JPS63258900A - Cosmetics preparation containing novel elastin derivative - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The skin Iff consists of numerous overlapping layers of cells. The outermost layer of the skin is called the stratum corneum and is made up of dead, keratinized cells. This layer protects the skin from physical and atmospheric damage while acting as a barrier against external hazards. The stratum corneum is rather dry compared to the lower layer of the epidermis. When the lower layers of the skin are dehydrated,
Fine wrinkles appear and make you look older. However, water deficiency in the stratum corneum is even more pronounced, so this is the layer we focus on.

The skin becomes rough, the thin skin starts to peel, and in worse cases, cracks appear and the skin actually peels off, indicating that the skin is dry. If dryness becomes severe and severe, the skin may become reddish in appearance and even irritated. At least one scientist has shown that the stratum corneum remains soft and supple as long as its water content exceeds 10%. Below that, the skin becomes hard, brittle, and opaque.

With age, degenerative changes occur in the lower layers of the skin, which become deficient not only in water but also in significant amounts of lipids and fatty substances. When using cosmetics, it is the outermost layer of the skin that is most often benefited by the use of topical lotions and creams. If this outermost layer can be made plump, clear, and healthy, the overall skin texture will exhibit a more youthful appearance. However, research on the epidermis shows that the stratum corneum only absorbs water;
It has been shown that it can be maintained. It does not accept lipids or fatty substances. Substances used to moisturize the skin have no direct effect on increasing the amount of hydration in epidermal cells.

In addition to the lack of water in the epidermal layer of the skin, as a result of aging and exposure to various climatic conditions, such as sunlight, wind and other factors, the amount of water present in the skin and beyond, such as elastin and collagen, decreases. It has been found that degradation of certain complex polypeptides can lead to a lack of elasticity, skin normality, and texture.

Elastin is a highly cross-linked amino acid complex that is the main component of elastic fibers found in animal skin and connective tissue, and is responsible for providing physiological elasticity. In normal human skin, these elastic tissue proteins represent only a relatively small portion of the total skin protein, but they play an important role in maintaining or enhancing the health and structure of the skin. is playing.

The densely cross-linked structure of elastin makes it extremely difficult to solubilize, however, this can be done enzymatically or by various types of hydrolytic methods, as described for example in U.S. Pat. No. 4,363,70. achieved.

Attempts have been made to utilize elastin as a component of cosmetic compositions, particularly when it has been solubilized by hydrolysis.

However, elastin is only slightly absorbed by the skin, and it has been found that it does not penetrate well enough into the skin to produce a substantial effect on the skin.

The present invention relates to the discovery that by derivatizing solubilized, i.e. partially hydrolyzed elastin, it is possible to produce a substance with increased permeability into the epidermal layer of human skin. .

Therefore, by bonding a fatty acid moiety to hydrolyzed elastin according to the method of the present invention, when used on human skin, it can penetrate the stratum corneum surface layer with sufficient penetration to the 10th to 12th layers. It has now been discovered that a product can be obtained which is found to have the property of penetrating much deeper than the conventional method. This is in sharp contrast to the penetration achieved using underivatized, unsolubilized elastin in the skin.

In studying the structure of the stratum corneum, dermatologists use pieces of plastic adhesive tape, such as the well-known ``°°Scotch'' (5cotch) tape strips, to layer the stratum corneum with each strip of tape. This structure was revealed by coloring the cells that were removed one by one and then performing a histological examination.In most people, the stratum corneum consists of about 12 to 18 layers of cells. (sometimes thought to be 10 to 20 layers), when these layers are peeled off one by one from the same area of the stratum corneum, they are known as the "glistening layer" of the epidermis. It is so named because tissue fluid oozes out from the living cells in this layer.

These layers of the stratum corneum are peeled off, followed by analysis of one or more layers, which is believed to give a good indication of the degree of permeability of the substance into the skin.

In the case of elastin, the degree of absorption appears to be important in restoring the fibrous protein to the surface layers of the skin. The resulting improvement in skin health and structure often results in a reduction in fine lines.

At the stage of development of the present invention, hydrolyzed elastin itself has only a slight permeability that passes through the first and second layers of the stratum corneum, but at this permeability it has no significant effect as a skin conditioner. It was first confirmed that it was insufficient to give . In order to improve the permeability of elastin, it was decided to see if this objective could be achieved by adding a suitable alkyl group to the N-terminal group of the elastin molecule. It was therefore decided to try to attach fatty acids (moieties) such as lauric acid, palmitic acid or oleic acid.

The alkylation operation first converts the fatty acid to the corresponding anhydride and then alkylates elastin in aqueous solution to form the corresponding amide or, depending on the purpose, lauric acid,
This was carried out by obtaining elastin-fatty acid derivatives in the form of N-acyl derivatives of fatty acids such as oleic acid or valmitic acid or mixtures thereof. The resulting product was then treated as described in the Examples herein.
Elastin is alkylated using tritiated fatty acid moieties, the product is applied to the surface of the skin, layers of the skin are peeled off, and a liquid scintillation spectrometer is used to measure the absorption of radioactivity in these layers. was measured and compared to soluble elastin to test its permeability into the skin. The test results show that tritiated hydrolyzed elastin with N-alkylated tritium acetate exhibits only modest penetration into the subsurface stratum corneum, whereas this is further detailed below. As described in , the corresponding fatty acid derivatives showed much higher penetration into the lower layers of the stratum corneum.

Acetic anhydride treated elastin, lauric anhydride treated elastin, elastin and valmitoyl/oleoyl treated elastin are all standard 15mm x 180mm.
The BioRad P2 gel filtration method layer gave essentially identical retention images. A two- to three-fold increase in retention time was obtained for each of the tritiated acetate markers, tritiated lauric acid, and tritiated 9,10-palmitic acid, each converted to its sodium salt. The longer retention times required for the pure fatty acid salts indicated that the reaction between the acid anhydride and elastin in each case was successful.

60°C in 0.5N sodium hydroxide salt,
Hydrolysis for 30 minutes did not produce any free acid in each case, indicating that an amide bond was formed between the elastin and the reacted anhydride.

When a 5 or 10% preparation of elastin laurate or valmitoyl/oleoyl elastin becomes cloudy when cooled to 4°C, this may be due to the water solubility of these intermediates, i.e., long-chain elastin derivatives. This shows that the number of people has decreased. These preparations also resulted in some foaming at room temperature. This indicates that there is a certain degree of mild cleaning effect. The 10% elastin itself is
It shows no stagnation upon cooling and less foaming at room temperature.

When the conductive elastin is incorporated into cosmetic preparations such as skin creams and used on the skin for an extended period of time, it has a remarkable moisturizing and firming effect.

In addition to this, fine lines were often reduced or disappeared, which is taken as evidence that the deep absorption of elastin is effective.

Example 1 Penetration of elastin into the stratum corneum of human skin was confirmed by hydrolyzed elastin [chlorastin G, C,
(crolastin G, (:,) molecular weight approximately 4.00
0, protein content 10% solution] was reacted with 5 m of tritiated acetic anhydride at room temperature for 48 hours to acylate some of the terminal nitrogen groups of elastin molecules. Although most of the N1 sites are probably acylated under these conditions, tritiated acylation is obtained on only a small proportion of the active groups.

The resulting tritiated product is
The specially prepared product was subjected to repeated dialysis until it showed a radioactivity of 523 counts per milligram.

Two milligrams (1046 counts) of the product was applied over one parallel centimeter of the front shoulder of the human body and left in place for two and a half hours, after which five pieces of "scotch" tape were removed one by one from the stratum corneum and used for analysis. into a liquid scintillation counting glass bottle. The results obtained are shown in the table below.

:I-5327963 These results indicated that the degree of penetration below the second layer of the stratum corneum was small. That is, the penetration into the first two layers, measured by radioactivity, was 88% of the recovered counts, while the penetration into the third to fifth layers was only 9% of the recovered counts. There wasn't.

Example 2 Production of lauric acid amide of elastin (elastin laurate) and permeability test.

100 of hydrolyzed elastin aqueous solution (protein concentration 10%)
mj! Add 1.1 g of lauric anhydride drop by drop to the reaction mixture at 40°C for 1 hour with stirring, and extract twice with 50 volumes of chloroform to remove unreacted fatty acids from each extract. Separate the organic layer. The aqueous reaction mixture was then dialyzed to further remove unreacted lauric acid and lauric anhydride. The final solution was prepared to have a protein (lauryl-elastin) concentration of 5%.

Lauric acid amide of elastin is included in the solution at a concentration of 5%.

For testing the permeability of this product to human skin, elastin is reacted with tritiated lauric anhydride and an aqueous solution of the lauric acid derivative is prepared at a concentration of 5% in the same manner as above.

The aqueous solution of the tritiated elastin lauric acid compound thus obtained was then investigated for permeability to human skin as follows.

Two milligrams of a product with a radioactivity of 4021 units per minute was examined over an anterior shoulder surface area of approximately 1 parallel centimeter.

Two milligrams of product with radioactivity of approximately 4021 fits per minute was applied to approximately 1 parallel centimeter of anterior shoulder surface area (
After 1 hour, several strips of "Scotch" (5coLch) tape were made and counted in a liquid scintillation spectrometer. The following results were obtained.

9-II 390 II
194+2-14 130 4
The result of 65■ indicates substantial transmittance.

Example 3 Tritiated elastin palmitate/oleate was reacted in a manner similar to Example 2 by reacting tritiated valmitic anhydride and oleic anhydride with solubilized elastin (10% protein concentration). Manufactured. The mixture of balmitic anhydride/oleic anhydride resulted in a more soluble product than when palmitic anhydride alone was used.

The product, the palmitic acid/oleic acid amide of elastin, had a radioactivity equivalent to 82 counts per minute per milligram (3) 1-9.10-palmitate). Apply the solution to the skin (previous 111) with a glass rod, part 1
Direct application was carried out at a rate equal to about 2 milligrams of product per parallel centimeter, and two exposures were tested, % hour and 1 hour, respectively.

Several strips of "5cotch" tape were removed from each layer of skin and scintillation measurements were performed on the removed samples.

The results are described below.

(a) LA time exposure (b) 1 hour exposure: I-919,641239 10-121,7421 Example 4 In the procedure of Example 3, instead of applying it as a lotion, a tritiated elastin-palmitic acid compound solution was applied. Using a porous patch of dampened agarose (0.5%), measure out a square centimeter of it and cover the circumference with adhesive tape, several pieces of "SCotch" tape. The test was performed while the cloth piece was left in the same position for 3 hours. The following results were obtained.

3-'l 30 64 3751
0-12 1! 23 137 As shown in Examples 1 to 4 described above, the permeability expressed by radioactivity counts and the corresponding measured values in microdulum of elastin and elastinamide absorbed in each layer are based on fatty acid groups in molecules. was significantly enhanced by the presence of It is also clear that the amount and degree of penetration are proportional to the time of skin contact or exposure.

In Example 3, layers 3-9 provided significant absorption and layers 10-13 did not provide any absorption over time. On the other hand, 1 hour exposure showed significant penetration into layers 10-12.

In Example 4, a patch of cloth was used instead of lotion.
) and the results show that high penetration was obtained when exposed for 3 hours.

Example 5 The fatty acid elastinamides described herein are preferably incorporated into conventional cosmetic creams or lotions for application to the skin of the human body.

A typical skin cream containing elastinamide, as prepared in Example 2, has the following composition (parts are by weight):

Friend-l Glycerin 7'nostearate 5 Stearic acid 4 Isopropyl myristate 3 Cetyl alcohol
1 lanolin knee, varnish, bee, anhydrous 1--l water
50 glycerin
3 Triethanolamine 1 Lauric acid amide of elastin 2 Preservative (methylparaben), 02 Phase A melts at 70°C. Slowly add phase B little by little to the molten phase A, which has been preheated to about 50°C while stirring. Appropriate fragrances can then be added. Then put it in a wide mouth bottle and homogenize it.

When the above cream is applied to the skin and left for 1 to 3 hours, or overnight depending on the purpose, it is found to gradually improve and soften the skin after a period of several days of use. The skin becomes soft and the elastin derivative absorbs.Example 6 A simple emulsion to be used on the skin to achieve skin softening and penetration with elastin is lauric acid amide of elastin (Example 2) or Palmitic acid/oleic acid amide of elastin (Example 3) 2-
It can be prepared by adding 5 parts to a solution consisting of 100 parts of distilled water, 15 parts of an emulsifier such as propylene glycol monostearate, and a small amount of a preservative such as methylparaben and mixing thoroughly to emulsify. .

In general, the elastin fatty acid amides of the present invention are incorporated in significant proportions into conventional cosmetic preparations for a sufficient period of time, i.e., 1 to 3 hours during the day, or - at night.
If left on, it appears to result in a high degree of penetration, as shown by the results obtained using tritiated materials in the examples above. Various proportions of the amide compound can be tried, but 2-10% is generally expected. Various ratios of the amide compound can be tried, but generally 2
A ratio of ~10% appears to be adequate to obtain significant effects.

Claims (1)

Claims: 1. A cosmetic preparation for application to the skin, characterized in that it comprises a fatty acid amide compound of solubilized elastin, in which the fatty acid moiety is attached to the N-terminal group of the elastin molecule. 2. A cosmetic preparation according to claim 1, wherein the fatty acid amide is elastin lauric acid amide. 3. A cosmetic preparation according to claim 1, wherein the fatty acid amide is palmitic acid amide of elastin. 4. A cosmetic preparation according to claim 1, wherein the fatty acid amide is elastin oleic acid amide. 5. Reaction product of fatty acid anhydride and solubilized elastin to produce the corresponding amide in which the fatty acid moiety is attached to the N-terminal group of the elastin molecule, capable of substantially penetrating the stratum corneum of the human skin. An elastin derivative characterized by: 6. Reacting the fatty acid anhydride with the hydrolyzed elastin in an aqueous solution in order to attach the fatty acid moiety to the nitrogen end group of the elastin molecule, and recovering the fatty acid amide of the elastin thus produced. A method for producing elastin fatty acid amide having a substantial penetration into the epidermis of the human body. 7. The manufacturing method according to claim 6, wherein the fatty acid anhydride is an anhydride of lauric acid, and the resulting product is lauric acid amide of elastin. 8. The method according to claim 6, wherein the fatty acid anhydride is an anhydride of palmitic acid, and the resulting product is palmitic acid amide of elastin. 9. The method according to claim 6, wherein the fatty acid anhydride is an oleic anhydride, and the resulting product is an oleic acid amide of elastin. 10. An amide of elastin, which is prepared by the method according to claim 6.