JPH0632719A - External preparation for skin - Google Patents

Abstract

PURPOSE:To obtain an external preparation for skin remarkably improved in stability of vitamin A and/or its fatty acid ester. CONSTITUTION:This external preparation for skin is obtained by blending vitamin A and/or its fatty acid ester with one or two or more kinds of acidic amino acids or their salts. As the acidic amino acids and their salts, acidic amino acids such as aspartic acid and glutamic acid, their salts of inorganic alkali such as sodium and potassium salts and their salts of organic fases such as ethanolamine and of basic amino acid are exemplified. Pyrrolidone carboxylic acid and its salt is also applicable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external preparation for skin in which the stability of vitamin A and / or its fatty acid ester is remarkably improved.

[0002]

2. Description of the Related Art Vitamin A and its fatty acid esters are known to be effective components for the prevention and treatment of cutaneous keratoses and the like, and the prevention and recovery of skin aging.

However, vitamin A and its fatty acid ester are structurally extremely unstable, and light, air,
Since various isomerizations, decompositions, polymerizations, etc. are easily caused by heat, metal ions, etc., it has been difficult to stably blend them in the skin external preparation.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of intensive studies in view of such circumstances, the present inventors have found that vitamin A and / or fatty acid esters thereof can be combined with one or more acidic amino acids and acidic amino acid salts to obtain vitamins. The inventors have found that the stability of A and / or its fatty acid ester is remarkably improved, and have completed the present invention.

[0005]

That is, the gist of the present invention is to provide vitamin A and / or a fatty acid ester thereof, and
It is present in a skin external preparation characterized by containing one or more of acidic amino acids and acidic amino acid salts.

The structure of the present invention will be described in detail below.

Vitamin A and / or used in the present invention
Alternatively, examples of the fatty acid ester thereof include vitamin A (also known as retinol), vitamin A acetate (also known as retinol acetate), and vitamin A palmitate (also known as retinol palmitate), all-trans type or 13-cis. It is preferably a mold and may be a mixture thereof. Further included are fatty oils obtained from fresh aquatic animals liver and pyloric appendix, and concentrates thereof.

There is no particular limitation on the amount to be added to the skin external preparation according to the present invention, but considering the effect of vitamin A on the skin, it is 0.0001% by weight or more, and the effect of vitamin A is strongly appealed. In order to
It is 1% by weight or more. The upper limit of the compounding ratio is preferably 10% by weight in view of the property as an external preparation for skin.

The acidic amino acid and the acidic amino acid salt which are mixed for the purpose of exerting the effects of the present invention include acidic amino acids such as aspartic acid and glutamic acid and inorganic alkaline salts such as sodium and potassium of acidic amino acids, ethanolamine, and bases. Examples thereof include organic alkali salts of organic amino acids and the like. Further, pyrrolidone carboxylic acid and its salt can also be applied.

These are blended in one kind or two or more kinds,
The amount to be blended for the purpose of exerting the effect of the present invention is 0.001% by weight or more, and an excessive blending does not impair the effect of the present invention. However, it should be noted that if the amounts are excessively blended, the respective solubilities will be exceeded, and the quality of the external skin preparation such as precipitation of crystals may be deteriorated. Preferably 10% by weight
It is the following.

In the present invention, as a skin external preparation base to which vitamin A and / or its fatty acid ester and an acidic amino acid and an acidic amino acid salt are blended, any ordinary skin external preparation base can be used. That is, liquid, gel, paste, cream, powder, solid or the like, as a component for modifying the skin external preparation, a moisturizer, an oil, a surfactant, a thickener, a sequestering agent, etc. It goes without saying that the ultraviolet absorbers, drugs, dyes, fragrances, etc. can be used in combination.

[0012]

EXAMPLES The present invention will now be described in more detail with reference to more examples, but the present invention is not limited thereto.

[0013]

[Table 1]

In Examples 1, 2 and 3, the stability of retinol acetate is improved as compared with Comparative Example, which is an effect according to the present invention.

Quantitative Method for Retinol Acetate According to the Japanese Pharmacopoeia (11th revision) Vitamin A Quantitative Method Method 1, quantification was carried out by an absorbance measurement method using isopropanol.

Example 4 Cream (wt%) A. Cetanol 3 Glyceryl monostearate 2 POE (25) cetyl ether 1 Stearic acid 3 Vaseline 3 Olive oil 3 Isopropyl palmitate 1 Squalane 5 Retinol acetate 0.1 Retinol palmitate 0.3 BHT 0.05 Fragrance B. Propylene glycol 3 Potassium hydroxide 0.2 Monosodium glutamate 5 Purified water based on the total amount of 100 The oil phase portion of A and the water phase portion of B are dissolved by heating at 70 ° C., and A is added to B to emulsify. Then, it is cooled to obtain a cream.

Example 5 Beauty Essence (wt%) Carboxyvinyl Polymer 0.4 Glycerin 5 Propylene Glycol 5 Aspartic Acid Arginine Salt 0.001 Triethanolamine 3.4 POE (60) Castor Oil 0.5 Retinol 0.001 Squalane 1 α-Tocopherol 1 Methylparaben 0.2 Ethyl alcohol 6 Purified water Amount based on 100 as a whole

Example 6 Lotion (wt%) Glycerin 2 Ethanol 7 POE (50) Oleyl ether 0.5 Oleyl alcohol 0.002 Retinol 0.0001 Aspartic acid 0.001 Lactic acid 0.02 Sodium lactate 0.1 Methylparaben 0 １ Purified water amount of 100

Example 7 Oil gel (wt%) Retinol acetate 8 Retinol palmitate 2 2-Ethylhexanoic acid triglyceride 40 Olive oil 10 BHT 0.1 BHA 0.05 POE (20) Octyldodecyl ether 16 Glycerin 15 Sodium glutamate 0. 01 Purified water 100 as a whole

Example 8 Serum (wt%) Retinol 0.3 Isopropyl myristate 3 POE (60) Hydrogenated castor oil 0.6 Xanthan gum 0.8 Glycerin 30 Propylene glycol 5 Sodium pyrrolidonecarboxylate (50% liquid) 20 Ethanol 6 Methylparaben 0.1 Purified water Amount based on 100

Example 9 Night Cream (wt%) Squalane 15 Microcrystalline Wax 4 Isopropyl myristate 5 Vaseline 4 Octyldodecanol 2 Butylparaben 0.15 Retinol palmitate 0.2 Retinol 0.2 Diglycerin diisostearate 4 Glycerin 3 Propylene glycol 3 Monosodium glutamate 1 Purified water Amount based on 100

The skin external preparations of Examples 4 to 9 were excellent in stability of vitamin A and / or its fatty acid ester in daily use.

[0023]

INDUSTRIAL APPLICABILITY In the external preparation for skin of the present invention, the stability of vitamin A and / or its fatty acid ester can be remarkably improved by incorporating an acidic amino acid and its salt.

Claims (1)

[Claims] 1. An external preparation for skin, comprising one or more kinds of acidic amino acids and acidic amino acid salts together with vitamin A and / or a fatty acid ester thereof.