JPH11310510A - Humectant, skin cosmetic and bathing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain humectant which possesses excellent hygroscopicity and moisture retention, can exert the agreeable touch and is useful as the components of a skin cosmetic and a bathing agent by making the humectant contain a natural humectant factor of L-serine N-methylated derivative as an active ingredient. SOLUTION: This humectant comprises N-methyl serine (Preferably N-methyl- L-serine. Further, N-methyl-DL-serine or N-methyl-D-serine is also similarly usable). This moisturizer can be added into e.g. a skin cosmetic, a bathing agent or the like and is blended preferably, for example, in proportions of 0.001-10.0 wt.% based on the whole weight of the skin cosmetic and 0.01-10.0 wt.% based on the whole weight of the bathing agent to be used. As a result, the humectant having excellent hygroscopicity and humectant property is obtained and further, the skin cosmetic and the bathing agent having the agreeable touch can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a humectant which is safe and has a high moisturizing effect, and a skin cosmetic and a bath containing the same.

[0002]

2. Description of the Related Art The skin has a function of protecting the living body from various environmental changes and stimuli from the outside world. In particular, the stratum corneum located at the outermost layer of the epidermis acts as a buffer between the outside world and the living body. Is responsible for.

[0003] The stratum corneum needs a moderate amount of water in order to flexibly respond to various activities of the living body and to maintain elasticity, flexibility, protection function and the like. One of the mechanisms by which the stratum corneum retains its own water is NMF (Natural mois
turizing factor), the main components of this NMF are sodium pyrrolidonecarboxylate and amino acids. Further, it is known that if moisture in the stratum corneum is lost due to a change in the external environment or the like, the elasticity, flexibility, protection function, and the like of the skin are impaired, causing various troubles. Therefore, in order to maintain an appropriate amount of water in the stratum corneum, to repair or prevent skin problems,
Although hydrophilic humectants such as hyaluronic acid and collagen are blended in cosmetics, sodium pyrrolidonecarboxylate and amino acids are NMF components and are therefore widely used as humectants. However, sodium pyrrolidonecarboxylate has a disadvantage that it has a high stickiness and a poor feeling of use because it has a much higher hygroscopic property in a high-humidity environment than in a low-humidity environment where moisturizing ability is more required. In addition, since amino acids are small molecules that can penetrate the skin, they may be absorbed in the stratum corneum and function similarly to the NMF that originally exists, but the amino acids themselves have the ability to absorb and retain moisture. There was a disadvantage that it was not excellent.

[0004]

Under such circumstances,
The present inventors have conducted intensive studies to solve the above problems,
L contained most among amino acids which are NMF components
N-methyl-L- which is an N-methylated derivative of serine
The present inventors have found that serine is excellent as a humectant having excellent moisture absorption / moisturizing ability and a favorable feel, and completed the present invention.

[0005] That is, an object of the present invention is to provide a humectant, a skin cosmetic and a bathing agent which have excellent hygroscopicity and humectant ability and have no sticky feeling.

[0006]

The above-mentioned object is achieved by a humectant characterized by comprising N-methylserine, and a skin cosmetic and a bath preparation characterized by containing the humectant. That is, the present invention provides a humectant characterized by using N-methylserine as an active ingredient, and a skin cosmetic and a bath preparation characterized by containing the humectant.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

[0008] N-methyl-L-serine used in the present invention is a known substance and can be easily synthesized by a known method. N-methyl-DL-serine or N-methyl-DL-serine
-Methyl-D-serine can be used as well.

The humectant of the present invention can be incorporated into, for example, skin cosmetics and other cosmetics, bath additives, pharmaceuticals, quasi-drugs, foods, and the like.

The humectant of the present invention is preferably used in an amount of 0.001 to 10.0% by weight (hereinafter referred to as w) based on the total weight of the skin cosmetic.
t%), more preferably 0.01 to 5.0.
wt% is used. If the amount is less than 0.001% by weight, the effect of the present invention may not be sufficiently exhibited. On the other hand, even if the amount exceeds 10.0% by weight, the effect corresponding to the amount may not be obtained.

The skin cosmetic of the present invention can be made into various dosage forms such as lotions, emulsions, creams, ointments, packs and the like in accordance with a conventional method.

The humectant of the present invention is preferably used in an amount of 0.01 to 10.0 wt%, more preferably 0.1 to 5.0 wt%, based on the total weight of the bath agent. 0.0
If the amount is less than 1 wt%, the effect of the present invention may not be sufficiently exhibited. On the other hand, even if the amount exceeds 10.0 wt%, the effect corresponding to the amount may not be obtained.

The bath preparation of the present invention comprises a powder,
Various dosage forms such as granules, tablets, and liquid preparations can be made.

The skin cosmetics and bath preparations of the present invention may further contain surfactants, fungicides,
Preservatives, keratolytic agents, organic and inorganic acids, antioxidants, oils and fats, polyhydric alcohols, pigments, crude drugs and herbs, flavors,
Dyes and the like can be appropriately compounded within a range that achieves the object of the present invention.

[0015]

EXAMPLES Hereinafter, test examples and examples for clarifying the effect of the humectant according to the present invention will be described. Note that the present invention is not limited to these.

Test Example 1: Measurement of N-methyl-L-serine's ability to absorb and retain moisture In order to compare the ability of N-methyl-L-serine to absorb and retain moisture with other humectants, each sample was subjected to a low humidity environment. And a change in weight when placed in a high-humidity environment was measured to calculate a moisture absorption rate and a moisture retention rate. N-methyl-L-serine, L-serine and sodium pyrrolidonecarboxylate (hereinafter abbreviated as PCA soda) were allowed to stand for 5 days in a low humidity environment of 23 ° C. and 14% RH (relative humidity), and The (dry) weight was measured (= Wa0). Thereafter, the sample was allowed to stand for 7 days in a high humidity environment of 23 ° C. and 99% RH (relative humidity), and the sample weight was measured (= Wa7). Furthermore, it was transferred to a low humidity environment of 23 ° C. and 14% RH (relative humidity) and dried,
The weight was measured after lapse of 7.9 days (= Wb1,3,5)
7, 9). The moisture absorption of each sample was calculated by the following equation, and the obtained results are shown in Table 1 below. The numerical values are average values (n =
4).

[0017]

(Equation 1)

The amount of moisture absorption (Wa7-Wa0) is 100
The moisturizing rate (percentage of residual moisture over time) was calculated by the following equation, and the obtained results are shown in Table 2 and FIG.
The numerical values are average values (n = 4).

[0019]

(Equation 2)

[0020]

[Table 1]

As apparent from Table 1, N-methyl-L
The hygroscopic ratio of -serine was about 1/2 of that of PCA soda, but it was confirmed that it was significantly higher than that of L-serine.

[0022]

[Table 2]

As is clear from Table 2 and FIG. 1, L-serine lost most of the moisture absorbed in a high humidity environment on the first day after being transferred to a low humidity environment and dried. PCA soda gradually lost water after being transferred to a low humidity environment, and fell to about 20% on the fifth day, whereas N-methyl-L-serine was 1% after starting drying.
The moisturizing rate on the day was almost maintained until the ninth day.

From the results of the measurement of the moisture absorption / moisturizing ability, N-methyl-L-serine has the ability to maintain and retain at least 1/2 of the moisture absorbed in a high humidity environment even when it is moved to a dry state. It became clear. Therefore, it has been proved that the compound has a high moisture absorbing ability in a high humidity environment, but has a very excellent moisture retaining ability as compared with sodium pyrrolidonecarboxylate, which loses most of the moisture when moved to a dry state. In addition, it was found that both the moisture absorption rate and the moisture retention rate were superior to L-serine.

Test Example 2: Sensory test (Example 1, Comparative Examples 1 and 2) N-methyl-L-serine-containing skin lotion and PC
The feeling of use with the skin lotion containing A soda was compared.
A cosmetic skin lotion having the formulation shown in Table 3 below was prepared by mixing and dissolving in a conventional manner.

[0026]

[Table 3]

20 female panelists (aged 35 to 55) who feel these feelings of dry skin by the blind method
Twice a day (morning and evening) for one week on the face,
"Improvement of flexibility", "Improvement of beam", "Sticky feeling",
The item of "moist feeling" was compared and evaluated.

The evaluation criteria were as shown in Table 4 below, and evaluation was made at the average point. Table 5 shows the evaluation results.

[0029]

[Table 4]

[0030]

[Table 5]

From the results shown in Table 5, N-methyl-L-serine-containing skin lotion has the same or higher improvement in flexibility, tension and moist feeling as PCA soda-containing skin lotion, but is evaluated as non-greasy. It turned out that it was.

The following is a formulation example of a composition to which the present invention is applied. In addition, the value in a table | surface shows wt%.

Examples 2 to 4 (Cream)

[0034]

[Table 6]

After the component (A) in Table 6 was uniformly mixed and dissolved at 80 ° C., the component (B) was mixed and dissolved therein (mixture I). Separately, component (D) was uniformly mixed and dissolved at 80 ° C., and then component (C) was mixed and dissolved therein (mixed solution).
II). Next, gradually add the mixed solution II to the mixed solution I,
The mixture was cooled to 30 ° C. with sufficient stirring to obtain a cream.

Examples 5 to 7 (Lotion)

[0037]

[Table 7]

Each component was mixed and dissolved to prepare a lotion.

Example 8 (bath additive)

[0040]

[Table 8]

Each of the components shown in Table 8 was mixed by a conventional method,
A bath preparation was prepared. In addition, this bath agent is used for about 3 at the time of normal use.
It is used after being diluted 000-fold.

Examples 8 to 9 (gel)

[0043]

[Table 9]

Each component of (A) in Table 9 was swollen with a portion of water (D), and the component (C) was dissolved with the remaining water (D), and then both were uniformly mixed (mixing). Liquid I). Separately, the component (B) was uniformly mixed (mixture II).
The mixed solution I was added to the mixed solution I and dispersed to obtain a gel.

Examples 10 to 11 (hair tonic)

[0046]

[Table 10]

In Table 10 above, in the component (A), the perfume was dissolved with a perfume solubilizer, then dissolved in ethanol while stirring at room temperature, and the component (B) was sequentially added and dissolved (mixed liquid). I). Separately, the component (C) was dissolved and added to the mixed solution I with stirring to make the mixture uniform, followed by filtration to obtain a hair tonic.

[0048]

As described above, according to the present invention, moisture absorption and
N-methyl-L-serine is useful as a moisturizer with excellent moisturizing properties, and skin cosmetics with excellent moisturizing properties and a more favorable feel by blending N-methyl-L-serine as moisturizing agents It is clear that bath and bath salts can be provided.

[Brief description of the drawings]

FIG. 1 is a graph showing a change in a moisture retention rate in a low humidity environment.

Claims (3)

[Claims] 1. A humectant comprising N-methylserine. 2. A skin cosmetic comprising the humectant according to claim 1. 3. A bath preparation comprising the humectant according to claim 1.