JP4277135B2 - W / O / W emulsion composition - Google Patents

Description

  The present invention relates to a W / O / W emulsion composition excellent in long-term emulsification stability and prevention of leakage of inner aqueous phase components.

  The W / O / W emulsion composition is a composite emulsion composition comprising a water-in-oil emulsion in an aqueous component. This emulsion composition can be used as a functional emulsion composition having effects such as sustained release and oxidation prevention by encapsulating various useful components in the inner aqueous phase of the W / O / W emulsion. They are very useful as medicines, cosmetics, foods, and the like. Since the emulsification stability of W / O / W emulsions is extremely low, as a method for improving the emulsification stability, a method of stabilizing using a polymer (Patent Document 1), a method of stabilizing using a specific emulsifier ( Patent documents 2, 3 and 4) have been reported. However, the present situation is that the emulsion stability higher than the emulsion stability obtained by these methods is demanded.

Furthermore, recently, when a W / O / W emulsion containing a useful component in the inner aqueous phase is stored for a long period of time, the problem that the inner aqueous phase component leaks even though it looks stable in appearance is attracting attention. Development of a W / O / W type emulsion having emulsion stability and prevention of leakage of the inner aqueous phase component has been demanded.
JP-A-11-33391 JP 60-183031 A JP-A-60-199833 JP 2001-25360 A

  Accordingly, an object of the present invention is to provide a W / O / W emulsion composition that is excellent in long-term emulsification stability and prevention of leakage of the inner aqueous phase component.

  As a result of intensive studies in view of the above-mentioned problems of the prior art, the present inventor has obtained a W / O / W type containing a branched or unsaturated fatty acid ester that is liquid at 25 ° C. and a polyhydroxy fatty acid ester of polyethylene glycol. The present inventors have found that the emulsion composition is excellent in long-term emulsification stability and prevention of leakage of the inner aqueous phase component, and completed the present invention.

That is, the present invention provides the following emulsion composition.
Item W / O / W emulsion composition containing a branched or unsaturated fatty acid ester which is liquid at 1.25 ° C. and a polyhydroxy fatty acid ester of polyethylene glycol.
Item 2. The branched or unsaturated fatty acid ester is at least one ester selected from the group consisting of isononanoic acid ester, 2-ethylhexanoic acid ester, isostearic acid ester, triisostearic acid ester, tetraisostearic acid ester and oleic acid ester Item 2. The composition according to Item 1.
Item 3. Branched or unsaturated fatty acid ester is cetyl 2-ethylhexanoate, hexyldecyl 2-ethylhexanoate, isononyl isononanoate, isodecyl isononanoate, isotridecyl isononanoate, ethyl isostearate, isopropyl isostearate, hexyldecyl isostearate, isostearic acid Item 1 or 2 which is at least one ester selected from the group consisting of isostearyl, glyceryl triisostearate, trimethylolpropane triisostearate, pentaerythritol tetraisostearate, decyl oleate, isopropyl oleate and ethyl oleate A composition according to 1.
Item 4. Item 4. The composition according to any one of Items 1 to 3, wherein the branched or unsaturated fatty acid ester is isostearyl isostearate.
Item 5. Item 5. The composition according to any one of Items 1 to 4, wherein the polyhydroxy fatty acid ester of polyethylene glycol is a dipolyhydroxy fatty acid ester of polyethylene glycol.
Item 6. Item 6. The composition according to any one of Items 1 to 5, wherein the polyhydroxy fatty acid ester of polyethylene glycol is a dipolyhydroxystearic acid ester of polyethylene glycol.

  The present invention will be described below. The W / O / W emulsion composition of the present invention contains a branched or unsaturated fatty acid ester that is liquid at 25 ° C. and a polyhydroxy fatty acid ester of polyethylene glycol.

  In the composition of the present invention, the branched or unsaturated fatty acid ester is not particularly limited as long as it is liquid at 25 ° C. Here, the term “branched or unsaturated” means that the carbon skeleton of the fatty acid portion of the fatty acid ester is branched or unsaturated. Preference is given to branched fatty acid monoesters.

  The carbon number of the fatty acid moiety of the branched or unsaturated fatty acid ester is usually 6 to 22, preferably 8 to 20. The unsaturated bond in the unsaturated fatty acid part of the unsaturated fatty acid ester is usually 1 to 3, preferably 1. Specific examples of the fatty acid of the branched or unsaturated fatty acid ester include 2-ethylhexanoic acid, isononanoic acid, isostearic acid, oleic acid, linoleic acid, and linolenic acid, and preferably 2-ethylhexane. An acid, isononanoic acid, isostearic acid, and oleic acid, more preferably isostearic acid.

  Preferred compounds of branched or unsaturated fatty acid esters are cetyl 2-ethylhexanoate, hexyldecyl 2-ethylhexanoate, isononyl isononanoate, isodecyl isononanoate, isotridecyl isononanoate, ethyl isostearate, isopropyl isostearate, hexyldecyl isostearate , Isostearyl isostearate, glyceryl triisostearate, trimethylolpropane triisostearate, pentaerythritol tetraisostearate, decyl oleate, isopropyl oleate, ethyl oleate, etc., alone or in combination of two or more Can be used. A preferred compound is isostearyl isostearate.

  In the composition of the present invention, the polyhydroxy fatty acid ester of polyethylene glycol is a compound in which polyhydroxy fatty acid is ester-bonded to both ends or one end of polyethylene glycol. The dipolyhydroxy fatty acid ester of polyethylene glycol is a compound in which polyhydroxy fatty acid is ester-bonded to both ends of polyethylene glycol, and the monopolyhydroxy fatty acid ester of polyethylene glycol is a compound in which polyhydroxy fatty acid is ester-bonded to only one end of polyethylene glycol. Preference is given to dipolyhydroxy fatty acid esters of polyethylene glycol.

  There are commercially available polyhydroxy fatty acid esters of polyethylene glycol. For example, PEG-30 DIPOLYHYDROXYSTEARATE (trade name: ARACEL P-135, manufactured by Uniqema) can be used. For example, it can be obtained by ester reaction of acid chloride obtained by reacting a halogenating agent (thionyl chloride or the like) with polyhydroxy fatty acid and polyethylene glycol under basic conditions.

  Here, the polyhydroxy fatty acid is a condensate obtained by condensing a carboxylic acid of a hydroxy fatty acid and a hydroxyl group, and can be obtained, for example, by subjecting a hydroxy fatty acid to a polycondensation reaction using an alkali as a catalyst. The polyhydroxy fatty acid is preferably one in which 2 to 10 hydroxy fatty acids are condensed, more preferably 3 to 8 condensed. Examples of the polyhydroxy fatty acid include poly (12-hydroxystearic acid), poly (9,10-dihydroxystearic acid), and polyricinolenic acid.

  Moreover, 10-100 are preferable and, as for the average polymerization degree of the polyethyleneglycol part which comprises the polyhydroxy fatty acid ester of polyethyleneglycol, 20-40 are more preferable.

  Polyethylene glycol polyhydroxy fatty acid esters include polyethylene glycol monopoly (12-hydroxystearic acid) ester or dipoly (12-hydroxystearic acid) ester, polyethylene glycol monopoly (9,10-dihydroxystearic acid) ester or dipoly ( 9,10-dihydroxystearic acid) ester, polyethylene glycol monopolyricinoleic acid ester or dipolyricinolenic acid ester can be preferably used. More preferred are monopoly (12-hydroxystearic acid) esters or dipoly (12-hydroxystearic acid) esters of polyethylene glycol, and even more preferred are dipoly (12-hydroxystearic acid) esters of polyethylene glycol. .

  The W / O / W emulsion of the present invention contains a branched or unsaturated fatty acid ester and a polyhydroxy fatty acid ester of polyethylene glycol. The content of the branched or unsaturated fatty acid ester is not particularly limited, but is preferably 0.0001 to 50% by weight, more preferably 0.01 to 30% by weight. The content ratio of the polyhydroxy fatty acid ester of polyethylene glycol is not particularly limited, but is preferably 0.00001 to 10% by weight, more preferably 0.001 to 5% by weight.

  Next, the oil phase of the W / O / W emulsion composition of the present invention will be described. As the oil phase component, a branched or unsaturated fatty acid ester which is liquid at 25 ° C. and a polyhydroxy fatty acid ester of polyethylene glycol are contained. In addition, hydrocarbons such as liquid paraffin; fatty acid esters other than branched or unsaturated fatty acid esters (such as isopropyl palmitate) that are liquid at 25 ° C .; Silicones such as siloxane; oil bodies such as dialkyl ethers may be included. In addition, other components (fats, waxes, oil-soluble medicinal agents, fragrances, pigments, emulsifiers, etc.) may be included.

  Typical examples of fats are glycerides, waxes such as beeswax and paraffin wax, and oil-soluble medicinal agents such as vitamin E, tocopherol acetate and palmitic acid ester of ascorbic acid.

  Next, the inner aqueous phase of the W / O / W emulsion of the present invention will be described. The inner aqueous phase processed into a primary W / O emulsion together with the oil phase preferably contains, in addition to water, polyols such as glycerin and 1,2-hexanediol, electrolyte salts such as sodium chloride, preservatives such as paraben and phenoxyethanol, It may contain water-soluble medicinal agents such as pyridoxine hydrochloride, vitamin C, dipotassium glycyrrhizinate, plant extract, and hydrolyzed protein.

  Next, the outer aqueous phase of the W / O / W emulsion of the present invention will be described. The outer aqueous phase that gives the primary W / O emulsion W / O / W type emulsion may basically contain the same substances as the inner aqueous phase. Specifically, an emulsifier that generally forms an O / W emulsion, a polymer thickener, and the like may be contained in addition to the main component water. Representative examples of this are polysaccharides, especially xanthan gum, guar gum, agar, alginate, polyethylene glycol, carboxymethyl cellulose and hydroxyethyl cellulose, as well as high molecular weight polyethylene glycol mono and di fatty acid esters, polyacrylates, polyvinyl alcohol and Such as polyvinylpyrrolidone. Further, for example, preservatives such as phenoxyethanol, parabens, and sorbic acid, fragrances, and coloring agents may also be contained.

  The W / O / W emulsion of the present invention can be produced by a known method. For example, it manufactures as shown below. A liquid branched or unsaturated fatty acid ester at 25 ° C., a polyhydroxy fatty acid ester of polyethylene glycol and other oil phase components are heated to a temperature in the range of 50 to 90 ° C. as necessary, and a homogenizer, a high-pressure homogenizer, A primary W / O emulsion is prepared by mixing the inner aqueous phase components while stirring with an ultrasonic emulsifier. The weight ratio of the oil phase to the inner aqueous phase is preferably 80:20 to 20:80, more preferably 60:40 to 40:60.

  After the preparation of the primary W / O emulsion, this is stirred with the outer aqueous phase at room temperature to prepare a W / O / W type emulsion. The weight ratio of the primary W / O emulsion to the outer aqueous phase is preferably 5:95 to 70:30, more preferably 5:95 to 50:50. Next, the emulsion may be adjusted to a desired pH value by adding an alkali metal hydroxide, an organic acid, an organic acid salt, or the like.

  The W / O / W emulsion composition of the present invention is excellent in long-term emulsification stability and leakage prevention of inner aqueous phase components. For this reason, the W / O / W type emulsion of the present invention can be used in a field where a conventional W / O / W type emulsion has been used. For example, it is a field of pharmaceuticals, quasi drugs, cosmetics, and the like. More specifically, hair tonic, scalp lotion, hair milk, hair treatment, hair conditioner, shampoo, hair cream, milk, foundation, massage cream, hand cream, skin lotion, body lotion, body cream, face cream, beauty liquid, etc. Can be used as

  The W / O / W emulsion composition of the present invention is excellent in long-term (for example, 3 months at 40 ° C.) emulsification stability and leakage prevention of the internal aqueous phase component. For this reason, even after long-term storage, it is possible to exhibit the antioxidant and sustained release properties of the inner aqueous phase component of the W / O / W emulsion. In particular, the W / O / W emulsion obtained when isostearyl isostearate and dipolyhydroxy fatty acid ester of polyethylene glycol are used in combination is very excellent in long-term emulsification stability and leakage prevention of internal aqueous phase components. It is an emulsion.

  EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited to the following Example. Paraben was used as the preservative.

Example 1
(1) Production of W / O type emulsion The components shown in W / O of Table 1 were used (the amounts in the table indicate parts by weight). The inner aqueous phase component was mixed with the oil phase component and emulsified with a high-pressure homogenizer (1000 kg / cm ² ) to produce a W / O type emulsion.
(2) Manufacture of W / O / W type emulsion The W / O type emulsion manufactured in (1) is mixed with the external water phase component and stirred for 10 minutes at 250 rpm using a propeller stirrer, W / O / W type An emulsion was prepared.
(3) Appearance stability test and leakage test The sample obtained in (2) was subjected to appearance stability test and leakage test by the following method. The test was performed immediately after the manufacture of each sample (initial stage) and after standing at 40 ° C. for 3 months. The results are shown in Table 1.
Appearance stability test The appearance stability test was performed by visual observation (oil floating) and microscopic observation (observation of emulsion particles), and evaluated according to the following criteria.
A: No oil floating, no coalescence or disintegration of W / O / W emulsion is observed. ○: No oil floating, but coalescence or disintegration is observed for a part of W / O / W emulsion. Δ: Slightly oil floating, coalescence or disintegration is observed for a part of the W / O / W type emulsion ×: Oil floating is substantial and coalescence or disintegration is observed for most of the W / O / W type emulsion Is recognized
Leakage test Each sample was adjusted to pH 2 by adding phosphoric acid, and then centrifuged (1000 rpm, 5 minutes) to separate the outer aqueous phase and the W / O emulsion phase to separate the outer aqueous phase. The color difference (A value) of the outer water phase was measured with a color meter (Color Meter ZE2000 (Nippon Denshoku Industries Co., Ltd.)). The color difference (B value) of a solution in which the same amount of edible yellow No. 5 (0.001 part by weight) as the emulsion was dissolved in the outer aqueous phase component (total 70 parts by weight) in Fig. 1 was measured. The leakage rate was measured by the following formula, and the leakage rate was used for evaluation according to the following evaluation criteria.

Leakage rate (%) = 100 × A / B
Evaluation criteria ◎: Leakage rate is less than 10% ○: Leakage rate is less than 50% ×: Leakage rate is 50% or more (4) Comprehensive evaluation Using the appearance stability test and leak test results of (3), the following evaluation criteria A comprehensive evaluation was conducted.

Comprehensive evaluation criteria ◎: No evaluation result x, 3 or more ◎ ○: No evaluation result x, 1 or 2 ◎: Evaluation result x

試験の結果、イソステアリン酸イソステアリルにポリエチレングリコールのジポリ１２−ヒドロキシステアリン酸エステルまたはポリエチレングリコールのモノポリ１２−ヒドロキシステアリン酸エステルを併用することにより、イソステアリン酸イソステアリルに他の油相成分を併用した場合と比較して、乳化状態が良好で内水相中の色素の漏洩が少ないことが示された。

As a result of the test, when the dipoly 12-hydroxy stearate of polyethylene glycol or the monopoly 12-hydroxy stearate of polyethylene glycol is used in combination with isostearyl isostearate and other oil phase components are used in combination with isostearyl isostearate. As compared with, it was shown that the emulsified state was good and the leakage of the pigment in the inner aqueous phase was small.

Example 2
Using the components shown in Tables 2 to 4, W / O / W emulsions were produced in the same manner as in Example 1. About each obtained sample, the external stability test and the leak test were done by the same method as Example 1, and comprehensive evaluation was performed based on the result. The results are shown in Tables 2-4. In Samples 2-1 to 2-15, a branched or unsaturated fatty acid ester that is liquid at 25 ° C. is used as the oil, and in the case of 2-16 to 2-21, a linear fatty acid ester, hydrocarbon, and solid at 25 ° C. are used as the oil. The fatty acid ester etc. are used.

  As a result of the test, by using a liquid branched or unsaturated fatty acid ester at 25 ° C., the emulsified state is good and the leakage of the dye in the inner aqueous phase is less than when other fatty acid esters are used. It was shown that.

Claims (2)

Contains at least one branched fatty acid ester selected from the group consisting of ethyl isostearate, isopropyl isostearate, hexyldecyl isostearate, isostearyl isostearate and glyceryl triisostearate, and dipolyhydroxystearate of polyethylene glycol W / O / W type emulsion composition. A W / O / W emulsion composition comprising isostearyl isostearate and dipolyhydroxystearate of polyethylene glycol.