JP7163261B2 - OIL-IN-WATER EMULSION COMPOSITION AND EXTERNAL SKIN PREPARATION - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to an oil-in-water emulsion composition and an external preparation for skin.

Tetrahydropiperine is a component obtained from black pepper, and is known to have actions such as promotion of percutaneous absorption and promotion of blood circulation. As a technique utilizing the action of tetrahydropiperine, for example, Patent Document 1 discloses a method for improving the bioavailability of nutrients, drugs, etc. by administering nutrients, drugs, etc. together with tetrahydropiperine. there is

Japanese translation of PCT publication No. 2003-534295

Since tetrahydropiperine alone is a component that is difficult to dissolve in an aqueous medium, it is difficult to incorporate it into aqueous cosmetics. For example, when tetrahydropiperine is dispersed in the form of solid particles and formulated as a solid dispersion, high skin penetration of tetrahydropiperine when applied to the skin cannot be expected.
The present inventors confirmed that tetrahydropiperine contained in emulsified particles and dispersed in an aqueous medium to form an oil-in-water emulsified composition facilitates incorporation into aqueous cosmetics.

By the way, water-based cosmetics are required to easily permeate sebum-rich areas such as pores. In order to effectively exhibit the action of tetrahydropiperine, an emulsified composition containing tetrahydropiperine is required to have good affinity with sebum (so-called sebum compatibility). In addition, the emulsified composition is generally required to have stability over time at low temperatures.

An object of one aspect of the present disclosure is to provide an oil-in-water emulsion composition that contains tetrahydropiperine, has good compatibility with sebum, and has excellent stability over time at low temperatures.
Another aspect of the present disclosure aims to provide an external preparation for skin containing an oil-in-water emulsified composition.

Specific means for solving the above problems include the following embodiments.
[1] Tetrahydropiperine;
an oily component having a value representing the ratio of the inorganic value to the organic value [so-called IOB (Inorganic Organic Balance) value] in the range of more than 0.16 and less than 0.40;
an emulsifier;
water and,
An oil-in-water emulsion composition comprising:
[2] The oil-in-water emulsion composition according to [1], wherein the emulsion particles have an average particle size of 100 nm or less.
[3] The oil-in-water emulsion composition according to [1] or [2], wherein the emulsifier contains at least one selected from the group consisting of sucrose fatty acid esters, polyglycerin fatty acid esters, and phospholipids.
[4] The oil-in-water emulsion composition according to [3], wherein the monoester content in the sucrose fatty acid ester is 80% by mass or more relative to the total mass of the sucrose fatty acid ester.
[5] The oil-in-water emulsion composition according to [3] or [4], wherein the polyglycerol fatty acid ester contains a fatty acid structure having at least one of a branched chain and an unsaturated carbon bond.
[6] The oil-in-water emulsion composition according to any one of [1] to [5], wherein the oily component is at least one of isononyl isononanoate and ethylhexyl isononanoate.
[7] An external skin preparation comprising the oil-in-water emulsion composition according to any one of [1] to [6].
[8] The external preparation for skin according to [7], which is an aqueous cosmetic.

According to one aspect of the present disclosure, there is provided an oil-in-water emulsion composition that contains tetrahydropiperine, has good compatibility with sebum, and has excellent stability over time at low temperatures.
According to another aspect of the present disclosure, there is provided an external preparation for skin containing the oil-in-water emulsion composition.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is by no means limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the purpose of the present invention.

In the present disclosure, a numerical range indicated using "to" means a range including the numerical values before and after "to" as the minimum and maximum values, respectively.
In the present disclosure, in the numerical ranges described in stages, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. Also, in the numerical ranges described in the present disclosure, the upper or lower limits of a certain numerical range may be replaced with the values shown in the examples.
In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect.
In the present disclosure, the amount of each component in the oil-in-water emulsion composition is the oil-in-water emulsion composition unless otherwise specified when a plurality of substances corresponding to each component are present in the oil-in-water emulsion composition. It means the total amount of multiple substances present in an object.

In the present disclosure, the “oil phase” means the dispersed phase in an oil-in-water dosage form, and includes a liquid medium of the dispersed phase and components dispersed or dissolved in the liquid medium.
In the present disclosure, the "aqueous phase" means the continuous phase in an oil-in-water dosage form, and includes the liquid medium of the continuous phase and components dispersed or dissolved in the liquid medium.

[Oil-in-water emulsion composition]
In the oil-in-water emulsion composition of the present disclosure, tetrahydropiperine and a value representing the ratio of the inorganic value to the organic value (hereinafter referred to as “IOB value”) are more than 0.16 and less than 0.40 (hereinafter referred to as “specific oily component” as appropriate), an emulsifier, and water.
The oil-in-water emulsion composition of the present disclosure contains tetrahydropiperine, has good compatibility with sebum, and is excellent in stability over time at low temperatures.

Each component of the oil-in-water emulsion composition of the present disclosure will be described in detail below.

[Tetrahydropiperine]
The oil-in-water emulsion composition of the present disclosure comprises tetrahydropiperine.
Tetrahydropiperine is a component obtained from black pepper.
Tetrahydropiperine has actions such as promotion of percutaneous absorption and promotion of blood circulation, and for example, it can increase the skin permeability of ingredients applied to the skin together with tetrahydropiperine.

A commercial item can be used as tetrahydropiperine.
Examples of commercially available tetrahydropiperine include Cosmoperine [trade name, purity: 99% by mass, Sabinsa Japan Corporation].

The content of tetrahydropiperine in the oil-in-water emulsion composition of the present disclosure is not particularly limited, but is, for example, 0.1% by mass to 5.0% by mass with respect to the total mass of the oil-in-water emulsion composition. is preferably 0.1% by mass to 4.0% by mass, more preferably 0.1% by mass to 3.0% by mass, and 0.5% by mass to 1.0% by mass % is particularly preferred.
Tetrahydropiperine is a component that is difficult to dissolve in an aqueous medium by itself, but the oil-in-water emulsion composition of the present disclosure has an oil-in-water dosage form in which tetrahydropiperine is included in emulsified particles and dispersed in an aqueous medium. Therefore, for example, tetrahydropiperine can be contained at a relatively high concentration of 5.0% by mass relative to the total mass of the oil-in-water emulsified composition.

[Oil component with an IOB value in the range of more than 0.16 and less than 0.40]
The oil-in-water emulsified composition of the present disclosure contains an oily component (that is, a specific oily component) having an IOB value in the range of more than 0.16 and less than 0.40.
In the present disclosure, "oily component" means a component that has a solubility in water of less than 0.1% by mass (less than 1 g/L) at 25°C.

The specific oily component is preferably, for example, a component that is generally used as an oily component in the fields of cosmetics and quasi-drugs. Moreover, the specific oily component is preferably a component that can be applied to the skin.
The specific oily component is preferably liquid, more preferably liquid at 25°C. Here, the expression that the oil component is "liquid at 25°C" means that the melting point or softening point of the oil component is lower than 25°C. The specific oily component may be, for example, solid at 25°C and soluble in other oily components at 25°C.

The type of the specific oily component is not particularly limited as long as it is an oily component with an IOB value in the range of more than 0.16 and less than 0.40.
Types of specific oily components include, for example, ester oils, hydrocarbon oils, silicone oils, and animal and vegetable oils and fats.
Among these, ester oils are preferable as the type of the specific oily component, for example, when formulating cosmetics or quasi-drugs (eg, medicinal cosmetics).

The IOB value of the specific oily component is in the range of more than 0.16 and less than 0.40, preferably in the range of 0.17 or more and 0.35 or less, and in the range of 0.18 or more and 0.25 or less more preferably 0.19 or more and 0.23 or less, and particularly preferably 0.19 or more and 0.21 or less.
When the IOB value of the specific oily component exceeds 0.16, the oil-in-water emulsion composition tends to exhibit excellent stability over time at low temperatures.
When the IOB value of the specific oily component is less than 0.40, the oil-in-water emulsified composition tends to have good sebum compatibility.

The IOB value is a value that represents the ratio of the inorganic value (IV: Inorganic Value) to the organic value (OV: Organic Value), which is obtained based on an organic conceptual diagram, and is an index that indicates the degree of polarity of an organic compound. Well known.
The IOB value is represented by the following formula (I). A higher IOB value indicates a higher polarity. The IOB value is explained in detail in "Organic Conceptual Diagram" (Yoshio Koda, Sankyo Publishing, 1984). Specifically, the IOB value is described in "Prediction of Organic Compounds and Organic Conceptual Diagram", Fujita (Kagaku no Ryoryo 11-10), 1957, p. 719-p. 725, "Emulsion formulation design based on organic conceptual diagram", Nippon Emulsion Co., Ltd., Yaguchi, 1985, p. 98].
IOB value = Inorganic value (IV)/Organic value (OV) (I)

In the present disclosure, reference values for the organic value (OV) and inorganic value (IV) used to calculate the IOB value are shown below.
Intramolecular carbon (OV: 20, IV: 0)
Carbon-carbon double bond (OV: 0, IV: 2)
Carbon-carbon triple bond (OV: 0, IV: 3)
Carbon chain branching (OV: -10, IV: 0)
COO (OV: 0, IV: 60)
-OH (OV: 0, IV: 100)
-O- (OV: 0, IV: 20)

Specific examples of specific oily components include isobutyl myristate (IOB value: 0.17), isopropyl myristate (IOB value: 0.18), isodecyl isononanoate (IOB value: 0.18), isononyl isononanoate (IOB value: 0.20), ethylhexyl isononanoate (IOB value: 0.20), isodecyl neopentanoate (IOB value: 0.22), diethylhexyl sebacate (IOB value: 0.24), neopentyl glycol diethylhexanoate (IOB value: 0.25), diisostearyl malate (IOB value: 0.28), pentaerythrityl tetraethylhexanoate (IOB value: 0.35), and the like.
Among these, the specific oily components include, for example, isononyl isononanoate and ethylhexyl isononanoate, from the viewpoint of achieving both excellent stability over time at low temperatures and good compatibility with sebum in an oil-in-water emulsified composition in a well-balanced manner. At least one of is preferred.

A commercial item can be used as a specific oil-based component.
Examples of commercial products of the specific oily component include NIKKOL (registered trademark) IPM-100 [trade name, chemical name: isopropyl myristate, Nikko Chemicals Co., Ltd.], EMALEX NINI-99 [trade name, chemical name: isononanoic acid. Isononyl, Nippon Emulsion Co., Ltd.], EMALEX NIO-98 [trade name, chemical name: ethylhexyl isononanoate, Nippon Emulsion Co., Ltd.], KAK NDO [trade name, chemical name: neopentyl glycol diethylhexanoate, KOKYU ALCOHOL KOGYO Ltd.], NIKKOL (registered trademark) DISM [trade name, chemical name: diisostearyl malate, Nikko Chemicals Co., Ltd.], Salacos 5408 [trade name, chemical name: pentaerythrityl tetraethylhexanoate, Nisshin OilliO Group Co., Ltd.] and the like.

The oil-in-water emulsion composition of the present disclosure may contain only one type of specific oily component, or may contain two or more types.

The content of the specific oily component in the oil-in-water emulsion composition of the present disclosure is not particularly limited, but is preferably, for example, 1% by mass to 50% by mass with respect to the total mass of the oil-in-water emulsion composition. , more preferably 3% to 30% by mass, even more preferably 5% to 20% by mass, and particularly preferably 8% to 15% by mass.
When the content of the specific oily component in the oil-in-water emulsion composition of the present disclosure is 1% by mass or more with respect to the total mass of the oil-in-water emulsion composition, the concentration of tetrahydropiperine is not too low, more moderate becomes.
When the content of the specific oil component in the oil-in-water emulsion composition of the present disclosure is 50% by mass or less with respect to the total mass of the oil-in-water emulsion composition, the emulsification dispersibility of the oil-in-water emulsion composition is more show a tendency to excel.

In addition, the content of the specific oil component in the oil-in-water emulsion composition of the present disclosure, for example, from the viewpoint that the stability over time of the oil-in-water emulsion composition at low temperatures tends to be more excellent, the content of the emulsifier described later With respect to the amount, on a mass basis, it is preferably 0.1 to 4.0, more preferably 0.3 to 3.0, even more preferably 0.5 to 2.0, 0.8 to 1.7 is particularly preferred.

〔emulsifier〕
The oil-in-water emulsion composition of the present disclosure includes an emulsifier.
Although the emulsifier is not particularly limited, it is preferably a component generally used as an emulsifier in the fields of cosmetics and quasi-drugs, for example. Also, the emulsifier is preferably a component that can be applied to the skin.

Emulsifying agents include, for example, surfactants and phospholipids.
The HLB value of the emulsifier is, for example, preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more, from the viewpoint of emulsification dispersibility of the oil-in-water emulsified composition.
Although the upper limit of the HLB value of the emulsifier is not particularly limited, it is generally 20 or less, preferably 18 or less.
HLB means hydrophilic-hydrophobic balance, commonly used in the field of surfactants. The HLB value is calculated using the Kawakami formula shown below. In addition, when using a commercial product as an emulsifier, a commercial catalog data is preferentially adopted.

HLB = 7 + 11.7 log (Mw/Mo)
Here, Mw indicates the molecular weight of the hydrophilic group, and Mo indicates the molecular weight of the hydrophobic group.

The type of surfactant is not particularly limited, and may be an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or a nonionic surfactant.
Among these, as the type of surfactant, it is less irritating to the skin, has less impact on the environment, and has less effect on the emulsification dispersibility of the oil-in-water emulsion composition due to pH. Therefore, nonionic surfactants are preferred.

Examples of nonionic surfactants include sucrose fatty acid esters, polyglycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and the like.
Among these, as the nonionic surfactant, for example, at least one selected from the group consisting of sucrose fatty acid esters and polyglycerin fatty acid esters is preferred.

Sucrose fatty acid ester is not particularly limited.
The number of carbon atoms in the fatty acid structure contained in the sucrose fatty acid ester is preferably 12 or more, more preferably 12-20.
Specific examples of sucrose fatty acid esters include sucrose dioleate, sucrose distearate, sucrose dipalmitate, sucrose dimyristate, sucrose dilaurate, sucrose monooleate, sucrose sugar monostearate, sucrose monopalmitate, sucrose monomyristate, sucrose monolaurate and the like.
Among these, sucrose monostearate (cosmetics labeling name: sucrose stearate) is preferable as the sucrose fatty acid ester.

The content of the monoester in the sucrose fatty acid ester is not particularly limited, but for example, from the viewpoint that the oil-in-water emulsified composition tends to exhibit better stability over time at low temperatures, the total mass of the sucrose fatty acid ester is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and particularly preferably 80% by mass or more.
The upper limit of the monoester content in the sucrose fatty acid ester is not particularly limited, but may be, for example, 100% by mass with respect to the total mass of the sucrose fatty acid ester.

The content of monoester in sucrose fatty acid ester is a value obtained by the following method.

<How to determine the content of monoester in sucrose fatty acid ester>
-Sample preparation-
A sucrose fatty acid ester is dissolved in tetrahydrofuran to prepare a sample solution with a concentration of 1 mg/mL.
-Measurement condition-
Apparatus used: high-performance liquid chromatography [trade name: Prominence, Shimadzu Corporation]
Detection method: Corona charged particle detection method Column: CAPCELL PAK (registered trademark) C18 [trade name, type: UG120, inner diameter 4.6 mm x length 150 mm, Osaka Soda Co., Ltd.]
Column temperature: 40°C
Eluent: A solution prepared by adding ammonium acetate to a concentration of 10 mM in water/methanol = 50/50 (v/v) and dissolving it Flow rate: 1 mL/min Injection volume: 10 μL
- Calculation method -
Calculate the ratio of the peak area at the retention time of 17 to 22 minutes to the total area of the peak at the retention time of 15 to 30 minutes detected in the chromatogram obtained by the above method. The obtained value is rounded off to the first decimal place and taken as the monoester content.

A commercial item can be used as a sucrose fatty acid ester.
Examples of commercially available sucrose fatty acid esters include Mitsubishi Chemical Foods Co., Ltd. "Ryoto (registered trademark) sugar ester" series "S-070" [HLB value (catalog value): 1 or less, monoester ( Catalog value): about 0% by mass], “S-170” [HLB value (catalog value): about 1, monoester body (catalog value): about 1% by mass], “S-270” [HLB value (catalog value) value): about 2, monoester (catalog value): about 10% by mass], “S-370” [HLB value (catalog value): about 3, monoester (catalog value): about 20% by mass], "S-370F" [HLB value (catalog value): about 3, monoester body (catalog value): about 20% by mass], "S-570" [HLB value (catalog value): about 5, monoester body ( Catalog value): about 30% by mass], “S-770” [HLB value (catalog value): about 7, monoester body (catalog value): about 40% by mass], “S-970” [HLB value (catalog value): about 40% by mass] value): about 9, monoester body (catalog value): about 50% by mass], “S-1170” [HLB value (catalog value): about 11, monoester body (catalog value): about 55% by mass], "S-1170F" [HLB value (catalog value): about 11, monoester body (catalog value): about 55% by mass], "S-1570" [HLB value (catalog value): about 15, monoester body ( Catalog value): about 70% by mass], “S-1670” [HLB value (catalog value): about 16, monoester body (catalog value): about 75% by mass] (above, sucrose stearate), etc. mentioned.
Examples of commercially available sucrose fatty acid esters include Daiichi Kogyo Seiyaku Co., Ltd.'s "DK Ester (registered trademark)" series "SS" [HLB value (catalog value): about 19, monoester ( Catalog value): 97% by mass], “F-160”, “F-140”, “F-110”, “F-90”, “F-70”, “F-50”, “F-20W” , "F-10", "FA-10E", "Cosmelike (registered trademark)" series "S-10", "S-50", "S-70", "S-110", "S- 160", "S-190" [HLB value (catalog value): about 19, monoester (catalog value): 97% by mass] and the like.
Among them, commercial products of sucrose fatty acid esters include "Ryoto (registered trademark) sugar ester" series "S-1170", "S-1170F", "S-1570" and "S-1670", "DK Ester (registered trademark)" series "SS", "F-160", "F140", and "F110", and "Cosmelike (registered trademark)" series "S-110", "S- 160", and at least one selected from the group consisting of "S-190". and "S-190" of the "Cosmelike (registered trademark)" series is particularly preferred.

Polyglycerin fatty acid ester is not particularly limited.
The polyglycerin structure contained in the polyglycerin fatty acid ester may be linear, branched, or cyclic.
The average degree of polymerization of the polyglycerin structure contained in the polyglycerol fatty acid ester is preferably 2 or more, more preferably 2-10.
The number of carbon atoms in the fatty acid structure contained in the polyglycerin fatty acid ester is not particularly limited, but is preferably 6 to 22, more preferably 12 to 22, and even more preferably 12 to 20, 12-18 is particularly preferred.
The fatty acid structure contained in the polyglycerol fatty acid ester may have at least one of a branched chain and an unsaturated carbon bond, for example, from the viewpoint that the oil-in-water emulsified composition tends to exhibit better stability over time at low temperatures. preferable.

The polyglycerin fatty acid ester may be one molecule of polyglycerol in which one type of fatty acid is ester-bonded, or one molecule of polyglycerin in which two or more types of fatty acids are ester-bonded.

The polyglycerol fatty acid ester may contain a fatty acid structure having at least one of a branched chain and an unsaturated carbon bond, for example, from the viewpoint that the oil-in-water emulsified composition tends to exhibit better stability over time at low temperatures. More preferably, it contains a fatty acid structure having either a branched chain or an unsaturated carbon bond.

Specific examples of polyglycerol fatty acid esters include polyglyceryl-6 laurate, polyglyceryl-6 myristate, polyglyceryl-6 stearate, polyglyceryl-6 isostearate, polyglyceryl-6 oleate, polyglyceryl-10 laurate, polyglyceryl-myristate- 10, polyglyceryl-10 stearate, polyglyceryl-10 isostearate, polyglyceryl-10 oleate, polyglyceryl-10 linoleate and the like.
Among them, the polyglycerol fatty acid ester is at least one selected from the group consisting of polyglyceryl-6 oleate, polyglyceryl-10 oleate, polyglyceryl-10 linoleate, polyglyceryl-6 isostearate, and polyglyceryl-10 isostearate. is preferred, and at least one selected from polyglyceryl-10 isostearate and polyglyceryl-10 oleate is more preferred.

A commercial item can be used as a polyglycerol fatty acid ester.
Examples of commercially available polyglycerol fatty acid esters include Nikko Chemicals Co., Ltd.'s "NIKKOL (registered trademark) Decaglyn" series "1-ISV", "1-OV", "1-LN", Mitsubishi Chemical Foods ( Co., Ltd. “Ryoto (registered trademark) Polyglyester” series “O-15D” and “O-50D”, Taiyo Kagaku Co., Ltd. “Sunsoft QS” series “Q-17S”, Riken Vitamin "J-0381V" of the "Poem" series of Co., Ltd., and the like.

Phospholipids include, for example, lecithin, which is a phospholipid derived from natural products.
Lecithin refers to phosphatidylcholine itself or a mixture containing at least phosphatidylcholine.
A mixture containing at least phosphatidylcholine generally includes, in addition to phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, phosphatidylinositol, N-acylphosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, lysophosphatidylcholine, lysophosphatidic acid, sphingomyelin, It is a mixture that can include sphingoethanolamine and the like.

Enzyme-decomposed lecithin (so-called lysolecithin) can be used as retitin.
Enzymatically degraded lecithin is a composition containing lysophosphatidylcholine from which one fatty acid of the phosphatidylcholine molecule has been lost by an enzyme such as phospholipase. In the oil-in-water emulsified composition of the present disclosure, the enzymatically decomposed lecithin is a so-called hydrogenated enzymatically decomposed lecithin in which oxidation stability is improved by performing a hydrogenation treatment to convert the bound fatty acid to a saturated fatty acid. include.

The purity of lecithin is, for example, preferably 80% by mass or more, more preferably 90% by mass or more, from the viewpoint of emulsification dispersibility.
The purity of lecithin is determined from the weight of toluene-insoluble matter and acetone-soluble matter, taking advantage of the fact that lecithin is easily soluble in toluene but not acetone.

A commercially available product can be used as the phospholipid.
Examples of commercially available phospholipids include SLP-White [trade name, Tsuji Oil Co., Ltd.], Ratio P [trade name, Riken Vitamin Co., Ltd.], and the like.

The emulsifier, for example, from the viewpoint that skin irritation tends to be lower, preferably contains at least one selected from the group consisting of sucrose fatty acid esters, polyglycerin fatty acid esters, and phospholipids, and sucrose fatty acid esters , polyglycerol fatty acid esters, and phospholipids.
In addition, the emulsifier is, for example, a sucrose fatty acid ester, a polyglycerin fatty acid ester, and a phosphorus, from the viewpoint that it is possible to realize an oil-in-water emulsified composition with better sebum compatibility and more excellent stability over time at low temperatures. It is preferred to include combinations with lipids.

The oil-in-water emulsion composition of the present disclosure may contain only one emulsifier, or may contain two or more emulsifiers.

The content of the emulsifier in the oil-in-water emulsion composition of the present disclosure is not particularly limited. It is more preferably from 7% by mass to 20% by mass, and even more preferably from 7% by mass to 15% by mass.
When the content of the emulsifier in the oil-in-water emulsion composition of the present disclosure is 1% by mass or more with respect to the total mass of the oil-in-water emulsion composition, the interfacial tension between the oil phase and the water phase is further lowered. , tend to be easier to emulsify.
When the content of the emulsifier in the oil-in-water emulsion composition of the present disclosure is 30% by mass or less with respect to the total mass of the oil-in-water emulsion composition, the occurrence of foaming in the oil-in-water emulsion composition can be further suppressed. Tend.

〔water〕
The oil-in-water emulsion composition of the present disclosure contains water.
Water is not particularly limited, and examples thereof include natural water, purified water, distilled water, ion-exchanged water, pure water, and ultrapure water (eg, Milli-Q water). Note that Milli-Q water is ultrapure water obtained by Merck's Milli-Q (registered trademark) water maker.
The water contained in the oil-in-water emulsion composition of the present disclosure is preferably purified water, distilled water, ion-exchanged water, pure water, or ultrapure water, for example, from the viewpoint of less impurities.

The water content in the oil-in-water emulsified composition of the present disclosure is not particularly limited, and can be appropriately set according to the purpose.

[Other ingredients]
The oil-in-water emulsion composition of the present disclosure optionally contains tetrahydropiperine, a specific oily component, an emulsifier, and components other than water (so-called other components) within a range that does not impair the effects of the present disclosure. You can
Other components include, for example, additive components commonly used in cosmetics (hereinafter also simply referred to as “additive components”).

(Additional component)
The oil-in-water emulsion composition of the present disclosure may contain additional components.
Examples of additive components include functional components that exhibit useful cosmetic effects (moisturizing effect, whitening effect, skin conditioning effect, etc.) when used in cosmetics.
Examples of such functional ingredients include carotenoids such as β-carotene, astaxanthin, zeaxanthin, lycopene, and lutein; vitamin E such as tocopherol and tocotrienol; ubiquinone such as coenzyme Q10; glycerin, 1,3-butylene glycol, and dipropylene glycol. polyhydric alcohols such as hyaluronic acid, erythritol, xylitol, glucose, sorbitol, and trehalose; polysaccharides such as glucosylceramide and galactosylceramide; glycosphingolipids such as hydrolyzed collagen and water-soluble collagen; amino acid; hydrolyzed silobanal lupin protein; nicotinic acid amide;
Additives other than those mentioned above include preservatives, ultraviolet absorbers, anti-inflammatory agents, colorants, fragrances, and the like.
One of these additive components may serve two or more functions.

When the oil-in-water emulsion composition of the present disclosure contains an additive component, the content of the additive component in the oil-in-water emulsion composition is not particularly limited, and can be appropriately set according to the purpose.

-Average particle size of emulsified particles-
The average particle size of the emulsified particles in the oil-in-water emulsion composition of the present disclosure is not particularly limited, but is, for example, preferably 100 nm or less, more preferably 60 nm or less, and even more preferably 30 nm or less. , 10 nm or less.
Although the lower limit of the average particle size of the emulsified particles in the oil-in-water emulsion composition of the present disclosure is not particularly limited, it is preferably 5 nm or more, for example.

In the present disclosure, the "average particle size" of emulsified particles means the volume average particle size.
The average particle size of emulsified particles is measured by a dynamic light scattering method using a particle size distribution meter after diluting the oil-in-water emulsified composition 10 times with ultrapure water.
As the particle size distribution analyzer, for example, Nanotrac UPA (trade name) manufactured by Microtrac Bell Co., Ltd. can be preferably used. However, the particle size distribution meter is not limited to this.

[Use of oil-in-water emulsion composition]
The oil-in-water emulsion composition of the present disclosure can be suitably used as a raw material for cosmetics, quasi-drugs (eg, medicinal cosmetics), and the like.

[Method for producing oil-in-water emulsion composition]
The method for producing the oil-in-water emulsion composition of the present disclosure is not particularly limited.
The oil-in-water emulsion composition of the present disclosure is a known oil-in-water emulsion composition using tetrahydropiperine, a specific oil component, an emulsifier, water, and, if necessary, the aforementioned additive components. can be manufactured according to the manufacturing method of

One of the preferred methods for producing the oil-in-water emulsion composition of the present disclosure is to mix an oil phase composition containing tetrahydropiperine and a specific oily component and an aqueous phase composition containing water to obtain a mixed solution. It is a method of emulsifying and dispersing the mixed liquid obtained. In this method, the emulsifier may be contained in the oil phase composition, may be contained in the aqueous phase composition, or may be contained in both the oil phase composition and the aqueous phase composition. , can be appropriately set according to the characteristics of the emulsifier.

The oil phase composition can be prepared, for example, by mixing tetrahydropiperine, a specific oily component, an emulsifier, and oily additive components among optional additive components.
In preparing the oil phase composition, all the components to be blended in the oil phase composition may be mixed at once, or each component to be blended in the oil phase composition may be divided into several and mixed. .
The components to be blended into the oil phase composition may be simply mixed in the oil phase composition, and are preferably uniformly mixed.
The mixing method is not particularly limited, and examples thereof include a method of mixing by stirring.
A general stirring instrument or stirring device can be used for stirring.

The stirring temperature is not particularly limited, but is preferably set to 50° C. or higher, for example, from the viewpoint of increasing the solubility of tetrahydropiperine.
Means for adjusting the temperature are not particularly limited, and a common heating device (eg, water bath) can be used.
The stirring time is not particularly limited, and can be appropriately set according to the type of stirring instrument or stirring device, the composition of the oil phase composition, and the like.
A preferred example of the stirring temperature and stirring time is a mode in which the stirring temperature is 80° C. and the stirring time is 1 hour.

The aqueous phase composition can be prepared, for example, by mixing water, an emulsifier, and water-based additive components among optional additive components.
When preparing the aqueous phase composition, all the components to be blended in the aqueous phase composition may be mixed at once, or each component to be blended in the aqueous phase composition may be divided into several and mixed. .
The components to be incorporated into the aqueous phase composition may be simply mixed in the aqueous phase composition, and preferably uniformly mixed.
The mixing method is not particularly limited, and examples thereof include a method of mixing by stirring.
A general stirring instrument or stirring device can be used for stirring.

The stirring temperature is not particularly limited, but is preferably set to 100°C or lower, more preferably 60°C to 90°C, from the viewpoint of preventing bumping.
Means for adjusting the temperature are not particularly limited, and a common heating device (eg, water bath) can be used.
The stirring time is not particularly limited, and can be appropriately set according to the type of stirring instrument or stirring device, the composition of the aqueous phase composition, and the like.
A preferred example of the stirring temperature and stirring time is a mode in which the stirring temperature is 80° C. and the stirring time is 1 hour.

When mixing the oil phase composition and the water phase composition, the oil phase composition and the water phase composition may be mixed at once, or one may be mixed while adding the other little by little.
The mixing method is not particularly limited, and examples thereof include a method of mixing by stirring.
A general stirring instrument or stirring device can be used for stirring.

The temperature of the oil phase composition when mixed with the water phase composition is preferably set to 100° C. or less, more preferably 60° C. to 90° C., from the viewpoint of preventing bumping.
The temperature of the aqueous phase composition is preferably set to, for example, 60°C to 90°C.
The stirring time is not particularly limited, and can be appropriately set according to the type of stirring instrument or stirring device, the composition of the oil phase composition and the aqueous phase composition, and the like.

The emulsifying and dispersing method is not particularly limited.
For emulsifying and dispersing, for example, after emulsifying and dispersing using a normal emulsifying and dispersing device such as an ultrasonic homogenizer and a homomixer, a high-pressure emulsifying device [for example, a high-pressure homogenizer such as Starburst Mini manufactured by Sugino Machine Co., Ltd.] is used. It is preferable to use two or more emulsifying devices in combination, such as emulsifying and dispersing using
Using a high-pressure emulsifier makes it possible to make the emulsified particles more uniform in particle size.
For the purpose of further homogenizing the particle size, emulsification and dispersion may be performed multiple times.

The high-pressure emulsifying apparatus includes a chamber-type high-pressure homogenizer having a chamber in which the flow path of the processing liquid is fixed, a homogenization valve-type high-pressure homogenizer having a homogenization valve, and the like.

The pressure of the high-pressure homogenizer is preferably 100 MPa or higher, more preferably 100 MPa to 250 MPa, still more preferably 150 MPa to 250 MPa.

The ratio of the oil phase composition to the aqueous phase composition (oil phase composition/aqueous phase composition) is not particularly limited, but is preferably 1/99 to 50/50 on a mass basis. /97 to 40/60, more preferably 5/95 to 30/70, and particularly preferably 10/90 to 20/80.
When the ratio of the oil phase composition to the water phase composition is 1/99 or more on a mass basis, the concentration of tetrahydropiperine does not become too low and becomes more moderate.
When the ratio of the oil phase composition to the aqueous phase composition is 50/50 or less on a mass basis, the oil-in-water emulsified composition tends to have better emulsification dispersibility.

[External preparation for skin]
The external preparation for skin of the present disclosure includes the oil-in-water emulsion composition of the present disclosure described above.
The oil-in-water emulsion composition of the present disclosure contains tetrahydropiperine, has good compatibility with sebum, and has excellent stability over time at low temperatures. , promotion of percutaneous absorption, promotion of blood circulation, etc. are effectively exhibited.

The external preparation for skin of the present disclosure is preferably an aqueous cosmetic.
In the present disclosure, "aqueous cosmetic" means a cosmetic having a water content of 50% by mass or more with respect to the total mass of the aqueous cosmetic.
Tetrahydropiperine alone is difficult to dissolve in an aqueous medium, and when tetrahydropiperine is dispersed in the state of solid particles and formulated as a solid dispersion, high skin penetration of tetrahydropiperine when applied to the skin cannot be expected. In contrast, the oil-in-water emulsion composition of the present disclosure has an oil-in-water dosage form in which tetrahydropiperine is dispersed in an aqueous medium by including tetrahydropiperine in emulsified particles. Expected to be highly permeable to the skin.

The content of the oil-in-water emulsified composition of the present disclosure in the external preparation for skin of the present disclosure is not particularly limited, and can be appropriately set according to the purpose.
For example, the content of the oil-in-water emulsified composition of the present disclosure may be 0.01% by mass to 5% by mass with respect to the total mass of the external skin preparation.

Hereinafter, the oil-in-water emulsion composition of the present disclosure will be described more specifically with reference to examples. However, the oil-in-water emulsion composition of the present disclosure is not limited to the following examples as long as the gist thereof is not exceeded.

[Preparation of oil-in-water emulsion composition]
[Example 1]
Each component constituting the oil phase composition shown in Table 2 below was placed in a container and stirred in a water bath at 80° C. for 1 hour using a stirrer to obtain an oil phase composition. Next, each component constituting the aqueous phase composition shown in Table 2 below is placed in a container and stirred for 1 hour using a stirrer in a water bath at 80 ° C. to obtain an aqueous phase composition. rice field.
Next, the aqueous phase composition was stirred using a stirrer in a water bath at 80° C., and the oil phase composition was gradually added to the stirred aqueous phase composition to obtain a mixed liquid. The resulting mixture was subjected to dispersion treatment for 1 minute per 100 g of the mixture using an ultrasonic homogenizer [model number: US600-AT, Nippon Seiki Seisakusho Co., Ltd.] to obtain a coarse dispersion. Next, using a high-pressure emulsifying device [product name: Starburst Mini, Sugino Machine Co., Ltd.], emulsification treatment (pressure: 245 MPa, 2 passes in a pass method) is performed on the obtained coarse dispersion. An oil-in-water emulsion composition of Example 1 was obtained.

[Example 2 and Example 3]
In Examples 2 and 3, the same operation as in Example 1 was performed, except that the composition of the oil phase composition was changed to the composition shown in Table 2. An oil-type emulsion composition was obtained.

[Examples 4 to 7]
In Examples 4 to 7, the same operation as in Example 1 was performed except that the composition of the oil phase composition was changed to the composition shown in Table 3. An oil-type emulsion composition was obtained.

[Examples 8 to 10]
In Examples 8 to 10, the same operation as in Example 1 was performed, except that the composition of the aqueous phase composition was changed to the composition shown in Table 4. An oil-type emulsion composition was obtained.

[Example 11 and Example 12]
In Examples 11 and 12, the same operation as in Example 1 was performed, except that the composition of the aqueous phase composition was changed to the composition shown in Table 5. An oil-type emulsion composition was obtained.

[Examples 13 to 17]
In Examples 13 to 17, the same operation as in Example 1 was performed, except that the compositions of the oil phase composition and the aqueous phase composition were changed to the compositions shown in Table 6. Each oil-in-water emulsion composition of Example 17 was obtained.

[Comparative Examples 1 to 4]
In Comparative Examples 1 to 4, the same operation as in Example 1 was performed, except that the composition of the oil phase composition was changed to the composition shown in Table 3. An oil-type emulsion composition was obtained.

[Measurement of average particle size]
Immediately after preparation (within 24 hours from preparation), the oil-in-water emulsion composition was diluted 10-fold with Milli-Q (registered trademark) water. Then, the average particle size (volume average particle size) of the emulsified particles in the oil-in-water emulsion composition after dilution was measured under an atmosphere temperature of 25 ° C. with a particle size distribution meter [trade names: Nanotrac UPA, Microtrac Bell Co., Ltd.] was used for measurement by the dynamic light scattering method. The average particle size of the emulsified particles was determined as the volume average particle size when the refractive index of the dispersion medium was set to 1.333 (pure water) and the viscosity of the dispersion medium was set to the viscosity of pure water. The results are shown in Tables 2-6.

[evaluation]
For each oil-in-water emulsion composition of Examples 1 to 17 and Comparative Examples 1 to 4, the following evaluations were performed. The results are shown in Tables 2-6.

1. Ability to adapt to sebum A model sebum was produced with reference to the literature shown below. Table 1 shows the composition of the prepared model sebum.
After adding 2 mg of model sebum to 10 g of the oil-in-water emulsified composition, the mixture was stirred for 30 minutes at an ambient temperature of 25° C. using a stirrer. After stirring, the presence or absence of insoluble matter is visually confirmed, and if no insoluble matter is confirmed, the process of "further adding 2 mg of model sebum and stirring for 30 minutes" is repeated to obtain an oil-in-water emulsification. The amount of model sebum dissolved in 10 g of the composition was measured. Then, based on the measured model sebum amount, the sebum compatibility of the oil-in-water emulsified composition was evaluated according to the following evaluation criteria.
If the evaluation result was "A" or "B", it was judged to be an oil-in-water emulsified composition with good sebum compatibility. In the following evaluation criteria, "A" is the most excellent.

Literature: J. Soc. Cosmetic Chemists, 20, 565-575 (Aug. 19, 1969), CARL B. FELGER, Ph.D. "The Etiology of Acne. I. Composition of Sebum Before and After Puberty"

-Evaluation criteria-
A: The amount of dissolved model sebum is 8 mg or more.
B: The amount of dissolved model sebum is 4 mg or more and less than 8 mg.
C: The amount of dissolved model sebum is less than 4 mg.

2. Initial Emulsification Dispersibility Immediately after preparation (within 24 hours after preparation), the oil-in-water emulsion composition was diluted 10-fold with Milli-Q (registered trademark) water. Then, the transmittance of the diluted oil-in-water emulsion composition at a wavelength of 650 nm was measured using a spectrophotometer [model number: V-630, manufactured by JASCO Corporation] under an atmosphere temperature of 25°C. The obtained measured value was defined as turbidity, and based on this turbidity, the initial emulsification dispersibility of the oil-in-water emulsion composition was evaluated according to the following evaluation criteria.
If the evaluation result was "A" or "B", it was judged to be an oil-in-water emulsified composition having excellent emulsifying dispersibility. In the following evaluation criteria, "A" is the most excellent.

-Evaluation criteria-
A: Turbidity is 0.10 or less.
B: Turbidity is over 0.10 and 0.50 or less.
C: Turbidity exceeds 0.50.

3. Temporal Stability at Low Temperature The oil-in-water emulsified composition was stored in an environment with an ambient temperature of 10° C. for 6 months. The stored oil-in-water emulsion composition was diluted 10-fold with Milli-Q (registered trademark) water. Then, the transmittance of the diluted oil-in-water emulsion composition at a wavelength of 650 nm was measured using a spectrophotometer [model number: V-630, manufactured by JASCO Corporation] under an atmosphere temperature of 25°C. The obtained measured value was defined as turbidity, and based on this turbidity, the stability over time of the oil-in-water emulsion composition at low temperature was evaluated according to the following evaluation criteria.
If the evaluation result was "A" or "B", it was judged to be an oil-in-water emulsified composition with excellent stability over time at low temperatures. In the following evaluation criteria, "A" is the most excellent.

-Evaluation criteria-
A: Turbidity is 0.10 or less.
B: Turbidity is over 0.10 and 0.50 or less.
C: Turbidity exceeds 0.50.

In Tables 3 to 6, "-" described in the composition column means that the corresponding component is not included.
In Tables 2 to 6, for convenience, components corresponding to tetrahydropiperine, specific oily components, sucrose fatty acid esters, polyglycerin fatty acid esters, phospholipids, and water are represented by "A", "B", "C1", They were classified into "C2", "C3", and "D".
In Tables 2 to 6, "C18" means that the number of carbon atoms in the fatty acid structure contained in the polyglycerol fatty acid ester is "18". In Table 4, "C14" means that the number of carbon atoms in the fatty acid structure contained in the polyglycerin fatty acid ester is "14".
In Tables 2 to 6, "straight chain", "branched chain", "saturated", and "unsaturated" all indicate details of the fatty acid structure contained in the polyglycerin fatty acid ester. For example, "unsaturated" means that the polyglycerol fatty acid ester contains fatty acid structures with unsaturated carbon bonds, and "saturated" means that the polyglycerol fatty acid ester contains fatty acids with no unsaturated carbon bonds. It is meant to contain structure.

Details of each component listed in Tables 2 to 6 are as follows.
<Tetrahydropiperine>
・Tetrahydropiperine [trade name: Cosmoperine, purity: 99% by mass, Sabinsa Japan Corporation]

<Specific oily component>
・Isopropyl myristate [trade name: NIKKOL (registered trademark) IPM-100, IOB value: 0.18, Nikko Chemicals Co., Ltd.]
・Isononyl isononanoate [trade name: Emalex NINI-99, IOB value: 0.20, Nippon Emulsion Co., Ltd.]
・ Ethylhexyl isononanoate [trade name: EMALEX NIO-98, IOB value: 0.20, Nippon Emulsion Co., Ltd.]
・Neopentyl glycol diethylhexanoate [trade name: KAK NDO, IOB value: 0.25, KOKYU ALCOHOL KOGYO Co., Ltd.]
・ Pentaerythrityl tetraethylhexanoate [trade name: Salacos 5408, IOB value: 0.35, Nisshin Oillio Group Co., Ltd.]
<Oil-based ingredients other than specific oil-based ingredients>
・Isopropyl palmitate [trade name: IPP, IOB value: 0.16, KOKYU ALCOHOL KOGYO Co., Ltd.]
・Diisopropyl sebacate [trade name: IPSE, IOB value: 0.40, Nippon Fine Chemical Co., Ltd.]
・Diisopropyl adipate [trade name: NIKKOL (registered trademark) DID, IOB value: 0.55, Nikko Chemicals Co., Ltd.]
- PG caprylate [trade name: NIKKOL (registered trademark) Sefsol-218, chemical name: propylene glycol monocaprate, IOB value: 0.73, Nikko Chemicals Co., Ltd.]

<Emulsifier>
(sucrose fatty acid ester)
・ Sucrose stearate [trade name: Ryoto (registered trademark) Sugar Ester S-1170, HLB value (catalog value): about 11, monoester body (catalog value): 55% by mass, Mitsubishi Chemical Foods Co., Ltd.]
・ Sucrose stearate [trade name: Ryoto (registered trademark) Sugar Ester S-1670, HLB value (catalog value): about 16, monoester body (catalog value): 75% by mass, Mitsubishi Chemical Foods Co., Ltd.]
・ Sucrose stearate [trade name: DK Ester (registered trademark) SS, HLB value (catalog value): about 19, monoester (catalog value): 97% by mass, Mitsubishi Chemical Foods Co., Ltd.]
(Polyglycerol fatty acid ester)
- Polyglyceryl-10 stearate [trade name: NIKKOL (registered trademark) Decaglyn 1-SV, HLB value (catalog value): 12, number of carbon atoms in fatty acid structure: 18, Nikko Chemicals Co., Ltd.]
・ Polyglyceryl-10 myristate [trade name: NIKKOL (registered trademark) Decaglyn 1-M, HLB value (catalog value): 14, number of carbon atoms in fatty acid structure: 14, Nikko Chemicals Co., Ltd.]
・Polyglyceryl Isostearate-10 [trade name: NIKKOL (registered trademark) Decaglyn 1-ISV, HLB value (catalog value): 12, number of carbon atoms in fatty acid structure: 18, including fatty acid structure with branched chain, Nikko Chemicals Co., Ltd. )]
・Polyglyceryl oleate-10 [trade name: NIKKOL (registered trademark) Decaglyn 1-OV, HLB value (catalog value): 12, number of carbon atoms in fatty acid structure: 18, including fatty acid structure with unsaturated carbon bond, Nikko Chemicals (stock)〕
(Phospholipid)
・ Lecithin [Product name: SLP-White, Tsuji Oil Co., Ltd.]

<Others>
・Glycerin (Kao Corporation)
<Water>
・Water: purified water

As shown in Tables 2 to 6, Example 1 containing tetrahydropiperine, an oil component having an IOB value in the range of more than 0.16 and less than 0.40 (that is, a specific oil component), an emulsifier, and water All of the oil-in-water emulsion compositions of Examples 17 to 17 were excellent in initial emulsification dispersibility. Further, the oil-in-water emulsion compositions of Examples 1 to 17 all had good compatibility with sebum and excellent stability over time at low temperatures.

On the other hand, as shown in Table 3, the oil-in-water emulsion composition of Comparative Example 1 containing an oily component having an IOB value of 0.16 instead of the specific oily component was compared with the oil-in-water emulsion composition of Examples. In addition, the stability over time at low temperatures was poor.
The oil-in-water emulsion composition of Comparative Example 2 containing an oily component with an IOB value of 0.40 instead of the specific oily component was inferior in sebum compatibility compared to the oil-in-water emulsion composition of the example. .
The oil-in-water emulsion composition of Comparative Example 3 containing an oily component with an IOB value of 0.55 instead of the specific oily component was inferior in sebum compatibility compared to the oil-in-water emulsion composition of the example. .
The oil-in-water emulsion composition of Comparative Example 4 containing an oily component with an IOB value of 0.73 instead of the specific oily component was inferior in sebum compatibility compared to the oil-in-water emulsion composition of the example. . In addition, the oil-in-water emulsion composition of Comparative Example 4 has a higher initial turbidity than the oil-in-water emulsion composition of Examples, and is inferior in both emulsification dispersibility and low-temperature stability over time. rice field.

Claims (5)

0.1% by mass to 5.0% by mass of tetrahydropiperine relative to the total mass of the oil-in-water emulsion composition ,
The value representing the ratio of the inorganic value to the organic value is in the range of more than 0.16 and less than 0.40 The oil component is 1% by mass to 50% by mass with respect to the total mass of the oil-in-water emulsion composition ,
1% by mass to 30% by mass of the emulsifier with respect to the total mass of the oil-in-water emulsion composition ,
water and,
An oil-in-water emulsion composition comprising
the oily component is at least one of isononyl isononanoate and ethylhexyl isononanoate,
The emulsifier contains sucrose fatty acid ester and polyglycerin fatty acid ester,
The monoester content in the sucrose fatty acid ester is 80% by mass or more with respect to the total mass of the sucrose fatty acid ester,
An oil-in-water emulsion composition, wherein the polyglycerin fatty acid ester contains a fatty acid structure having at least one of a branched chain and an unsaturated carbon bond . 2. The oil-in-water emulsion composition according to claim 1, wherein the emulsion particles have an average particle size of 100 nm or less. 3. The oil-in-water emulsion composition according to claim 1 or 2, wherein the emulsifier further comprises a phospholipid . An external skin preparation comprising the oil-in-water emulsified composition according to any one of claims 1 to 3 . 5. The external preparation for skin according to claim 4 , which is an aqueous cosmetic.