JPH10212477A - Prevention of oxidation of o/w type emulsion, antioxidant composition and w/o type emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an oil phase component, especially a highly unsaturated fatty acid from an oxidation by blending an antioxidant at the boundary of an oil phase and an aqueous phase of an O/W type emulsion in which the oil phase disperses in the aqueous phase. SOLUTION: This method for preventing an O/W type emulsion is to blend an antioxidant at the boundary of an aqueous phase and an oil phase in the O/W emulsion in which the oil phase disperses in the aqueous phase. In order to blend the antioxidant at the boundary of the aqueous phase and the oil phase, it is preferable to form a compound body in which the antioxidant is included with an oil soluble surfactant by adding an oil soluble surfactant having <=8 HLB together with the antioxidant. It is preferable to mix the antioxidant with the oil soluble surfactant having <=8 HLB beforehand and mix the mixture into the oil phase, and further emulsifying the oil phase with a water soluble surfactant to form the O/W type emulsion. As the oil soluble surfactant, a polyglycerol fatty acid ester and lecithins are preferable, since these compounds tend to take the antioxidant therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antioxidation method for preventing oxidation of constituents of an oil phase in an O / W emulsion (oil-in-water emulsion) in which an oil phase is dispersed as a dispersed phase in an aqueous phase. , An antioxidant composition (antioxidant), and an O / W emulsion containing the antioxidant composition. The O / W emulsion can be used as a cosmetic or a skin treatment preparation.

[0002]

2. Description of the Related Art Recently, it has been known that polyunsaturated fatty acids and their derivatives have some excellent physiological and dermatological effects, and their use as oil phase components in cosmetics is being studied. . Specifically, evening primrose oil, rosehip oil,
Oils and fats containing polyunsaturated fatty acids, such as kukui nut oil and borage oil, synthesize various hormone-like substances such as proctaglandins, strengthen cell membranes by contributing to linoleic acid-containing sphingolipids in the skin, and promote tissue regeneration It has the function of preventing skin aging due to. In addition, it is said that the deficiency of essential fatty acids causes skin lesions and is completely cured by supplementing linoleic acid.

[0003] Further, since oil phase components containing these highly unsaturated fatty acids are particularly unstable against oxidation, various antioxidants such as water-soluble antioxidants and oil-soluble antioxidants have been proposed. .

Examples of the water-soluble antioxidant include plant extracts comprising ascorbic acid and ascorbate, erythorbic acid such as erythorbic acid and sodium erysorbate, and polyphenols such as catechin and tannin.

The oil-soluble antioxidants include α-tocopherol, vitamin E derivatives such as vitamin E acetate and vitamin E palmitate, butylhydroxyanisole (BHA), butylhydroxytoluene (BHT), eugenol, isoeugenol, vitamin K5, Ascorbic acid esters such as ascorbic acid palmitate, or natural antioxidants contained in vegetable oils or antioxidants derived therefrom, for example, liquorice extract containing flavonoids, sesame oil, cottonseed oil-derived, sesamin, Episesamin and the like.

[0006] These antioxidants are used alone or as a mixture of two or more, added directly to an oil phase component, or added to an emulsion preparation. For example, Japanese Patent Application Laid-Open No. Hei 6-298624 discloses that an oil-soluble antioxidant is contained in an oil phase of an O / W emulsion containing a polyunsaturated fatty acid, and a water-soluble antioxidant is contained in an aqueous phase. A method for preventing oxidation of an O / W emulsion to the effect of containing it is described. JP-A-7-227227 discloses a natural oil containing docosahexaenoic acid, a hydrophilic polyglycerin fatty acid ester or a lecithin having an HLB of 10 or more necessary for emulsifying the same, and an antioxidant (ascorbic acid, Catechins, tocopherols, etc.)
And a hydrophilic medium (glycerin, water, etc.) are described.

[0007]

Generally, cosmetics and skin treatment preparations are emulsions containing oil phase components, and these oil phase components have a tendency to be oxidized to some extent even at room temperature. As a result, the formulation becomes odorous over time, or the formulation is separated by polar substances such as aldehydes generated as a result of oxidation, resulting in an unfavorable situation in terms of formulation stability.

Further, lipid peroxides, hydroxy free radicals, epoxides, singlet oxygen and the like generated as a result of oxidation of the oil phase component damage skin cells and promote aging of the skin. Adversely affect.

[0009] These oxidation tendencies are remarkable in O / W emulsions in which the oil phase component is dispersed as oil droplets in water. This is due to the fact that the oil phase is in contact with a large absolute water phase having a large amount of dissolved oxygen and a large contact area.

However, the conventional technology relating to antioxidation is as follows.
Most of them aim at preventing oxidation of a single-phase oil component instead of an emulsion, and there is no technology effective enough to prevent oxidation of an oil-phase component in an O / W emulsion formulation.

Although there are some techniques for preventing the oxidation of the oil phase component in the O / W emulsion preparation, the above oil-soluble antioxidant is dissolved in the oil phase component to achieve the antioxidant effect. Technology is the main. However, this technology
Since the oil-soluble antioxidant stays inside the oil phase component, it is not sufficiently effective in preventing the oxidation of the oil phase in the O / W emulsion preparation. In addition, even if the water-soluble antioxidant is added to the O / W emulsion formulation for the purpose of preventing oxidation of the oil phase of the O / W emulsion formulation, the water-soluble antioxidant remains in the aqueous phase, The antioxidant effect on the oil phase component can hardly be exhibited.

That is, the method of preventing oxidation of an O / W emulsion disclosed in Japanese Patent Application Laid-Open No.
No. 227227, the stable emulsified composition described in
/ W emulsion is not sufficiently effective in preventing the oxidation of the constituents of the oil phase. Therefore, the oil phase components containing the highly unsaturated fatty acids, which are particularly unstable to oxidation, have a high O 2 content due to the above-mentioned problems caused by oxidation, despite their excellent properties as oil components for cosmetics. The use in / W emulsion formulations has been limited.

The method for preventing oxidation of an O / W emulsion disclosed in Japanese Patent Application Laid-Open No. 6-298624 is complicated in the preparation method and, as a water-soluble antioxidant, ascorbate having a high ionic strength in an aqueous phase. In addition, there is a fatal problem that the separation of the emulsion occurs.

The present invention solves the above-mentioned problems of the prior art, and shows a sufficiently effective antioxidant power to an oil phase component (particularly, a highly unsaturated fatty acid and a derivative thereof) in an O / W emulsion. An object of the present invention is to provide a method for preventing oxidation of an O / W emulsion and an antioxidant composition. Another object of the present invention is to provide an antioxidant composition which is easy to handle, has no adverse effect on the formulation to be added (separation of emulsion, etc.), and is safe for the skin. Another object of the present invention is to provide an O / W emulsion, a cosmetic and an external preparation for skin containing the antioxidant composition.

[0015]

The inventor of the present invention has conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, HL
That the antioxidant can be easily disposed at the interface between the water phase and the oil phase in the O / W emulsion by using an oil-soluble surfactant of B8 or less, and that the antioxidant is disposed at the interface. As a result, the present inventors have found that oxidation of the constituent components of the oil phase can be dramatically prevented, and have completed the present invention. That is, according to the present invention, the above problem can be solved by the following method for preventing oxidation of an O / W emulsion, an antioxidant composition, an O / W emulsion, a cosmetic, and a skin external preparation.

(1) An antioxidant is disposed at the interface between the water phase and the oil phase of the O / W emulsion in which the oil phase is dispersed in the water phase.
A method for preventing oxidation of an O / W emulsion which prevents oxidation of the constituent components of the oil phase (viewpoint 1). A method for preventing oxidation of the O / W emulsion in which the antioxidant is disposed at the interface with an oil-soluble surfactant having an HLB of 8 or less (viewpoint 2).

(2) An antioxidant composition for an O / W emulsion containing an antioxidant and an oil-soluble surfactant having an HLB of 8 or less (viewpoint 3). An antioxidant composition for the O / W emulsion containing a hydrophilic medium (viewpoint 4). The antioxidant composition for an O / W emulsion, wherein the weight ratio A / B of the weight A of the antioxidant to the weight B of the oil-soluble surfactant having an HLB of 8 or less is 100 or less (viewpoint 5).

The oil-soluble surfactant having an HLB of 8 or less,
One of polyglycerin fatty acid ester and lecithin
An antioxidant composition for the O / W emulsion, which is at least one kind (viewpoint 6). The O / W, wherein the hydrophilic medium is at least one of glycerin, sorbitol, propylene glycol, 1.3-butanediol and ethanol.
Antioxidant composition for type emulsion (viewpoint 7).

(3) An O / W emulsion in which an oil phase is dispersed in an aqueous phase, and an antioxidant and an oil-soluble surfactant having an HLB of 8 or less are present at the interface between the aqueous phase and the oil phase. 8). The O / W emulsion (view 9), wherein the oil phase contains one or more of polyunsaturated fatty acids and their derivatives. The total content of the antioxidant and the oil-soluble surfactant having an HLB of 8 or less is 0.001 to 20% by weight.
W-type emulsion (viewpoint 10).

(4) Cosmetics comprising the O / W emulsion (viewpoint 11). (5) A skin external preparation comprising the O / W emulsion (viewpoint 12). In the present invention, the description of the numerical range includes not only both end values, but also all arbitrary intermediate values included therein.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

[Method of preventing oxidation of O / W emulsion]
In the method of preventing oxidation of a W-type emulsion, an antioxidant is disposed at an interface between an aqueous phase and an oil phase to prevent oxidation of the components of the oil phase. The antioxidant can be disposed on the interface by an oil-soluble surfactant having an HLB of 8 or less. Antioxidants and H
The oil-soluble surfactant having an LB of 8 or less may be added to the aqueous phase or the oil phase when preparing the O / W emulsion, or may be added to the emulsion after preparing the O / W emulsion. . All of the antioxidants provided at the interface can be oil-soluble antioxidants (or an oil-soluble antioxidant and a water-soluble antioxidant).

[Antioxidant composition for O / W emulsion] The antioxidant composition for the O / W emulsion of the present invention contains an antioxidant and an oil-soluble surfactant having an HLB of 8 or less. All of the antioxidants can be oil-soluble antioxidants (or an oil-soluble antioxidant and a water-soluble antioxidant).
In order for the antioxidant to effectively exhibit antioxidant performance in the O / W emulsion formulation, the antioxidant is present (located) at the interface between the oil phase and the aqueous phase, and the oil is dissolved by the dissolved oxygen in the water. It is necessary to prevent oxidation. Therefore, the antioxidant composition of the present invention uses a carrier that carries the antioxidant to the interface between the oil phase and the aqueous phase. Generally, it is conceivable to use various surfactants for this purpose, but hydrophilic surfactants having an HLB of more than 8 remain in the aqueous phase by themselves and do not show a favorable carrier effect. Forms a complex with the antioxidant, leaving the antioxidant in the aqueous phase.

On the other hand, an oil-soluble (lipophilic) surfactant having an HLB of 8 or less is a complex of an antioxidant and a lipophilic surfactant (an oil-soluble (lipophilic) interface with an antioxidant having an HLB of 8 or less). (Complex encapsulated in the active agent), and itself is lipophilic and located at the interface between the oil phase and the aqueous phase, so that it exerts the carrier effect of the antioxidant. Among the oil-soluble (lipophilic) surfactants having an HLB of 8 or less, polyglycerin fatty acid esters and lecithins are particularly bulky and have a complicated molecular structure, so that they easily incorporate an antioxidant and are suitable as carriers.

(Antioxidants) Antioxidants include oil-soluble antioxidants, water-soluble antioxidants, and antioxidants of an intermediate polarity between oil-soluble and water-soluble. Examples of oil-soluble antioxidants include α-tocopherol, vitamin E derivatives such as vitamin E acetate and vitamin E palmitate, ascorbic acid esters such as BHA, BHT, eugenol, isoeugenol, vitamin K5, ascorbic acid palmitate, and vegetable oils. Included are natural antioxidants or antioxidants derived therefrom, such as licorice extract containing flavonoids, sesame oil, cottonseed oil-derived sesamin, episesamin, β-carotene and analogs thereof.

Examples of the water-soluble antioxidant include ascorbic acid, ascorbate, erythorbic acid, erysorbate, water-soluble plant extracts and the like. Water-soluble plant extracts include ethanol, propylene glycol, 1.3
-It is an extract extracted from plants with a mixed extract of water and a water-soluble solvent such as butanediol, and shows water solubility.

More specifically, the water-soluble plant extract may be selected from the group consisting of Eijitsu (a mature fruit of Rosa multiflora), Peony (Root of Paeonia lactiflora), Melissa (leaf of Melissa officinalis), and Thyme (Thymus vulgar).
is whole plant), clove (Eugenia aromatica flower bud),
Rosemary (leaves of Rosmarinus officinalis), liquorice (Glycyrrhiza uralensis, roots and rhizomes of G. glabra, G. inflata), enmeiso (whole plant of lsodon japonicus), oak (bark of Phellodendron amurense), gin (Sophora angustifolia root) ), Hops (Humulus
The active ingredient is an extract of water or a hydrophilic organic solvent or a mixture of one or more plants selected from eucalyptus (Eupalyptus globulus leaves), eucalyptus (Eucalyptus globulus leaves) and tea (Camellia sinensis leaves) Things.

Specific examples of preferred hydrophilic organic solvents for extraction include lower alcohols such as methanol and ethanol; polyhydric alcohols having 2 to 4 carbon atoms such as glycerin, 1,3-butylene glycol and propylene glycol; Acetone and the like. Extraction with water, ethanol, or a mixture thereof is particularly preferable because there is no possibility that the extraction solvent remains toxic even if it remains in the O / W emulsion preparation.

There is no particular limitation on the extraction, and the extraction can be carried out at room temperature or under reflux using any apparatus.
The extraction material can be easily extracted by putting the extraction raw material into a treatment tank filled with the extraction solvent and stirring occasionally as necessary to elute the soluble component. The obtained extract can be used as it is or as a component of the antioxidant composition of the present invention after being appropriately concentrated and dried.

[0029] Specifically, thyme extract, clove extract, rosemary extract, licorice extract, edible extract, peony extract, melissa extract, enmeso extract, oubak extract, jinjin extract, hop Extract, eucalyptus extract, mukuroji extract, green tea extract and the like, which are mainly composed of tannin, polyphenols such as catechin, flavonoids, alkaloids,
It is a mixture composed of saponins and the like. These plant extracts are suitably provided to the antioxidant composition of the present invention as a solution dissolved in the extract or as a powder from which the extraction solvent has been removed by freeze-drying or the like.

The oil-soluble and water-soluble intermediate antioxidants are ethanol, isopropyl alcohol (IPA),
It is soluble in short to medium chain alcohols such as n-butanol, polyhydric alcohols such as ethylene glycol, 1.3-butanediol, propylene glycol and glycerin, but is insoluble in non-polar oils such as liquid paraffin. Specific examples include licorice extract and ascorbic acid ester (low esterification degree).

(Oil-soluble surfactant having an HLB of 8 or less) HL
The oil-soluble surfactant having a B of 8 or less has a lower solubility in the aqueous phase than in the oil phase. At room temperature, the surfactant is mainly dissolved in a micelle or a large amount in the monomer phase in the oil phase. The HLB of the oil-soluble surfactant is 8 or less, preferably 7 or less, more preferably 5 or less. HL
B is a hydrophilic-lipophilic balance.

Examples of such an oil-soluble surfactant include sorbitan monooleate, sorbitan monostearate,
Sorbitan sesquiolate, sorbitan fatty acid esters such as sorbitan sesquistearate, glycerin monofatty acid esters such as glycerin monocaprylate, diglycerin monooleate, tetraglycerin monostearate, hexaglycerin distearate, hexaglycerin polyricinoleate, Polyglycerin fatty acid esters such as hexaglycerin triricinoleate, decaglycerin tristearate, decaglycerin triolate, decaglycerin 12-hydroxystearate, decaglycerin polyricinoleate, polyoxyethylene alkyl fatty acid esters and polyoxyethylene alkyl ( Alkylphenyl) ethers having a short polyoxyethylene chain and an HLB of 8 or less, sucrose dioleate, sucrose disteare Sucrose fatty acid esters such as bets and the like.

In addition, such ionic oil-soluble surfactants include long-chain alkyls such as lecithins, dialkyl phosphate esters, dialkyl sulfosuccinates, and dialkyldimethylammonium salts. Those having high solubility in the oil phase at room temperature can be mentioned. Among these, polyglycerin fatty acid esters and lecithins are particularly suitable for the present invention.

Lecithin is preferably derived from soybean, egg yolk, milk and the like. For the purpose of improving its own stability, etc., the unsaturated bond of the alkyl group is hydrogenated or hydroxylated, sulfated or the like. It may be a modified one. Alternatively, lysolecithin, which is obtained by treating lecithin with an enzyme to reduce the number of alkyl chains to one, may be used. In general, lecithin is a mixture of several types of phospholipids such as phosphatidylcholine, phosphatidylethanolamine and the like, and their composition varies depending on the raw material from which they are derived. However, in the present invention, the composition is not particularly limited.

In the antioxidant composition for the O / W emulsion, the weight ratio A / B of the weight A of the antioxidant to the weight B of the oil-soluble surfactant having an HLB of 8 or less is preferably 100 or less. And more preferably 100 to 1/20
0, more preferably 10 to 1/100, and most preferably 10 to 1/50.

The antioxidant composition of the present invention comprises an antioxidant and H
An oil-soluble surfactant having an LB of 8 or less can be mixed in advance and used as an antioxidant composition. For example, it can be easily prepared as follows. Each is charged into a stainless steel mixer within the above-mentioned ratio range and mixed for a certain time. In that case, the antioxidant composition of the present invention may contain a hydrophilic medium in order to homogenize the composition. Glycerin, sorbitol, propylene glycol, 1,3-butanediol, and ethanol are preferred as the hydrophilic medium.

When a plant extract is used as an antioxidant, the extract may be diluted with the extract, converted into a concentration so as to have the above mixing ratio, and used as it is. Further, water may be added to the antioxidant composition for the purpose of homogenizing the antioxidant composition.

The total blending amount (% by weight) of the antioxidant and the oil-soluble surfactant having an HLB of 8 or less in the antioxidant composition of the present invention is not particularly limited, but may be added to the O / W emulsion preparation. In consideration of the amount of addition of the antioxidant composition and the appearance and viscosity of the antioxidant composition, 1.0 to 50% by weight is appropriate.

The antioxidant composition thus prepared is
O / W emulsion preparation containing polyunsaturated fatty acids and their derivatives as an oil phase component (cosmetics and external preparation for skin)
It is suitably used as an antioxidant. The method of compounding the antioxidant composition of the present invention into an O / W emulsion preparation can be performed by adding and mixing the oil phase before emulsification in advance and mixing it with the aqueous phase before emulsification. It can be blended, and it can be blended by newly adding and mixing it into the emulsion preparation after the preparation.

When the antioxidant composition for an O / W emulsion of the present invention comprises only an antioxidant and an oil-soluble surfactant having an HLB of 8 or less, the content of the antioxidant is preferably 9%.
9.0-0.5% by weight, more preferably 90.0-1.
0% by weight, more preferably 90.0 to 2.0% by weight.

When the antioxidant composition for an O / W emulsion of the present invention comprises only an antioxidant, an oil-soluble surfactant having an HLB of 8 or less, and a hydrophilic medium, the content of the antioxidant is preferably 99. The content of the oil-soluble surfactant of 0 to 0.5% by weight and the HLB of 8 or less is 1.0 to 99.5% by weight, more preferably the content of the antioxidant is 90.0 to 1.0% by weight.
And a content of an oil-soluble surfactant having an HLB of 8 or less 10.0
To 99.0% by weight, more preferably 90.0 to 2.0% by weight of an antioxidant and 10.0 to 98.0% by weight of an oil-soluble surfactant having an HLB of 8 or less.

[O / W emulsion] O / W of the present invention
The type emulsion is composed of an oil phase dispersed in an aqueous phase, and an antioxidant and an oil-soluble surfactant having an HLB of 8 or less are present (located) at the interface between the aqueous phase and the oil phase. The antioxidant and the oil-soluble surfactant having an HLB of 8 or less are preferably
A complex (a complex in which an antioxidant is included in an oil-soluble surfactant having an HLB of 8 or less) is formed, and more preferably, the complex is formed and oriented to the interface. The antioxidant prevents oxidation of the oil phase component due to dissolved oxygen in the water phase. All of the antioxidants located at the interface can be oil-soluble antioxidants (or an oil-soluble antioxidant and a water-soluble antioxidant).

If the antioxidant is located at the interface in such an amount that the oxidation of the oil phase component can be prevented, the antioxidant may not be contained in the aqueous phase or the oil phase. A water-soluble antioxidant can be contained in the water phase, and an oil-soluble antioxidant can be contained in the oil phase.

The O / W emulsion of the present invention contains an emulsifier for dispersing an oil phase in an aqueous phase at a content sufficient to form an O / W emulsion. Such an emulsifier is preferably HLB 10 or more (more preferably HLB 11 to HLB 11).
14) The water-soluble surfactant is used.

In the O / W emulsion of the present invention,
The required amount of the mixture of the antioxidant and the oil-soluble surfactant having an HLB of 8 or less can be 0.001 to 20% by weight, preferably 0.01 to 20% by weight, more preferably 0.1 to 20% by weight. 20% by weight.

The oil phase of the O / W emulsion of the present invention can contain one or more of polyunsaturated fatty acids and their derivatives.

Examples of the oil phase component in which natural oxidation is effectively suppressed by the antioxidant composition of the present invention include kukui nut oil, evening primrose oil, rosehip oil, borage oil and the like. These are all glycerides of fatty acids containing polyunsaturated fatty acids such as oleic acid, arachidonic acid, linoleic acid and linolenic acid as main components.

As the oil phase component, alkyl esters of the above fatty acids, for example, methyl linoleate, α-
Examples thereof include methyl linolenate, ethyl oleate, and oleyl oleate, and further include methyl eicosapentaenoate and methyl docosahexaenoate. further,
Examples of the oil phase component include highly unsaturated fatty acid amides such as linoleic acid amide, α-linolenic acid amide, and arachidonic acid amide. The above highly unsaturated fatty acid derivatives can be used alone or as a mixture.
Further, a mixture with the above-mentioned highly unsaturated fatty acids may be used.

The O / W emulsion of the present invention can be preferably produced as follows. An antioxidant and an oil-soluble surfactant having an HLB of 8 or less are previously mixed to obtain a mixture (a hydrophilic medium is added if necessary), and the mixture is mixed in an oil phase. The O / W emulsion is obtained by dispersing (emulsifying) in an aqueous phase with a surfactant. Further, an antioxidant and an oil-soluble surfactant having an HLB of 8 or less are simultaneously or separately mixed in the oil phase, and the oil phase is dispersed (emulsified) in the water phase with the water-soluble surfactant. An O / W emulsion is obtained.

[0050]

【Example】

[Examples 1 to 4] Preparation of oil-soluble antioxidant composition In a stainless steel mixer equipped with a thermometer and a temperature controller, which can be replaced with nitrogen, an antioxidant, an oil-soluble surfactant having an HLB of 8 or less, and water solubility A solvent and water were charged at the compounding ratio shown in Table 1 (each value is part by weight), and the mixture was added at 25 ° C. ± 3 in a nitrogen atmosphere.
C. for 2 hours to obtain oil-soluble antioxidant compositions of Examples 1 to 4 shown in Table 1. The antioxidants used in each Example were dl-α-tocopherol, as shown in Table 1.
Vitamin E acetate, ascorbic acid dipalmitate, licorice extract.

In this case, those without an oil-soluble surfactant having an HLB of 8 or less and those with a hydrophilic surfactant having an HLB greater than 8 are shown in Table 1 as Comparative Examples 1 to 5.

[0052]

[Table 1]

Examples 5 to 8 Preparation of Water-Soluble Antioxidant Compositions Examples 1 to 4 were prepared by using the components shown in Table 2 below and at the mixing ratios shown in Table 2 (each value is part by weight). A water-soluble antioxidant composition was prepared in the same manner as described above. As shown in Table 2, the antioxidants used in each example were as follows: Clove extract, Eigetsu extract, Peony extract, Rosemary extract,
Thyme extract.

In the surfactants of Tables 1 and 2, "P"
“OE” means polyoxyethylene, and the numerical value in parentheses thereafter indicates the number of moles of polyethylene oxide added.

[0055]

[Table 2]

Example 9 Evaluation of Antioxidant Performance of Oil-soluble Antioxidant Composition Preparation of Emulsion Formulation An emulsification formulation having the composition shown in Table 3 below was prepared using a homomixer. The preparation method is as follows. An emulsifier (decaglycerin monomyristate of HLB14) is mixed in water at a compounding ratio shown in Table 3 below (each value is part by weight). And a premix of the present invention (each of Examples 1 to 4) or the oil phase component and the comparative example (each of Comparative Examples 1 to 5) are gradually added in 15 minutes, and homogenized for further 30 minutes. Mixer treatment was performed to prepare each emulsified preparation. The homomixer conditions were as follows: rotation speed: 8000 rpm (rotation / minute), emulsification temperature: 2
The temperature was adjusted to 5 ° C. ± 3 ° C.

[0057]

[Table 3]

Antioxidant Performance Evaluation Test Each of the emulsified preparations thus prepared was allowed to stand in a thermostat at 50 ° C. ± 0.3 ° C. for 30 days. Reference fat and oil analysis test method, 2.4.12-86
Quantitative determination was performed according to the method for measuring the peroxide value specified in the above.

This value was compared with the peroxide value measured immediately after the preparation of the emulsion preparation, and the rate of increase (%) was calculated to evaluate the antioxidant performance. Peroxide value increase rate (%) = (POV2-POV1) / P
OV1 × 100 Here, POV1 is the peroxide value of the sample immediately after preparation, and POV2 is the peroxide value of the sample after standing in a thermostat. Table 4 shows the obtained results.

[0060]

[Table 4]

Example 10 Evaluation of Antioxidant Performance of Water-Soluble Antioxidant Composition Preparation of Emulsion Formulation In the same manner as in the preparation of an emulsion formulation using the oil-soluble antioxidant composition, the results are shown in Table 5 below. An emulsified formulation having the following formulation was prepared. In addition, each value of Table 5 is a weight part.

[0062]

[Table 5]

Antioxidant Performance Evaluation Test The oil-soluble antioxidant composition was evaluated in the same manner as the antioxidant performance evaluation test. Table 6 shows the obtained results.

[0064]

[Table 6]

[0065]

According to the method for preventing oxidation of an O / W emulsion according to claims 1 and 2, an antioxidant is added to the interface between the water phase and the oil phase of the O / W emulsion in which the oil phase is dispersed in the water phase. To prevent oxidation of the constituents of the oil phase, so that an antioxidant which is extremely effective for the constituents of the oil phase in the O / W emulsion (also for highly unsaturated fatty acids and their derivatives) Show power. In the method for preventing oxidation of an O / W emulsion according to claim 2, since the antioxidant is disposed on the interface by an oil-soluble surfactant having an HLB of 8 or less, the antioxidant can be disposed on the interface easily. it can.

The antioxidant composition for an O / W emulsion according to claims 3 to 7 contains an antioxidant and an oil-soluble surfactant having an HLB of 8 or less. In particular, it shows an effective antioxidant activity against polyunsaturated fatty acids and their derivatives). Therefore, excellent properties can be exhibited by using the oil phase component (particularly, highly unsaturated fatty acids and their derivatives) safely as a component of the oil phase of the O / W emulsion. In addition, it is easy to handle, has no adverse effects on the added formulation (separation of emulsion, etc.), and is safe for the skin. Claim 4
The above effects of the antioxidant compositions for O / W emulsions of Nos. To 7 are remarkable.

An O / W emulsion according to claims 8 to 10,
The cosmetic according to claim 11 and the external preparation for skin according to claim 12, wherein an oil phase is dispersed in an aqueous phase, and an antioxidant and an oil-soluble surfactant having an HLB of 8 or less are provided at the interface between the aqueous phase and the oil phase. , Exhibit a very effective antioxidant activity against the components of the oil phase in the O / W emulsion (also against highly unsaturated fatty acids and their derivatives). Therefore, constituents of the oil phase (particularly, highly unsaturated fatty acids and their derivatives)
Can be safely used as a component of the oil phase of the O / W emulsion, and the components of the oil phase can exhibit excellent characteristics. The effects described above are remarkable in the O / W emulsions according to claims 9 to 10.

Claims (12)

[Claims] An antioxidant is disposed at an interface between an aqueous phase and an oil phase of an O / W emulsion in which an oil phase is dispersed in an aqueous phase to prevent oxidation of components of the oil phase. Characteristic O / W
For preventing oxidation of emulsions. 2. The method for preventing oxidation of an O / W emulsion according to claim 1, wherein the antioxidant is disposed on the interface by an oil-soluble surfactant having an HLB of 8 or less. 3. An antioxidant composition for an O / W emulsion comprising an antioxidant and an oil-soluble surfactant having an HLB of 8 or less. 4. The antioxidant composition for an O / W emulsion according to claim 3, further comprising a hydrophilic medium. 5. The method according to claim 3, wherein the weight ratio A / B of the weight A of the antioxidant to the weight B of the oil-soluble surfactant having an HLB of 8 or less is 100 or less. O
/ Antioxidant composition for W emulsions. 6. The oil-soluble surfactant having an HLB of 8 or less,
One of polyglycerin fatty acid ester and lecithin
The antioxidant composition for an O / W emulsion according to any one of claims 3 to 5, wherein the composition is at least one kind. 7. The method according to claim 4, wherein the hydrophilic medium is at least one of glycerin, sorbitol, propylene glycol, 1.3-butanediol and ethanol. An antioxidant composition for an O / W emulsion. 8. An O / W comprising an oil phase dispersed in an aqueous phase, wherein an antioxidant and an oil-soluble surfactant having an HLB of 8 or less are present at the interface between the aqueous phase and the oil phase. Type emulsion. 9. The O / W emulsion according to claim 8, wherein the oil phase contains one or more of polyunsaturated fatty acids and their derivatives. 10. The method according to claim 8, wherein the total content of the antioxidant and the oil-soluble surfactant having an HLB of 8 or less is 0.001 to 20% by weight. /
W-type emulsion. 11. The O / C according to claim 8, wherein
A cosmetic comprising a W-type emulsion. 12. The O / C according to claim 8, wherein
An external skin preparation comprising a W emulsion.