JP2003095956A - Microemulsion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a microemulsion composition effective for especially reducing pruritus of patients suffering from atopic dermatitis and having good preservation stability even under severe conditions in relation to microemulsion compositions having excellent humectant and obstruction properties and suitable for application to wide ranges of the skin. SOLUTION: This microemulsion composition comprises an oily ingredient composed of vaseline in an amount of >=90 wt.% based on the total amount, lecithin, betaines and water and is obtained by treating the oily ingredient, lecithin, betaines and water with both a high-speed stirrer and a high-pressure homogenizer. The resultant microemulsion has <=300 nm particle diameter of the inner phase. Furthermore, one or more kinds of polyhydric alcohols selected from 1,3-butylene glycol, glycerol, diglycerin, polyethylene glycol and 1,2- pentanediol are formulated therein.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fine emulsion composition obtained by emulsifying petrolatum with lecithin and betaines, which has excellent moisturizing properties and occlusive properties and is suitable for application to a wide range of skins, and particularly has an atopic property. The present invention relates to a fine emulsion composition which is effective for reducing itchiness in dermatitis patients and has good storage stability even under severe conditions.

[0002]

It is known that transepidermal water loss (TEWL) is enhanced in the skin of patients with atopic dermatitis, and remarkable itching occurs due to dryness of the skin. therefore,
In the treatment of patients with atopic dermatitis, petrolatum has been used as a base to improve the occlusivity of the skin. However, since vaseline has a paste-like shape and has a poor spreadability and has a noticeable sticky feeling after application, there is a problem in use feeling and usability when applied to a wide range of skin showing atopic dermatitis.

Emulsified bases such as emulsions and creams are generally used as a base containing an oily component.
In order to be used by consumers with sensitive skin, including patients with atopic dermatitis, in order to reduce skin irritation as much as possible, a surfactant with low skin irritation and skin sensitization when preparing an emulsified base. Had to use.

However, among the surfactants reported to have low skin irritation and skin sensitization properties, many have low emulsifying power, and a stable emulsified system cannot often be obtained.

Therefore, an emulsion composition which is effective in reducing itching in patients with atopic dermatitis can be favorably applied to a wide range of skin without stickiness, and has low irritation to the skin and good stability. Various studies have been conducted in order to obtain the same. For example, an oily component of which 90% by weight or more of the total amount is petrolatum and a surfactant and water of 1% by weight or less with respect to the total amount of cosmetics are used for high-speed stirring. Liquid emulsion type skin composition, characterized by having an inner oil phase particle size of 500 nm or less and a viscosity at 25 ° C. of 1,000 mPa · S or less, obtained by treatment with both a machine and a high pressure homogenizer. Is disclosed (Japanese Patent Application Laid-Open No. 2-212058).
001-72581).

However, even the liquid emulsion type skin composition has a problem in storage stability under severe conditions such as repeated freeze-thawing.

[0007]

Therefore, in the present invention, it is excellent in moisturizing property and occlusive property, suitable for application to a wide range of skins, particularly effective for reducing itch in atopic dermatitis patients, and harsh. The object is to provide a fine emulsion composition having good storage stability under the conditions.

[0008]

Means for Solving the Problems The present inventor has conducted diligent studies to solve the above problems, and as a result, by using lecithin and betaines in combination, a good moisturizing effect can be exhibited. The inventors have found that a fine emulsion that is effective in reducing itching in patients with atopic dermatitis and that has good storage stability even under severe conditions such as repeated freeze-thawing has been completed, and completed the present invention.

That is, in the fine emulsion composition according to the present invention, an oily component of which 90% by weight or more of the total amount is petrolatum, lecithin, betaines, and water are treated with both a high-speed stirrer and a high-pressure homogenizer. And is emulsified, and the internal oil phase particle diameter is 300 nm or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The fine emulsion composition according to the present invention contains an oily component containing petrolatum as a main component. The content of petrolatum with respect to the total amount of oily components is 9
It needs to be 0% by weight or more, and the oily component may be composed only of petrolatum.

In the fine emulsion composition according to the present invention, lecithin and betaines are used as surfactants.

As the lecithin, natural lecithin derived from animals and plants such as soybean lecithin and egg yolk lecithin, as well as products thereof and industrially synthesized ones can be used. Moreover, the lyso form and hydrogenated product of the said lecithin, and also the hydrogenated product of the lyso form can be used. Lecithin can be blended in an amount of 0.1 to 5% by weight based on the total amount of the cosmetic, and the blending amount is preferably set to the minimum necessary amount depending on the blending amount and composition of the oil component.

Betaines are N-trialkyl-substituted amino acids, and include, for example, trimethylglycine, γ-butyrobetaine, homarin, trigonelline, β-alanine betaine, carnitine, atrinin, homoserine betaine, antopreurine, valine betaine, lysine. Betaine, ornithine betaine, alanine betaine, taurobetaine, stachydrin, betaine glutamate, phenylalanine betaine, etc. are exemplified, and one or more of them are selected and used. Among these betaines, trimethylglycine is particularly preferable from the viewpoint of the effect of the present invention. Betaines may be added in an amount of 0.1 to 20% by weight based on the total amount of the fine emulsion composition, although it may vary depending on the amount and composition of the oil component.

In the present invention, in order to further improve the moisturizing effect and the stability of the fine emulsion composition,
One or more polyhydric alcohols selected from 3-butylene glycol, glycerin, diglycerin, polyethylene glycol and 1,2-pentanediol can be blended. Among these polyhydric alcohols, especially 1,3-
By blending one or two selected from butylene glycol and 1,2-pentanediol, it becomes possible to reduce the amount of the preservative that may cause skin irritation. The polyhydric alcohol can be added in an amount of 1 to 20% by weight based on the total amount of the fine emulsion.

In the present invention, an oily component containing petrolatum as a main component, lecithin, betaines and water are treated by both a high speed stirrer and a high pressure homogenizer to be emulsified. A stable fine emulsion composition cannot be obtained by emulsification with either a high-speed stirrer or a high-pressure homogenizer treatment. Further, in order to obtain good coatability and spreadability, in the fine emulsion composition according to the present invention,
The inner oil phase particle size is adjusted to 300 nm or less.

The fine emulsion composition according to the present invention comprises
It may be provided as a skin emulsion or emulsion. Furthermore, in the fine emulsion composition according to the present invention, in addition to the above components, amino acids such as sodium lactate and sodium pyrrolidonecarboxylate, carboxyvinyl polymer,
Water-soluble polymers such as hydroxyethyl cellulose, pullulan and xanthan gum, mucopolysaccharides such as sodium hyaluronate, anti-inflammatory agents such as azulene and allantoin, ascorbic acid, vitamin B ₁ , vitamin B ₂ , vitamin B ₆ and pantothenic acid Ingredients for general external use such as vitamins such as vitamin E, organ extracts such as placenta extract, plant extracts, preservatives and the like can be added. However, for the purpose of the present invention, it is necessary to select one having low irritation and sensitization to the skin, or to mix it at a concentration that does not cause skin irritation.

[0017]

EXAMPLES The features of the present invention will be described in detail with reference to Examples.

Emulsions according to Examples 1 and 2 and Comparative Example of the present invention having the formulations shown in Table 1 were prepared by the following method.

Production method: The oil phase components of (1) and (2) are mixed, heated and dissolved to 80 ° C. On the other hand, after mixing and dissolving the water phase components (3) to (5) and heating to 80 ° C, the oil phase component was added to this and the temperature was kept at 70 ° C, while using a high speed stirrer at 6000 rpm.
Pre-emulsify for 9 minutes. Next, while maintaining the temperature at 70 ° C., a high pressure homogenizer treatment is performed at a pressure of 1.4 × 10 ⁸ N / m ² to emulsify and then cooled to obtain a cream liquid. To (6)
Dissolve the component (7) and add it to the cream at 35 ° C.
Mix and homogenize.

[0020]

[Table 1]

Regarding Example 1, Example 2 and Comparative Example,
The measurement of the particle size of the inner oil phase, the evaluation of the emulsion stability and the usage test were performed by the methods described below. The results are shown in Table 3.

The particle size of the inner oil phase was measured by a dynamic light scattering method using a Microtrac particle size analyzer UPA150 manufactured by Nikkiso Co., Ltd.

The emulsification stability depends on the contents of the components when the samples of Examples and Comparative Examples are stored at 50 ° C. for 1 month and when the operation of freezing at −20 ° C. and then thawing is repeated 5 times. Evaluations were made by observing the presence or absence of state changes such as aggregation, precipitation, and phase separation. The evaluation results are "○; no change in state", "△; slight change in state",
It was evaluated as “×; noticeable change in state”.

On the other hand, in the use test, 20 male and female panelists in their 10s to 50s exhibiting atopic dermatitis were treated as one group, and each group was allowed to use the Examples and Comparative Examples blindly. The growth, stickiness, irritation and itching improvement status were sensory evaluated according to the evaluation criteria shown in Table 2 and scored, and the results are shown as the average value of the evaluation points of 20 persons.

[0025]

[Table 2]

[0026]

[Table 3]

As is clear from Table 3, in Examples 1 and 2 of the present invention, the average particle size of the inner oil phase was 227 nm and 1
Both were 59 nm and 300 nm or less, but in the comparative example in which trimethylglycine, which is one of the betaines, was not blended, the average particle diameter of 496 nm was larger than that in the example. In addition, Example 1 of the present invention
Also, in Example 2, a good emulsified state was maintained both when stored at 50 ° C. for 1 month and when freeze-thawing was repeated. On the other hand, in the comparative example, the stable emulsified state was not maintained.

[0028]

[Table 4]

The emulsions according to Examples 3 to 6 were prepared by the following method according to the formulations shown in Table 4.

Production method: The oil phase components of (1) and (2) are mixed, dissolved by heating and brought to 80 ° C. On the other hand, after mixing and dissolving the water phase components (3) to (5) and heating to 80 ° C, the oil phase component was added to this and the temperature was kept at 70 ° C, while using a high speed stirrer at 6000 rpm.
Pre-emulsify for 9 minutes. Next, while maintaining the temperature at 70 ° C., a high pressure homogenizer treatment is performed at a pressure of 1.4 × 10 ⁸ N / m ² to emulsify and then cooled to obtain a cream liquid. (6) ~
The component (9) is dissolved and homogenized, added to the cream liquid at 35 ° C., mixed and homogenized.

Example 7 Emulsion (1) Vaseline 10.0 (wt%) (2) Jojoba oil 0.5 (3) Hydrogenated lysolecithin 2.0 (4) Trimethylglycine 10.0 (5) Purified water 7.5 (6) Purified water 70.0 Production method: The oil phase components of (1) to (3) are mixed, heated and dissolved, and then 80
℃. On the other hand, the water phase components of (4) and (5) are mixed and dissolved,
After heating to 80 ° C., an oil phase component is added thereto and, while maintaining 70 ° C., preliminary emulsification is performed with a high-speed stirrer at 6000 rpm for 9 minutes. Then 1.4x keeping the temperature at 70 ° C
A high pressure homogenizer treatment is performed at a pressure of 10 ⁸ N / m ² to emulsify and then cooled to obtain a cream liquid. (6) is added to the cream solution at 35 ° C, mixed and homogenized.

[0032] [Example 8] Emulsion (1) Vaseline 12.0 (wt%) (2) Hydrogenated soybean lecithin 2.5 (3) Dipotassium glycyrrhizinate 0.5 (4) Trimethylglycine 8.0 (5) 1,2-Pentanediol 5.0 (6) Methyl paraoxybenzoate 0.02 (7) Purified water 71.98 Production method: Mix the oil phase components of (1) and (2), heat and dissolve,
℃. On the other hand, the water phase components (3) to (7) are mixed and dissolved,
After heating to 80 ° C, add the oil phase component to it and stir at high speed.
Pre-emulsified in a machine, then keeping the temperature at 75 ° C
1.4 x 10⁸N / m ²High pressure homogenizer treatment with pressure
After emulsification and emulsification, cool.

[0033] Example 9 Emulsion (1) Vaseline 14.50 (wt%) (2) d-δ-tocopherol 0.50 (3) Lysolecithin 3.00 (4) Trimethylglycine 7.00 (5) Glycerin 5.00 (6) Methyl paraoxybenzoate 0.02 (7) Purified water 69.98 Manufacturing method: The oil phase components (1) to (3) are mixed, heated and dissolved,
℃. On the other hand, mix and dissolve the water phase components (4) to (7),
After heating to 80 ° C, add the oil phase component to it and stir at high speed.
Pre-emulsified in a machine, then keeping the temperature at 75 ° C
1.4 x 10⁸N / m ²High pressure homogenizer treatment with pressure
After emulsification and emulsification, cool.

For Examples 3 to 9, the particle size of the inner oil phase was measured, the emulsion stability was evaluated, and the usage test was conducted. The results are shown in Table 5.

[0035]

[Table 5]

As shown in Table 5, Examples 3 to 3 of the present invention were conducted.
Each of Example 9 had an average particle size of 300 nm or less, and showed good emulsion stability even when stored at 50 ° C. for 1 month and when freeze-thawing was repeated. In addition, it was shown that the growth was good, there was no problematic stickiness due to petrolatum, no irritation during use was observed, and itching was effectively ameliorated due to atopic dermatitis.

[0037]

INDUSTRIAL APPLICABILITY As described in detail above, according to the present invention, it is excellent in moisturizing property and occlusive property, suitable for application to a wide range of skin, particularly effective for reducing itch in atopic dermatitis patients, and having storage stability. A good fine emulsion composition could be obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) A61P 17/16 A61P 17/16 F term (reference) 4C083 AA122 AC011 AC012 AC111 AC112 AC121 AC122 AC482 AC711 AC712 AD041 AD532 AD571 AD572 AD662 CC05 EE01 EE12 EE13 4C086 AA02 FA01 MA28 MA63 NA03 ZA89

Claims (2)

[Claims] 1. An oily component of which 90% by weight or more of the total amount is petrolatum, lecithin, betaines and water, and is obtained by treating with both a high speed stirrer and a high pressure homogenizer. A fine emulsion composition having an oil phase particle size of 300 nm or less. 2. Further, 1,3-butylene glycol, glycerin, diglycerin, polyethylene glycol, 1,2-
The fine emulsion composition according to claim 1, containing one or more polyhydric alcohols selected from pentanediol.