JPH03123724A - Humectant for skin external use - Google Patents

Abstract

PURPOSE:To obtain a humectant for skin external use carrying out the same water adjustment as the skin of human body, increasing effects of existing various components, having excellent moisture retention, durability, etc., comprising a deoxypentose nucleic acid having a specific average molecular weight or a salt thereof. CONSTITUTION:A skin humectant for external use containing a deoxypentose nucleic acid having (1-800)X10<4> average molecular weight or a salt thereof. In blending the humectant with a skin external preparation, the amount of the humectant added is preferably an amount to make 0.1-5.0wt.% concentration. In blending, the humectant is dissolved in or mixed with an arbitrarily selected one of widely used surfactant, oil, wetting agent, etc., generally in cosmetic, drug, etc., depending upon use, individually separately or with a combination of two or more of cosmetic, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a moisturizer for external use on the skin in various fields such as cosmetics, pharmaceuticals, and quasi-drugs.

[Conventional technology]

Conventionally, glycols such as glycerin, propylene glycol, 1,3-butylene glycol, sorbitol, and polyethylene glycol have been widely used as external skin moisturizers. Recently, technology has been developed to incorporate natural moisturizing factors (abbreviated as NMF) such as collagen, elastin, sodium hyaluronate, sodium chondroitin sulfate, and sodium pyrrolidone carboxylate into cosmetics as moisturizing agents, for example, No. 52733, same 5
It has been disclosed in various publications such as No. 9-116204 and No. 59-134706.

However, the moisturizing properties of the conventional glycols are based on substances that are originally dermatologically foreign substances, whereas the substance called NMF is a substance derived from natural products.
Although they are far more preferable than the aforementioned glycols from a dermatological point of view, their moisturizing effects are not necessarily satisfactory.

[Problem to be solved by the invention]

As described above, with conventional technology, there is a problem in that an external skin moisturizer that is a dermatologically preferable substance and exhibits ideal moisturizing ability has not yet been obtained, and it is an issue to solve this problem. was.

[Means to solve the problem]

In order to solve the above-mentioned LID, the present invention employs a method of using a nucleic acid or its salts having an average molecular weight of (1 to 800) x 10' as an external skin moisturizer,
The details will be described below.

First, the deoxypentose nucleic acid in this invention is a polymeric polynucleotide (D
It is sometimes called deoxyribonucleic acid (abbreviated as NA), and because no previously obtained DNA has been found to contain sugars other than deoxyribose. These deoxypentose nucleic acids are widely present in the cells of living organisms and are important biopolymer substances that are related to the genetic phenomena of living organisms and the biosynthesis of specific proteins, and their molecular weight is up to 10 million. It is. However, if the nucleic acid preferred in this invention has a low molecular weight of less than 10,000, the moisturizing effect will be weak, whereas if it has a high molecular weight of more than 8 million, it will form a thick film and provide ideal moisture to the skin. Since it becomes difficult to adjust the average molecular weight (1 to 800)
It will be 10'.

In addition to such deoxypentose nucleic acids,
For example, alkali metals such as sodium and potassium,
Inorganic salts of deoxypentose nucleic acids with alkaline earth metals such as calcium and magnesium, arginine,
Basic amino acids such as lysine, histidine, and ornithine, basic oligopeptide salts having these as bases, and salts such as basic amine salts such as monoethanolamine, jetanolamine, and triethanolamine can also be used. The average molecular weight in this case is also the same as in the case of deoxypentose nucleic acid.

In addition, in order to impart appropriate moisturizing ability to not only cosmetics but also pharmaceuticals or quasi-drugs for the skin, etc., when blending the salts of nucleic acid or deoxypentose nucleic acid, which is the moisturizing agent of this invention, 0.1 It is desirable to add it to a concentration of ~5.0% by weight.

This is because if the amount is less than 0.1% by weight, no moisturizing effect can be expected, and if the amount is more than 5.0% by weight, the
- This is because it becomes difficult to dissolve salts of cypentose nucleic acid or deoxypentose nucleic acid in water. and,
The specific method of compounding is not particularly limited, and usually,
Surfactants, oils, wetting agents, thickeners, and various additives commonly used in various fields such as cosmetics, pharmaceuticals, and quasi-drugs,
The medicinal ingredients, coloring agents, flavoring agents, preservatives, bactericidal agents, etc. may be arbitrarily selected according to the intended use, and these may be dissolved and mixed individually or in a suitable combination of two or more.

[Function] Deoxypentose nucleic acid or its salt, which is the main component of the external skin moisturizer of this invention, forms a kind of thin film on the surface of the skin to which it is applied, and this thin film acts in the same way as human skin. In order to ideally adjust water and various other active ingredients that coexist in cosmetics, pharmaceuticals, or quasi-drugs, the external skin moisturizer of the present invention exhibits special effects not found in conventional moisturizers. considered to be a thing.

〔Example〕

Example 1 and Comparative Examples 1 to 3: Deoxypentose nucleic acid potassium DNA-K with an average molecular weight of 4 million obtained from fish testes was selected as the deoxypentose nucleic acid, and glycerin and collagen were selected as control products, and the results shown in Table 1 Four types of aqueous solutions (Example 1 and Comparative Examples 1 to 3) were prepared in the proportions (wt%) shown in . In order to compare the characteristics of each moisturizer, the following sensory test was conducted.

Table 1 Sensory test method: Select 30 adult women, apply an appropriate amount of the above aqueous solution to their faces after washing their faces, and evaluate the moisturizing properties (skin moistness) and feeling of use (1.3 and 6 hours after application). Feeling of stickiness) and affinity (presence or absence of discomfort with the skin) are evaluated throughout the seasons. The evaluation criteria are as follows.

Moisturizing properties (moist and moist are better) [Yes]
2 points, “somewhat” 11 points, “no” 0 points.

Feeling of use (good without sticky feeling) "No"
2 points, 1 point for “somewhat”, and 10 points for “somewhat”.

Affinity (good if there is no discomfort after application): 12 points for “no,” 1 point for “somewhat,” 10 points for “yes.”

The obtained evaluation scores were totaled and summarized in Table 2 for moisturizing properties, Table 3 for range of use, and Table 4 for affinity. Here, the ratio (effectiveness) of the total score of the 30 subjects to the full score (60 points) was determined using the formula %, and these values were entered in parentheses in the table. Also, in the spring, the temperature on April 10, 1988 was 17.4°C, and the humidity was 62%; in the summer, the temperature was 29.6°C, 29.6°C, and the humidity was 64% on August 5, 1988; in the autumn, the temperature was 18.4°C on November 1, 1988. , humidity 7
0%, and in winter, on February 1st of the same year, the temperature was 7.5°C and the humidity was 59%.
This is the result.

Table (below the margins) (below the margins) (below the margins),'5! J As is clear from Table 2, in Comparative Examples 1 and 2 in which glycerin was used as a humectant, the moisturizing properties (moist feeling) decreased over time throughout the seasons, and the tendency toward 1lJi was particularly strong in the winter. In addition, Comparative Example 3 using collagen also showed a tendency for moisture retention in autumn and winter to decrease over time, but in the case of Example 1 using DNA-K, there was almost no tendency for moisture retention to decrease. I can't admit it.

Furthermore, as is clear from Table 3 (feeling of use) and Table 4 (affinity), Comparative Examples 1 and 2 using glycerin also
In the case of Comparative Example 3 using collagen, the feeling of use was poor throughout the seasons, especially in the summer when using glycerin (stickiness).
was very bad.

On the other hand, in the case of Example 1 using DNA-K, there was almost no effect on the elapsed time throughout the four seasons, no deterioration in any performance was observed, and good evaluation results were maintained.

Example 2: Weight % Phase A Octyldodecyl myristate 3.0 Squalane 8.0 Stearic acid
10.0 jojoba oil
2.02-Octyldodecanol 5.0 Natural vitamin EO11 Polyoxyethylene sorbitan monostearate (20E, 0.) 1.0B phase DNA-K 1.5 Xanthan gum 0. IL-Arginine
1.0 concentrated glycerin 4
．． 01.3-Butylene glycol 4.0 Preservative 0.1 Purified water
60.2 First, Phase A was heated and dissolved at 80°C, and Phase B, which had been heated and dissolved at the same temperature, was added thereto, thoroughly mixed with a homogenizer, and then cooled to 35°C to obtain a skin cream. The moisturizing properties of this skin cream were evaluated by the same sensory test as in Example 1, and the results were good.

Example 3: Phase A: 1,3-butylene glycol carboxyvinyl polymer, DNA, potassium hydroxide, sodium polyacrylate, purified water, Phase B: Beeswax stearate, squalane, myristate, octyldodecylcetanol, monostearate, glycerin monostearate, polyoxyethylene sorbitan (20E, O,) Weight% 2.0 0.15 1.0 0.15 0.003 89.047 1.0 0.5 2.0! , 5 1.5 1.0 0.5 First, the human phase was heated and melted at 80"C, and phase B, which was heated and melted at the same temperature, was added thereto, thoroughly mixed with a homogenizer, and then cooled to 4o"C. A milky lotion was obtained. This emulsion was also subjected to a sensory test in the same manner as in Example 2, and very good evaluation results were obtained.

Example 4: Weight % Phase A Ethanol 5.0 Glycerin 10.0 Preservative
0.1B phase Epsilon aminocaproic acid 0.1D N A -K
1.0 Chamomile extract 0.2 Purified water 83.6 Phase A was mixed and dissolved, then phase B, which had been homogeneously dissolved, was added and mixed well to obtain a lotion. When this lotion was also subjected to a sensory test, very good evaluation results were obtained.

Example 5; Weight % Phase A White petrolatum 25.0 Stearyl alcohol 22.0 Propylene glycol 12. .

Sodium lauryl sulfate 1.5 Ethyl paraoxybenzoate 0.025 Propyl paraoxybenzoate 0.015 Phase B D N A -K
2.5 Purified water
First, according to the 10th revised Japanese Pharmacopoeia "Hydrophilic Ointment Manufacturing Method," phase A was dissolved by heating and maintained at 75°C, and the solution of phase B heated and dissolved at 75°C was added to the remaining amount. The mixture was cooled while stirring to obtain a hydrophilic ointment of the Japanese Pharmacopoeia. When this ointment was applied to five adults with dry skin, excellent moisturizing effects were confirmed.

In addition, instead of DNAK used in Examples 1 to 5, tests were conducted using DNA with an average molecular weight of 10,000 and 8 million, but no difference was observed in either case, and conventional moisturizing It exhibited excellent moisturizing properties, feeling of use, and affinity, which were not found in other formulations.

〔effect〕

As described above, when a skin external preparation containing the skin external moisturizer of the present invention is applied, the nucleic acid or its salt forms a thin film, and this film regulates moisture in the same way as human skin. This further enhances the effects of water and other various components that coexist. Therefore, the moisturizing agent of the present invention has excellent moisturizing properties, durability, feeling of use, and affinity, and is essentially different from conventional moisturizing agents such as glycols or natural moisturizing factors (NMF). It can be said that the upper trowel was also desired.

Claims (1)

[Claims] (1) An external skin moisturizer comprising deoxypentose nucleic acid or its salts having an average molecular weight of (1 to 800) x 10^4.