temperature of the emulsion becomes 50 ° C. or lower, a solution (temperature 50 ° C.) in which the components (8) to (10) are mixed is added to this emulsion and stirred and mixed. The latex was obtained.

  The average particle diameter of the obtained emulsion was 220 nm. Moreover, about the obtained emulsion, a storage stability test (5 degreeC, 25 degreeC, 40 degreeC, 50 degreeC, a cycle), a freeze thaw test, a shear test, the sensory evaluation of a feeling of use, and skin irritation evaluation are described above. The results of the storage stability test (5 ° C., 25 ° C., 40 ° C., 50 ° C., cycle), the freeze-thaw test, and the shear test are all “◯”, and the sensory evaluation and skin irritation were performed. The evaluation results were “4.30” and “0”, respectively.

Claims (5)

  It is obtained by blending (d) a basic amino acid at a temperature of 55 ° C. or less with a microemulsion containing (a) a nonionic surfactant, (b) an oily component and (c) a polyol as essential components. A microemulsion composition.   The microemulsion composition according to claim 1, wherein the nonionic surfactant comprises a polyglycerin fatty acid ester.   The microemulsion composition according to claim 1 or 2, wherein at least one compound selected from the group consisting of arginine, lysine and histidine is blended as the basic amino acid. A microemulsion preparation step of preparing a microemulsion comprising (a) a nonionic surfactant, (b) an oil component, (c) a polyol, and water;
(D) a basic amino acid mixing step of mixing the basic amino acid and the microemulsion at a temperature of 55 ° C. or less after the microemulsion preparation step;
A process for producing a microemulsion composition, comprising: An oil phase preparation step of preparing an oil phase comprising (a) a nonionic surfactant, (b) an oil component, and a first polyol;
An aqueous phase preparation step of preparing an aqueous phase containing a second polyol and water;
A microemulsion preparation step of preparing a microemulsion comprising the oil phase and the aqueous phase;
(D) a basic amino acid mixing step of mixing the basic amino acid and the microemulsion at a temperature of 55 ° C. or less after the microemulsion preparation step;
A process for producing a microemulsion composition, comprising: