CN1660081B - skin topical - Google Patents

Abstract

Provided is a skin care preparation for external use by solubilizing water soluble ascorbic acid stably. This preparation is obtained by blending a low molecular betaine with a skin care preparation for external use containing water soluble ascorbic acid, a glycol ether or a specific polyhydric alcohol for solubilizing the water soluble ascorbic acid stably. Thereby, it is possible to obtain the preparation blended with the water soluble ascorbic acid in a high concentration stably, and to exhibit various activities that the ascorbic acid originally has, in accordance with its blended amount. Also, it is possible to provide the preparation without having a sticky feeling after the application on the skin and having a moist feeling and a good compatibility to the skin.

Description

skin topical

technical field

The present invention relates to an external preparation for skin which stably solubilizes ascorbic acid or a salt thereof.

Background technique

Ascorbic acid is known to exhibit so-called anti-inflammatory effects, acne-improving effects, whitening effects, anti-aging effects, antioxidant effects, cell activation effects that promote the synthesis of biological components such as collagen, and inhibition of cell damage or DNA damage in epidermal keratinocytes by ultraviolet rays Various effects of the effect, and these effects are expected to be widely used as skin external preparations. However, ascorbic acid is easily oxidized in the presence of water in an aqueous solution, so it is sought to reduce the water in the preparation, but the problem is that a small amount of water cannot sufficiently dissolve ascorbic acid. For this reason, several methods for sufficiently dissolving ascorbic acid in water-based external skin preparations have been studied. In a solution composed of glycol, 22-29% propylene glycol, and fragrance, the solubilization of ascorbic acid is stabilized (Patent Document 1: WO02/19972)

In addition, methods for stably dissolving ascorbic acid in non-aqueous skin external preparations have also been studied. Ascorbic acid is stably soluble in a non-aqueous medium of an agent (Patent Document 2: WO00/76547).

On the other hand, low-molecular-weight trimethylglycine represented by trimethylglycine is widely used as a moisturizer for external skin preparations. For example, by combining urea and low-molecular-weight glycine trimethalin, excellent improvement in rough skin can be obtained Effects (Patent Document JP-A-9-48720), the transdermal absorbability of the whitening agent is improved by blending whitening ingredients, low-molecular-weight glycine trimethalin, and silicone oil (Patent Document 4: JP-A-2001-89321), etc. However, there is no insight regarding the solubilization of ascorbic acid.

Contents of the invention

The subject of the present invention is to provide an external skin preparation that can stably dissolve ascorbic acid or a salt thereof in an external preparation for skin containing ascorbic acid or a salt thereof, thereby enabling high-concentration ascorbic acid or a salt thereof to be blended.

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems, and as a result, found that ascorbic acid or its salt can be used in combination with a low-molecular-weight glycine triglyceride in an external skin preparation containing ascorbic acid or a salt thereof and a glycol ether or a specific polyhydric alcohol. The salt is stably soluble, and high-concentration compounding becomes possible, thereby becoming a high-efficiency external preparation.

That is, the present invention is an external preparation for skin as shown in (1) to (7) below.

(1) External skin preparations containing the following compounds:

(A) 3% by weight or more of ascorbic acid or a salt thereof,

(B) One or more selected from glycols, glycol ethers, glycerin, and diglycerin,

(C) low molecular glycine trimethyl salt, and

(D) water.

(2) External skin preparations containing the following compounds:

(A) 3% by weight or more of ascorbic acid or a salt thereof,

(B) One or more selected from diol, glycerin and diglycerin,

(C) glycol ether

(D) low molecular glycine trimethyl salt, and

(E) water.

(3) The external preparation for skin as described in (1) or (2) in which the low-molecular-weight glycine trimethylinyl salt is trimethylglycine.

(4) The external preparation for skin according to any one of (1) to (3) containing 5 to 35% by weight of water.

(5) External skin preparations containing the following compounds:

(A) 10 to 20% by weight of ascorbic acid or a salt thereof,

(B) 3 to 25% by weight of one or two or more selected from diol, glycerin, and diglycerin,

(C) Glycol ether 45-55% by weight

(D) 1 to 5% by weight of low-molecular glycine trimethyl salt, and

(E) 5 to 25% by weight of water.

(6) External skin preparations containing the following compounds:

(A) 15 to 20% by weight or more of ascorbic acid or a salt thereof,

(B) 4 to 21% by weight of one or two or more selected from diol, glycerin, and diglycerin,

(C) Glycol ether 50-53% by weight

(D) 2 to 4% by weight of low-molecular glycine trimethyl salt, and

(E) 10 to 20% by weight of water.

(7) The skin external preparation according to any one of (1) to (6) further comprising at least one selected from a whitening component, an anti-inflammatory component, an antioxidant component, an anti-aging component, and a moisturizing component.

However, in this specification, unless otherwise mentioned, % means weight%.

In the present invention, ascorbic acid or a salt thereof can be stably solubilized by blending a low-molecular-weight glycine triglyceride in an external skin preparation containing ascorbic acid or a salt thereof, a glycol ether, or a specific polyhydric alcohol. Therefore, it is possible to obtain a skin external preparation in which ascorbic acid or a salt thereof is stably blended at a high concentration, and ascorbic acid can effectively exhibit various inherent functions according to the blending amount. In addition, it is possible to prepare a formulation that does not give a sticky feeling after application to the skin, has a moist feeling, and has good adaptability to the skin.

Detailed ways

Ascorbic acid used in the present invention can be used as ascorbic acid commercially available as a component of external skin preparations in the field of pharmaceuticals, non-pharmaceutical products, or cosmetics, and these generally refer to L-body products.

In addition, ascorbic acid can be used as a pharmaceutically acceptable salt, and examples thereof include salts with basic organic substances (for example, trimethylamine salts, triethylamine salts, monoethanolamine salts, triethanolamine salts, pyridinium salts, etc., and salts of tertiary amines, basic ammonium salts such as arginine, etc.), and salts of inorganic bases (for example, alkali metal salts such as ammonium salts, sodium salts, and potassium salts, alkaline earth metal salts such as calcium salts and magnesium salts, aluminum salts, etc.), etc., particularly preferably The preferred salts are sodium salts and potassium salts. Specifically, sodium ascorbate, potassium ascorbate, etc. are mentioned.

In the present invention, ascorbic acid or its salts can be used in combination of 1 type or 2 or more types.

The skin external preparation of the present invention can stably solubilize ascorbic acid by compounding low-molecular glycine trimethyl salt, so the compounding amount of ascorbic acid is preferably 3 to 30% by weight relative to the total weight of the skin external preparation, and it can be within this range. An appropriate selection is made according to various functions of the desired ascorbic acid or the use of the external preparation for the skin. In view of the effects of the present invention, it is more preferably in the range of 5 to 25% by weight, particularly preferably in the range of 5 to 20% by weight.

In the present invention, a diol refers to a dihydric alcohol that is used as a component of an external skin preparation in the field of pharmaceuticals, products other than pharmaceuticals, or cosmetics and is liquid at 25° C., for example, by the general formula C _n H _2n ( Diol represented by OH)2 or a polycondensate of a single or two or more of the above-mentioned diols, and the like. Specifically, ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, isopropanol, 1,2 - Pentanediol, 1,2-hexanediol, caprylyl glycol, etc., as the polycondensate, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, etc. are exemplified. Propylene glycol and 1,3-butanediol are preferred.

In addition, glycerin and diglycerin used in the present invention are well-known compounds that are frequently used in skin external preparations and the like.

The amount of glycol, glycerin, or diglycerin used in the present invention is not particularly limited as long as the present invention is effective, and can be appropriately selected and used in consideration of the feeling and effect on the skin, but compared to the entire skin external preparation, usually It may be 1 to 95% by weight, preferably 5 to 90% by weight, more preferably 10 to 80% by weight, particularly preferably 15 to 65% by weight.

These diols, glycerin, and diglycerin can be used alone or in combination, and the total amount of diol, glycerin, and diglycerin is preferably 30 to 95% by weight, more preferably 40 to 90% by weight, based on the entire skin external preparation. %, more preferably 45 to 80% by weight, particularly preferably 50 to 75% by weight, and there is no particular limitation as long as the present invention is effective.

Glycol ether in the present invention refers to a compound in which one or both of the hydroxyl groups in the glycol is etherified. If it is used as a skin external preparation in the field of pharmaceuticals, products other than pharmaceuticals, or cosmetics, there is no In particular, the diol is a diol that is liquid at 25°C, for example, a diol represented by the general formula C _n H _2n (OH) ₂ or a polycondensate of a single or two or more of the above-mentioned diols . Examples thereof include ethylene glycol monoether, diethylene glycol monoether, propylene glycol monoether, and dipropylene glycol monoether, among which diethylene glycol monoether is preferred. Specifically, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, etc., preferably diethylene glycol monomethyl ether, Diethylene glycol monoethyl ether, diethylene glycol monopropyl ether.

The compounding amount of the glycol ether used in the present invention is not particularly limited as long as the present invention is effective, and can be appropriately selected and used in consideration of the feeling or effect on the skin, but it can usually be 1 to 95 % by weight, preferably 5 to 90% by weight, more preferably 10 to 80% by weight, particularly preferably 15 to 65% by weight.

In the present invention, the compounding amount of one or more selected from glycols, glycol ethers, glycerin, and diglycerin is preferably 30 to 95% by weight based on the total amount of the external preparation for skin. , more preferably 40 to 90% by weight, further preferably 45 to 80% by weight, particularly preferably 50 to 75% by weight, and there is no particular limitation as long as the present invention is effective.

Furthermore, it is more preferable to use one or more selected from glycols, glycerin, and diglycerin in combination with glycol ethers. The compounding amount is the total amount of them, and it is preferably 30 to 95% by weight based on the entire skin external preparation. , more preferably 40 to 90% by weight, further preferably 45 to 80% by weight, particularly preferably 50 to 75% by weight, and there is no particular limitation as long as the present invention is effective.

The external preparation for skin of the present invention contains low-molecular-weight glycine trimethine salt, glycol ether, etc., and ascorbic acid or its salt is stably dissolved in the preparation.

The low-molecular glycine trimethyl salt in the present invention refers to a compound with a molecular weight of 200 or less and forms zwitterions in the molecule. Specifically, it can be exemplified by quaternary ammonium bases, quaternary phosphonium bases, and tertiary sulfonium bases. The nature of the active agent. Among them, N,N,N-trialkylamino acids represented by the following formula (1) are preferred.

式(1)

Formula 1)

(In the formula, R ₁ , R ₂ and R ₃ independently represent an alkyl group having 1 to 6 carbon atoms, and n represents 1 to 6.)

As R ₁ to R ₃ , linear or branched alkyl groups having 1 to 6 carbon atoms can be widely used. That is, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, Isohexyl, 3-methylpentyl, 2,2-dimethylbutyl or 2,3-dimethylbutyl, etc. Among them, R ₁ to R ₃ may be the same or different.

Specifically, trimethylglycine, triethylglycine, tripropylglycine, triisopropylglycine, n=2 trimethyl-β-alanine, n=3 trimethylglycine, n=3 Trimethyl-γ-aminobutyric acid and the like, preferably trimethylglycine.

In addition, these low-molecular-weight glycine trimethyl salts can be substituted, specifically, N, N, N-trimethylalanine, N, N, N-triethylalanine, N , N,N-triisopropylalanine, N,N,N-trimethylmethylalanine, carnitine, acetylcarnitine, etc., preferably carnitine.

In the external skin preparation of the present invention, the compounding amount of the low-molecular glycine trimethylinyl salt is preferably 0.5 to 10% by weight relative to the total weight of the external skin preparation, depending on the various functions of ascorbic acid or its salt or the use of the external skin preparation. , can be appropriately selected within this range. In view of the effects of the present invention, the range is more preferably 0.5 to 9% by weight, particularly preferably 1 to 8% by weight. If it is less than 0.1% by weight, the effect may not be exhibited, and if it exceeds 10% by weight, the usability may be deteriorated.

The external preparation for skin of the present invention can further suppress precipitation of ascorbic acid or its salt by mixing water.

The compounding amount of the glycol ether used in the present invention is not particularly limited as long as the present invention is effective, and can be appropriately selected and used in consideration of the feeling of use and the effect on the skin, but it can usually be 1 to 95% by weight relative to the entire skin external preparation %, preferably 5 to 90% by weight, more preferably 10 to 80% by weight, particularly preferably 15 to 65% by weight.

The mixing ratio of water in the skin external preparation of the present invention may be 2 parts by weight or less with respect to 1 part by weight of ascorbic acid or a salt thereof, more preferably 1.5 parts by weight or less, more preferably 1 part by weight or less. When it exceeds 2 parts by weight, there is a tendency that the decomposition of ascorbic acid or its salt cannot be allowed.

The amount of water incorporated in the external preparation for skin of the present invention is not particularly limited as long as the present invention is effective, but the amount is 5 to 35% by weight relative to the entire external preparation for skin. It can be appropriately selected and used within this range, but from the viewpoint of the stability of ascorbic acid or a salt thereof, it is preferably in the range of 5 to 20% by weight, particularly preferably in the range of 8 to 13% by weight.

As a preferable embodiment of the external preparation for skin of this invention, it is more preferable to combine each component by the following compounding quantity.

(A) 10 to 20% by weight or more of ascorbic acid or a salt thereof,

(B) 3 to 25% by weight of one or two or more selected from diol, glycerin, and diglycerin,

(C) Glycol ether 45-55% by weight

(D) 1 to 5% by weight of low-molecular glycine trimethyl salt, and

(E) 5 to 25% by weight of water.

As a component, ascorbic acid is more preferably ascorbic acid or its salts, propylene glycol and diglycerin are more preferable among glycols, glycerin, and diglycerin, diethylene glycol monoethyl ether is more preferable as glycol ethers, and low-molecular-weight glycine trimethyl ether is more preferable. salt, more preferably trimethylglycine.

As the most preferable embodiment of the external preparation for skin of this invention, it is especially preferable to combine each component by the following compounding quantity.

(A) 15 to 20% by weight or more of ascorbic acid or a salt thereof,

(B) 4 to 21% by weight of one or two or more selected from diol, glycerin, and diglycerin,

(C) Glycol ether 50-53% by weight

(D) 2 to 4% by weight of low-molecular glycine trimethyl salt, and

(E) 10 to 20% by weight of water.

As a component, ascorbic acid is more preferably ascorbic acid or its salts, propylene glycol and diglycerin are more preferable among glycols, glycerin, and diglycerin, diethylene glycol monoethyl ether is more preferable as glycol ethers, and low-molecular-weight glycine trimethyl ether is more preferable. salt, more preferably trimethylglycine.

In the skin external preparation of the present invention, in addition to the above-mentioned ascorbic acid or its salt, in order to enhance or supplement the various effects of ascorbic acid or its salt, it is also possible to combine whitening ingredients, anti-inflammatory ingredients, antibacterial ingredients, and cell activation ingredients. ingredients, astringent ingredients, antioxidant ingredients, acne-improving ingredients, anti-aging ingredients, synthesis-promoting ingredients of biological ingredients such as collagen, blood circulation-promoting ingredients, moisturizing ingredients, anti-aging ingredients, etc. Coordinated to add other useful effects to skin external preparations. Preferable are one or two or more of a whitening component, an anti-inflammatory component, an antioxidant component, an anti-aging component, or a moisturizing component. As a combination of these components, particularly preferable are a combination of ascorbic acid or a salt thereof and a whitening component, a combination of ascorbic acid or a salt thereof, a whitening component and an antioxidant component, a combination of ascorbic acid or a salt thereof and an antioxidant component, ascorbic acid or its A combination of salt and an antiaging ingredient, a combination of ascorbic acid or a salt thereof, and a whitening ingredient and an antiaging ingredient. These components have been used conventionally as components of pharmaceuticals, products other than pharmaceuticals, and skin external preparations in the field of cosmetics. In addition, as long as they are components to be used in the future, there are no particular restrictions, and any component can be selected and used as appropriate. .

For example, examples of whitening ingredients include arbutin, ellagic acid, phytic acid, lucinol, kamomila ET, vitamin A or its derivatives, vitamin E or its derivatives, pantothenic acid or its derivatives vitamins etc. Among these, pantothenic acid or its derivatives, ellagic acid, phytic acid, vitamin A or its derivatives, vitamin E or its derivatives are mentioned as a preferable component. These whitening ingredients can be used 1 type or 2 or more types.

When the above-mentioned whitening component is used, the proportion of the external preparation for skin of the present invention is preferably 0.0003 to 10% by weight, more preferably 0.01 to 5% by weight. In addition, the whitening component is preferably blended in a ratio of 0.001 to 1000 parts by weight, preferably 0.005 to 500 parts by weight, more preferably 0.01 to 100 parts by weight, based on 100 parts by weight of ascorbic acid or a salt thereof contained in the external preparation for skin of the present invention.

Examples of anti-inflammatory ingredients include allantoin, calamine, glycyrrhetinic acid or its derivatives, zinc oxide, guaiacol, tocopheryl acetate, pyridoxine hydrochloride, menthol, camphor, turpentine, anti-inflammatory Pain, salicylic acid or its derivatives, etc. Preferred are allantoin, glycyrrhetinic acid or derivatives thereof, glycyrrhetinic acid or derivatives thereof, guaiazulene, menthol.

When the above-mentioned anti-inflammatory component is used, the ratio to be incorporated in the external skin preparation of the present invention is preferably 0.0003 to 10% by weight, more preferably 0.01 to 5% by weight. In addition, the anti-inflammatory component is desirably blended in a ratio of 0.001 to 1000 parts by weight, preferably 0.005 to 500 parts by weight, more preferably 0.01 to 100 parts by weight, based on 100 parts by weight of ascorbic acid or a salt thereof contained in the external preparation for skin of the present invention. .

Examples of antioxidant components include tocopherol and its derivatives, butylated hydroxyanisole, dibutyl hydroxytoluene, sodium bisulfite, erythorbic acid and its salts, flavonoids, glutathione, glutathione Peroxidase, glutathione-S-transferase, catalase, superoxide dismutase, sulfur-oxidized protein, taurine, thiotaurine, hypotaurine, etc. Preferred are tocopherol and its derivatives, thiotaurine, hypotaurine, sulfoxylated proteins, flavonoids.

When an antioxidant component is used, the proportion of the external preparation for skin of the present invention is usually 0.00001 to 10% by weight, preferably 0.0001 to 5% by weight, more preferably 0.001 to 5% by weight. Moreover, it is desirable to mix|blend in the ratio of 0.001-1000 weight part, Preferably it is 0.005-500 weight part, More preferably, it is 0.01-100 weight part with respect to 100 weight part of ascorbic acid or its salt contained in the skin external preparation of this invention.

Examples of anti-aging ingredients include retinoids (vitamin A, vitamin A acid, vitamin A aldehyde, etc.), vitamin B15, kinetin, p-phenylenediamine, turmeric extract from Zingiberaceae, sphingosine derivatives, silicon , silicic acid, N-methyl-L-serine, methyl dihydroxypentanone, etc. Preferable are retinoids (vitamin A, retinoic acid, retinoid, etc.), kinetins.

When the above-mentioned anti-aging component is used, the proportion of the skin external preparation of the present invention is preferably 0.0003 to 10% by weight, more preferably 0.01 to 5% by weight. In addition, the anti-aging component is preferably blended in a ratio of 0.001 to 1000 parts by weight, preferably 0.005 to 500 parts by weight, more preferably 0.01 to 100 parts by weight, based on 100 parts by weight of ascorbic acid or a salt thereof contained in the external skin preparation of the present invention. .

As moisturizing ingredients, in addition to amino acids such as alanine, serine, leucine, isoleucine, threonine, glycine, proline, hydroxyproline, glucosamine, theanine, and derivatives thereof Collagen, collagen peptide, gelatin and other peptides, glycerin, 1,3-butanediol, propylene glycol, polyethylene glycol and other polyols, sorbitol and other sugar alcohols, lecithin and hydrogenated lecithin and other phospholipids, hyaluronic acid , heparin, chondroitin and other mucopolysaccharides, lactic acid, sodium pyrrolidone carboxylate, urea and other NMF-derived components, polyglutamic acid and the like can also be exemplified. Preferred are alanine, serine, glycine, proline, hydroxyproline, glucosamine, theanine, collagen, collagen peptides, glycerin, 1,3-butanediol, hydrogenated lecithin, hyaluronic acid , heparin, chondroitin, lactic acid, sodium pyrrolidone carboxylate, polyglutamic acid.

When a moisturizing component is used, the ratio to be blended in the external preparation for skin of the present invention is usually 0.1 to 10% by weight, preferably 0.5 to 5% by weight, and more preferably 0.5 to 5% by weight.

The skin external preparation of the present invention may further contain stabilizers, surfactants, solubilizing components, oils and fats, sugars, or transdermal absorption promoting components in addition to the above-mentioned components. In particular, the stability, effectiveness, and usability of ascorbic acid or a salt thereof in an aqueous solvent can be further improved by adding a stabilizer, a surfactant, a soluble component, or fats and oils.

In the external preparation for skin of the present invention, without impairing the quality such as appearance stability or viscosity, and within the range of the amount and quality that do not impair the effect of the present invention, it may be used in the field of pharmaceuticals, products other than pharmaceuticals, or cosmetics if necessary. , Various components commonly used as external preparation components can be formulated, such as amino acids, irritation reducing agents, thickening agents, preservatives, UV protection agents, colorants, dispersants, pH regulators, fragrances, etc. However, these components can be arbitrarily blended individually by 1 type, and can also arbitrarily blend 2 or more types.

The skin external preparation of the present invention is a combination of one or more selected from the above-mentioned glycols, glycerin, and diglycerin, glycol ethers, ascorbic acid or its salts, low-molecular-weight glycine trimerin salts, and any of the above-mentioned ones when necessary. The components are mixed and compounded, and if necessary, by adding other solvents or bases of commonly used external preparations, etc., it can be prepared into paste, foam, gel, liquid, latex, cream, sheet (supported by the base material) ), aerosol, mist and other required forms. They can be produced by methods commonly used in the industry.

The skin external preparation of the present invention may have a liquid property of usually pH 1 to 8, but from the viewpoint of the stability of ascorbic acid or its salt, low irritation to the skin or mucous membranes, and the benefits of skin use, it is desirable to have a liquid pH of 1 to 8 at a preferred pH. It is 2-7, More preferably, it is the acidic range of pH 2-6.

The external preparation for skin of the present invention can be used as cosmetic materials such as foundation, lipstick, mascara, eyelid cream, eyeliner, eyebrow cream, and nail art materials; basic cosmetic materials such as emulsion, cream, lotion, oil, and facial masks; face washing materials or Cleaning agent, body washing material and other washing materials; anti-underarm odor agent, tinea pedis treatment agent, antipruritic agent, wound healing agent, wiping agent, detergent, anti-inflammatory analgesic, acne treatment agent, hemorrhoid medicine, bactericidal disinfectant, whitening Various compositions for external use belonging to the field of pharmaceuticals, products other than pharmaceuticals, or cosmetics, such as pharmaceuticals, UV protective agents, etc. From the effect on the skin, the present invention is preferably used in a preparation applied to the skin such as an external preparation for the skin (preparation for the skin).

Example

Hereinafter, the present invention will be described in more detail based on examples and test examples, but the present invention is not limited to these examples and the like.

Test Example 1 Solubilization, use feeling and residual rate test of ascorbic acid

According to the prescription (weight %) shown in table 1 in trimethylglycine, diethylene glycol monoethyl ether, 1,3-butanediol, polyoxyethylene (60) in the mixed solution of solidified castor oil, water , adding ascorbic acid, heating, mixing to dissolve, and preparing a preparation.

<Soluble>

After each formulation was left at 4° C. and room temperature for one month, each test solution was visually observed to determine whether or not crystals had precipitated.

<Sense of use, sense of effect>

With 30 test subjects as objects, the following items were used to evaluate the feeling of use of each preparation immediately after application on the skin, and the effect feeling after using each preparation for one month.

Feeling in use: Stretch of the preparation when applied, skin affinity, rough feeling

Sense of effect: whitening effects such as thinning of blemishes and disappearance of pigmentation on the face

Improves skin elasticity such as wrinkles and pores become less conspicuous

Moisturizing effect such as smooth skin surface

Regarding the above items, comprehensively evaluate the feeling of use and the sense of effect at 5 points: satisfied, slightly satisfied, general, slightly dissatisfied, and dissatisfied. When the number of subjects who are satisfied and slightly satisfied is 20 or more, record ○, when the number of satisfied or slightly satisfied subjects is 10 to 19, it is marked as △, and when the number of satisfied or slightly satisfied subjects is 9 or less, it is marked as ×.

<Residual rate>

The formulations of Example 1 and Comparative Example 4 were left at 50° C. for 2 weeks, and the residual rate (%) of ascorbic acid was measured.

The results are shown in Table 1.

Table 1

In the formulation containing water, Comparative Example 2 had poor usability as in Comparative Example 1, and in terms of poor usability, precipitation over time occurred, so a one-month test could not be performed. In addition, in Comparative Example 3, a surfactant was blended instead of trimethylglycine, but ascorbic acid could not be dissolved during preparation, and a formulation was not formed. and then. In Comparative Example 4, the sense of effect was poor, and the residual rate was significantly lowered in terms of crystallization at 4°C. On the other hand, in Example 2, the solubilization, feeling in use, feeling of effect, and residual rate were all satisfactory.

Thus, the present invention containing low-molecular-weight glycinate can stably solubilize ascorbic acid or a salt thereof, have excellent feeling of use and effect, and have a high residual rate of ascorbic acid or a salt thereof.

Next, preparation examples are given.

Example 3

Ascorbic acid 20

Trimethylglycine 3

Diethylene glycol monoethyl ether 1 52.4

Diglycerin 4

Refined water 20

Spices 0.5

Grapefruit Extract 0.1

Total 100%

Example 4

Ascorbic acid 15

Trimethylglycine 3

Diethylene glycol monoethyl ether 50.9

Propylene Glycol 20

Refined water 10

Diglycerin 1

Acerola Extract 0.1

Total 100%

Example 5

Ascorbic acid 30

Trimethylglycine 9

Diethylene glycol monoethyl ether 30.9

Refined water 30

Orange Extract 0.1

Total 100%

Claims (7)

1. A skin external preparation, is characterized in that, contains: (A) 5-20% by weight of ascorbic acid or its salt, (B) One or more selected from glycols, glycol ethers, glycerin, and diglycerin, (C) one or two low-molecular glycine trimethyl salts selected from trimethylglycine and carnitine, and (D) water 5-20% by weight, The glycol ether is one or more selected from diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monopropyl ether. 2. A skin external preparation, is characterized in that, contains: (A) 5-20% by weight of ascorbic acid or its salt, (B) One or more selected from diol, glycerin and diglycerin, (C) One or more glycol ethers selected from diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monopropyl ether, (D) one or two low-molecular-weight glycine trimethyl salts selected from trimethylglycine and carnitine, and (E) Water 5-20% by weight. 3. A skin external preparation, is characterized in that, contains: (A) 10 to 20% by weight of ascorbic acid or a salt thereof, (B) 3 to 25% by weight of one or two or more selected from diol, glycerin, and diglycerin, (C) 45 to 55% by weight of one or more glycol ethers selected from diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monopropyl ether, (D) 1 to 5% by weight of low-molecular-weight glycine trimethyl salts selected from trimethylglycine and carnitine, and (E) 5 to 25% by weight of water. 4. An external preparation for skin, characterized in that it contains: (A) 5-20% by weight of ascorbic acid or its salt, (B) One or more selected from glycols, glycol ethers, glycerin, and diglycerin, (C) one or two low-molecular glycine trimethyl salts selected from trimethylglycine and carnitine, and (D) water, The glycol ether is one or more selected from diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monopropyl ether, And (D) water is 2 weight part or less with respect to 1 weight part of (A) ascorbic acid or its salt. 5. The external preparation for skin according to any one of claims 1 to 3, wherein water is 2 parts by weight or less with respect to 1 part by weight of ascorbic acid or a salt thereof. 6. The skin external preparation according to any one of claims 1-4, wherein the glycol ether is diethylene glycol monoethyl ether. 7. The external preparation for skin according to any one of claims 1-4, wherein the low-molecular-weight glycine trimethylinyl salt is trimethylglycine.