JP2000229837A - Cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cosmetic which maintains the original hyaluronic acid structure present in an organism, is excellent in safety and biocompatibility, improves its retentivity on the skin and promotes beauty effects by including a gel formed by a specific hyaluronic acid alone. SOLUTION: This cosmetic contains a gel formed by a hyaluronic acid alone with poor solubility in a neutral aqueous solution. It is preferable that the gel has a dissolution rate of >=50% for 12 h in a neutral 37 deg.C aqueous solution, the solubilized hyaluronic acid formed by treating a hyaluronic acid gel under the condition of the promoting acid hydrolysis of hyaluronic acid has branched structure, the hyaluronic acid thus solubilized partially contains a molecular weight fraction with a branching degree of >=0.5, and furthermore, the above gel is a kind selected from the group consisting of sheet-like, crushed and fluid ones.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cosmetic containing a gel formed of hyaluronic acid alone, which is hardly soluble in a neutral aqueous solution.

[0002]

2. Description of the Related Art Keeping skin moisture in an appropriate range
It is very important from the viewpoint of beauty, and there are many cosmetics for moisturizing purposes. Studies have been conducted on substances involved in moisturizing the skin, and many moisturizers have been used, including polyhydric alcohols such as propylene glycol and sorbitol. Particularly recently, attention has been paid to hyaluronic acid. Hyaluronic acid is a natural moisturizing factor for skin and has excellent properties as a moisturizer,
It activates skin cells, accelerates the metabolism of aging skin, and has a remarkable effect on improving skin roughness and keratin, as well as giving the skin a moist, smooth, firm and glossy effect, and has the effect of making the skin beautiful. Have been.

[0003] Many cosmetics such as various cosmetic creams, emulsions, lotions, essences and the like containing hyaluronic acid having such an effect are provided. Further, cosmetics containing a substance having a whitening effect in hyaluronic acid and cosmetics containing a substance having an effect of improving skin roughness are also provided.

[0004]

As described above, hyaluronic acid has cosmetic effects such as skin roughness improvement effect, keratin improvement effect, and moisturizing effect. The effect is expected to be significantly improved. One-point cosmetics, eyelids, corners of the eyes,
Various attempts have been made to apply a sheet of hyaluronic acid to the forehead, mouth, neck, etc., and to chemically crosslink hyaluronic acid to improve retention (Japanese Patent Laid-Open No. 3-112).
No. 914, U.S. Pat. No. 4,582,865, JP-B-6-37575, and JP-A-7-9740.
No. 1, JP-A-60-130601).

However, the sheet of hyaluronic acid has high solubility in water and lotion, and the crosslinked hyaluronic acid by the crosslinking agent is no longer essentially hyaluronic acid itself. Considering that it is difficult to completely deny the remaining cross-linking agent, safety to the skin cannot be unconditionally guaranteed. We have found a hyaluronic acid gel that is sparingly soluble in neutral aqueous solutions formed essentially of hyaluronic acid alone without a cross-linking agent. PCT / JP98 / 03536
No.), the present inventors have intensively studied the possibility of applying this poorly water-soluble hyaluronic acid gel to cosmetics, and have found the usefulness thereof, and have completed the present invention.

[0006]

That is, the present invention provides:
(1) a cosmetic containing a gel formed of hyaluronic acid alone, which is hardly soluble in a neutral aqueous solution, (2) the following (a),
A cosmetic comprising a gel formed of hyaluronic acid alone which satisfies the requirement of (b), (a) neutral 3
(B) hyaluronic acid solubilized by treating the hyaluronic acid gel under conditions of accelerated acid hydrolysis of hyaluronic acid having a dissolution rate of 50% or less in an aqueous solution at 7 ° C. for 12 hours has a branched structure. (3) A gel formed solely of hyaluronic acid, wherein the solubilized hyaluronic acid partially contains a molecular weight fraction having a degree of branching of 0.5 or more,
(4) The cosmetic according to (2), wherein the cosmetic is one selected from the group consisting of a sheet, a crushed form, and a fluid form.
50% dissolution rate in 12 hours in neutral 37 ° C aqueous solution
Hyaluronic acid solubilized by treating the hyaluronic acid gel under conditions of accelerated acid hydrolysis of hyaluronic acid has a branched structure, and the degree of branching in the solubilized hyaluronic acid is 0. Hyaluronic acid gel partially containing a molecular weight fraction of 5 or more, cosmetics containing ungelled hyaluronic acid, (5) hyaluronic acid formed of hyaluronic acid alone in sheet, crushed or fluid state It is a cosmetic containing a gel and non-gelled hyaluronic acid.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The hyaluronic acid gel referred to in the present invention is a polymer having a three-dimensional network structure and a swollen body thereof. The three-dimensional network structure is formed by a cross-linked structure of hyaluronic acid.

One example is the pH of hyaluronic acid.
The aqueous solution of 3.5 or less is frozen and then thawed to obtain a hyaluronic acid gel that is hardly soluble in a sheet, film, crushed, or fluid neutral aqueous solution.
This will be described more specifically below.

The hyaluronic acid used in the present invention can be used regardless of its origin, whether it is extracted from animal tissues or produced by fermentation. The strain used in the fermentation method is a microorganism having hyaluronic acid-producing ability, such as Streptococcus sp.
No. 3-123392, Streptococcus equi FM-100 (Microtechnical Laboratories No. 9027), and Streptococcus equi FM-300 described in Japanese Patent Application Laid-Open No. Hei 2-234689 (Microtechnical Labs No. 2319) )), A mutant which stably produces hyaluronic acid in high yield is desirable. Those cultured and purified using the above mutant strains are used.

The molecular weight of the hyaluronic acid used in the present invention is preferably in the range of about 1 × 10 ⁵ to about 1 × 10 ⁷ daltons. In addition, as long as it has a molecular weight within the above range, those obtained by subjecting them to hydrolysis treatment or the like from those having a higher molecular weight can also be preferably used. It should be noted that the hyaluronic acid according to the present invention is used in a concept that also includes alkali metal salts thereof, for example, sodium, potassium and lithium salts.

The term "hyaluronic acid alone" as used in the present invention means that no chemical cross-linking agent or chemical modifier other than hyaluronic acid is used, and that it is not complexed with a cationic polymer. .

The hyaluronic acid gel referred to in the present invention can be decomposed and solubilized by treating the hyaluronic acid gel under the conditions of the accelerated acid hydrolysis reaction of hyaluronic acid. When the solubilized hyaluronic acid retains a crosslinked structure,
Hyaluronic acid having a branch point can be distinguished from linear hyaluronic acid in terms of polymer solution theory.

The conditions for the accelerated acid hydrolysis reaction of hyaluronic acid referred to in the present invention are as follows: pH 1.5 of aqueous solution, temperature 60 ° C.
Is appropriate. The main chain cleavage reaction due to hydrolysis of the glycosidic bond of hyaluronic acid, compared with neutral aqueous solution,
Significantly promoted in acidic or alkaline aqueous solutions. Further, the acid hydrolysis reaction is promoted at a higher reaction temperature.

In the present invention, the GPC-MALLS method is used,
The molecular weight and the degree of branching of the molecular weight fraction separated by GPC were continuously measured online. In the present invention, the degree of branching is measured by using the elution volume method of calculating the degree of branching by comparing the molecular weight of the solubilized hyaluronic acid of the fraction having the same elution volume with the molecular weight of the linear hyaluronic acid as a control. Was. The degree of branching is the number of branch points present per one polymer chain of solubilized hyaluronic acid, and is plotted against the molecular weight of solubilized hyaluronic acid.

[0015] The solubilized hyaluronic acid was diluted with a GPC solvent to adjust the concentration, filtered through a 0.2 µm membrane filter, and used for measurement. In the case where the hyaluronic acid gel referred to in the present invention has a cross-linked structure that is stably present even under the accelerated acid hydrolysis conditions of hyaluronic acid, a branched structure is confirmed in the solubilized hyaluronic acid in terms of a polymer solution. The degree of branching of the hyaluronic acid gel referred to in the present invention is 0.5
That is all.

As the acid used for adjusting the pH of the aqueous solution of hyaluronic acid, any acid can be used as long as the pH can be adjusted to 3.5 or less. In order to reduce the amount of acid used, it is desirable to use a strong acid, for example, hydrochloric acid, nitric acid, sulfuric acid and the like.

When preparing a fluid gel, 0.1 to 0.1
10% by weight of metal salt are added. As the metal salt, sodium chloride, potassium chloride and the like can be used.

The pH of the aqueous solution of hyaluronic acid is such that the carboxyl groups of hyaluronic acid are protonated at a sufficient rate.
Adjust to H. The pH to be adjusted is appropriately determined according to various kinds of properties such as the type of the counter ion of the hyaluronic acid salt, the molecular weight of the hyaluronic acid, the concentration of the aqueous solution, the conditions for freezing and thawing, and the strength of the gel to be formed. The pH is adjusted to 0.5 or less, preferably to 2.5 or less.

For freezing and thawing, an operation of placing an acidic aqueous solution of hyaluronic acid in an arbitrary container, freezing it at a predetermined temperature, and thawing at a predetermined temperature after freezing is performed at least once. . The temperature and time for freezing and thawing are appropriately determined within the range of the temperature and time for freezing and thawing the acidic aqueous solution of hyaluronic acid depending on the size of the container and the amount of the aqueous solution. Is preferred. Freezing and thawing time can be shortened,
More preferably, a freezing temperature of −5 ° C. or less and a thawing temperature of 5 ° C. or more are selected. The time is not particularly limited as long as it is equal to or longer than the time at which freezing and thawing is completed at that temperature.

The number of repetitions of the operation of freezing and then thawing the adjusted acidic aqueous solution of hyaluronic acid depends on the molecular weight of the hyaluronic acid used, the concentration of the aqueous solution, the pH of the aqueous solution, the temperature and time of freezing and thawing, and the gel formed. It is appropriately determined according to various characteristics such as the strength of the rubber. Normally, it is preferable to repeat it one or more times. Further, each time the operation of freezing and thawing is repeated, the temperature and time of freezing and thawing may be changed.

The hyaluronic acid gel obtained by freezing and thawing the adjusted acidic solution of hyaluronic acid needs to exclude components such as acids used for adjusting the acidity in order to avoid acid hydrolysis of hyaluronic acid. is there. In order to remove components such as acids, washing or dialysis is usually performed with an aqueous solvent. When preparing a fluid gel, dialysis is mainly used.
The solvent to be used is not particularly limited as long as it does not impair the function of the hyaluronic acid gel.For example, water, saline, phosphate buffer and the like are used. A buffer solution or the like is used.

The washing / dialysis method is not particularly limited, but is usually a batch method, a filtration method, a method of filling a column or the like, and passing the solution through. A method using a filtration membrane or the like is suitably used. These conditions are:
Any conditions can be used as long as the components to be removed, including the amount of liquid and the number of times, can be reduced to the target concentration or less, and can be appropriately selected depending on the form and use of the hyaluronic acid gel.

The washed and dialyzed hyaluronic acid gel may be immersed in a solvent, wet with a solvent, air-dried, dried under reduced pressure or freeze-dried depending on the purpose of use. Is provided as cosmetics.

Processing such as molding of hyaluronic acid gel is as follows:
At the time of preparation, a hyaluronic acid gel in a desired form such as a sheet, a film, a crushed form, and a fluid form can be prepared by selecting a container and a method at the time of freezing the adjusted acidic solution of the hyaluronic acid. For example, a film-like or sheet-like form can be obtained by casting and freezing on a plate, or a crushed form can be obtained by freeze-thawing with vigorous mixing and stirring with an organic solvent immiscible with water.

The hyaluronic acid gel, which is hardly soluble in a neutral aqueous solution, has remarkably improved retentivity on the skin as compared with the hyaluronic acid solution, so that hyaluronic acid improves skin roughness, keratin, moisturizing effect, and the like. Is to enhance the sustainability of the skin whitening effect by blending a substance having a skin whitening effect or the skin roughness improving effect by blending a substance having a skin roughness improving effect.

Examples of substances having a whitening effect include L-ascorbic acid, kojic acid and derivatives thereof (fatty acids, sulfuric acid, phosphate esters, etc.), cysteine or glutathione and its derivatives, vitamin E derivatives, arbutin, hydroquinone and the like. No.

Examples of the substance having an effect of improving skin roughness include docosahexaenoic acid, eicopentaenoic acid, allantoin, aloe extract, ginseng extract, placenta extract, bovine blood slow protein, and fermentation metabolite.

The cosmetics can be used for one-point cosmetics, various cosmetic creams, emulsions, lotions, serums, packs, under makeup, foundations, jellies, ointments, and the like. In addition, the shape can be selected from a sheet, a film, a crushed shape, and a fluidized shape according to an application site.

[0029]

The present invention will be described in detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 Preparation of Hyaluronic Acid Gel Cosmetic Insoluble in Sheet-like Neutral Aqueous Solution Sodium hyaluronate having a molecular weight of 2 × 10 ⁶ daltons was dissolved in distilled water, and a 1% by weight aqueous solution of hyaluronic acid was prepared. Was prepared. The pH of this aqueous solution was adjusted to pH 1.5 with 1N hydrochloric acid to obtain an acidic aqueous solution of hyaluronic acid. 30 ml of this aqueous hyaluronic acid solution was placed in a 180 mm × 180 mm square plastic petri dish and placed in a freezer set at −20 ° C. Freezing for 22 hours and thawing for 2 hours at 25 ° C. were repeated twice to obtain a sponge-shaped hyaluronic acid gel. Next, this was neutralized by immersion in 100 ml of a phosphate buffered physiological saline of pH 7 adjusted by adding a phosphate buffer component at a concentration of 50 mM to physiological saline at 5 ° C. for 24 hours, and then sufficiently washed with distilled water. did. Then, this was freeze-dried to obtain a hyaluronic acid gel cosmetic which was sparingly soluble in a sheet-like neutral aqueous solution having a size of 180 mm × 180 mm.

Example 2 Preparation of Hyaluronic Acid Gel Cosmetic Insoluble in Film-like Neutral Aqueous Solution Sodium hyaluronate having a molecular weight of 2 × 10 ⁶ daltons was dissolved in distilled water, and a 1% by weight aqueous solution of hyaluronic acid was prepared. Was prepared. The pH of this aqueous solution was adjusted to pH 1.5 with 1N hydrochloric acid to obtain an acidic aqueous solution of hyaluronic acid. 30 ml of this aqueous hyaluronic acid solution was placed in a 180 mm × 180 mm square plastic petri dish and placed in a freezer set at −20 ° C. Freezing for 22 hours and thawing for 2 hours at 25 ° C. were repeated twice to obtain a sponge-shaped hyaluronic acid gel. Next, this was neutralized by immersion in 100 ml of a phosphate buffered physiological saline of pH 7 adjusted by adding a phosphate buffer component at a concentration of 50 mM to physiological saline at 5 ° C. for 24 hours, and then sufficiently washed with distilled water. did. Then, this is dried in an oven at 40 ° C. for 3 hours, and is 180 mm × 180 mm
A hyaluronic acid gel cosmetic which is hardly soluble in a large film-like neutral aqueous solution was obtained.

Example 3 Preparation of Hyaluronic Acid Gel Cosmetic Insoluble in Crushed Neutral Aqueous Solution Sodium hyaluronate having a molecular weight of 2 × 10 ⁶ daltons was dissolved in distilled water, and a 1% by weight aqueous solution of hyaluronic acid was prepared. Was prepared. The pH of this aqueous solution was adjusted to pH 1.5 with 1N hydrochloric acid to obtain an acidic aqueous solution of hyaluronic acid. 30 ml of this aqueous hyaluronic acid solution was placed in a 180 mm × 180 mm square plastic petri dish and placed in a freezer set at −20 ° C. Freezing for 22 hours and thawing for 2 hours at 25 ° C. were repeated twice to obtain a sponge-shaped hyaluronic acid gel. Next, this was neutralized by immersion in 100 ml of a phosphate buffered physiological saline of pH 7 adjusted by adding a phosphate buffer component at a concentration of 50 mM to physiological saline at 5 ° C. for 24 hours, and then sufficiently washed with distilled water. did. Then, crushing treatment was performed using a microhomogenizer to obtain a hyaluronic acid gel cosmetic which was hardly soluble in a crushed neutral aqueous solution.

Example 4 Preparation of Hyaluronic Acid Gel Cosmetic which is Insoluble in Fluid Neutral Aqueous Solution Sodium hyaluronate having a molecular weight of 2 × 10 ⁶ daltons was dissolved in a 1.0% by weight sodium chloride solution. 1.0
A weight% aqueous solution of hyaluronic acid was prepared. The pH of this aqueous solution was adjusted to pH 1.5 with 1N hydrochloric acid to obtain an acidic aqueous solution of hyaluronic acid. This hyaluronic acid acidic aqueous solution 50m
was placed in a metal container and placed in a freezer set at -20 ° C. After 120 hours, it was taken out and thawed at 25 ° C. to obtain a fluid gel. This was then dialyzed thoroughly against distilled water to remove excess acid. Subsequently, it was sufficiently dialyzed and neutralized with a buffered physiological saline solution containing 25 mM phosphoric acid at pH 7 to obtain a hyaluronic acid gel cosmetic which was hardly soluble in a fluid neutral aqueous solution.

Comparative Example 1 Preparation of Heat-Dried Hyaluronic Acid Sheet Sodium hyaluronate having a molecular weight of 2 × 10 ⁶ daltons was dissolved in distilled water to prepare a 1% by weight aqueous solution of hyaluronic acid. 30 ml of this solution is 180 mm x 180 mm
Was placed in a freezer set at −20 ° C. and frozen. Then, this was freeze-dried to obtain a hyaluronic acid sheet having a size of 180 mm × 180 mm.

Comparative Example 2 Preparation of Lyophilized Hyaluronic Acid Film Sodium hyaluronate having a molecular weight of 2 × 10 ⁶ daltons was dissolved in distilled water to prepare a 1% by weight aqueous solution of hyaluronic acid. 30 ml of this solution is 180 mm x 180 mm
And dried in an oven at 40 ° C. for 3 hours to obtain a 180 mm × 180 mm
A large hyaluronic acid film was obtained.

Comparative Example 3 Preparation of Hyaluronic Acid Solution Sodium hyaluronate having a molecular weight of 2 × 10 ⁶ daltons was dissolved in physiological saline to obtain a 1% by weight hyaluronic acid solution.

Example 5 Preparation of Hyaluronic Acid Gel Cosmetic That Is Poorly Soluble in Neutral Aqueous Solution Containing Magnesium Phosphate-L-Ascorbyl Phosphate Hyaluronic Acid Poorly Soluble in Neutral Aqueous Solution Prepared in Example 1 The gel sheet was immersed in 5 ml of 2% magnesium L-ascorbyl phosphate and freeze-dried again to obtain a film-form hyaluronic acid gel cosmetic which was hardly soluble in a neutral aqueous solution containing magnesium L-ascorbyl phosphate. .

Example 6: Solubility test of hyaluronic acid gel which is hardly soluble in neutral aqueous solution A phosphate buffer component was added to physiological saline at a concentration of 50 mM, and p
H7 phosphate buffered saline was prepared. Sheets prepared in Examples 1 to 5 and Comparative Examples 1 and 2 (30 × 3
0 mm), film (30 × 30 mm), crushed gel 5
ml and 5 ml of the fluid gel were immersed in 50 ml of a phosphate buffered saline and gently stirred. The percentage of hyaluronic acid eluted in phosphate buffered saline at 37 ° C. was determined from the concentration of hyaluronic acid in phosphate buffered saline.

Measurement of Hyaluronic Acid Concentration Hyaluronic acid concentration in phosphate buffered saline was measured by GPC
Was determined from the peak area of the differential refractive index detector.
Table 1 shows the results.

[0040]

[Table 1]

From Table 1, it can be seen that Experiment No. Experiment Nos. 5 to 7 were easy to dissolve. The hyaluronic acid gels of 1-4 were found to be poorly soluble in neutral aqueous solutions.

Example 7: Measurement of the degree of branching of the hyaluronic acid gel which is hardly soluble in a neutral aqueous solution The hyaluronic acid gel which is hardly soluble in a neutral aqueous solution obtained in Examples 1 and 2 was treated with a pH of 1.5. Hydrochloric acid aqueous solution 15m
and hydrolyzed at 60 ° C. for 6 hours. The gel was solubilized by hydrolysis, and diluted twice with GPC solvent to adjust the concentration to 0.05% by weight.
After filtration through a membrane filter of No. 1, 0.1 ml was injected and GPC-MALLS was measured. The degree of branching of each of the poorly water-soluble hyaluronic acid gels obtained in Example 1 and Example 2 was 0.5 or more.

Example 8: Actual use test of female panelists The effects of the cosmetics, sheets and films produced in Examples 1 to 5 and Comparative Examples 1 to 3 were described.
Judgment and evaluation were performed in a practical use test by 10 female panelists. The sheet and film were used by shaping the eyes, nose and mouth into a face mask. The solution was used as is. In the test, before going to bed at night and after washing the face, an appropriate amount of water such as physiological saline was applied to the entire face, and the formed sheet and film were stuck thereon. An appropriate amount of the solution was applied to the entire face, and the solution was spread well. I kept it overnight and washed my face with water the next morning. The test is performed for 2 months, and the effectiveness of the sheet is evaluated for moisture, firmness, rough skin,
The female panelists themselves evaluated the four items of whitening effect. Table 2 shows the results.

[0044]

[Table 2]

From Table 2, it can be seen that in Examples 1 to 5, which are gels formed of hyaluronic acid alone, which is hardly soluble in neutral aqueous solutions, the hyaluronic acid was made into a sheet, film, or solution. As compared with Examples 1 to 3, it showed an effect of improving skin moisture, firming skin, rough skin, and whitening effect.

[0046]

According to the present invention, a cosmetic containing a poorly water-soluble hyaluronic acid gel formed of hyaluronic acid alone can be provided. Such a cosmetic of the present invention does not use a cross-linking agent and thus maintains the original structure of hyaluronic acid present in the living body, is excellent in safety and biocompatibility, and further improves retention in the skin. This enhances the beauty effect.

Claims (5)

[Claims] 1. A cosmetic containing a gel formed of hyaluronic acid alone, which is hardly soluble in a neutral aqueous solution. 2. A cosmetic comprising a gel formed of hyaluronic acid alone, which satisfies the following requirements (a) and (b). (A) The dissolution rate in a neutral 37 ° C. aqueous solution at 12 hours is 50% or less. (B) Solubilized by treating the hyaluronic acid gel under conditions of accelerated acid hydrolysis of hyaluronic acid. Hyaluronic acid has a branched structure, and the solubilized hyaluronic acid partially contains a molecular weight fraction having a degree of branching of 0.5 or more. 3. A gel formed with hyaluronic acid alone,
3. The cosmetic according to claim 2, wherein the cosmetic is one selected from the group consisting of a sheet, a crushed form, and a fluidized form. 4. Hyaluronic acid having a solubility of 50% or less in 12 hours in a neutral aqueous solution at 37 ° C. and solubilized by treating a hyaluronic acid gel under conditions of accelerated acid hydrolysis of hyaluronic acid. Cosmetics comprising a hyaluronic acid gel in which an acid has a branched structure and the solubilized hyaluronic acid partially contains a molecular weight fraction having a degree of branching of 0.5 or more, and a non-gelled hyaluronic acid. 5. A cosmetic composition comprising a hyaluronic acid gel formed of hyaluronic acid alone in a sheet, crushed or fluid form, and a non-gelled hyaluronic acid.