JP6968463B1 - External composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for enhancing the permeability to the skin and improving the usability in an external composition containing ascorbic acids. SOLUTION: One or more compounds selected from the group consisting of the following components (a) to (d); (a) ascorbic acid, derivatives thereof and salts thereof (b) N-lower alkyl-2-pyrrolidone. (C) Propylene glycol monofatty acid ester (d) Containing polyhydric alcohol, the content of the component (c) is 0.05 to 0.3% by mass, and the content of the component (d) is 5 to 40% by mass. % Is an external composition. [Selection diagram] None

Description

The present invention relates to an external composition, and more particularly to an external composition containing ascorbic acids and having excellent skin permeability and usability.

Ascorbic acids are widely used as vitamin C in pharmaceuticals and cosmetics. Ascorbic acids have a strong reducing power, and are blended in cosmetics for the purpose of whitening the skin and preventing wrinkles and sagging due to antioxidant action.

Ascorbic acids are components that are easily soluble in water, but they are not stable in water and are rapidly decomposed in an aqueous solution to lose their activity. On the other hand, ascorbic acids are generally relatively stable in an organic solvent such as ethanol, but have lower solubility than water.

On the other hand, in Patent Document 1, a high concentration of ascorbic acids can be dissolved by using N-lower alkyl-2-pyrrolidone alone as a solvent or by using it in combination with a co-solvent such as dimethylisosorbide. It has been reported that its decomposition and discoloration are also suppressed.

Japanese Unexamined Patent Publication No. 2001-261559

However, the composition of Patent Document 1 has low permeability to the skin, and it cannot be said that the effect is sufficiently exhibited even if a high concentration of ascorbic acids is blended. In addition, there was room for improvement in usability, such as feeling slightly slimy or sticky when applied to the skin.

Therefore, it is an object of the present invention to provide an external composition containing ascorbic acid, which has high permeability to the skin and is also excellent in usability.

As a result of diligent research to solve the above problems, the present inventors combined N-lower alkyl-2-pyrrolidone with a specific amount of polyhydric alcohol as a solvent in an external composition containing ascorbic acids. At the same time, it was found that by using a specific amount of propylene glycol monofatty acid ester, the permeability of ascorbic acids to the skin is enhanced, and stickiness and sliminess during application are suppressed, and an excellent usability can be obtained. , The present invention has been completed.

That is, the present invention has the following components (a) to (d);
(A) One or more compounds selected from the group consisting of ascorbic acid, its derivatives and salts thereof (b) N-lower alkyl-2-pyrrolidone (c) propylene glycol monofatty acid ester (d) polyhydric alcohol. It is an external composition containing 0.05 to 0.3% by mass of the component (c) and 5 to 40% by mass of the component (d).

The external composition of the present invention has high permeability to the skin of ascorbic acid, which is an active ingredient, sufficiently exerts its pharmacological effect, suppresses stickiness and sliminess, and has a good usability. .. Furthermore, by using a specific component as a polyhydric alcohol in combination, it is possible to further enhance the stability of ascorbic acids, such as suppressing discoloration of ascorbic acids during storage for a long period of time.

In the composition for external use of the present invention, the component (a) ascorbic acid, its derivative and a salt thereof (hereinafter, these are collectively referred to as "ascorbic acids") are used. The derivative of ascorbic acid is not particularly limited as long as it is pharmacologically acceptable, and examples thereof include ascorbic acid alkyl ester, ascorbic acid phosphate ester, ascorbic acid alkyl ether, and ascorbic acid glucoside. Examples of the salt of ascorbic acid or a derivative thereof include alkali metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as calcium salt and magnesium salt. These ascorbic acids may be D-form, L-form or DL-form, but are preferably L-form. Further, as the ascorbic acid, one may be selected from ascorbic acid, its derivative and a salt thereof, and two or more thereof may be used in combination. Since the effectiveness of ascorbic acid derivatives and salts is derived from ascorbic acid produced by undergoing metabolism and hydrolysis after use, ascorbic acid is among these ascorbic acids from the viewpoint of immediate effect and effectiveness. Is preferable, and L-ascorbic acid is particularly preferable.

The content of the component (a) in the external composition of the present invention is not particularly limited, but is 5 to 40% by mass (hereinafter, 5 to 40% by mass) from the viewpoint of improving the pharmacological effect of the ascorbic acids and the stable blending of the ascorbic acids. (Simply expressed as "%") is preferable, 10 to 30% is more preferable, and 20 to 30% is particularly preferable.

Further, the component (b) N-lower alkyl-2-pyrrolidone is used in the external composition of the present invention. The lower alkyl group in N-lower alkyl-2-pyrrolidone is a linear or branched alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group and a butyl group. .. Among these, a methyl group is preferable, and N-methyl-2-pyrrolidone is preferably used from the viewpoint of permeability, usability and the like.

The content of the component (b) in the external composition of the present invention is not particularly limited, but is preferably 20 to 90%, more preferably 35 to 80%, and 40. ~ 70% is particularly preferable.

The component (c) propylene glycol fatty acid monoester used in the external composition of the present invention is a monoester of propylene glycol and a fatty acid. The number of carbon atoms of the constituent fatty acids is not particularly limited, but 14 to 22 carbon atoms are preferable, and 16 to 20 carbon atoms are more preferable, from the viewpoint of permeability and usability. Further, it may be linear or branched, but the branched chain is preferable. Examples of such propylene glycol fatty acid esters include propylene glycol monopalmitate, propylene glycol monoisostearate, propylene glycol monostearate, propylene glycol monooleate, and the like. Among these, propylene glycol monoisostearate (INCI name:: Propylene Glycol Isostearate) is preferably used in terms of permeability and usability.

The content of the component (c) in the external composition of the present invention is 0.05 to 0.3%, preferably 0.1 to 0.2%, and 0. 1 to 0.15% is more preferable.

The component (d) polyhydric alcohol used in the external composition of the present invention is not particularly limited, and is not particularly limited, and glycerin, diglycerin, sorbitol, 1,2-propanediol, 1,3-propanediol, propylene glycol, and the like. Examples thereof include dipropylene glycol, isoprene glycol, 3-methyl-1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,3-butylene glycol, polyethylene glycol and the like, and one of them. Alternatively, two or more types can be used in combination.

Among the above polyhydric alcohols, diglycerin, propylene glycol, 1,3-butylene glycol, glycerin and polyethylene glycol are preferable, and diglycerin, propylene glycol and 1,3-butylene glycol are preferable from the viewpoint of suppressing discoloration of ascorbic acids. More preferred. Only one of these may be used, but when two or more of them are used in combination, the stability of ascorbic acids can be further enhanced, and in particular, three types of diglycerin, propylene glycol and 1,3-butylene glycol can be used in combination. Then, a particularly excellent effect is obtained in improving the stability of ascorbic acids.

The content of the component (d) in the external composition of the present invention is 5 to 40%, preferably 10 to 35%, and more preferably 10 to 30% from the viewpoint of permeability and usability. Further, from the viewpoint of improving the stability of ascorbic acids, the content mass ratio ((d) :( b)) of the component (b) to the component (d) is preferably 1: 1 to 1:10, 1: 1. 3 to 1: 8 is more preferable, and 1: 1.8 to 1: 6.5 is even more preferable.

When (d1) diglycerin, (d2) propylene glycol and (d3) 1,3-butylene glycol are used in combination as the component (d), the component (d) in the external composition is used from the viewpoint of improving the stability of ascorbic acids. The content of d1) is preferably 1 to 8%, more preferably 3 to 6%. The content of the component (d2) is preferably 3 to 9%, more preferably 5 to 7%. The content of the component (d3) is preferably 2 to 10%, more preferably 4 to 8%. Further, the mass ratio of the components (d1), (d2), and (d3) ((d1) :( d2) :( d3)) is assumed to be 1 from the viewpoint of improving the stability of ascorbic acids. , 1: (0.5 to 3): (0.3 to 3) is preferable, 1: (0.8 to 2.4): (0.6 to 2.7) is more preferable, and 1: ( 0.8 to 1.8): (0.6 to 2.7) is preferable.

It is preferable that the external composition of the present invention contains substantially no water. The term "substantially free" means that the content of water in the external composition is preferably 1% or less, more preferably 0.1% or less, still more preferably 0.01% or less.

In addition to the above-mentioned components (a) to (d), the external composition of the present invention may contain, if necessary, components used in external compositions such as cosmetics, quasi-drugs, and pharmaceuticals. Examples of such optional components include wetting agents, antioxidants, thickeners, gelling agents, chelating agents, pH adjusters, preservatives, ultraviolet absorbers, pigments, pigments, fragrances and the like.

Examples of preferable compositions in the external composition of the present invention are shown in Table 1 below. The numerical values in the table are unit mass%.

The external composition of the present invention can be produced by stirring and mixing the above-mentioned components (a) to (d) and optional components to be blended as necessary by a known method.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1
An external composition was prepared by the following production method according to the formulation shown in Table 2 below. The obtained external composition was evaluated for permeability and usability by the following evaluation method. The results are also shown in Table 2. Overall, it was acceptable if the evaluations of permeability and usability were both 〇, or one was 〇 and the other was Δ. The unit of the numerical value in Table 2 is mass%, and the same applies to the following table.

(Production method)
After mixing all the components, the mixture was heated to 60 to 80 ° C. to dissolve ascorbic acid and uniformly stirred and mixed to obtain an external composition.

(Permeability evaluation method)
About 0.5 mL of each external composition was dropped onto oil-blotting paper (manufactured by Ryohin Keikaku Co., Ltd., trade name "oil blotting paper"), and after about 60 seconds, the droplets were removed by suction. Visually after removal, it was evaluated as permeable (〇) if stains due to the external composition remained on the oil removing paper, and non-permeability (×) if no stains remained.

(Evaluation method of usability)
About 0.5 mL of each external composition was taken with a finger and evaluated based on the following criteria by sensory evaluation when applied to the skin.
<Evaluation criteria>
〇: No stickiness or slimy feeling △: Somewhat sticky or slimy feeling ×: Feeling sticky or slimy

As shown in Table 2, all of the products of the present invention were excellent in permeability and had a good usability, whereas Comparative Product 1 containing propylene glycol isostearate was inferior in permeability.

Example 2
An external composition was prepared in the same manner as in Example 1 except that the formulations were changed to those shown in Tables 3 and 4 below, and the permeability and usability were evaluated. The results are also shown in Tables 3 and 4.

From Tables 3 and 4, Comparative Product 2 which did not use propylene glycol isostearate was inferior in permeability, and Comparative Product 3 which did not use polyhydric alcohol was inferior in not only permeability but also usability. .. On the other hand, all of the products of the present invention had good permeability and usability. Similar results can be obtained when only one of the three components is blended as the polyhydric alcohol in the total amount of the three components. The same applies when a polyhydric alcohol other than the three components is used alone.

Example 3
An external composition was prepared in the same manner as in Example 1 according to the formulations shown in Tables 5 and 6 below. Each external composition was placed in a transparent glass container and stored at 40 ° C. for 1 month, and then the stability of ascorbic acid was evaluated according to the following method. The results are also shown in Tables 5 and 6.

(Evaluation method of stability of ascorbic acid)
The composition for external use after storage was visually inspected and evaluated on a 5-point scale based on the following criteria.
<Criteria>
5) No change in color tone.
4) It is slightly yellowed.
3) It is slightly yellowing.
2) It is yellowing.
1) It is significantly yellowed.

From Tables 5 and 6, the comparative products 4 to 6 containing no propylene glycol isostearate showed a significant yellowing after storage at 40 ° C. for 1 month, whereas the products of the present invention showed almost no change in color tone. It was confirmed that the stability of ascorbic acid was excellent.

Example 4
An external composition was prepared in the same manner as in Example 1 according to the formulations shown in Table 7 below. Each external composition was placed in a transparent glass container and stored at 50 ° C. for 1 month, and then the stability of ascorbic acid was evaluated in the same manner as in Example 3. The results are also shown in Table 7.

From Table 7, it was confirmed that the product of the present invention showed excellent stability with almost no change in the color tone of ascorbic acid even under harsh storage conditions of 50 ° C.

The external composition of the present invention has high permeability of the active ingredient ascorbic acid to the skin, suppresses stickiness and sliminess, and has an excellent usability. Therefore, it can be used as a cosmetic or a quasi-drug.

Claims (10)

The following components (a) to (d);
(A) One or more compounds selected from the group consisting of ascorbic acid, its derivatives and salts thereof (b) N-lower alkyl-2-pyrrolidone (c) propylene glycol monofatty acid ester (d) polyhydric alcohol. An external composition containing 0.05 to 0.3% by mass of the component (c) and 5 to 40% by mass of the component (d) ( provided that it contains a lactone compound). Except for ). The external composition according to claim 1, wherein the component (a) is ascorbic acid. The external composition according to claim 1 or 2, wherein the content of the component (a) is 5 to 40% by mass. The external composition according to any one of claims 1 to 3, wherein the component (b) is N-methyl-2-pyrrolidone. The external composition according to any one of claims 1 to 4, wherein the content of the component (b) is 20 to 90% by mass. The external composition according to any one of claims 1 to 5, wherein the component (c) is propylene glycol isostearate. The component (d) is glycerin, diglycerin, sorbitol, 1,2-propanediol, 1,3-propanediol, propylene glycol, dipropylene glycol, isoprene glycol, 3-methyl-1,3-butanediol, 1, The external composition according to any one of claims 1 to 6, which is one or more selected from the group consisting of 2-pentanediol, 1,3-pentanediol, 1,3-butylene glycol and polyethylene glycol. The external composition according to claim 7, wherein the component (d) is one or more selected from the group consisting of diglycerin, propylene glycol and 1,3-butylene glycol. The external composition according to claim 8, wherein the component (d) contains diglycerin, propylene glycol and 1,3-butylene glycol. The external composition according to claim 9, wherein the content mass ratio of diglycerin, propylene glycol, and 1,3-butylene glycol is 1: (0.5 to 3) :( 0.3 to 3).