JP2015105249A - Cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cosmetic comprising α-lipoic acid and having excellent odor inhibitory effect.SOLUTION: A cosmetic comprises at least one selected from the group consisting of α-lipoic acid and salt thereof, and has pH of 7 or more.

Description

  The present invention relates to a cosmetic.

Since α-lipoic acid has a disulfide group and is highly reactive, it is known to exhibit various effects in vivo. Scalp hair removal treatment (Patent Document 1), whitening cosmetic (patent) Literature 2) and application to various preparations such as cosmetics containing α-lipoic acid, an antioxidant and a vitamin (Patent Literature 3) have been reported.
However, α-lipoic acid is a raw material with many problems due to its high reactivity and unique structure when it is added to a preparation.
For example, α-lipoic acid has low solubility in water in the region of pH 7 or lower, and is difficult to formulate. For this reason, a technique for improving solubility by derivatization such as introduction of a sulfonic acid group has been reported (Patent Document 4).
Further, α-lipoic acid has low stability to light, and it is known that dihydrolipoic acid is generated and polymerized by light irradiation (Non-patent Document 1).
In addition to the solubility, depending on the formulation of the preparation, a sulfur odor caused by an intramolecular disulfide group is generated, which makes the preparation more difficult.

JP 2008-174453 A Japanese Patent No. 4605774 JP-A-10-007541 Japanese Patent No. 4716666

Biochem. Mol. Bio. vol38, (1) 1996, pp 51-59).

However, as described in Patent Document 4, in the method in which α-lipoic acid is derivatized and dissolved, the formulation is limited or the derivatization reduces the effectiveness of the physiological activity of α-lipoic acid. There is a concern that.
On the other hand, as a general method for suppressing odor, there is a method such as masking with a fragrance or adsorption to an inclusion compound. However, masking with a fragrance limits the fragrance and makes it difficult to apply to various preparations, and the present situation is that an odor suppressing effect sufficient for the preparation cannot be obtained only by adsorption to the inclusion compound.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the cosmetics excellent in the odor suppression effect containing (alpha) -lipoic acid.

Means for solving the above problems are as follows.
[1] A cosmetic comprising at least one selected from the group consisting of α-lipoic acid and a salt thereof and having a pH of 7 or more.
[2] The cosmetic according to [1], wherein the pH is 7.2 or more and 10 or less.
[3] The cosmetic according to [1] or [2], which is an aqueous cosmetic.
[4] The cosmetic according to [3], containing at least one selected from the group consisting of cyclodextrin and derivatives thereof.
[5] At least one selected from the group consisting of cyclodextrin and derivatives thereof is at least one selected from the group consisting of γ-cyclodextrin and hydroxypropyl-β-cyclodextrin. Cosmetics.

[6] The cosmetic according to any one of [1] to [5], which contains at least one antioxidant selected from the group consisting of oil-based antioxidants and ascorbic acid derivatives.
[7] The composition according to any one of [1] to [6], comprising at least one selected from the group consisting of astaxanthin, tocopherol, tocotrienol (vitamin E), lycopene, and magnesium ascorbyl phosphate (APM). Cosmetics.

  ADVANTAGE OF THE INVENTION According to this invention, the cosmetics excellent in the odor suppression effect containing alpha lipoic acid can be provided.

  The cosmetic of the present invention is a cosmetic containing at least one selected from the group consisting of α-lipoic acid and salts thereof and having a pH of 7 or more.

In the present invention, by setting the pH of the cosmetic containing α-lipoic acid to 7 or more, the odor caused by α-lipoic acid is effectively suppressed, and the cosmetic preparation containing α-lipoic acid is formulated. The degree of freedom of prescription is improved, and a cosmetic product that makes use of the physiological activity of α-lipoic acid can be provided.
Moreover, since the secondary effect of improving the solubility of α-lipoic acid in an aqueous solvent can be obtained by setting the pH of the cosmetic to 7 or more, the cosmetic of the present invention is a water-based cosmetic. When applied, the effect of the present invention is remarkable.
In addition, water-in-oil type emulsified cosmetics can be expected to have a certain degree of odor suppression effect by dissolving α-lipoic acid in the oil, but do not contain an oil or contain a very small amount of water. However, since the effect cannot be expected, according to the present invention, since effective odor suppression is achieved, it is considered that it is suitably used for aqueous cosmetics from such a viewpoint.

In addition, the numerical value range shown using "to" in this specification shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively.
In the present invention, “aqueous phase” is used as a term for “oil phase” regardless of the type of solvent.
In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended purpose of this process is achieved even when it cannot be clearly distinguished from other processes. .
In the present invention, the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. Means.
The present invention will be described below.

<Cosmetics>
The cosmetic of the present invention is a cosmetic containing at least one compound selected from the group consisting of α-lipoic acid and salts thereof and having a pH of 7 or more.

(A) At least one selected from the group consisting of α-lipoic acid and salts thereof α-lipoic acid in the present invention (sometimes referred to as “thioctic acid”) typically has the following structure: And a compound represented by the chemical formula C ₈ H ₁₄ O ₂ S ₂ (molecular weight 206.3).
In the present invention, α-lipoic acid may be used in the form of a carboxylate. Examples of the salt include sodium salt, potassium salt, magnesium salt, calcium salt, aluminum salt and the like.
In the present specification, at least one selected from the group consisting of α-lipoic acid and a salt thereof may hereinafter be simply referred to as α-lipoic acid.
In the present specification, α-lipoic acid includes a salt form, but does not include α-lipoic acid and derivatives other than the salt.
For example, as described in Patent Document 4, one of the sulfur atoms in the disulfide bond reacts with another compound, or α-lipoic acid is oxidized to open the disulfide bond. This is because the physiological activity of α-lipoic acid may be reduced.

α-Lipoic acid is a compound that exhibits optical activity. In the present invention, α-lipoic acid is R, S-(+/−)-α-lipoic acid (hereinafter sometimes referred to as racemate), R-(+)-α-lipoic acid (hereinafter referred to as R-form). And S-(−)-α-lipoic acid (hereinafter sometimes referred to as S-form), or a mixture thereof.
From the viewpoint of safety when used in cosmetics, racemic and R forms are preferred.

As α-lipoic acid, a generally used synthetic product may be used, or an extract derived from a natural product component may be used.
As α-lipoic acid, a commercially available product can be used. Examples of commercially available products include α-lipoic acid standard products (Wako Pure Chemical Industries, Ltd.), DL-α-lipoic acid (Cayman Chemical Co.), (+)-α-lipoic acid (Toronto Research Chemicals). Inc.).

Since α-lipoic acid exists in the form of powder or crystals, α-lipoic acid in the form of powder or crystals may be used.
As described above, α-lipoic acid may be in the form of a salt.
Examples of the physiologically active action of α-lipoic acid include an action of enhancing cell ceramide production and an action of improving the skin barrier function. Specifically, effects such as improvement of skin moisture retention function, improvement of skin turnover, prevention of skin dryness, improvement of rough skin due to drying, and improvement of keratin proliferation can be expected.

The cosmetic of the present invention may contain only one kind of the above-mentioned α-lipoic acid or may contain two or more kinds.
The content of α-lipoic acid in the cosmetic is preferably 1% by mass or less, more preferably 0.0001% by mass to 1% by mass, and still more preferably 0.001% by mass to 0.1% by mass. It is.
When the content is 0.0001% by mass or more, biochemical effectiveness is obtained, and when the content is 1% by mass or less, the occurrence of roughness when the cosmetic is applied to the skin and dried is suppressed. Therefore, it is preferable.

(B) Cosmetic pH
The pH of the cosmetic is required to be 7 or higher. If the pH of the cosmetic is less than 7, the effect of suppressing odor is remarkably lowered, and the discomfort when the cosmetic is used on the face is particularly unfavorable.
The pH of the cosmetic is preferably pH 7.2 or higher, more preferably 7.5 or higher. Although there is no restriction | limiting in particular in the upper limit of pH, From a viewpoint of the safety to skin, it is preferable that it is 10 or less, and it is more preferable that it is 8.5 or less. That is, the pH of the cosmetic is preferably 7.2 or more and 10 or less, and more preferably 7.5 or more and 8.5 or less.
The pH of the cosmetic can be adjusted by a known method. That is, the pH can be adjusted using a known pH adjusting agent, buffering agent or the like.
As the pH adjusting agent and buffer used for adjusting the pH of the cosmetic of the present invention, any pH adjusting agent and buffer that are usually used in cosmetics can be used.
As the pH adjuster, at least one selected from the group consisting of inorganic acids, organic acids, inorganic bases and salts thereof can be used. Specifically, citric acid, gluconic acid, carboxylic acid, tartaric acid, succinic acid, acetic acid, phthalic acid, trifluoroacetic acid, morpholinoethanesulfonic acid, 2- [4- (2-hydroxyethyl) -1-piperazinyl] ethane Organic acids selected from the group consisting of sulfonic acids and salts thereof; organic bases selected from the group consisting of tris (hydroxymethyl), aminomethane, and ammonia; inorganic acids selected from the group consisting of hydrochloric acid, perchloric acid, and carbonic acid And an salt thereof; an inorganic base selected from the group consisting of sodium phosphate, potassium phosphate, calcium hydroxide, sodium hydroxide, potassium hydroxide, and magnesium hydroxide; from a group consisting of sodium hydrogen phosphate and sodium hydrogen carbonate Examples thereof include inorganic hydrogen salts selected, but are not limited thereto.
Among these, hydrochloric acid, malic acid, sodium malate, citric acid, sodium citrate, phosphoric acid, sodium phosphate, sodium hydroxide, potassium hydroxide and the like are preferable as the pH adjuster. About sodium salt and potassium salt, you may change a valence suitably as needed.
The pH adjuster is preferably used in a liquid having a concentration of 0.01 N to 3 N, and more preferably in a liquid having a concentration of 0.1 N to 1 N. By setting the concentration of the pH adjusting agent in the above-described range, the aggregation of the cosmetic-containing component that occurs when the concentration of the pH adjusting solution is too high, and the decrease in the emulsion stability of the emulsion composition are suppressed, and the cosmetic The pH fluctuation of the cosmetics is suppressed to a small range, and the concentration of each component of the cosmetic is undesirably lowered due to the addition of a large amount of the pH adjusting agent for pH adjustment caused by the pH adjusting agent being too thin. There is no concern about production problems or situations in which the desired effect of the active ingredient contained in the cosmetic cannot be obtained.
The pH of the cosmetic can be measured by a known method such as using a pH meter (manufactured by Horiba, Ltd.). The pH of the cosmetic in the present invention is a value measured at room temperature (25 ° C.).
The adjustment of the pH of the cosmetic, that is, the addition of the pH adjuster to the cosmetic may be performed in any of the steps for preparing the cosmetic.
When the cosmetic is an aqueous cosmetic, a pH adjuster can be added directly to the cosmetic. In the case of emulsified cosmetics, a pH adjuster is added to either or both of the aqueous phase composition and the oil phase composition before the emulsification dispersion step, and then the emulsification step is performed to adjust the pH. can do. Moreover, after preparing emulsified cosmetics, a pH adjuster can be added and pH can also be adjusted.

The cosmetic composition of the present invention is not particularly limited in its dosage form, and may be either an aqueous cosmetic composition or an emulsified cosmetic composition. The emulsified cosmetic may be an oil-in-water (O / W) emulsified cosmetic or a water-in-oil (W / O) emulsified cosmetic.
As described above, α-lipoic acid is hardly dissolved in an aqueous solvent, and the effect of the present invention is remarkable when applied to an aqueous cosmetic that cannot normally be expected to have an odor suppressing effect by coexisting with an oil component.
In the present specification, the water-based cosmetic is a cosmetic containing at least one liquid component selected from water and an aqueous solvent. In the UV-Vis absorption spectrum, the cosmetic is not diluted. Permeability can be measured and refers to visually transparent cosmetics.
The aqueous cosmetic may contain an oil component such as an oil agent. When the oily component is contained in the aqueous cosmetic, the aqueous cosmetic is a liquid composition containing the oily component in a solubilized state, or the content of the oily component with respect to the total amount of the cosmetic is 3% by mass. The embodiment is an oil-in-water (O / W type) emulsified composition in which the particle size of the emulsified particles containing an oil component is less than 200 nm.
In the present specification, the emulsified cosmetic refers to a water-in-oil type (W / O) containing 1% by mass or more of an oily component such as an oil with respect to the total amount of the cosmetic and having a particle diameter of the emulsified particles of 200 nm or more. Type) or an oil-in-water type (O / W type) emulsified composition.
In addition, the measurement of UV-Vis spectrum can be implemented at 25 degreeC using Hitachi, Ltd. U-3310 and the quartz cell whose optical path length is 1 cm.
Hereinafter, optional components that can be used in the cosmetic of the present invention will be described.

(C) Other component (C-1) At least one selected from the group consisting of cyclodextrin and derivatives thereof The cosmetic of the present invention has a viewpoint that the odor of α-lipoic acid can be more effectively suppressed. Therefore, it is preferable to contain at least one selected from the group consisting of cyclodextrin and derivatives thereof.
The cyclodextrin that can be used in the cosmetic of the present invention may be a cyclic oligosaccharide in which several molecules of D-glucose are linked by α-1,4 glucoside bonds to form a cyclic structure, for example, 6 to 12 And cyclodextrin containing a glucose unit thereof, and derivatives thereof.

  Specific examples of cyclodextrins include α-cyclodextrin in which 6 D-glucose is cyclic, β-cyclodextrin in which 7 D-glucose is cyclic, and 8 D-glucose in cyclic form. Γ-cyclodextrins, derivatives of these cyclodextrins, polymers that partially or partially arrange the cyclodextrin structure, and the like. Further, cyclodextrin or a cyclodextrin derivative has a cyclic structure capable of including α-lipoic acid, and the inside of the cyclic structure is hydrophobic and the outside is hydrophilic.

Cyclodextrin derivatives are compounds in which some or all of the hydroxyl groups at 2, 3, and 6 positions of glucose in the cyclodextrin are substituted with other functional groups, such as alkyl derivatives, hydroxyalkyl derivatives, alkoxy derivatives, sulfoalkyls. Examples thereof include ether derivatives and sugar bond derivatives.
Specific examples of cyclodextrin derivatives include hydroxymethylcyclodextrin, hydroxyethylcyclodextrin, hydroxypropylcyclodextrin, hydroxybutylcyclodextrin, dimethylcyclodextrin, trimethylcyclodextrin, diethylcyclodextrin, triethylcyclodextrin, carboxymethyl Examples thereof include cyclodextrin, glucosyl cyclodextrin, maltosyl cyclodextrin, dimaltosyl cyclodextrin, monochlorotriazinyl cyclodextrin, cyclodextrin epichlorohydrin polymer and the like.

  More specific compounds include, for example, sugar-linked derivatives that are branched cyclodextrins such as glucosyl-α-cyclodextrin, glucosyl-β-cyclodextrin, glucosyl-γ-cyclodextrin, and the like; 2,6-di-O— Methyl-α-cyclodextrin, 2,3,6-tri-O-methyl-α-cyclodextrin, 2,6-di-O-methyl-β-cyclodextrin, 2,3,6-tri-O-methyl Alkylated cyclodextrins such as β-cyclodextrin, 2,6-di-O-methyl-γ-cyclodextrin, 2,3,6-tri-O-methyl-γ-cyclodextrin; 2-hydroxyethyl-α -Cyclodextrin, 2-hydroxypropyl-α-cyclodextrin, 3-hydroxypropyl-α-cyclodextrin, 2,3 Dihydroxypropyl-α-cyclodextrin, 2-hydroxyethyl-β-cyclodextrin, 2-hydroxypropyl-β-cyclodextrin, 2,3-dihydroxypropyl-β-cyclodextrin, 2-hydroxyethyl-γ-cyclodextrin, Hydroxyalkylated cyclodextrins such as 2-hydroxypropyl-γ-cyclodextrin, 3-hydroxypropyl-γ-cyclodextrin, 2,3-dihydroxypropyl-γ-cyclodextrin; O-carboxymethyl-α-cyclodextrin, O -Carboxyalkylated cyclodextrins such as carboxymethyl-β-cyclodextrin, O-carboxymethyl-γ-cyclodextrin, sulfobutyl ether-α-cyclodextrin, sulfobutyl ether It can be exemplified methoxy cyclodextrin, alkoxylated cyclodextrin such as ethoxy cyclodextrin; Tel -β- cyclodextrin, sulfoalkyl ether derivatives, such as sulfobutyl ether -γ- cyclodextrin.

The at least one selected from the group consisting of cyclodextrins and derivatives thereof used in the cosmetics of the present invention may be any kind of cyclodextrins among the aforementioned cyclodextrins. From the viewpoints of further improving the odor suppressing effect of α-lipoic acid, availability, and easy handling, γ-cyclodextrin, 2-hydroxypropyl-γ-cyclodextrin, 2-hydroxypropyl-β- Cyclodextrin, 2,3-dihydroxypropyl-β-cyclodextrin and the like are preferable, and γ-cyclodextrin or 2-hydroxypropyl-β-cyclodextrin is more preferable.
A cyclodextrin may be used individually by 1 type in the cosmetics of this invention, and may use 2 or more types together.

  Moreover, a commercial item can be used for cyclodextrin. Examples of commercially available products include CAVAMAX W6 and CAVAMAX W6 Pharma (manufactured by Wacker Chemicals East Asia Co., Ltd.), Lindex A (manufactured by Mercian), Celdex A-100 (manufactured by Nippon Shokuhin Kako), Toyodelin (manufactured by Asahi Kasei), Dexipearl Α-cyclodextrin marketed as (manufactured by Shimizu Minato Sugar Co., Ltd.), α-cyclodextrin (manufactured by Hayashibara), etc .; CAVAMAX W7 (manufactured by Wacker Chemicals East Asia) and CAVAMAX W7 PHARMA (manufactured by Wacker Chemicals East Asia), Lindex B (manufactured by Mercian), Celdex B-100 (manufactured by Nippon Shokuhin Kako), Dexipearl β-100 (manufactured by Shimizu Minato), Oligoseven H (manufactured by Dainippon Pharmaceutical), β-cyclodextrin (manufactured by Hayashibara), etc. As commercially available Β-cyclodextrin; CAVAMAX W8, CAVAMAX W8 Food and CAVAMAX W8 Pharma (manufactured by Wacker Chemicals East Asia Co., Ltd.), Lindex C (manufactured by Mercian), Dexipal γ-100 (manufactured by Sakaiminato Sugar Co., Ltd.), Celdex G-100 Γ-cyclodextrin marketed as (made by Nippon Shokuhin Kako); CAVASOL W7 M, CAVASOL W7 M Pharma (manufactured by Wacker Chemicals East Asia Co., Ltd.) and CAVASOL W7 M TL (manufactured by Wacker Chemicals East Asia Co., Ltd.) Methyl-β-cyclodextrin; CAVASOL W7 HP (manufactured by Wacker Chemicals East Asia Co., Ltd.) and CAVASOL W7 HP Pharma (Wacker Chemica) Hydroxypropyl-β-cyclodextrin marketed as Luz East Asia Co., Ltd .; Monoacetyl-β-cyclodextrin marketed as CAVASOL W7 A (wacker chemicals East Asia Co., Ltd.); CAVASOL W7 TA (Wacker Chemicals East) Triacetyl-β-cyclodextrin marketed as ASIA Corporation); and monochlorotriazinyl-β-cyclodextrin marketed as CAVASOL W7 MCT (manufactured by Wacker Chemicals East Asia Co., Ltd.).

At least one selected from the group consisting of cyclodextrin and derivatives thereof may be used for both aqueous cosmetics and emulsified cosmetics, but is particularly preferably used for aqueous cosmetics.
The content in the case of using at least one selected from the group consisting of cyclodextrin and derivatives thereof in the cosmetic of the present invention is preferably 0.001% by mass to 5% by mass with respect to the total mass of the cosmetic, 0.005 mass%-2 mass% are more preferable, and 0.01 mass%-1 mass% are still more preferable.
When the cyclodextrin content is within the above range, the odor suppressing effect of α-lipoic acid can be further improved. Moreover, precipitation of cyclodextrin during formulation can be effectively suppressed.

(C-2) Antioxidant The cosmetic of the present invention preferably contains an antioxidant.
There is no restriction | limiting in particular in an antioxidant, A well-known antioxidant can be selected suitably and can be used. The antioxidant may be an oily antioxidant or an aqueous antioxidant. Of these, at least one antioxidant selected from the group consisting of oil-based antioxidants and aqueous ascorbic acid derivatives is preferable from the viewpoint of further improving the stability of α-lipoic acid and odor control.
Examples of oil-based antioxidants include carotenoids and radical scavengers containing oil-soluble vitamins. Hereinafter, the oil-based antioxidant will be described.

As carotenoids, carotenoids containing natural pigments can be preferably used. Examples of carotenoids that can be applied to the present invention include yellow to red terpenoid pigments, and those derived from plants, algae, and bacteria. Moreover, it is not limited to the thing of natural origin, A synthesis | combination and biosynthesis may be sufficient.
Carotenoids include actinioerythrol, astaxanthin, bixin, canthaxanthin, capsanthin, capsorubin, β-8′-apo-carotenal (apocarotenal), β-12′-apo-carotenal, α-carotene, β-carotene, “ Carotenes "(mixtures of α- and β-carotenes), γ-carotene, β-cryptoxanthin, echinone, lutein, lycopene, violaxanthin, zeaxanthin, and esters of those containing a hydroxyl group or a carboxyl group, etc. Can be mentioned.

  Examples of oil-soluble vitamins having an antioxidant action include vitamin E, retinoids, oil-soluble derivatives of ascorbic acid, etc. Among them, vitamin E that has a high antioxidant function and is useful as a radical scavenger (antioxidant). Is preferred.

  Vitamin E is not particularly limited, and examples thereof include those selected from a compound group consisting of tocopherol and its derivatives, and a compound group consisting of tocotrienol and its derivatives. These may be used alone or in combination. Moreover, you may use combining the compound group which consists of a tocopherol and its derivative (s), and the compound group which consists of a tocotrienol and its derivative (s), respectively.

  Tocopherol and its derivatives refer to tocopherol and derivatives having tocopherol as the basic skeleton. Specifically, α, β, γ, and δ tocopherol, which are isomers of tocopherol, are modified with fatty acids. Examples include tocopherol acetate and tocotrienol having a basic skeleton as a tocol. The origin of tocopherol and its derivatives is not particularly limited, and specifically may be sunflower, corn, olive, rapeseed, soybean, peanut, almond. The tocopherol derivatives may be used alone or in combination.

  The compound group consisting of tocopherol and its derivatives includes dl-α-tocopherol, dl-β-tocopherol, dl-γ-tocopherol, dl-δ-tocopherol, dl-α-tocopherol acetate, nicotinic acid-dl-α-tocopherol Linoleic acid-dl-α-tocopherol, succinic acid dl-α-tocopherol and the like. Among these, at least one selected from the group consisting of dl-α-tocopherol, dl-β-tocopherol, dl-γ-tocopherol, dl-δ-tocopherol, and a mixture thereof (mixed tocopherol) is more. preferable. In addition, as the tocopherol derivative, these acetates are preferably used.

  The compound group consisting of tocotrienol and derivatives thereof includes α-tocotrienol, β-tocotrienol, γ-tocotrienol, δ-tocotrienol and the like. In addition, as the tocotrienol derivative, these acetates are preferably used. Tocotrienol is a tocopherol-like compound contained in wheat, rice bran, palm oil, and the like, and has three double bonds in the side chain portion of tocopherol and has excellent antioxidant performance.

  Examples of retinoids include retinol, 3-hydroretinol, retinal, 3-hydroretinal, retinoic acid, 3-dehydroretinoic acid, vitamin A acetate and other vitamin A; α, β, γ-carotene, β-cryptoxanthin, Examples include carotenoids such as echinenone and provitamins A such as xanthophyll.

Examples of oil-solubilized derivatives of ascorbic acid include stearic acid L-ascorbyl ester, tetraisopalmitic acid L-ascorbyl ester, palmitic acid L-ascorbyl ester, palmitic acid erythorbyl ester, tetraisopalmitic acid erythorbyl ester, and ascorbyl dioleate. of vitamin C fatty acid esters, dipalmitate pyridoxine, tripalmitate pyridoxine dilaurate pyridoxine, fatty acid esters of vitamin B ₆ such as dioctanoate pyridoxine and the like.
As oil-based antioxidants, carotenoids such as astaxanthin, lycopene, and tocopherol and tocotrienol included in vitamin E are preferable from the viewpoint of the stability of α-lipoic acid.

Examples of aqueous antioxidants include ascorbic acid and its water-soluble derivatives, glutathione, uric acid, urobilinogen, hydroquinone and its derivatives, gallic acid and its derivatives, etc., from the viewpoint of applicability to cosmetics and availability. An esterified product of ascorbic acid which is a water-soluble derivative of ascorbic acid is preferable.
Ascorbic acid and its derivatives include ascorbic acid, sodium ascorbate, potassium ascorbate, calcium ascorbate, L-ascorbic acid phosphate, magnesium ascorbyl phosphate (magnesium ascorbyl phosphate: APM), ascorbyl phosphate Sodium, ascorbyl sulfate, ascorbyl sulfate disodium salt, ascorbyl-2-glucoside and the like can be mentioned.
Ascorbic acid (vitamin C) and its salts, ascorbyl phosphate palmitate (APPS) and the like have extremely high antioxidant properties, and depending on the formulation, there is a concern of affecting the stability of α-lipoic acid. From the viewpoint of further improving the stability of α-lipoic acid, ascorbic acid glucoside, ascorbyl phosphate Na (APS), and magnesium ascorbyl phosphate (APM) are preferred.

  As content of an antioxidant, in the case of water-based cosmetics, 0.0001 mass%-7 mass% are preferable with respect to the total amount of cosmetics, 0.001 mass%-5 mass% are more preferable, 0.01 mass%-3 mass% are still more preferable. In the case of an emulsified cosmetic, the content is preferably 0.0001% by mass to 2% by mass and more preferably 0.001% by mass to 1% by mass with respect to the total amount of the cosmetic.

(C-3) Oil agent The cosmetic of the present invention may contain an oil agent. The oil agent is not particularly limited as long as it does not dissolve in an aqueous medium. Examples of the oil agent include phospholipids, liquid fats and oils, fatty acid esters, and oil-soluble vitamins other than the various compounds mentioned as the oil-based antioxidant described above.
(Phospholipid)
Phospholipids can be used alone or in the form of a mixture of two or more.
Examples of the phospholipid include glycerophospholipid. Examples of glycerophospholipids include phosphatidic acid, bisphosphatidic acid, lecithin (phosphatidylcholine), phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatidylglycerin, diphosphatidylglycerin (cardiolipin), and the like. Examples thereof include those derived from plants such as soybean, corn, peanut, rapeseed and wheat, those derived from animals such as egg yolk and cattle, and various lecithins derived from microorganisms such as Escherichia coli.

Further, as the glycerophospholipid, enzymatically decomposed glycerophospholipid can be used. For example, lysolecithin obtained by enzymatic degradation of lecithin (enzymatic degradation lecithin) can be obtained by hydrolysis of lecithin with an acid or alkali catalyst, but can also be obtained by hydrolysis of lecithin using phospholipase A ₁ or A ₂ . When lyso compounds represented by such lysolecithin are represented by compound names, lysophosphatidic acid, lysophosphatidylglycerin, lysophosphatidylinositol, lysophosphatidylethanolamine, lysophosphatidylmethylethanolamine, lysophosphatidylcholine (lysolecithin), lysophosphatidylserine, etc. Is mentioned.

  A lecithin having a purity of 60% by mass or more is industrially used as lecithin. In the present invention, a lecithin purity of generally 80% by mass or more, generally referred to as “high-purity lecithin” is preferred, and more preferably 90% by mass or more.

  Of these, phospholipids other than enzyme-treated lysolecithin, lecithin, or hydrogenated lecithin can be preferably selected from the viewpoint of easy formulation into an emulsified cosmetic. Moreover, from the viewpoint of emulsion stability when blending a wide variety of components in cosmetics, phospholipids other than hydrogenated lecithin can be selected as the phospholipid.

(Oil-soluble vitamin)
Examples of oil-soluble vitamins include retinoids, vitamin Ds, and oil-soluble derivatives of erythorbic acid.
Examples of the fats and oils other than the above include liquid fats and oils (fatty oils) and solid fats and oils (fats) at room temperature.
(Liquid fat)
Examples of liquid oils include olive oil, camellia oil, macadamia nut oil, castor oil, avocado oil, evening primrose oil, turtle oil, corn oil, mink oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, southern oil, Linseed oil, cottonseed oil, eno oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, cinnagari oil, Japanese kiri oil, jojoba oil, germ oil, triglycerin, trioctanoic acid glycerin, triisopalmitic acid glycerin, Salad oil, safflower oil (safflower oil), palm oil, coconut oil, almond oil, hazelnut oil, walnut oil, grape seed oil, squalene, squalane and the like.
(Solid fat)
Solid fats include beef tallow, hardened beef tallow, beef leg fat, beef bone fat, mink oil, egg yolk oil, pork tallow, horse fat, sheep fat, hardened oil, cocoa butter, hardened coconut oil, palm hardened oil, owl, and owl Examples include kernel oil and hydrogenated castor oil.

(Fatty acid ester)
Preferred examples of the fatty acid ester include fatty acid esters having 10 to 18 carbon atoms. Examples of fatty acids constituting fatty acid esters having 10 to 18 carbon atoms include capric acid, sebacic acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, vacenoic acid, linoleic acid , Linolenic acid, eleostearic acid and the like, preferably myristic acid, palmitic acid and sebacic acid. Examples of the alcohol reacted with the fatty acid include monohydric alcohols such as methanol, ethanol, propanol, butanol and pentanol, and polyhydric alcohols such as ethylene glycol, butylene glycol, propylene glycol and glycerin. The alcohol to be reacted with the fatty acid may be linear or branched.

  As the fatty acid ester having 10 to 18 carbon atoms, isopropyl myristate, isopropyl palmitate, diisopropyl sebacate, propylene glycol caprate and propylene glycol dicaprate are preferable from the viewpoint of solubility of the glycyrrhetinic acid derivative, and tri (capryl / More preferred are glyceryl caprate, isopropyl myristate, isopropyl palmitate, and diisopropyl sebacate.

Among these oil agents, particularly preferred oil agents include isopropyl myristate, isopropyl palmitate, ethylhexyl palmitate, cetyl ethylhexanoate, isononyl isononanoate, diethyl sebacate, isopropyl adipate, isopropyl sebacate, diisostearyl malate, etc. Fatty acid esters, such as propylene glycol monocaprylate, propylene glycol dicaprylate, propylene glycol dicaprate, triethylhexanoin, tri (capryl / capric acid) glyceryl, and polyhydric alcohol fatty acid esters such as butylethylpropanediol ethylhexanoate Examples thereof include fatty acid esters having 10 to 18 carbon atoms.
1 mass% or more is preferable, 4 mass% or more is more preferable, and 8 mass% or more is still more preferable.

(C-4) Polyhydric alcohol The cosmetics of this invention can contain a polyhydric alcohol.
The polyhydric alcohol is generally a compound having a moisturizing function and a viscosity adjusting function. Furthermore, when polyhydric alcohol is used for the emulsified cosmetic, it also has a function of reducing the interfacial tension between water and the oil component and facilitating the formation of fine particles.
For this reason, for example, when used for aqueous cosmetics, the particle diameter of the dispersed particles contained in the cosmetics can be further refined. In addition, the addition of polyhydric alcohol has the advantage that the water activity of the aqueous cosmetic can be lowered and the growth of microorganisms can be suppressed.
In the present invention, “polyhydric alcohol” means a substance having two or more hydroxyl groups in a compound and liquid at 25 ° C.

Examples of the polyhydric alcohol that can be used in the present invention include propylene glycol, glycerin, 1,3-butyleneglycol diglycerin, isoprene glycol, dipropylene glycol, ethoxydiglycol (diethylene glycol monoethyl ether), pentylene glycol, And xylene glycol.
A polyhydric alcohol may contain only 1 type and may use 2 or more types together.
The content of the polyhydric alcohol used in the cosmetic is preferably 0.1% by mass to 35% by mass, and more preferably 1% by mass to 20% by mass with respect to the total amount of the cosmetic.

(C-5) Surfactant The cosmetic of the present invention can contain a surfactant. In the case of emulsified cosmetics, the oil / water phase interfacial tension can be greatly reduced, and stable emulsified particles can be formed. In the case of aqueous cosmetics, the oiliness required for cosmetics A surfactant is used to solubilize the components, such as oil-based antioxidants and oil agents, or to form fine particles having a particle system of less than 200 nm.
There is no restriction | limiting in particular as surfactant, The surfactant which can be used for cosmetics can be suitably selected and used according to a dosage form and the objective. As the surfactant, any of cationic, anionic, amphoteric and nonionic surfactants can be used.
In addition, when using for aqueous | water-based cosmetics, it is preferable that surfactant is a water-soluble surfactant.

Examples of the ionic surfactant include alkyl sulfonate, alkyl sulfate, monoalkyl phosphate, lecithin and the like. As the salts, sodium chloride, sodium citrate, sodium ascorbate and the like are used.
The content of these ionic surfactants is preferably 0.1 times or less with respect to the total mass of the oil component from the viewpoint of skin irritation when used in cosmetics. More preferably, it is not included.

Examples of nonionic surfactants include glycerin fatty acid ester, organic acid monoglyceride, polyglycerin fatty acid ester, propylene glycol fatty acid ester, polyglycerin condensed ricinoleic acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters. These nonionic surfactants can be contained as an oil phase component in the aqueous cosmetic of the present invention.
When the present aqueous cosmetic contains a nonionic surfactant, the content of the nonionic surfactant is 1% by mass or less with respect to the total mass of the aqueous cosmetic from the viewpoint of finer dispersion particles. , Preferably 0.5% by mass or less, and preferably 0.3% by mass or more.

  Such a nonionic surfactant is preferably a polyglycerin fatty acid ester from the viewpoint of emulsion stability. Particularly, a polyglycerin fatty acid ester having an HLB of 10 to 16 (hereinafter referred to as “specific polyglycerin as appropriate”). More preferably, it is referred to as “fatty acid ester”. The polyglycerin fatty acid ester may be contained in the oil phase.

  Surfactants such as specific polyglycerin fatty acid esters can greatly reduce the oil / water phase interfacial tension and, as a result, reduce the particle size of the emulsion contained in the aqueous cosmetic as the oil phase. It is preferable in that it can be performed.

Here, HLB is a balance between hydrophilicity and hydrophobicity that is usually used in the field of surfactants, and a commonly used calculation formula such as the Kawakami formula can be used. In the present invention, the following Kawakami equation is adopted.
HLB = 7 + 11.7 log (M _w / M _O )
Here, M _w molecular weight of the hydrophilic groups, M _O is the molecular weight of the hydrophobic group.

  Moreover, you may use the numerical value of HLB described in the catalog etc. Further, as can be seen from the above formula, a surfactant having an arbitrary HLB value can be obtained by utilizing the additivity of HLB.

  The water-soluble surfactant is preferably HLB 8 or more, more preferably 10 or more, and particularly preferably 12 or more, from the viewpoint of emulsion stability. The upper limit value of the HLB value of the water-soluble surfactant is not particularly limited, but is generally 20 or less, and preferably 18 or less.

  Water-soluble nonionic surfactants include glycerin fatty acid ester, organic acid monoglyceride, polyglycerin fatty acid ester, propylene glycol fatty acid ester, polyglycerin condensed ricinoleic acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters. The water-soluble surfactant is not necessarily highly purified by distillation or the like, and may be a reaction mixture.

  More preferable examples of the water-soluble surfactant include polyglycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, and polyoxyethylene sorbitan fatty acid ester. The water-soluble surfactant most preferably used in the present invention is at least one selected from the group consisting of sucrose fatty acid ester and polyglycerin fatty acid ester, and it is particularly preferable to use these in combination.

The polyglycerol fatty acid ester used in the present invention has an average degree of polymerization of 2 or more, preferably 6 to 15, more preferably 8 to 10 and a fatty acid having 8 to 18 carbon atoms such as caprylic acid and capric acid. An ester with lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid is preferred. Preferred examples of polyglycerol fatty acid esters include hexaglycerol monooleate, hexaglycerol monostearate, hexaglycerol monopalmitate, hexaglycerol monomyristate, hexaglycerol monolaurate, decaglycerol monooleate , Decaglycerin monostearic acid ester, decaglycerin monopalmitic acid ester, decaglycerin monomyristic acid ester, decaglycerin monolauric acid ester and the like. Among these, more preferably, decaglycerol monooleate (HLB = 12), decaglycerol monostearate (HLB = 12), decaglycerol monopalmitate (HLB = 13), decaglycerol monomyristate (HLB = 14), decaglycerin monolaurate (HLB = 16) and the like.
Polyglycerol fatty acid ester may be used individually by 1 type, and may use 2 or more types together.

As sucrose fatty acid ester used for this invention, the carbon number of a fatty acid is 12 or more, and the thing of 12-20 is more preferable. Preferred examples of sucrose fatty acid esters include sucrose dioleate, sucrose distearate, sucrose dipalmitate, sucrose dimyristic ester, sucrose dilaurate, sucrose monooleate, sucrose Examples include sugar monostearate, sucrose monopalmitate, sucrose monomyristic ester, and sucrose monolaurate. Among these, sucrose monooleate, sucrose monostearate, sucrose Monopalmitate, sucrose monomyristate, and sucrose monolaurate are more preferable.
In the cosmetics of the present invention, sucrose fatty acid esters may be used alone or in combination of two or more.

The sorbitan fatty acid ester used in the present invention preferably has a fatty acid having 8 or more carbon atoms, more preferably 12 or more. Preferred examples of sorbitan fatty acid esters include sorbitan monocaprylate, sorbitan monolaurate, sorbitan monostearate, sorbitan sesquistearate, sorbitan tristearate, sorbitan isostearate, sorbitan sesquiisostearate, sorbitan oleate, sorbitan sesquioleate And sorbitan trioleate.
Sorbitan fatty acid ester may be used individually by 1 type, and may use 2 or more types together.

  The polyoxyethylene sorbitan fatty acid ester used in the present invention preferably has a fatty acid having 8 or more carbon atoms, more preferably 12 or more. Moreover, as length (average addition mole number) of the ethylene oxide of polyoxyethylene, 2-100 are preferable and 4-50 are more preferable. Preferable examples of polyoxyethylene sorbitan fatty acid ester include sorbitan polyoxyethylene monocaprylate, sorbitan polyoxyethylene monolaurate, sorbitan polyoxyethylene monostearate, sorbitan polyoxyethylene sesquistearate, sorbitan polyoxyethylene tristearate Sorbitan polyoxyethylene isostearate, sorbitan polyoxyethylene sesquiisostearate, sorbitan polyoxyethylene oleate, sorbitan polyoxyethylene sesquioleate, sorbitan polyoxyethylene trioleate, and the like.

These surfactants may be used individually by 1 type, and may be used in combination of multiple types.
The addition amount of the surfactant is appropriately selected depending on the dosage form of the cosmetic, but generally 0.5% by mass to 30% by mass is preferable with respect to the total amount of the cosmetic, and 1% by mass to 20%. More preferably, it is more preferably 2% by mass to 15% by mass. By setting the surfactant amount to 0.5% by mass or more, the interfacial tension between the oil phase and the water phase can be easily lowered, and by setting it to 30% by mass or less, the surfactant is not excessive. It is preferable because irritation to the skin hardly occurs.

(C-6) Other components In addition to the above components, the cosmetic of the present invention may appropriately contain additive components that are usually used in the fields of foods, cosmetics, and the like depending on the form.
The other additive component can be contained in the cosmetic of the present invention as an oil-soluble or water-soluble additive component depending on its characteristics.

For example, as other additive components,
Monosaccharides or polysaccharides such as glucose, sucrose, copper carrageenan, locust bean gum, guar gum, hydroxypropyl guar gum, xanthan gum, karaya gum, tamarind seed polysaccharide, gum arabic, tragacanth gum, hyaluronic acid, sodium hyaluronate, sodium chondroitin sulfate, dextrin ;
Sugar alcohols such as sorbitol, mannitol, maltitol, lactose, maltotriitol, xylitol;
Inorganic salts such as sodium chloride and sodium sulfate;
Proteins with a molecular weight exceeding 5000, such as casein, albumin, methylated collagen, hydrolyzed collagen, water-soluble collagen, gelatin, etc .;
Amino acids such as glycine, alanine, valine, leucine, isoleucine, serine, threonine, aspartic acid, glutamic acid, cystine, methionine, lysine, hydroxylysine, arginine, histidine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, acetylhydroxyproline, etc. Their derivatives;
Synthetic polymers such as carboxyvinyl polymer, sodium polyacrylate, polyvinyl alcohol, polyethylene glycol, ethylene oxide / propylene oxide block copolymer;
Water-soluble cellulose derivatives such as hydroxyethyl cellulose and methyl cellulose;
Flavonoids such as catechin, anthocyanin, flavone, isoflavone, flavan, flavanone, rutin;
Phenolic compounds such as chlorogenic acid, ellagic acid, gallic acid, propyl gallate;
Hydroxystilbenes including lignans, curcumins, coumarins, pterostilbene and the like; phenoxyethanol and the like can be mentioned.
These compounds may be included as functional components, excipients, viscosity modifiers, radical scavengers and the like based on their functions.
In addition, in the present invention, for example, various medicinal components, ultraviolet absorbers, preservatives, fragrances, colorants, etc., other additives that are usually used in the application can be used in combination.

<Cosmetics dosage form and cosmetic production method>
The cosmetic of the present invention contains α-lipoic acid and has a pH of 7 or more, and there is no particular limitation on the dosage form, and it may be either an aqueous cosmetic or an emulsified cosmetic.
The manufacturing method of cosmetics is not specifically limited, It can manufacture according to a well-known method.
As a method for producing an aqueous cosmetic, for example, a) an α-lipoic acid, a water-soluble surfactant and other water-soluble components are dissolved in an aqueous medium (water, etc.) to obtain an aqueous phase composition. B-1) Solubilizing oil agents such as oil-based antioxidants, oil agents, and oil-soluble active ingredients (such as carotenoids) that are optionally contained using a surfactant or the like c) obtained under stirring Production including each step of mixing a solubilized oil agent or a dispersion of the oil agent into an aqueous phase composition, adding a pH adjuster to adjust the pH to 7 or more, and obtaining an aqueous cosmetic. The method is preferred.

As a method for producing an emulsified cosmetic, for example, a) an α-lipoic acid, a water-soluble surfactant, and other water-soluble components are dissolved in an aqueous medium (such as water) to obtain an aqueous phase composition. B) Mixing or dissolving oil-based antioxidants, oil agents, and oil-soluble active ingredients (carotenoids, etc.) contained as required to obtain an oil phase composition, c) Aqueous phase composition and oil phase under stirring A production method including the steps of mixing the composition, emulsifying and dispersing, adding a pH adjuster to adjust the pH to 7 or more, and obtaining an emulsified cosmetic is preferable.
In addition, although the example which added the pH adjuster after adjusting cosmetics was described here, you may use a pH adjuster before and after preparing cosmetics. When using a pH adjuster before an emulsification process, you may add a pH adjuster to any of the water phase composition before an emulsification process, and an oil phase composition.

When cosmetics contain an oil phase and an aqueous phase, the ratio (mass) of an oil phase and an aqueous phase is not specifically limited, It selects suitably according to the dosage form of cosmetics.
By appropriately selecting the oil phase / water phase ratio, it is possible to prepare a cosmetic that sufficiently exhibits the physiological activity of α-lipoic acid, further suppresses odor, and does not deteriorate stability.

  The emulsification or mixing method is not particularly limited, and known means, for example, known stirrers and emulsifiers such as a stirrer, impeller, disper, homomixer, and high-pressure emulsifier can be used.

  In both aqueous cosmetics and emulsified cosmetics, when emulsifying and dispersing, one step of emulsification may be performed, but performing two or more steps of emulsification yields uniform and fine emulsified particles. It is preferable from the point. Specifically, in addition to a one-step emulsification operation in which emulsification is performed using a normal emulsification apparatus (for example, stirrer or impeller stirring, homomixer, continuous flow shearing apparatus, etc.) using a shearing action, a high-pressure homogenizer, It is particularly preferable to use two or more types of emulsifying devices together by a method such as emulsification through an ultrasonic disperser or the like. By using a high-pressure homogenizer, the emulsion can be arranged into even more uniform droplets of fine particles. Further, it may be performed a plurality of times for the purpose of forming a droplet having a more uniform particle diameter.

[Cosmetics of cosmetics]
When transparency is required for the cosmetic of the present invention, turbidity can be used as an index of transparency regarding the cosmetic.
The turbidity in this invention is prescribed | regulated by the light absorbency measured at 25 degreeC using the light of wavelength 650nm. In the present invention, the absorbance (turbidity) serving as an index of “transparency” is measured using a spectrophotometer (for example, V-630, manufactured by JASCO Corporation). The turbidity (absorbance) of the highly transparent cosmetic in the present invention is preferably 0.001 to 0.20, more preferably 0.001 to 0.18, still more preferably 0.001 to 0.00. 15.

[Usage]
The cosmetics of the present invention include lotions (skin lotions), essences (beauty serums), milky lotions, clay packs, impregnating liquids for lotion masks, fragrance cosmetics, creams, packs, facial cleansers, shampoos, conditioners, hair restorers and the like. A typical example is given.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to them at all.
Unless otherwise specified, the numerical value indicating the content is “mass%”.

[Reference Example 1, Examples 1 to 3 and Comparative Examples 1 to 4: Aqueous Cosmetics]
(1) Preparation of aqueous cosmetics The ingredients listed in Table 1 below are dissolved for 1 hour while heating at 40 ° C, then cooled to room temperature, and using a pH adjuster (1N Na hydroxide, 1M hydrochloric acid). By adjusting to the pH described in Table 1, an aqueous cosmetic is obtained.

(2) Evaluation of cosmetics / Odor evaluation The odor of the obtained cosmetics is sensory-evaluated on the basis of the following criteria by 10 monitors. The results are also shown in Table 1. As an evaluation result, an average value of 10 monitors is adopted.
The ranks S to B + are odor levels that can be used as cosmetics.
(Evaluation criteria)
S: Sulfur odor cannot be recognized even if consciously sniffed A: Slight sulfur odor can be recognized if sniffed consciously B +: Slightly sulfur odor can be recognized without consciousness, but acceptable as cosmetics B- : Slightly sulfur odor can be recognized without being conscious, Level C which is a problem as cosmetics C: Clear sulfur odor can be recognized D: Sulfur odor is remarkable

From the results in Table 1, when 0.01% by mass of α-lipoic acid was added to the formulation of Reference Example 1 which is a standard aqueous cosmetic, as described in Comparative Example 2, the same formulation was used. It has a clear sulfur odor and is not suitable for cosmetics. Moreover, in the comparative example 1 which made pH lower, a sulfur smell is felt more strongly. When the pH is raised, the odor level becomes lower, but even in Comparative Example 4 where the pH is 6.5, a sulfur odor is felt without being conscious, and it is unsuitable for use as a cosmetic.
On the other hand, in the aqueous cosmetics of Examples 1 to 3 according to the present invention, the sulfur odor is hardly recognized, it is a level that can be used as a cosmetic, and can be sufficiently masked by a general scent.

[Example 4, Comparative Example 5: Emulsified cosmetic]
(Preparation of emulsified cosmetics)
In Table 2 below, the constituents of A phase (oil phase), B phase (oil phase), and C phase (aqueous phase) are heated to 70 ° C. and mixed well for 30 minutes to obtain an A phase composition, B A phase composition and a C phase composition are respectively prepared.
The C-phase composition is stirred at 1000 rpm in the A-phase composition heated to 50 ° C. and emulsified and stirred for 5 minutes while applying a shearing force to obtain an emulsion. Similarly, the B phase composition is added, emulsified and stirred, cooled to room temperature (25 ° C.) while stirring at 30 rpm, and a pH adjuster (0.2N hydroxide K, 0.1M citric acid) is added as appropriate. By adjusting the pH described in Table 2, an emulsified cosmetic is obtained.

When the odors of the emulsified cosmetics of Example 4 and Comparative Example 5 obtained were evaluated in the same manner as in Example 1, the emulsified cosmetic of Example 4 is at a level where the sulfur odor is hardly noticed. On the other hand, in the emulsified cosmetic of Comparative Example 5, a sulfur odor is felt without being conscious, and it is difficult to use as a cosmetic.
In addition, compared with the aqueous cosmetic of Comparative Example 2, the emulsified cosmetic of Comparative Example 5 has a slightly improved odor even at the same pH. This is because a part of α-lipoic acid is an emulsified cosmetic. This is thought to be due to the fact that it was adsorbed on the oil phase and the generation of odor was alleviated.

[Examples 5 to 6, Comparative Example 6: aqueous cosmetic]
Each component described in Table 3 below was heated to 40 ° C., sufficiently stirred and mixed at 100 rpm for 30 minutes, and then cooled to room temperature, and then a pH adjuster (0.1 M citric acid) , 0.1 M Na citrate) to adjust the pH as shown in Table 3 to prepare an aqueous cosmetic.

  The odors of the obtained aqueous cosmetics of Examples 5 to 6 and Comparative Example 6 were evaluated in the same manner as in Example 1. As a result, the emulsified cosmetics of Examples 5 to 6 were at a level at which the sulfur odor was hardly noticed. It is. On the other hand, in the water-based cosmetic of Comparative Example 6, a sulfur odor is felt without being conscious, and it is difficult to use as a cosmetic.

[Examples 7 to 13: aqueous cosmetic]
Each component described in Table 4 below is heated to 40 ° C., sufficiently stirred and mixed at 100 rpm for 30 minutes, and then cooled to room temperature to prepare an aqueous cosmetic.

  When the odors of the obtained aqueous cosmetics of Examples 7 to 13 were evaluated in the same manner as in Example 1, the emulsified cosmetics of Examples 7 to 13 were at a level where the sulfur odor was hardly noticed. Example 8 containing hydroxypropyl-β-cyclodextrin, which is a cyclodextrin, is extremely excellent in odor control effect. As a control, the formulation and evaluation results of Example 1 are shown in Table 4. In the comparison between Example 1 and Examples 7 to 13, it is found that the odor of α-lipoic acid is more effectively suppressed in the aqueous cosmetic by adding cyclodextrin.

[Examples 14 to 22: aqueous cosmetic]
Each component described in the following Table 5 is heated to 40 ° C., sufficiently stirred and mixed for 30 minutes under the condition of 100 rpm, and then cooled to room temperature, and a pH adjuster (1N Na hydroxide, 1M Aqueous cosmetics are prepared by adjusting the pH as shown in Table 5 using hydrochloric acid.
In the cosmetics of Examples 14 to 22, in addition to odor, the stability of α-lipoic acid contained is evaluated according to the following criteria.
-Stability evaluation of α-lipoic acid α-lipoic acid-containing cosmetics were stored for 4 weeks under conditions of 50 ° C and humidity 55% RH.
Before and after storage, measure the content of α-lipoic acid by liquid high-performance chromatography, and calculate the residual ratio (mass ratio) from the content of α-lipoic acid after storage with respect to the content before storage And evaluated according to the following criteria. The results are shown in Table 5.
(Evaluation criteria)
A: The residual rate of α-lipoic acid is 90% by mass or more A: The residual rate of α-lipoic acid is 80% by mass or more and less than 90% by mass B: The residual rate of α-lipoic acid is less than 80% by mass

Table 5 shows the results of evaluating the odor of the obtained aqueous cosmetics of Examples 14 to 22 in the same manner as in Example 1.
From the results of Table 5, it can be seen that in the emulsified cosmetics of Examples 14 to 22, the sulfur odor is at a level that is hardly worrisome, and the usability as a cosmetic is good in terms of odor.
It can also be seen that the storage stability of α-lipoic acid is excellent. In addition, from comparison with Examples 14-16 and Examples 17-22, as an antioxidant, it is magnesium ascorbyl phosphate [In Table 5, it is described as Mg ascorbyl phosphate (APM)], and it is an oil-based antioxidant. Aqueous cosmetics containing tocotrienol, astaxanthin, lycopene, and tocopherol are more excellent in the stability of α-lipoic acid. Among them, as an antioxidant, ascorbyl phosphate, tocotrienol, It can be seen that it is preferable to use lycopene and tocopherol.

In addition, each component used by said Example and comparative example is as follows.
・ Water, ultrapure water: Milli-Q water (water with a specific resistance value of 18 MΩ · cm or more at 25 ° C. obtained by further purifying pure water)
-POE hydrogenated castor oil (HCO-60, manufactured by Nikko Chemicals)
-BG: 1,3 butylene glycol-Dimethicone: KF-96A, manufactured by Shin-Etsu Silicone Co., Ltd.-Diphenylsiloxyphenyl trimethicone: KF-56A, manufactured by Shin-Etsu Silicone Co., Ltd.-Polyglyceryl oleate-10: NIKKOL Decaglyn 1-OV, Nikko Chemicals -Polysorbate 60: NIKKOL TS-10V, manufactured by Nikko Chemicals-[Acrylates / alkyl acrylate (C10-30)] crosspolymer: AQUPEC HV-501ER, manufactured by Sumitomo Seika Co., Ltd., tri (caprylic acid / capric acid) glyceryl ： Coconard MT of Kao Corporation
・ PEG-240 / decyltetradeces-20 / hexamethyl diisocyanate: GT-700, manufactured by ADEKA ・ Hydroxypropyl-β-cyclodextrin: HP-β-CD, manufactured by Nippon Shokuhin Kako Co., Ltd. ・ Cluster cyclodextrin: glyconutrition Food Co., Ltd. Tocopherol: Riken E Oil 800 manufactured by Riken Vitamin Co., Ltd.
・ Lecithin: Purified lecithin: SLP-White, manufactured by Sakai Oil Co., Ltd. (derived from soybean)

  As described above, it can be seen that the cosmetics of Examples are cosmetics in which the odor of α-lipoic acid is suppressed and the stability with time of α-lipoic acid is good.

Claims (7)

  A cosmetic comprising at least one selected from the group consisting of α-lipoic acid and salts thereof and having a pH of 7 or more.   The cosmetic according to claim 1, having a pH of 7.2 or more and 10 or less.   The cosmetic according to claim 1 or 2, which is an aqueous cosmetic.   The cosmetic according to claim 3, comprising at least one selected from the group consisting of cyclodextrin and derivatives thereof.   The cosmetic according to claim 4, wherein at least one selected from the group consisting of cyclodextrin and derivatives thereof is at least one selected from the group consisting of γ-cyclodextrin and hydroxypropyl-β-cyclodextrin. .   The cosmetic according to any one of claims 1 to 5, comprising at least one antioxidant selected from the group consisting of an oily antioxidant and an ascorbic acid derivative.   The cosmetic according to any one of claims 1 to 6, comprising at least one selected from the group consisting of astaxanthin, tocopherol, tocotrienol, lycopene, and ascorbic acid phosphate magnesium salt.