JP2004307414A - W/o/w emulsion skin care preparation for external use and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a W/O/W emulsion skin care preparation for external use, having preservation stability, skin safety and sense of use improved by formulating an alkyl acrylate copolymer, a fatty acid ester of dextrin and a water-soluble active ingredient such as an ascorbic acid derivative; and to provide a method for producing the skin care preparation. <P>SOLUTION: The W/O/W emulsion skin care preparation for external use is obtained by formulating the water-soluble active ingredient such as the ascorbic acid derivative in a W/O/W emulsion comprising an acrylic acid-alkyl methacrylate copolymer and the fatty acid ester of the dextrin. The W/O/W emulsion is obtained by dispersing and emulsifying inner water phase parts containing the water-soluble active ingredient in an oil phase part containing the fatty acid ester of the dextrin, and dispersing and emulsifying the resultant emulsion in an outer aqueous phase part containing the acrylic acid-alkyl methacrylate copolymer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２０】
【表２】種々の親油性界面活性剤や油溶性増粘剤を使用したＷ／Ｏ／Ｗエマルションとの比較

【００２１】
表１および表２の結果より、アクリル酸メタクリル酸アルキル共重合体とデキストリン脂肪酸エステルを配合することにより、安定性や使用感に優れたＷ／Ｏ／Ｗエマルション皮膚外用組成物が得られることがわかった。また、内水相部のアスコルビン酸誘導体の安定性が高いことも実証された。
【００２２】
表３にアクリル酸メタクリル酸アルキル共重合体を様々な割合で配合した製剤を調製し、製剤自体の経時的変化および使用感について検討した結果を示す。また、表４にはデキストリン脂肪酸エステルを様々な割合で配合した製剤の経時的変化および使用感を検討した結果を示す。なお、それぞれの製造方法に関しては前述の表１、表２と同様に行い、アスコルビン酸誘導体や製剤の保存安定性および使用感評価も同じ指標で行った。
【００２３】
【表３】アクリル酸メタクリル酸アルキル共重合体の様々な濃度における試験結果

【００２４】
【表４】デキストリン脂肪酸エステルの様々な濃度における試験結果

【００２５】
表３および表４の結果より、アクリル酸メタクリル酸アルキル共重合体の配合量については、好ましくは０．０５〜５％、さらに好ましくは０．１〜２％とすると、十分な乳化能を示して保存安定性の顕著な向上が見られる。また、デキストリン脂肪酸エステルの配合量については、好ましくは０．０５〜１０％、さらに好ましくは０．１〜５％とすると、十分な乳化能を示して保存安定性も顕著に向上する。
【００２６】
表１から表４の結果より、アクリル酸メタクリル酸アルキル共重合体とデキストリン脂肪酸エステルからＷ／Ｏ／Ｗエマルションを生成し、その内水相部に水溶性活性成分であるアスコルビン酸誘導体を含有させることにより、保存安定性や使用感などに優れた有用なＷ／Ｏ／Ｗエマルション皮膚外用組成物が提供できることが明らかとなった。
【００２７】
【発明の実施の形態】
以下に本発明を詳細に説明するための実施例を挙げるが、本発明はこれらに限定されるものではない。
【００２８】
実施例１ 高機能クリーム
配合成分 配合量（重量％）
（１） デキストリン脂肪酸エステル
（レオパールＴＬ） ０．４
（２） 酢酸トコフェロール ０．３
（３） スクワラン １１．３
（４） ミリスチン酸オクチルドデシル ８．０
（５） メチルフェニルポリシロキサン ４．０
（６） 香料 ０．２
（７） アスコルビン酸リン酸ナトリウム ８．０
（８） クエン酸ナトリウム ８．０
（９） 硫酸アルミニウムカリウム ０．１
（１０）グリチルリチン酸ジカリウム ０．１
（１１）アクリル酸メタクリル酸アルキル共重合体
（ペミュレンＴＲ−１） ０．６
（１２）１，３−ブチレングリコール ８．０
（１３）パラベン 適 量
（１４）グリセリン ８．０
（１５）水酸化カリウム 適 量
（１６）精製水 残 余
【００２９】
〔製法〕（１６）の一部に（７）、（８）を溶解し、（１）〜（６）の油相部に７５℃の温度下で添加し乳化、Ｗ／Ｏエマルションを得た。これを一部の（１６）に（９）〜（１４）を分散溶解させた外水相部と混合し、残りの（１６）で溶解させた（１５）で中和し、均一分散させる。
【００３０】
実施例２ 乳液
配合成分 配合量（重量％）
（１） デキストリン脂肪酸エステル
（レオパールＴＴ） ０．２
（２） ＰＯＥ（４）グリセリルモノステアレート ０．１
（３） シクロメチコン ５．０
（４） ジカプリン酸ネオペンチルグリコール ５．０
（５） 香料 ０．１
（６） クエン酸カリウム ２．０
（７） アスコルビン酸リン酸マグネシウム ３．０
（８） アクリル酸メタクリル酸アルキル共重合体
（ペミュレンＴＲ−２） ０．２
（９） モノステアリン酸デカグリセリル ０．５
（１０）コハク酸トコフェロールカルシウム ８．０
（１１）１，３−ブチレングリコール ５．０
（１２）パラベン 適 量
（１３）グリセリン １０．０
（１４）エデト酸塩 ０．１
（１５）アミノメチルプロパンジオール 適 量
（１６）精製水 残 余
【００３１】
〔製法〕（１６）の一部に（６）、（７）を溶解し、（１）〜（５）の油相部に８０℃の温度下で添加し乳化、Ｗ／Ｏエマルションを得た。これを一部の（１６）に（８）〜（１４）を分散溶解させた外水相部と混合し、残りの（１６）で溶解させた（１５）で中和し、均一分散させる。
【００３２】
実施例３ 美白クリーム
配合成分 配合量（重量％）
（１） デキストリン脂肪酸エステル
（レオパールＫＬ） ２．０
（２） 流動パラフィン １０．０
（３） ジメチコン ５．０
（４） ニコチン酸トコフェロール ２．０
（５） 香料 ０．２
（６） クエン酸ナトリウム ２．０
（７） アスコルビン酸硫酸カリウム １０．０
（８） ポリリン酸ナトリウム ０．１
（９） アクリル酸メタクリル酸アルキル共重合体
（ペミュレンＴＲ−１） １．０
（１０）モノオレイン酸デカグリセリル ０．５
（１１）１，３−ブチレングリコール ５．０
（１２）パラベン 適 量
（１３）グリセリン １１．０
（１４）水酸化カリウム 適 量
（１５）精製水 残 余
【００３３】
〔製法〕（１５）の一部に（６）〜（８）を溶解し、（１）〜（５）の油相部に７０℃の温度下で添加し乳化、Ｗ／Ｏエマルションを得た。これを一部の（１５）に（９）〜（１３）を分散溶解させた外水相部と混合し、残りの（１５）で溶解させた（１４）で中和し、均一分散させる。
【００３４】
実施例１〜３で示した本発明品は、アクリル酸メタクリル酸アルキル共重合体とデキストリン脂肪酸エステルからＷ／Ｏ／Ｗエマルションを生成し、その内水相部には水溶性活性成分であるアスコルビン酸誘導体が含有されたＷ／Ｏ／Ｗエマルション皮膚外用組成物であり、保存安定性や皮膚安全性、使用感といった面で満足のできるものであった。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a W / O / W emulsion skin external composition and a method for producing the same. More specifically, the present invention relates to a W / O / W emulsion skin external composition excellent in storage stability, skin safety, feeling of use (spreadability, stickiness, moisturizing properties) and the like, and a method for producing the same.
[0002]
[Prior art]
Alkyl acrylate alkyl methacrylate copolymers are mainly used as water-soluble thickeners, but they also have a function as a hydrophilic emulsifier, so that an O / W emulsion can be prepared (Patent Document 1). Furthermore, a dextrin fatty acid ester known as an oil gelling agent also works as a lipophilic emulsifier, so that a W / O emulsion can be prepared (Patent Document 2). When an emulsion is prepared using these two types of polymers, the skin safety is high and the emulsifying ability is equal to or higher than that of the case using conventional various low molecular surfactants. Thus, a composition for external use on the skin with a better feeling of use can be obtained.
On the other hand, there are O / W and W / O emulsions as currently used emulsion skin external compositions, and W / O / W emulsion skin external compositions as emulsion skin external compositions that impart a new feeling of use. Attention has been paid. Some methods of obtaining a W / O / W emulsion using an alkyl acrylate alkyl methacrylate copolymer or a dextrin fatty acid ester are also disclosed (Patent Documents 3 to 5).
However, no report has been made yet on the combined use of an alkyl acrylate methacrylate copolymer and a dextrin fatty acid ester. In these known cases, the safety of W / O / W emulsions must be considered in order to enhance the stability of the emulsions in combination with a large amount of various low molecular surfactants. However, there are some problems such as the feeling of use being poor due to the combination with other thickeners.
In addition, ascorbic acid derivatives are known to have the effect of suppressing, reducing, and promoting the production of melanin, which causes spots and freckles, and are used as an active ingredient (whitening agent) of many whitening cosmetics. (Non-Patent Document 1). However, not only ascorbic acid derivatives but also various aqueous solutions of water-soluble active ingredients are extremely unstable and may be oxidized and decomposed by oxygen in the air. Is required.
[0003]
[Patent Document 1]
JP-A-8-126831 [Patent Document 2]
Japanese Patent No. 3236926 [Patent Document 3]
JP 2002-275029 A [Patent Document 4]
JP-A-11-33391 [Patent Document 5]
Japanese Patent Publication No. 7-530 [Non-Patent Document 1]
Shigeru Sekine, 5 others, "Cosmetics Handbook", Nikko Chemicals Co., Ltd., 2 other companies, November 1996, p. 462-465
[0004]
[Problems to be solved by the invention]
That is, the existing problems are, first of all, that there is no W / O / W emulsion skin external composition which satisfies all requirements in terms of storage stability, skin safety, feeling of use, and the like. Second, water-soluble active ingredients such as ascorbic acid derivatives are very unstable and easily decomposed in an aqueous solution.
The present invention provides a W / O / W emulsion in which the stability of a water-soluble active ingredient such as an ascorbic acid derivative, which is a problem of the prior art, is improved, and all problems such as storage stability, skin safety, and feeling of use are solved. An object of the present invention is to provide a composition for external use on the skin and a method for producing the same.
[0005]
[Means for Solving the Problems]
In view of the above, the present inventors have conducted intensive studies to obtain a better W / O / W emulsion skin external composition. As a result, first, a dextrin fatty acid ester was used to prepare a water-soluble active ingredient such as an ascorbic acid derivative. After preparing a W / O emulsion in which the internal aqueous phase portion is dispersed, the emulsion is dispersed and emulsified in an external aqueous phase containing an alkyl methacrylate copolymer to enhance the stability of the water-soluble active ingredient, and The present inventors succeeded in obtaining a W / O / W emulsion composition for external use on the skin which was superior to the conventional composition in terms of storage stability and feeling of use, and completed the present invention.
[0006]
That is, the present invention provides a W / O / W emulsion external skin composition comprising an alkyl methacrylate copolymer and a dextrin fatty acid ester, which contains a water-soluble active ingredient such as an ascorbic acid derivative in a stable state, and its composition. It is an invention that provides a manufacturing method. In the present invention, the “w / o / w emulsion skin external composition” means a composition that can be widely applied to the outer skin, and includes cosmetics, pharmaceuticals, and quasi-drugs of specific products. It does not question the distinction of pharmaceutical products under the Pharmaceutical Affairs Law.
[0007]
Hereinafter, the configuration of the present invention will be described in detail.
[0008]
The alkyl acrylate alkyl methacrylate copolymer used in the present invention preferably has a molecular weight of 500,000 to 3,000,000, and an alkyl group having 10 to 30 carbon atoms. Specific examples of commercially available products include Pemulen TR-1 and And Pemulen TR-2 (both manufactured by BF Goodrich). The dextrin fatty acid ester preferably has a degree of sugar polymerization of 5 to 50, a degree of ester substitution per saccharide unit of 1.0 to 2.5, and a fatty acid having 8 to 24 carbon atoms. Specific examples include Leopearl TL, Leopearl KL, and Leopearl TT (all manufactured by Chiba Flour Milling). Outside this range, there are some problems in emulsion stability, usability, and the like, which may not be preferable. Alkyl acrylate alkyl methacrylate copolymer and dextrin fatty acid ester can both be produced by a known method and blended in the composition for external use on skin of the present invention. Can be.
[0009]
The alkyl acrylate alkyl methacrylate copolymer is effective not only as a water-soluble thickener but also as a hydrophilic emulsifier. The blending amount is not particularly limited, but is preferably 0.05 to 5%, more preferably 0.1 to 2%, so that sufficient emulsifying ability is exhibited and storage stability is remarkably improved. The dextrin fatty acid ester also has a role as an oil gelling agent and a lipophilic emulsifier. Although the amount is not particularly limited, it is preferably 0.05 to 10%, more preferably 0.1 to 5%, so that sufficient emulsifying ability is exhibited and storage stability is remarkably improved. When these two types of emulsifiers are less than the respective concentration ranges, it may be difficult to obtain a sufficient emulsifying ability. On the other hand, when the emulsifying agents are blended beyond the concentration range, enhancement of the emulsifying ability is hardly recognized and is uneconomical. In some cases, problems such as twisting and squeaking may occur. On the other hand, when the concentration is within the range, a satisfactory emulsifying ability can be ensured even when no other surfactant or thickener is added.
[0010]
The water-soluble active ingredient used in the present invention is not particularly limited as long as it is an ingredient applicable to the outer skin. Specific examples include amino acids and their peptides, proteins, collagen, vitamins, polyhydric alcohols and polysaccharides, and various other plant and animal extracts and synthetics. Those water-soluble active ingredients which are produced by a known method can be blended in the composition for external use on the skin of the present invention, and commercially available ones can be used. Further, the amount is not particularly limited.
[0011]
Ascorbic acid derivatives, which are a kind of water-soluble active ingredient used in the present invention, include ascorbic acid phosphoric acid ester, ascorbic acid alkyl ester, ascorbic acid sulfate and the like. Specifically, ascorbic acid phosphates such as L-ascorbic acid-2-phosphate, L-ascorbic acid-3-phosphate, DL-α-tocopherol-2-L-ascorbic acid phosphate diester, Ascorbic acid alkyl esters such as L-ascorbyl palmitate, L-ascorbyl isostearate, L-ascorbyl dioleate, ascorbic acid sulfates such as L-ascorbic acid-2-sulfate, L-ascorbic acid-3-sulfate, etc. And these salts can also be used. For example, alkali metal salts such as sodium salt and potassium salt, and alkaline earth metal salts such as calcium salt and magnesium salt can be used.
[0012]
Further, it can be used for ascorbic acid glycoside. Specific examples include glycosides such as mannose, fructose, galactose, xylose, and arabinose.
[0013]
Ascorbic acid derivatives produced by a known method can be added to the skin external composition of the present invention, and commercially available products can be used.
[0014]
The amount of the ascorbic acid derivative is not particularly limited, but is preferably 0.01 to 20%. If it is less than 0.01%, a synergistic whitening effect may not be expected in some cases. It is possible to contain more than 20%, but no remarkable increase in whitening effect is observed and it is not economical. Further, by adding a tocopherol derivative, a further whitening effect can be expected.
[0015]
The method for producing the W / O / W emulsion skin external composition in the present invention is not particularly limited, and it can be produced by a conventional method. Preferably, W / O / W emulsion having excellent storage stability is prepared by the following production method. An O / W emulsion skin external composition is obtained. First, a W / O emulsion is obtained by dispersing and emulsifying an inner aqueous phase portion containing a water-soluble active ingredient in an oil phase portion containing a dextrin fatty acid ester. By setting the emulsification temperature at this time to preferably 60 to 90C, more preferably 70 to 85C, a stable W / O emulsion having finer particles can be prepared. Thereafter, this W / O emulsion part is preferably dispersed and emulsified in an external aqueous phase part containing an alkyl methacrylate acrylate copolymer under a temperature condition of preferably 70 ° C. or lower, so that a W / O / W emulsion for external use on the skin is obtained. A composition can be prepared.
[0016]
The composition for external use on the skin of the present invention, in addition to the above essential components, includes various components used in ordinary cosmetics, quasi-drugs, pharmaceuticals, and the like, such as oily components, emulsifiers, humectants, thickeners, medicinal components, and preservatives. Agents, pigments, powders, pH adjusters, ultraviolet absorbers, antioxidants, fragrances and the like can be appropriately compounded.
[0017]
【The invention's effect】
In the present invention, a water-soluble active ingredient such as an ascorbic acid derivative is blended in the inner aqueous phase of a W / O / W emulsion composed of an alkyl methacrylate copolymer and a dextrin fatty acid ester. Provided is a W / O / W emulsion skin external composition in which components are prevented from being decomposed and storage stability, skin safety and feeling of use are improved, and a method for producing the same.
[0018]
【Example】
Table 1 shows the temporal stability and usability of the ascorbic acid derivative and the preparation itself when various hydrophilic surfactants and water-soluble thickeners were used in place of the alkyl methacrylate copolymer. The results obtained are shown. In addition, Table 2 shows the results of examining the stability over time and the feeling of use of the preparation when the dextrin fatty acid ester was replaced with another lipophilic surfactant or an oil-soluble thickener.
In addition, about the manufacturing method of the preparation, all performed the same procedure. First, at a temperature of 80 ° C., an oil phase portion and an inner aqueous phase portion are dispersed and emulsified to prepare a W / O emulsion, and then the W / O emulsion and an outer aqueous phase portion are dispersed and emulsified and cooled to 30 ° C. The desired W / O / W emulsion formulation was obtained.
The stability of the ascorbic acid derivative in each preparation was determined by quantification by liquid chromatography. The measurement was performed at room temperature and 40 ° C. after a lapse of 6 months, and the evaluation criteria were evaluated according to the following four steps.
Ascorbic acid derivative stability evaluation item ：: The measured value after 6 months is within ± 3% of the quantitative measured value immediately after preparation.
：: The measured value after 6 months is within the range ± 5%.
Δ: The measured value after 6 months falls within the range of ± 10%.
×: The measured value after 6 months is out of the range ± 10% or more.
With respect to the time-lapse observation of the preparation, evaluation was performed after one year at room temperature and two months at 50 ° C., and the following four-stage storage stability evaluation items were used as indices.
Storage stability evaluation item A: Almost no change in phase state was observed.
：: A slight increase in the emulsified particle diameter can be confirmed by observation with a microscope.
Δ: No phase separation was observed, but a remarkable increase in the emulsified particle diameter was observed when observed with a microscope.
X: It can be visually confirmed that the two phases are separated.
In addition, the evaluation of feeling of use was evaluated by having 20 panelists actually use the skin external composition of the present invention. The spreadability at the time of application, the viscosity, and the moisturizing property after the application were evaluated by the following five grades of usability evaluation items.
Usability evaluation item 5 points: Very good 4 points: Good 3 points: Normal 2 points: Bad 1 point: Very poor The final judgment is made according to the following four grades of usability score evaluation of the obtained total points. did.
Evaluation score of usability ◎: The total score is 80 points or more, and the usability is very good.
：: The total score is 70 points or more, and the usability is good.
Δ: The total score is 50 points or more, and the usability is poor.
X: The total score is 50 points or less, and the usability is very poor.
In addition, each sample was usually used, and the raw material actually marketed was used.
[0019]
Table 1 Comparison with W / O / W emulsions using various hydrophilic surfactants and water-soluble thickeners

[0020]
Table 2 Comparison with W / O / W emulsions using various lipophilic surfactants and oil-soluble thickeners

[0021]
From the results in Tables 1 and 2, it can be seen that a W / O / W emulsion skin external composition excellent in stability and usability can be obtained by blending the alkyl methacrylate copolymer and the dextrin fatty acid ester. all right. It was also demonstrated that the stability of the ascorbic acid derivative in the inner aqueous phase was high.
[0022]
Table 3 shows the results obtained by preparing formulations in which alkyl acrylate alkyl methacrylate copolymers were blended in various ratios and examining the changes over time and the feeling of use of the formulations themselves. In addition, Table 4 shows the results of examining the changes over time and the feeling of use of the preparations containing dextrin fatty acid esters in various ratios. In addition, about each manufacturing method, it carried out similarly to Table 1 and Table 2 mentioned above, and evaluated the storage stability and usability | use_condition of an ascorbic acid derivative and a formulation with the same parameter | index.
[0023]
Table 3 Test results at various concentrations of alkyl acrylate alkyl methacrylate copolymer

[0024]
Table 4 Test results at various concentrations of dextrin fatty acid esters

[0025]
From the results of Tables 3 and 4, the compounding amount of the alkyl acrylate alkyl methacrylate copolymer is preferably 0.05 to 5%, more preferably 0.1 to 2%, and shows a sufficient emulsifying ability. Remarkably improved storage stability. When the amount of the dextrin fatty acid ester is preferably 0.05 to 10%, more preferably 0.1 to 5%, sufficient emulsifying ability is exhibited and storage stability is remarkably improved.
[0026]
From the results in Tables 1 to 4, a W / O / W emulsion was formed from the alkyl methacrylate copolymer and the dextrin fatty acid ester, and the aqueous phase contained an ascorbic acid derivative as a water-soluble active ingredient. As a result, it has been clarified that a useful W / O / W emulsion external composition for skin having excellent storage stability and usability can be provided.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
EXAMPLES Examples for describing the present invention in detail will be described below, but the present invention is not limited thereto.
[0028]
Example 1 Highly functional cream compounding ingredients Compounding amount (% by weight)
(1) Dextrin fatty acid ester (Leopearl TL) 0.4
(2) Tocopherol acetate 0.3
(3) Squalane 11.3
(4) Octyldodecyl myristate 8.0
(5) Methylphenyl polysiloxane 4.0
(6) Fragrance 0.2
(7) Sodium phosphate ascorbate 8.0
(8) Sodium citrate 8.0
(9) Potassium aluminum sulfate 0.1
(10) dipotassium glycyrrhizinate 0.1
(11) Acrylic acid alkyl methacrylate copolymer (Pemulen TR-1) 0.6
(12) 1,3-butylene glycol 8.0
(13) Paraben appropriate amount (14) Glycerin 8.0
(15) Appropriate amount of potassium hydroxide (16) Residue of purified water [0029]
[Production method] (7) and (8) were dissolved in a part of (16) and added to the oil phase of (1) to (6) at a temperature of 75 ° C to emulsify to obtain a W / O emulsion. . This is mixed with an external aqueous phase in which (9) to (14) are dispersed and dissolved in a part of (16), and neutralized with (15) dissolved in the remaining (16), and uniformly dispersed.
[0030]
Example 2 Emulsion compounding ingredients Compounding amount (% by weight)
(1) Dextrin fatty acid ester (Leopearl TT) 0.2
(2) POE (4) glyceryl monostearate 0.1
(3) Cyclomethicone 5.0
(4) Neopentyl glycol dicaprate 5.0
(5) Fragrance 0.1
(6) Potassium citrate 2.0
(7) Magnesium phosphate ascorbate 3.0
(8) Alkyl acrylate alkyl methacrylate copolymer (Pemulen TR-2) 0.2
(9) Decaglyceryl monostearate 0.5
(10) Tocopherol calcium succinate 8.0
(11) 1,3-butylene glycol 5.0
(12) Paraben dosage (13) Glycerin 10.0
(14) edetate 0.1
(15) Aminomethylpropanediol appropriate amount (16) Purified water residue
[Production method] (6) and (7) were dissolved in a part of (16), and added to the oil phase of (1) to (5) at a temperature of 80 ° C to emulsify to obtain a W / O emulsion. . This is mixed with an external aqueous phase in which (8) to (14) are dispersed and dissolved in a part of (16), neutralized with (15) dissolved in the remaining (16), and uniformly dispersed.
[0032]
Example 3 Whitening cream compounding ingredients Compounding amount (% by weight)
(1) Dextrin fatty acid ester (Leopearl KL) 2.0
(2) Liquid paraffin 10.0
(3) Dimethicone 5.0
(4) Tocopherol nicotinate 2.0
(5) Fragrance 0.2
(6) Sodium citrate 2.0
(7) Potassium ascorbate sulfate 10.0
(8) Sodium polyphosphate 0.1
(9) Alkyl acrylate alkyl methacrylate copolymer (Pemulen TR-1) 1.0
(10) Decaglyceryl monooleate 0.5
(11) 1,3-butylene glycol 5.0
(12) Paraben dosage (13) Glycerin 11.0
(14) Appropriate amount of potassium hydroxide (15) Residual purified water [0033]
[Production method] (6) to (8) were dissolved in a part of (15), and added to the oil phase of (1) to (5) at a temperature of 70 ° C. to obtain an emulsion to obtain a W / O emulsion. . This is mixed with an external aqueous phase in which (9) to (13) are dispersed and dissolved in a part of (15), neutralized with (14) dissolved in the remaining (15), and uniformly dispersed.
[0034]
The product of the present invention shown in Examples 1 to 3 produces a W / O / W emulsion from an alkyl methacrylate copolymer and a dextrin fatty acid ester. A W / O / W emulsion external composition containing an acid derivative, which was satisfactory in terms of storage stability, skin safety, and feeling of use.

Claims (7)

A W / O / W emulsion skin external composition comprising an alkyl acrylate alkyl methacrylate copolymer and a dextrin fatty acid ester. The W / O / W emulsion external composition for skin according to claim 1, wherein the inner aqueous phase contains a water-soluble active ingredient. 3. The W / O / W emulsion skin external composition according to claim 1, wherein the inner aqueous phase contains an ascorbic acid derivative. The W / O / W emulsion skin external composition according to any one of claims 1 to 3, wherein 0.1 to 2% of an alkyl acrylate methacrylate copolymer is blended. The dermatological composition according to any one of claims 1 to 4, wherein the dextrin fatty acid ester is incorporated in an amount of 0.1 to 5%. The W / O / W emulsion skin external composition according to any one of claims 1 to 5, wherein the ascorbic acid derivative is incorporated in an amount of 0.01 to 20%. A W / O emulsion is obtained by dispersing and emulsifying an inner aqueous phase portion containing a water-soluble active ingredient in an oil phase portion containing a dextrin fatty acid ester, and further, the W / O emulsion contains an alkyl acrylate alkyl methacrylate copolymer. A method for producing a W / O / W emulsion external composition for skin, comprising dispersing and emulsifying in an external aqueous phase.