JPH11228377A - Oil-in-water type emulsion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an emulsion composition containing a fatty acid ester of vitamin A stabilized in a preparation and especially useful as a cream-based skin preparation for external use. SOLUTION: This oil-in-water type emulsion composition has the following characteristics (1) to (3), and contains a fatty acid ester of vitamin A in combination with an oil-soluble antioxidant, an amphipathic material and a hydrophilic nonionic surfactant: (1) providing a get having >=50 deg.C transition temperature and formed in the formulated amphipathic material-hydrophilic nonionic surfactant-water system; (2) having >0.5 weight ratio of the amphipathic material to the hydrophilic nonionic surfactant; and (3) having <=5.0 wt.% content of the surfactant based on the whole composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an oil-in-water emulsion composition mainly used as an external preparation for skin and the like. More specifically, the invention relates to an oil-in-water emulsified composition in which a fatty acid ester of vitamin A is stabilized, particularly a cream type.

[0002]

2. Description of the Related Art Vitamin A, such as vitamin A and fatty acid esters of vitamin A, has been known as an effective component for the prevention and treatment of cutaneous keratosis, and also for the prevention and recovery of skin aging. It is blended as an active ingredient in various skin external preparations having these purposes.

[0003] However, these vitamins A are originally extremely unstable components. That is, vitamin A is a component that is easily degraded by isomerization, oxidative decomposition, and the like caused by many factors such as light, air, heat, and metal ions. Therefore, skin external preparations containing such vitamin A have a problem in stability over time,
In addition, there were inconveniences such as excessive care for preservation. Among such unstable vitamin A, various means have been proposed for vitamin A, such as using a chelating agent or an antioxidant, for the purpose of stabilizing the vitamin A in an external preparation for skin. ing.

[0004]

The fatty acid ester of vitamin A is superior in oxidative stability to vitamin A, but is susceptible to hydrolysis due to its structure. Therefore, the currently proposed stabilization method represented by the above-described method can only improve the oxidative stability of the fatty acid ester of vitamin A, and can improve the stability against hydrolysis, which is a problem. Can not. Therefore, the problem to be solved in the present invention is to provide means for improving the stability of the fatty acid ester of vitamin A against hydrolysis.

[0005]

Means for Solving the Problems To solve this problem, the present inventors have intensively studied, particularly, means for stabilizing a fatty acid ester of vitamin A in an essence oil-in-water emulsion composition. As a result, this problem is solved by coexisting an antioxidant in the oil phase of the oil-in-water emulsion composition and blending the amphiphilic substance and the hydrophilic nonionic surfactant under specific conditions. The present invention has been completed by finding what can be done.

That is, the present invention provides an oil-in-water emulsion composition comprising a fatty acid ester of vitamin A, an oil-soluble antioxidant, an amphiphilic substance and a hydrophilic nonionic surfactant, having the following characteristics: I will provide a. The transition temperature of the gel formed in the amphiphilic substance to be blended─hydrophilic nonionic surfactant─aqueous system is 50 ° C. or higher. The weight ratio of the amphiphilic substance to the hydrophilic nonionic surfactant is 0.5 or more by weight. The content of all the surfactants is 5.0% by weight or less based on the whole composition.

[0007] It is one of the factors that specify the properties of the emulsified composition of the present invention (described later). I.O.B. The value (short for Inorganic Organic Balance) is a measure of the polarity of the oil,
A value representing the ratio of inorganic to organic [The organic value is set to 20 for one carbon atom in the oil molecule, and the inorganic value is set to 100 for one hydroxyl group. Values calculated based on inorganic values of other substituents (inorganic groups): Fujita, “Organic Analysis” (1930)
Year) Kanya Shoten, same book, "Prediction of Organic Compounds and Conceptual Diagram of Organic Compounds (Chemical Domain 11-10)" (1957) 719-
725, Fujita and Akatsuka, "Systematic Organic Qualitative Analysis (Pure Product)", 487 (1970) Kazama Shoten, Koda, "Organic Concepts-Basics and Applications", 227 (1984) Sankyo Publishing, Yaguchi "Emulsion prescription design based on organic conceptual diagram" 9
8 pages (1985) Nippon Emulsion Co., Ltd., RH
Ewell, JMHarrison, L. Berg: Ind Eng Chem 36,871 (194
4)], specifically, IOB. Value = Inorganic value of the oil / Organic value of the oil.

[0008] Then, the I.O.
B. The value is I. of each oil component of the oil phase in the emulsion.
OB. This is the sum of the values. That is, {IOB. Value = Inorganic value of oil phase / Organic value of oil phase

[0009] In this formula, the inorganic value of the oil phase is represented by Axx + Bxy + Cxz +.
B, C... Represent inorganic values on the organic conceptual diagram of each oil constituting the oil phase in the emulsion, and x, y, z.
The individual oils A, B, C constituting the oil phase in the emulsion are present in the respective oil phases (x + y + z +
.. = 1)], and the organic value of the oil phase is A ′ × x
+ B ′ × y + C ′ × z + (where A ′, B ′, C ′ ·
Represents the organic value on the organic conceptual diagram of each oil constituting the oil phase in the emulsion). This {IOB.
When the value is large, it means that the oil phase has high inorganicity and consequently the polarity is large. In addition, as described later, silicones are excluded from the above “oil components constituting the oil phase”. In other words, when the silicone oil is present in the oil phase, the silicone oil is contained in the oil phase. Is considered not to exist in the above {IOB. The value is calculated.

[0010]

Embodiments of the present invention will be described below. The oil-in-water emulsified composition according to the present invention (hereinafter, referred to as the present emulsified composition) is, as described above, an emulsified composition intended to stabilize the particularly blended vitamin A fatty acid ester.

That is, the emulsified composition of the present invention is an oil-in-water emulsified composition on the premise that it contains a vitamin A fatty acid ester. Examples of the vitamin A fatty acid ester to be stabilized in the emulsified composition of the present invention include vitamin A acetate, vitamin A palmitate, vitamin A propionate and the like. It is not particularly limited as long as it is a "modified vitamin A", and is a target of stabilization in the emulsified composition of the present invention.

When a mixture of these vitamin A fatty acid esters, for example, an animal or vegetable oil containing a vitamin A fatty acid ester obtained from a marine animal or a plant, is added to the emulsion composition of the present invention, the vitamin contained in the animal or vegetable oil A fatty acid ester can also be an object of stabilization in the present invention.

The emulsified composition of the present invention comprises, under specific conditions, an oil-soluble antioxidant, an amphipathic substance and a hydrophilic nonionic surfactant as means for stabilizing the above-mentioned vitamin A fatty acid ester. , An oil-in-water emulsion composition.

The "oil-soluble antioxidant" that can be incorporated in the emulsion composition of the present invention is an "oil-soluble and antioxidant substance", as long as it can be incorporated in a skin external preparation in terms of safety. There is no particular limitation.

Specifically, for example, butylhydroxytoluene (hereinafter, referred to as BHT), butylhydroxyanisole (hereinafter, referred to as BHA), α, β, γ, δ-tocopherol, nordihydroguaiaretin, propyl gallate, vitamin Examples thereof include fatty acid esters of C and sorbic acid.

The amount of these oil-soluble antioxidants in the emulsified composition of the present invention is preferably 0.001% by weight or more based on the whole composition in order to sufficiently prevent this oxidative decomposition. 0.01% by weight or more is more preferable. Although the upper limit of the blending is not particularly limited, it is blended generally within a range of 10.0% by weight or less based on the whole composition.

These oil-soluble antioxidants are incorporated into the emulsified composition of the present invention mainly to prevent oxidative decomposition of vitamin A fatty acid esters. The amphiphilic substance that can be blended in the emulsion composition of the present invention has surface activity, but itself has a strong hydrophobicity and is a substance having less surface activity than a general surfactant, and has such properties. As long as it is not particularly limited, for example, higher aliphatic alcohol, monoglyceride,
Glycerol monoalkyl ether and the like can be exemplified.

The "hydrophilic nonionic surfactant" which can be incorporated in the emulsion composition of the present invention includes, for example, POE sorbitan such as polyoxyethylene (hereinafter sometimes abbreviated as POE) sorbitan monooleate. Fatty acid esters; POE sorbite fatty acid esters such as POE sorbit monooleate; PE such as POE glycerin monostearate, POE glycerin monoisostearate
OE glycerin fatty acid esters; P such as POE monooleate, POE distearate, POE dioleate, etc.
OE fatty acid esters; POE oleyl ether, PO
E stearyl ether, POE behenyl ether, PO
E2-octyldodecyl ether, POE2-hexyldecylether, POE2-heptylundecylether, POE2-decyltetradecylether, POE2
-POE alkyl ethers such as decyl pentadecyl ether and POE cholestanol ether; POE alkyl phenyl ethers such as POE octyl phenyl ether and POE nonyl phenyl ether; Pluronic type; POE POP cetyl ether, POE POP2
POE / POP alkyl ethers such as decyltetradecyl ether; POE castor oil such as POE castor oil;
Hydrogenated castor oil derivatives; P such as POE sorbit beeswax
OE beeswax / lanoline derivatives; polyglycerin monoalkyl esters / monoalkyl ethers; sucrose fatty acid esters such as sucrose monooleate; and silicone-based surfactants.

In the emulsified composition of the present invention, the amphipathic substance and the hydrophilic nonionic surfactant are combined with the amphiphile / hydrophilic nonionic surfactant / gel formed in the aqueous system. Transition temperature of 50 ° C. or higher, more preferably 6
The combination must be 0 ° C. or higher.

If the transition temperature of the gel is less than 50 ° C., the stability of the fatty acid ester of vitamin A in the system is undesirably reduced. Further, the weight ratio of the amphiphilic substance to the hydrophilic nonionic surfactant must be 0.5 or more by weight, preferably 0.7 or more, and more preferably 1. It is particularly preferable that it is 0 or more.

If the weight ratio is less than 0.7, the stability of the fatty acid ester of vitamin A in the system is undesirably reduced. Further, the amount of all the surfactants to be incorporated into the emulsion composition of the present invention, including these hydrophilic nonionic surfactants, may be 5.0% by weight or less based on the whole composition. It is necessary, and the content is preferably 3.0% by weight or less.

If the amount exceeds 5.0% by weight based on the whole composition, the stability of the vitamin A fatty acid ester in the system is undesirably reduced.

The surfactant that can be added to the emulsion composition of the present invention includes, in addition to the above-mentioned hydrophilic nonionic surfactant,
A lipophilic nonionic surfactant can be added as needed.

Other types of surfactants, specifically, cationic surfactants, anionic surfactants or amphoteric surfactants are blended while sufficiently maintaining the desired effects of the present invention. Although it is generally difficult to do so, the present invention does not preclude these formulations.

The oil component to be selectively blended in the emulsified composition of the present invention is the oil phase {IOB. The value is preferably selected and blended so as to be 0.043 or more.
It is preferable to select and mix them so as to be 28 or more.

The oil phase {IOB. If the value is less than 0.043, the stability of the drug in the system tends to decrease depending on the composition, which is not preferable. This {IOB. As the value increases, the polarity of the entire oil phase increases, the degree of migration of the vitamin A fatty acid ester in the oil phase into the aqueous phase decreases, and the stability of the vitamin A fatty acid ester in the oil phase can be improved. it can.

As the oil component of the emulsified composition of the present invention, silicone oil can be blended. However, in this silicone oil, since there is no carbon atom in the molecule in principle, the IOBB. Although excluded from the concept of values (as described above), these silicone oils have the intended effect of the present invention due to their formulation in the emulsified composition of the present invention.
It does not adversely affect the stability of the Vitamin A fatty acid ester, and its formulation may result in an oil phase of {IOB. It does not change the value.

The amount of the oil component in the emulsified composition of the present invention is preferably at least 1.0 by weight based on the total amount of the amphiphilic substance and the hydrophilic nonionic surfactant. It is particularly preferably 2.0 or more.

The amount of this compound is 1.1 by weight based on the total amount of the amphiphilic substance and the hydrophilic nonionic surfactant.
If it is less than 0, the stability of the vitamin A fatty acid ester in the system tends to decrease depending on the composition of the composition of the present invention, which is not preferable.

In the emulsified composition of the present invention, even if a relatively large amount of a hydrophilic nonionic surfactant is blended, it is allowed to coexist with an amphipathic substance, so that a gel formed in the system can be used. It can be considered that the released hydrophilic nonionic surfactant can be reduced or eliminated. The inventor of the present invention has conceived that this phenomenon can be used as a means for dramatically improving the stability of the vitamin A fatty acid ester, and has completed the emulsified composition of the present invention.

In the emulsified composition of the present invention, the oil component to be blended is not particularly limited as long as the above conditions are satisfied. Can be appropriately selected so as to satisfy the condition (1) and blended in the emulsion composition of the present invention.

The emulsion composition of the present invention is an oil-in-water emulsion composition which can be mainly used as an external preparation for skin of cosmetics, pharmaceuticals, quasi-drugs and the like. Some are referred to as the skin external preparation of the present invention). Due to its constitution, the skin external preparation of the present invention is, in principle, an oil-in-water cream-type preparation which forms a gel in the system. Hereinafter, an embodiment of the present invention as a skin external preparation will be described.

The external preparation for skin of the present invention may be any one of the general preparations for stabilizing the above-mentioned vitamin A fatty acid ester, as long as the intended effect of the present invention is not impaired, depending on the specific purpose of the external preparation for skin. It is possible to mix a basic medicinal component and a base component.

As a medicinal component, for example, when the external preparation for skin of the present invention is used as a sun care product, a benzoic acid-based ultraviolet absorber such as para-aminobenzoic acid; an anthranilic acid-based ultraviolet absorber such as methyl anthranilate; octyl salicylate , Salicylic acid-based UV absorbers such as phenyl salicylate and homomenthyl salicylate; isopropyl paramethoxycinnamate, octyl paramethoxycinnamate, 2-ethylhexyl paramethoxycinnamate, mono-2-ethylhexane diparamethoxycinnamate Glyceryl acid,
[4-bis (trimethylsiloxy) methylsilyl-3-
Methylbutyl] -3,4,5-trimethoxycinnamic acid ester and other cinnamic acid ultraviolet absorbers; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone- Benzophenone ultraviolet absorbers such as 5-sulfonic acid and sodium 2-hydroxy-4-methoxybenzophenone-5-sulfonate; urocanic acid, ethyl urocanate, 2-phenyl-5-methylbenzoxazole, 2- (2′- Ultraviolet absorbers such as (hydroxy-5'-methylphenyl) benzotriazole and 4- tert -butyl-4'-methoxydibenzoylmethane can be incorporated into the external preparation for skin of the present invention.

To impart a moisturizing effect to the external preparation for skin of the present invention, polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, hexylene glycol, glycerin, diglycerin, xylitol, maltitol, Maltose, D
-It may contain humectants such as mannitol, water candy, glucose, fructose, lactose, sodium chondroitin sulfate, sodium hyaluronate, sodium adenosine phosphate, sodium lactate, bile salts, pyrrolidone carboxylic acid, glucosamine, cyclodextrin, etc. it can.

Further, as drug components, vitamins having uses other than oil-soluble antioxidants; hormones such as estradiol and ethinylestradiol; amino acids such as arginine, aspartic acid, cystine, cysteine, methionine, serine, leucine and tryptophan. Anti-inflammatory agents such as allantoin, azulene and glycyrrhetinic acid;
Whitening agents such as arbutin; astringents such as zinc oxide and tannic acid; cooling agents such as L-menthol and camphor; sulfur; lysozyme chloride; pyridoxine hydrochloride; γ-oryzanol;

Further, various extracts having various medicinal effects can be blended. That is, dokudami extract,
Oak extract, melilot extract, bonito extract, liquorice extract, peonies extract, bonsai extract, loofah extract, kina extract, saxifrage extract,
Clara extract, cucumber extract, fennel extract, primrose extract, rose extract, syrup extract, lemon extract, sicon extract, aloe extract, shobu root extract, eucalyptus extract, horsetail extract, sage extract, thyme extract, tea extract, seaweed extract, cucumber extract, clove Extracts, raspberry extract, melissa extract, carrot extract, marronie extract, peach extract, peach leaf extract, mulberry extract, cornflower extract, hamamelis extract, placenta extract, thymus extract, silk extract, etc. may be incorporated into the external preparation for skin of the present invention. it can.

It should be noted that these active ingredients are not limited to active ingredients that can be incorporated into the skin external preparation of the present invention.
In addition to the above-mentioned medicinal ingredients being used alone in the external preparation for skin of the present invention, two or more kinds of the above-mentioned medicinal ingredients can be appropriately combined and compounded according to the purpose.

As the base component, a commonly known base component or the like may be used depending on the specific desired form and dosage form, as long as the desired effect of the present invention is not impaired by its blending (particularly, oil components). Must be mixed with care).

Linseed oil, camellia oil, macadamia nut oil, corn oil, mink oil, olive oil,
Avocado oil, sasanqua oil, castor oil, safflower oil, ginger oil, cinnamon oil, jojoba oil, grape oil, sunflower oil, almond oil, rapeseed oil, sesame oil, wheat germ oil,
Liquid oils such as rice germ oil, rice bran oil, cottonseed oil, soybean oil, peanut oil, teaseed oil, evening primrose oil, egg yolk oil, cow foot oil, liver oil, triglycerin, glycerin trioctanoate, glycerin triisopalmitate; Liquid or solid fats and oils such as oil, palm oil and palm kernel oil; solid fats and oils such as cacao butterfat, sheep butterfat, lard, horse fat, hardened oil, hardened castor oil, mocro, shea butter; beeswax, candelilla Waxes such as wax, cotton wax, carnauba wax, bayberry wax, ibotaro wax, whale wax, montan wax, bran wax, lanolin, reduced lanolin, hard lanolin, kapok wax, sugarcane wax, jojoba wax, shellac wax and the like may be incorporated into the external preparation for skin of the present invention. it can.

Also, octanoic acid esters such as cetyl octanoate, glycerin tri-2-ethylhexanoate, isooctanoic acid esters such as pentaerythritol tetra-2-ethylhexanoate, lauric esters such as hexyl laurate, and myristine Myristic acid esters such as isopropyl octyl myristate and octyl dodecyl myristate; palmitic acid esters such as octyl palmitate; stearic acid esters such as isocetyl stearate; ,
Oleic acid esters such as isodecyl oleate, adipic acid diesters such as diisopropyl adipate, sebacic acid diesters such as diethyl sebacate, and ester oils such as diisostearyl malate; liquid paraffin, ozokerite, squalane, squalene, pristane, paraffin, Hydrocarbon oils such as isoparaffin, ceresin, vaseline, and microcrystalline wax can be blended in the skin external preparation of the present invention.

Chain silicones such as dimethylpolysiloxane, methylphenylpolysiloxane and methylhydrogenpolysiloxane; cyclic silicones such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane;
Silicone such as silicone resin and silicone rubber having a three-dimensional network structure can be blended in the skin external preparation of the present invention.

Then, lower alcohols such as methanol, ethanol, propanol and isopropanol; and sterols such as cholesterol, sitosterol, phytosterol and lanosterol can be incorporated in the skin external preparation of the present invention.

Plants such as gum arabic, gum tragacanth, galactan, carob gum, guar gum, karaya gum, carrageenan, pectin, agar, quince seed (quince), alge colloid (brown algae extract), starch (rice, corn, potato, wheat) Macromolecules, microbial macromolecules such as dextran, succinoglucan, pullulan, starch macromolecules such as carboxymethyl starch and methylhydroxypropyl starch, animal macromolecules such as collagen, casein, albumin, gelatin, methylcellulose, nitro Cellulose, ethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, cellulose sodium sulfate,
Cellulosic polymers such as hydroxypropylcellulose, sodium carboxymethylcellulose, crystalline cellulose and cellulose powder; alginic acid polymers such as sodium alginate and propylene glycol alginate; and vinyl polymers such as polyvinyl methyl ether and carboxyvinyl polymer (such as CARBOPOL). Molecule, polyoxyethylene polymer, polyoxyethylene polyoxypropylene copolymer polymer, acrylic polymer such as sodium polyacrylate, polyethyl acrylate, polyacrylamide, polyethyleneimine, cationic polymer, bentonite, silica Water-soluble polymers such as inorganic water-soluble polymers such as aluminum magnesium silicate, laponite, hectorite, and silicic acid anhydride may be incorporated into the external preparation for skin of the present invention. Kill.

Further, sequestering agents such as alanine, sodium edetate, sodium polyphosphate, sodium metaphosphate, and phosphoric acid; 2-amino-2-methyl-
1-propanol, 2-amino-2-methyl-1,3-
Neutralizing agents such as propanediol, potassium hydroxide, sodium hydroxide, L-arginine, L-lysine, triethanolamine, sodium carbonate; lactic acid, citric acid, glycolic acid, succinic acid, tartaric acid, dl-malic acid, carbonic acid PH adjusters such as potassium, sodium bicarbonate, ammonium bicarbonate and the like can be incorporated into the skin external preparation of the present invention.

Also, benzoic acid, salicylic acid, carboxylic acid, paraoxybenzoic acid ester, parachloromethcresol, hexachlorophen, benzalkonium chloride, chlorhexidine chloride, trichlorocarbanilide, photosensitizer,
Antibacterial agents such as phenoxyethanol and parabens can be incorporated into the external preparation for skin of the present invention.

Further, if necessary, appropriate fragrances, pigments and the like can be added to the external preparation for skin of the present invention as long as the desired effects of the present invention are not impaired. Here, the above-mentioned base components are examples, and the base components that can be blended with the external preparation for skin of the present invention are not limited to these base components. These base components can be combined in the skin external preparation of the present invention in an appropriate combination in accordance with a formulation according to a desired form. The specific formulation of the emulsion composition of the present invention will be described later.

[0048]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the technical scope of the present invention. In addition, the compounding amount in these Examples is% by weight based on the whole system in which the component is compounded, unless otherwise specified.

Method for Stability Evaluation of Vitamin A Fatty Acid Esters
Method In this example, in order to evaluate the stability of the formulated vitamin A fatty acid ester, the residual ratio of the vitamin A fatty acid ester in the preparation was used as an evaluation index, and the light was shielded with aluminum foil for one month at 50 ° C. The residual ratio of the vitamin A fatty acid ester after storage relative to before storage in the preparation after storage was determined by analyzing with high performance liquid chromatography, and this was defined as the residual ratio (%) as the evaluation index ( Hereinafter, the residual rate obtained in this manner is
It is simply called the survival rate.)

High-performance liquid chromatography for determining the residual ratio was performed under the following conditions. Column: C18 column (manufactured by Shiseido Co., Ltd.) Detection: UV 310 nm Mobile phase: 72% methanol / 10% acetonitrile / 1
8% ion exchange water / 0.5% acetic acid (when detecting retinol acetate) 100% methanol / 0.5% acetic acid (when detecting retinol palmitate)

The residual ratio is preferably as close to 100% as possible. In the present invention, whether or not the residual ratio is 80% or more is determined by determining whether the stabilizing effect of the vitamin A fatty acid ester is recognized or not. Line. That is, those having a residual ratio of 80% or more were evaluated as acceptable products, and those having a residual ratio of less than 80% were evaluated as unacceptable products.

IOB. Method of calculating the value Based on the calculation method described above, the I.O.
B. Values were calculated.

In the examples and comparative examples of the formulations shown in Tables 1 to 3 below, the above-mentioned studies were carried out, and the effects of the present invention were examined. The results are also shown in these tables. Each preparation in each table was prepared by adding an oil phase also heated to 70 ° C. to an aqueous phase at 70 ° C., and uniformly emulsifying the mixture using a homomixer.

[0054]

[Table 1]

In Table 1, Examples 1 to 3 and Comparative Example 1 are examples in which the amount ratio of the amphiphilic substance to the hydrophilic nonionic surfactant was compared and examined. In Examples 1 to 3 in which the weight ratio satisfies the weight ratio of 0.5 or more, which is an allowable range, the stability over time of retinol acetate, which is a vitamin A fatty acid ester, was observed. In Comparative Example 1, which was 0.45, it was clear that the stability over time was inferior to the reference value of 80.

Examples 4 and 5 and Comparative Examples 2 and 3 are examples in which the amounts of the surfactants incorporated were examined. Example 4 and Example 5 in which this blended amount satisfies the reference value, "5.0% by weight or less based on the whole composition"
In Comparative Example 2, the stability over time of the vitamin A fatty acid ester was improved, but in Comparative Examples 2 and 3, which deviated from this standard, the stability over time was significantly reduced. It was revealed.

Examples 6 to 9 are examples in which the amount of the oil component was studied. Example 6 in which this blending amount satisfied the preferred range of "1.0 or more by weight ratio to the total amount of the amphiphilic substance and the hydrophilic nonionic surfactant".
No. 7 has good stability over time of the vitamin A fatty acid ester, but Examples 8 and 9 deviate from this preferred range.
The stability of vitamin A fatty acid ester over time in
It turned out to be close to the limit value.

Comparative Example 4 is an example in which the formulation of “amphiphilic substance / hydrophilic nonionic surfactant / water system” was set so that the transition temperature of the gel was less than 50 ° C. In Comparative Example 4, in the system in which the transition temperature of the gel was less than 50 ° C., the stability over time of the vitamin A fatty acid ester was inferior to the limit value.

[0059]

[Table 2]

In Table 2, Examples 10 to 14 are shown.
Sets the compounding ingredients variously and determines the stability of the vitamin A fatty acid ester in each example by the ΔI.
O. B. This is an example of study using values as indices. From these results, the oil phase ΔI. O. B. It was found that the higher the value, that is, the higher the inorganicity of the oil phase and the higher the polarity, the higher the stability over time of the vitamin A fatty acid ester.

[0061]

[Table 3]

In Table 3, Examples 15 to 17 are shown.
And Comparative Examples 5 to 8 are examples in which it was examined whether or not the same as the above-described Examples and Comparative Examples can be said when the vitamin A fatty acid ester to be blended is changed to retinol palmitate. . From these results, it has been clarified that even if the vitamin A fatty acid ester to be added is changed, the stability over time of the vitamin A fatty acid ester is improved in the emulsified composition of the present invention.

[0063]

According to the present invention, there is provided an emulsified composition in which a vitamin A fatty acid ester is stabilized in a preparation, particularly useful as an external preparation for skin.

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[Procedure amendment]

[Submission date] February 8, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

Means for Solving the Problems To solve this problem, the present inventors have intensively studied, particularly, means for stabilizing a fatty acid ester of vitamin A in a cream- based oil-in-water emulsion composition. As a result, this problem is solved by allowing an antioxidant to coexist in the oil phase of the oil-in-water emulsion composition and blending the amphiphilic substance and the hydrophilic nonionic surfactant under specific conditions. The present invention has been completed by finding what can be done.

Claims (4)

[Claims] An oil-in-water emulsion composition comprising an oil-soluble antioxidant, an amphiphilic substance and a hydrophilic nonionic surfactant together with a fatty acid ester of vitamin A having the following characteristics: The transition temperature of the gel formed in the aqueous substance─hydrophilic nonionic surfactant─aqueous system is 50 ° C. or higher; the weight ratio of the amphiphilic substance to the hydrophilic nonionic surfactant is weight ratio Is 0.5 or more; and the amount of all surfactants is 5.0% by weight or less based on the whole composition. 2. The amount of the oil component is 1.0% by weight based on the total amount of the amphiphilic substance and the hydrophilic nonionic surfactant.
The oil-in-water emulsion composition according to claim 1, which is the above. 3. The oil phase of {IOB. The oil-in-water emulsion composition according to claim 1 or 2, wherein the value is 0.043 or more. 4. The oil-in-water emulsion composition is an external preparation for skin.
The oil-in-water emulsion composition according to any one of claims 1 to 3.