JP2533776B2 - Topical skin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention provides a compound of isoferulic acid and / or a salt thereof with an organic acid and / or a salt thereof,
It is intended to provide a skin external preparation having an excellent UV protection effect, a whitening effect, and an excellent quality.

(Problems to be Solved by the Prior Art and Invention) It is known that, in general, sun rays not only cause sunburn but also promote skin aging due to the sunburn. Many ultraviolet absorbers have been developed to prevent the sun rays, but in reality, few of them have the effects and safety as well as the stability and solubility as a cosmetic raw material.

That is, the ultraviolet absorbers that have precedent use in Japan are roughly classified into benzophenone-based, urocanic acid-based, p-aminobenzoic acid-based, cinnamic acid-based, and other (salicylic acid-based,
For example, benzophenone series is one of the widely used raw materials with absorption maximum around 280 to 290 nm and 320 to 330 nm, but it is most involved in erythema induction. It has a characteristic that the absorption power in the vicinity of 305 to 310 nm is relatively low. In addition, urocanic acid is a biological component and is highly safe, but the maximum absorption is 280 to 290.
Since it is in the vicinity of nm, the practical effect is particularly low for UV-A. The p-aminobenzoic acid type and the cinnamic acid type have maximum absorption around 300 to 310 nm and a high absorption effect, but it is said to have a problem in safety such as contact photosensitivity. Further, the benzotriazole type has a drawback that it is not allowed to be added to cosmetics from the viewpoint of safety, and the salicylic acid type has a weak absorption maximum and has a drawback that it is difficult to retain the function as an ultraviolet protective agent unless a large amount is added.

In view of the current state of such conventional ultraviolet absorbers, the present inventors have repeated exploratory experimental studies on various materials, and as a result, isoferulic acid and / or its salt have both ultraviolet absorption and tyrosinase activity inhibitory action. We have found that the substance has significant properties and have already applied for a patent for a cosmetic composition containing this substance (Japanese Patent Application No. 60-259464 (Japanese Patent Application Laid-Open No. 62-12259).
0312)).

However, isoferulic acid and / or its salts are, by themselves, sparingly soluble in cold water (soluble in salts), alcohols, organic acids and / or their salts,
The compatibility with the system is not sufficient in the base for external use containing various components, and depending on the formulation system, it may precipitate as crystals in a relatively short time even if it is added to the skin external preparation in a dissolved state, There is a problem that crystals are precipitated even in the acidic region of pH.

Further, in the alkaline region of pH, the external preparation for skin may be discolored with time due to high temperature and sunlight.

Needless to say, the occurrence of crystal precipitation or discoloration significantly impairs the quality of the external preparation for skin, and even the original purpose of absorbing UV light was not achieved.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventor has found that organic ferric acid and / or its salt can be used in the skin external base agent against isoferulic acid and / or its salt. When used in combination, it is not affected by the external base composition, pH range, sunlight, etc., and is not only excellent in the effect of absorbing ultraviolet rays, but also a skin external preparation with excellent stability that does not cause long-term quality deterioration. They have found that they can be obtained and have completed the present invention.

That is, the present invention provides a skin external preparation having an excellent ultraviolet absorption effect, a whitening effect, and excellent quality.

 Hereinafter, the present invention will be described in detail.

In the present invention, isoferulic acid and / or its salt to be added to the external preparation for skin (specifically, inorganic salts such as lithium hydroxide salt, sodium hydroxide salt, potassium hydroxide salt, magnesium hydroxide salt, calcium hydroxide salt and the like). , Amino acid salts such as arginine, lysine, histidine, ornithine, monoethanolamine salt, diethanolamine salt,
The amount of an organic salt such as a triethanolamine salt) is arbitrary depending on the expected ultraviolet absorption effect, but is 0.01% by weight or more, and a particularly preferable amount is 0.5% by weight or more. However, even if the amount exceeds 10% by weight, the effect is hardly changed, and the quality of the external preparation for skin itself is impaired.

Examples of the organic acid and / or its salt include gluconic acid, succinic acid, oxalic acid, citric acid, sodium monohydrogen phosphate, lactic acid, tartaric acid, butyric acid, malonic acid, valeric acid, formic acid and acetic acid. One or more of these organic acids and / or salts thereof are blended, but the amount blended for the purpose of exerting the effect of the present invention is 10 to 100 relative to the amount of isoferulic acid and / or its salt. %, And p
It is desirable that H can be adjusted to 6.7 to 7.5, preferably 6.8 to 7.2.

In the present invention, as a skin external base for blending isoferuric acid and / or a salt thereof and an organic acid and / or a salt thereof, a normal skin external base is a liquid,
Any of gel, paste, cream and the like can be used.

That is, as a component constituting the external preparation for skin, a moisturizer, an oil, a surfactant, a thickener, a sequestering agent, an ultraviolet absorber other than isoferulic acid and / or its salt, a drug, a dye, a fragrance, etc. It goes without saying that they can be used together.

(Effects of the invention) As shown in Table 1, the samples are the external preparation for skin (Example 1) in which sodium isoferurate is mixed with citric acid and sodium monohydrogen phosphate according to the present invention, and the amount of citric acid in Example 1 is 0.2. % (Comparative example 1) and the citric acid content of example 1 was 0.01%, and sodium monohydrogen phosphate was changed to 0.2% (comparative example 2).

 The blending amount below is parts by weight.

Table 2 shows the storage stability.

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

(Example) Example 1 is as shown in Table 1 above. Example 2 Sunscreen cream (gel) Citric acid 0.06 Sodium monohydrogen phosphate 0.54 γ-tocopherol 0.02 Propylene glycol 10.0 Sodium isoferurate 2.0 Glycerin 2.0 Ethanol 4.0 Polyoxyethylene hydrogenated castor oil (50E0) 1.0 Carboxyvinyl polymer 0.5 Caustic potash 0.15 Purified water 79.73

Claims (1)

(57) [Claims] 1. An external skin preparation comprising isoferulic acid and / or a salt thereof and an organic acid and / or a salt thereof.