JP3192235B2 - External preparation for skin - Google Patents

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 which has significantly improved stability of vitamin A and / or its fatty acid ester.

[0002]

2. Description of the Related Art It is known that vitamin A and / or its fatty acid ester are effective components for preventing and treating cutaneous keratosis and the like, and for preventing and recovering skin aging.

[0003] However, vitamin A and / or its fatty acid esters are extremely unstable structurally,
Since various isomerizations, decompositions, and polymerizations are easily caused by air, heat, metal ions, and the like, it has been difficult to stably blend the composition into an external preparation for skin.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies in view of the above circumstances and found that vitamin A and / or a fatty acid ester thereof may be mixed with one or more water-soluble benzophenone compounds to obtain vitamin A. And / or found that the stability of the fatty acid ester is remarkably improved, and completed the present invention.

[0005]

That is, the gist of the present invention resides in an external preparation for skin characterized in that one or more water-soluble benzophenone compounds are blended together with vitamin A. The gist of the present invention is that a water-soluble benzophenone-based compound (oxybenzosulfonic acid, 2-
(Except for hydroxy-4-methoxybenzophenone) or a combination thereof.

Hereinafter, the configuration of the present invention will be described in detail.

[0007] Vitamin A and / or used in the present invention
Examples of the fatty acid ester include vitamin A (also known as retinol), vitamin A acetate (also known as retinol acetate), and vitamin A palmitate (also known as retinol palmitate), and all-trans or 13-cis. It is preferably a mold, and a mixture thereof may be used. It also includes fatty oils obtained from fresh liver and pylorus of marine animals, and concentrates thereof.

[0008] The amount to be incorporated into the external preparation for skin according to the present invention is not particularly limited, but considering the effect of vitamin A on the skin, the amount is 0.0001% by weight or more, and the effect of vitamin A is strongly appealed. Is preferably 0.00
1% by weight or more. The upper limit of the compounding amount is preferably 10% by weight in view of the properties as an external preparation for skin.

The water-soluble benzophenone compound used in the present invention is 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (hereinafter referred to as benzophenone-4).
And a salt thereof, sodium 2-hydroxy-4-methoxybenzophenone-5-sulfonate (hereinafter, benzophenone-5), disodium 2,2′-dihydroxy-4,4′-dimethoxybenzophenone-5,5′-disulfonate (hereinafter, referred to as “sodium salt”). Benzophenone-9) and the like.

The amount to be incorporated into the skin external preparation of the present invention is 0.001% by weight or more, and the upper limit of the composition is not particularly limited. However, the quality as an external preparation for skin cannot be maintained due to precipitation of crystals and the like. Preferably 5
% By weight or less.

The effect of benzophenone in the present invention will be described.

In addition to the above-mentioned essential components, the skin external preparation of the present invention contains other components usually used in cosmetics and quasi-drugs, such as humectants, surfactants, preservatives, water, alcohol, thickeners, Oils, drugs, chelating agents, fragrances, coloring agents, ultraviolet absorbers, and the like can be added as needed within a range that does not impair the effects of the present invention.

[0013]

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

[0014]

[Table 1]

In Examples 1 and 2, the stability of retinol acetate is improved as compared with the comparative example. This is the effect of adding the water-soluble benzophenone compound according to the present invention.

The manufacturing methods of Examples 1 and 2 and Comparative Examples 1 and 2
Temperature test method Tocopherol, octyl methoxycinnamate, oleyl alcohol, methyl paraben, PO
E (20) After completely dissolving octyldodecyl ether at 40 ° C., completely dissolve retinol acetate and rapidly cool to make an alcohol part. The alcohol part was added to the water part obtained by dissolving the other components in purified water, then sealed in a brown glass sample tube, further wrapped in aluminum foil and completely shielded from light,
Store in a 40 ° C constant temperature bath.

Quantitative method of retinol acetate Japanese Pharmacopoeia (11th edition) Vitamin A quantification was carried out by an absorbance measurement method using isopropanol in accordance with the first method.

[0018]

[Table 2]

In Examples 3 and 4, the stability of retinol is improved as compared with the comparative example. This is an effect according to the present invention.

The production methods of Examples 3 and 4 and Comparative Examples 3 and 4
Temperature test method After the oil components including BHT and tocopherol and the surfactant are completely dissolved at 70 ° C, retinol is completely dissolved immediately before emulsification to obtain an oil phase. Glycerin, propylene glycol, carboxyvinyl polymer, caustic potash, benzophenone-9 and benzophenone-5 are completely dissolved in purified water, and the oil phase is added to an aqueous phase heated to 70 ° C, and emulsified by a homomixer type emulsifier. Then heat exchanger 30
Cooling treatment to ° C. gives an emulsion. The emulsion is filled in a glass bottle coated with a metal, sealed, and stored in a constant temperature bath at 40 ° C.

Determination method of retinol The measurement was carried out by measuring the absorbance at 325 nm using ethanol. Samples from which retinol was removed from each of the examples and comparative examples were prepared, and the absorbance at 325 nm was measured to correct the absorbance of the base. (Absorbance at 325 nm of samples of Examples and Comparative Examples) − (Absorbance of extracted product) = Absorbance of retinol In calculating, absorption maximum 325 nm, E (1%, 1)
cm) = 1835.

Example 5 Lotion (wt%) Oleyl alcohol 0.002 Retinol acetate 0.0001 POE (50) Oleyl ether 0.7 Lactic acid 0.01 Trisodium citrate 0.09 Ethanol 8 Glycerin 2 Methylparaben 0.2 Benzophenone-12 2.5 Benzophenone-5 2.5 Purified water 100

[0023]

Example 6 Cream (% by weight) Squalane 15 2-Ethylhexanoic acid triglyceride 8 Isopropyl myristate 7 α-Tocopherol 0.05 Retinol 0.3 Vaseline 2 Butylparaben 0.1 Propylparaben 0.1 Monoglyceride oleate 3 Diglycerin diisostearate 2 PEG400 dioleate 1 glycerin 10 dipropylene glycol 5 disodium edetate 0.01 benzophenone-4 0.03 triethanolamine 0.04 purified water

Example 7 Oil gel (% by weight) 2-Ethylhexanoic acid triglyceride 60 POE (20) octyldodecyl ether 16 retinol 0.1 glycerin 16 benzophenone-5 0.05 Amount of purified water as 100

The skin external preparations of Examples 5 to 7 were excellent in stability of vitamin A and / or its fatty acid ester in daily use.

[0027]

EFFECT OF THE INVENTION In the external preparation for skin of the present invention, vitamin A can be prepared by blending a water-soluble benzophenone compound.
And / or the stability of the fatty acid ester thereof can be significantly improved.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61K 7/00 A61K 7/48

Claims (2)

(57) [Claims] 1. An external preparation for skin, comprising one or more water-soluble benzophenone compounds together with vitamin A. 2. One or more water-soluble benzophenone compounds (excluding oxybenzosulfonic acid and 2-hydroxy-4-methoxybenzophenone) are blended with one or more fatty acid esters of vitamin A. An external preparation for skin characterized by the following.