JPS6219510A - Cosmetic - Google Patents

Abstract

PURPOSE:To provide a cosmetic containing large amount of 4-hydroxycinnamic acid in combination with cyclodextrin and a neutralizing agent in high stability, and having excellent skin-beautifying effect and anti-suntan effect and improved durability of the anti-suntan effect. CONSTITUTION:The objective cosmetic contains (A) 0.1-20wt% (preferably 0.5-15wt%) 4-hydroxycinnamic acid, (B) 0.5-1.2mol (based on 1mol of the component A) of cyclodextrin and (C) a neutralizing agent (e.g. NaOH, arginine, etc.). The cyclodextrin forms a clathrate complex with the 4-hydroxycinnamic acid in the cosmetic to improve the solubility of 4-hydroxycinnamic acid in water. The skin-beautifying effect of the composition is supposed to be caused by the effect of the cyclodextrin to block the 4-hydroxycinnamic acid and protect the 4-hydroxycinnamic acid from decomposition. Since the apparent molecular weight is increased by the formation of a clathrate compound, the transcutaneous absorption can be suppressed and the durability of the anti-suntan effect can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a cosmetic containing 4-hydroxycinnamic acid as an active ingredient.

[Conventional technology]

Skin color is mainly determined by the amount of melanin in the epidermis. This melanin is produced at a constant rate within melanocytes, then released into surrounding keratinocytes and shed as it keratinizes. Therefore, a constant intraepidermal density is maintained.

Therefore, the skin color is uniform and shows little change throughout the year. However, ultraviolet rays, melanocyte-stimulating hormone (M2)
R) Due to aging etc., the melanin production function increases and clinically darkens the skin. □When this occurs locally, there is a clear difference from the surrounding normal skin.
Pigmented spots such as age spots and freckles may occur.

These spots, freckles, melasma, and pigmentation after sunburn occur and increase with age, and become difficult to disappear, making them one of the typical skin concerns of middle-aged and older people. .

Therefore, it has an inhibitory effect on chirosinase activity [Journal of the Society Cosmetic Chemistry (J, 8oc, Cosmet, Chem, ) 2]
5.61-66 (1974) 'l, 4-hydroxycinnamic acid is known as a compound having a melanin-suppressing effect. However, 4-hydroxycinnamic acid
It is crystalline and has low solubility in water by itself (0
, 06//100/), it is also poorly soluble in general alpha cosmetic oils, so it is difficult to incorporate it into cosmetics in large quantities, and there are problems in terms of compatibility with cosmetics. On the other hand, 4-methoxycinnamic acid, which is a similar compound of 4-hydroxycinnamic acid, becomes water-soluble when it is formed into a salt with ammonium ions such as triethanolamine and tris(hydroxymethylaminomethane). significantly increased,
It is known that it is more compatible with cosmetics (Japanese Patent Publication No. 59-20663, Japanese Patent Application Laid-Open No. 59-130209)
However, the above-mentioned ammonium salt of 4-hydroxycinnamic acid undergoes decomposition during long-term storage, shows noticeable discoloration, and also has a reduced effect, so it is not desirable as a cosmetic.

[Problem that the invention seeks to solve]

Under these circumstances, the present inventor conducted extensive studies on a method for stably incorporating 4-hydroxycinnamic acid into cosmetics in large quantities, and found that 4-hydroxycinnamic acid can be incorporated into cosmetics together with cyclodextrin. The present invention was completed based on the discovery that this objective could be achieved by blending the compound into the following.

That is, in the present invention, 4-hydroxycinnamic acid is
The present invention provides a cosmetic composition characterized by containing 20% by weight of cyclodextrin and cyclodextrin.

Examples of the cyclodextrins used in the present invention include various siphrobukis, IJnones, α-one, β-one, r-one, and dimethyl β-one.

Trimethyl β monolithic (e.g., JP-A-58-210901
Examples include derivatives described in the above publication. This dextrin is preferably blended into cosmetics in a molar ratio of 0.1 to 2.0, particularly 0.5 to 1.2, relative to 4-hydroxycinnamic acid.

In order to stably incorporate 4-hydroxycinnamic acid in a large amount using cyclodextrin into the cosmetics of the present invention,
For example, the following method can be adopted.

(1) After dissolving the desired amount of 4-hydroxycinnamic acid in water together with a neutralizing agent, cyclodextrin is added, and then water-soluble ingredients that are commonly used in cosmetics are added. method to make the aqueous phase.

As the neutralizing agent, monovalent metal hydroxides such as sodium hydroxide and potassium hydroxide, and organic cations such as arginine and jetanolamine are preferably used. The neutralizing agent is preferably used in an amount close to equivalent to 4-hydroxycinnamic acid, that is, in a molar ratio of 0.8 to 1.5.

Note that neutralization can be performed while measuring the pH using a glass electrode.

(11) After preparing a saturated or supersaturated aqueous solution of cyclodextrin, 4-hydroxycinnamic acid is added at room temperature or under heating and mixed for several hours.

Usually, the complex is separated as a precipitate. A method of redissolving this isolated complex into the aqueous phase of a cosmetic.

In addition, when redissolving, the neutralizing agent may be added in a molar ratio of 0.1 to 1 to 4-hydroxycinnamic acid as necessary.
It can also be used within the range of

In addition to the o+o act method, there is also a method of simply mixing cyclodextrin and 4-hydroxycinnamic acid in water.

This method also makes it possible to prepare a solution containing 4-hydroxycinnamic acid at a higher concentration than the saturated dissolution amount when cyclodextrin is not added.

This aqueous solution can be used as the aqueous phase of cosmetics.
Alternatively, the complex isolated as in (I+3) may be redissolved in the aqueous phase of the cosmetic.

The amount of 4-hydroxycinnamic acid added to cosmetics is not particularly limited as it may vary depending on the form of use, and it is sufficient that it is present in an effective amount, but generally it is 0.1 to 20% by weight based on the total composition. ,
Preferably it is 0.5 to 15% by weight.

The cosmetic of the present invention can be made into various forms using the aqueous phase by conventional methods, but generally, it is in the form of a lotion, a milky lotion, a cream, and a bag.

Preferably, it is in the form of a gel or the like. Suitable bases and solvents include ingredients commonly used in cosmetics,
For example, oily substances, moisturizers.

Thickeners, preservatives, emulsifiers, medicinal ingredients, fragrances, emulsion stabilizers, etc. can be used. Furthermore, the whitening effect can be improved by adding various active ingredients such as plantin, vitamin E acetate, glycyrrhizin, salicylic acid, urea, and various plant extracts. Furthermore, by adding various ultraviolet absorbing substances, it is possible to create cosmetics that have both sunburn prevention and whitening effects.

[For production]

Sifurobukis used in the present invention forms an inclusion complex with 4-hydroxycinnamic acid, improves the solubility of 4-hydroxycinnamic acid in water, and is susceptible to decomposition reactions. It is thought that it has a blocking effect to prevent it from occurring. In addition, transdermal absorption is suppressed due to an increase in apparent molecular weight due to conjugation.

〔Effect of the invention〕

The cosmetic of the present invention containing 4-hydroxycinnamic acid together with cyclodextrin contains 4-hydroxycinnamic acid, which has a melanin-suppressing effect.
Because it contains a large amount of hydroxycinnamic acid in a stable manner, it has an excellent whitening effect.

Furthermore, 4-hydroxycinnamic acid has a maximum absorption of 311nrrL with a molecular extinction coefficient of 24,000, and the present invention has opened the way to incorporating it into cosmetics in large quantities, so it can also be used to prevent sunburn. Available.

In addition, the percutaneous absorption of 4-hydroxycinnamic acid is suppressed due to the increase in apparent molecular weight due to the complexation with cyclodextrin, so that the durability of the sunburn prevention effect is also improved.

〔Example〕

Next, the explanation will be given with reference to test examples and examples.Example 1 An example of the method for isolating the complex of 4-hydroxycinnamic acid and cyclodextrin to be incorporated into the cosmetic of the present invention is as follows. .

Dissolve 2.83 P of β-cyclodextrin (2,5 x 10 mol) in 50 sj of water, then add 2.05 J' (1,25 x 10 mol) of 4-hydroxycinnamic acid, heat to 60 C, and stir vigorously for 5 hours. do. The mixture was separated into P parts under heating, and the P solution was left at 25r for 2 days, and then separated,
After washing and drying, the complex 3.12/ is obtained as white crystals. The composition of the 4-hydroxycinnamic acid: β
-cyclodextrin=1:1.1C molar ratio) was determined by ultraviolet spectroscopy of a dilute solution of the complex. The infrared absorption spectrum of the composite thus obtained is shown in FIG. 1, and the ultraviolet absorption spectrum thereof is shown in FIG.

Example 2 4-hydroxycinnamic acid was dissolved in water using various cyclodextrins shown in Table 1, and the amount of 4-hydroxycinnamic acid dissolved was measured.

The results are shown in Table 1.

From Table 1, it can be seen that an aqueous solution containing 4-hydroxycinnamic acid in an amount desired as a cosmetic can be prepared by using cyclodextrin in combination.

Table 1 Test Example 1 A solution in which 4-hydroxycinnamic acid (1!i%) was dissolved using the cyclodextrin shown in Table 2 was stored in a constant temperature bath at 50°C. The residual rate of 4-hydroxycinnamic acid was examined by the change in absorbance at 311 nm.

The results are shown in Table 2.

As is clear from Table 2, 4-hydroxycinnamic acid is stabilized by the addition of cyclodextrin.

Table 2 Example 3 Lotion: (Composition) 4-hydroxycinnamic acid 8%
Sodium hydroxide 2%α-cyclodextrin 25%
Glycerin 4%? Lioxyethylene (60) hydrogenated castor oil 1% ethanol
5% preservative
Appropriate amount of fragrance
Trace amount of pigment purified water Residual amount Example 4 Zerni (composition) 4-hydroxycinnamic acid 3% arginine 3% β-cyclodextrin 10% Zoroflengellicol 8% Calcium xypiel monolimer 0.5% Hydroxyethyl cellulose 0.1
% Purified water Remaining amount Example 5 Emulsion: (Composition) 4-hydroxycinnamic acid
3% zomethyl-β-cyclodextrin
30% stearic acid
1% cetanol
2% Vaseline
2.5% squalane 4
%Completely hardened oil 2%
? Lioxyethylene (20) Lupitan Monostearate 1.5% Lipophilic Glycerin Monostearate
1.5% glycerin
3% carboxyvinyl? Rimmer
0.1% preservative
Appropriate amount of fragrance
micro purified water
Residual amount Example 6 W/O type cream: (Composition) 4-hydroxycinnamic acid
3% triethanolamine
3% trimethyl-β-cyclodextrif
20% Vaseline
4% cetanol
0.5% sorbitan sesquiolate 3%
liquid lanolin
4% isopropyl myristate
8% liquid noq rough in
14% glycerin
3% preservative
Appropriate amount of fragrance Micro-purified water Remaining amount Example 7 O/Vill cream: (Composition) 4-Hydroxycinnamic acid and γ-cyclodext 3
Complex with 6% phosphorus (molar ratio 1:1.5) Sodium hydroxide 1% stearic acid 2% cetanol 4% petrolatum 5% squalane 8% hydrogenated salmon oil, 4% polyoxyethylene (20) sorbitan Monostearate 2%
sorbitan monooleate
2% glycerin
3% preservative
Appropriate amount of fragrance, trace amount of purified water, remaining amount 4゜Note)
The complex is prepared as in Example 1.

Example 8 NoQ Tsuk: (Composition) Arginine
3% sodium trimetaphosphate
0.5% vinyl alcohol
3% sodium carboxyvinyl cellulose 2% dipropylene glycol 2% glycerin 2% polyoxyethylene (20) hardening and mustard oil 0
．． 5% titanium oxide, 8% kaolin, 6% fragrance, trace preservatives
Appropriate amount of purified water
Residual Amount) A composite is prepared in the same manner as in Example 1.

[Brief explanation of drawings]

FIG. 1 shows an infrared absorption spectrum of the complex of 4-hydroxycinnamic acid and β-cyclodextrin obtained in Example 1, and FIG. 2 shows its ultraviolet absorption spectrum. that's all

Claims (1)

[Scope of Claims] A cosmetic comprising 0.1 to 20% by weight of 1,4-hydroxycinnamic acid and cyclodextrin. 2. The cosmetic according to claim 1, which further contains a neutralizing agent.