JPH06100437A - Oil-in-water cream base - Google Patents

Abstract

PURPOSE:To obtain the subject highly stable cream base, excellent in functionality, having hyarulonidase inhibitory activity, by incorporation of deoxyribonucleic acid dispensing with any surfactant followed by emulsification using a microfluidizer. CONSTITUTION:The objective cream base can be obtained by (A) incorporation of deoxyribonucleic acid which can be extracted from the matured soft roes of fishes such as salmon, herring or cod, and, if desired, (B) incorporation of medicine stock, other cosmetic stock, etc., followed by (C) emulsification using a microfluidizer. This base can be prepared into lotion, cream, milky lotion, or pack. Also, this base is high in safety to the skin, being highly stable. Besides, this base has the following advantages: (1) preserving cells and keeping skin wettability and flexibility through retaining water in the cell interstices of the human body and forming jellylike matrix in the tissues, and (2) preventing skin chapping and fine wrinkle development and maintaining skin dampishness through prohibiting the activity of hyarulonidase capable of decomposing hyarulonic acid which prevents cells from being infected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-in-water cream base which is highly safe to the skin and has good stability, for use in cosmetics or pharmaceuticals such as a skin external preparation.

[0002]

2. Description of the Related Art Conventionally, when a cream base for cosmetics or pharmaceuticals, that is, an emulsion is prepared, it is emulsified with a surfactant, but the surfactant has a problem in safety. Efforts are being made to reduce the blending amount as much as possible. For this reason, emulsification without using a surfactant has been earnestly studied, but until now, an emulsion having a high stability and a functional aspect could not be obtained.

Therefore, as one measure, instead of a surfactant, a colloidal hydrous silicate that has been conventionally used as a thickener or an emulsification aid is used to raise the yield value of the aqueous phase and increase the emulsion. Attempts have been made to stabilize the. However, even if this colloidal hydrous silicate was used, there were still problems in stability and sensory aspects.
As a solution to this problem, the applicant of the present invention has disclosed in Japanese Patent Laid-Open No. 3-8390.
No. 9 and Japanese Patent Application No. 3-221290 have been proposed. Japanese Unexamined Patent Publication No. 3-83909 is a cream base containing synthetic bentonite and silicone oil. By adding silicone oil, the blending amount of synthetic bentonite is reduced, and the squeaky feeling of the same substance is reduced, and its increase. The viscous action and the fineness of the bentonite particles maintain the stability of the emulsion. Moreover, Japanese Patent Application No. 3-221290 is a cream base containing a fatty acid dextrin and a colloidal hydrous silicate, and the fatty acid portion enhances the affinity with an oil component,
The affinity for the aqueous component is increased by the dextrin part,
It improves the stability of the emulsion.

On the other hand, a rotary homogenizer has been widely used as a conventional emulsification method for cosmetics and the like. Recently,
Although a high-pressure type homogenizer has appeared and the emulsifying power has also increased, the microfluidizer described in US Pat. No. 4,533,254 is superior among them. However, even with this microfluidizer, the conventional formulation has problems in separation and stability.

On the other hand, hyaluronidase is an enzyme that is widely distributed in the living body and is also present in the skin, and as its name implies, it decomposes hyaluronic acid. Hyaluronic acid is β-D-N
-A linear high molecular polysaccharide in which acetylglucosamine and β-D-glucuronic acid are alternately bonded, and is a kind of mucopolysaccharide. The action of hyaluronic acid in connective tissue is to retain water in the intercellular spaces, form a jelly-like matrix in the tissue to retain cells, maintain skin lubricity and flexibility, and apply external force ( Mechanical damage) and bacterial infections. In addition, it is said that hyaluronic acid in the skin decreases with age, resulting in aging such as wrinkles and bulkiness. Therefore, suppressing the activity of hyaluronidase that decomposes this hyaluronic acid, the stability of hyaluronic acid used in the formulation, the hyaluronic acid of the formulation after application to the skin and the hyaluronic acid present in the skin It is believed to contribute to stability. Hyaluronidase is also known as an inflammatory enzyme, and suppressing this activity is known to suppress inflammation and also allergies.

Deoxyribonucleic acid (hereinafter referred to simply as "D
NA) is a substance contained in all living organisms, and this DNA is a linear polymer of deoxyribonucleotides, and each nucleotide has a sugar 3 '.
And a polydeoxyribonucleotide linked by a 5'carbon phosphodiester bond. The bases that make up DNA are usually the purines adenine and guanine,
And pyrimidine thymine and cytosine. This DNA is currently used as an injection drug, a health drug, an anticancer drug, a radiation protection agent and a therapeutic agent, or as a diet for preventing aging as a health food, or as a cosmetic, a skin activating agent, a sunscreen cream, etc. ing.

[0007]

The object of the present invention is to obtain an excellent evaluation in terms of sensory aspects without using a surfactant to enhance safety, and to have a hyaluronidase inhibitory action. Moreover, it is to provide a stable oil-in-water cream base.

[0008]

The inventors of the present invention repeatedly conducted various experiments to solve the above-mentioned problems, and as a result, D
The present invention has been completed by finding that NA has a remarkably high hyaluronidase inhibitory activity and that the above-mentioned problems can be solved by the following formulation.

That is, the present invention is an oil-in-water cream base containing deoxyribonucleic acid and emulsified by a microfluidizer.

Although DNA is contained in all living organisms, the DNA extraction method from the living organisms that has been used so far is generally from salmon, herring or cod etc. Extracting. D from this fish
The NA extraction method is to grind testicular tissues such as mature agar,
Make a porridge, mix it with water, and add sodium acetate and sodium hydroxide or sodium hydroxide alone to heat and separate the proteins while separating the proteins.
Is separated and neutralized, alcohol, copper chloride,
It is a method of precipitating and separating DNA by precipitating DNA with lead acetate or the like, or adding picric acid, iron colloid and the like. Since this method uses an alkali, DNA is likely to be decomposed and coloring or the like may occur. Therefore, it was repeatedly washed with an aqueous solution of sodium citrate instead of alkali, extracted with salt, and then the DNA was precipitated with alcohol, the protein was removed with sodium dodecyl sulfate and sodium chloride, and the DNA was again precipitated with alcohol. The method of refining is better. Also,
Since some DNAs are commercially available in a purified state, they may be used. In addition, DNA is usually
Although present in the form of sodium salt or free acid, DNA such as potassium, magnesium and iron salts can also achieve the object of the present invention.

The blending amount of DNA depends on the formulation because it is influenced by the components of the aqueous phase, and also depends on the type and grade of the DNA. As a general range, it is 0.05 to 10.0 with respect to the aqueous phase. %.

As the emulsifying method, a general method can be applied, but it has been found that stability and safety are particularly improved by emulsifying using the microfluidizer described in US Pat. No. 4,533,254. When using a Microfluidizer, the processing pressure that exerts this function is 700 kg /
It is natural to process at cm ² or more. The average particle size of the cream is preferably 0.3 micron or less.
If the average particle size exceeds 0.3 micron, the cream tends to separate, which is not preferable.

As other raw materials contained in the oil-in-water cream base, the raw materials used in general cream bases can be utilized to formulate the formulation. All polyhydric alcohols can be used, but glycerin was the most dominant. The oil phase is preferably 40% or less.

The oil-in-water cream base of the present invention comprises the above-obtained DNA, a pharmaceutical raw material such as a skin external preparation, or other cosmetic raw material, for example, liquid oil such as squalane, jojoba oil, beeswax, cetyl alcohol. Etc., solid oils, various activators, humectants such as glycerin, 1,3-butylene glycol, etc. and various chemicals, and general cream base materials are mixed and emulsified with a microfluidizer to form various dosage forms. Can be prepared into a lotion, a cream, a milky lotion, a pack, and the like, and can be prepared into cosmetics of various usage forms according to the purpose.

[0015]

The following is a description of examples of practical use, but the present invention is not limited to these examples. In addition, "part" in an Example shows a "weight part" unless there is particular limitation.

Example 1 (Preparation of cream) A and B consisting of the following components were dissolved by heating, and then A and B were mixed with stirring and treated with a microfluidizer (M-110Y). A cream was prepared by treating with a pressure of 1600 kg / cm ² . A Squalane 10.0 parts Octyldodecyl myristate 10.0 parts Geyrow 5.0 parts Beeswax 5.0 parts Silicone 0.5 parts B Purified water 56.1 parts Deoxyribonucleic acid sodium (manufactured by Yuki Fines Co., Ltd., "HP-DNANa 0.2 part Colloidal hydrous silicate (Sumikton SA manufactured by Kunimine Industries Co., Ltd.) 0.5 part Glycerin 10.0 parts Polyoxyethylene glycol (molecular weight 4,000) 2.0 parts Methyl paraoxybenzoate 0.2 Part sodium hyaluronate 0.5 part

Example 2 (Preparation of Cream) A and B consisting of the following components were dissolved by heating, respectively, and then A and B were mixed with stirring and treated with a microfluidizer (M-110Y). A cream was prepared by treating with a pressure of 1600 kg / cm ² . A Squalane 10.0 parts Octyldodecyl myristate 10.0 parts Beeswax 1.0 parts Batyl alcohol 3.5 parts Stearyl alcohol 2.5 parts Stearyl acid 0.5 parts Silicon 0.5 parts B Purified water 48.8 parts Deoxyribo Nucleic acid potassium (manufactured by Yuki Fines Co., Ltd., hereinafter referred to as "HP-DNA-K") 0.5 part 2% crystalline cellulose aqueous solution 10.0 parts glycerin 10.0 parts polyoxyethylene glycol (molecular weight 4,000) 1.0 part Polyoxyethylene glycol (molecular weight 1,540) 1.0 part Methyl paraoxybenzoate 0.2 part Sodium hyaluronate 0.5 part

Comparative Example 1 The same procedure as in Example 1 was carried out except that the microfluidizer used in Example 1 was replaced by a tabletop homomixer (LR-1, manufactured by Mizuho Kogyo Co., Ltd.).

Comparative Example 2 The same procedure as in Example 1 was carried out except that the deoxyribonucleic acid used in Example 1 was mixed with water.

Comparative Example 3 The procedure of Example 1 was repeated except that the microfluidizer used in Example 2 was replaced by a tabletop homomixer (LR-1, manufactured by Mizuho Kogyo Co., Ltd.).

Comparative Example 4 The same treatment as in Example 1 was carried out except that the deoxyribonucleic acid used in Example 2 was mixed with water.

The properties of the creams obtained in Examples 1 and 2 and Comparative Examples 1 to 4, the average particle size, the state after centrifugation, and the storage state at 50 ° C. were evaluated by the following methods. did. The evaluation of these characteristics is shown in Table 1 below. Cream state: The state of the cream immediately after production was visually evaluated. Average particle diameter: Particle size distribution measuring instrument (Shimadzu Corporation, SAL
D-2000). State after centrifugation: After centrifuging at 6000 rpm for 30 minutes, the state of the cream was visually evaluated. Storage state at 50 ° C .: The cream was placed in a 50 ° C. constant temperature bath, and changes with time of the cream were observed.

[0023]

[Table 1]

As is clear from the results in Table 1, the creams (Examples 1 and 2) emulsified with the microfluidizer using the formulation of the present invention exhibited a strong creamy form,
It can be seen that the average particle size is also 0.1 micron or less, it does not separate even when subjected to a centrifuge, and it is stable for 3 months or more even when stored at 50 ° C. On the other hand, even with the formulation of the present invention, the creams (Comparative Examples 1 and 3) that were not emulsified by the microfluidizer were separated by centrifugation, and
It separates at 1 ° C for 1 day, which is not preferable as a cream base. Also, the creams (Comparative Examples 2 and 4) emulsified with a microfluidizer with a DNA-free formulation had a poor cream gloss and were separated by centrifugation and separated at 50 ° C. for 2 to 3 days. Therefore, it is not preferable as a cream base. From the above, in order to obtain the desired cream base without using a surfactant, it is necessary to use DNA and treat with a microfluidizer.

Hyaluronidase activity inhibition test (test method) 0.4% sodium hyaluronate 0.1M
After leaving 6 g of (pH 6.0) phosphate buffer solution in a constant temperature water bath at 37 ° C. for 5 minutes, 1.0 ml of a sample solution having a specified concentration was added and stirred, and 0.01% hyaluronidase (manufactured by Sigma) was added.
A test solution was prepared by adding 1 ml of 0.1 M (pH 6.0) phosphate buffer solution (type I-S, made by beef testis) and immediately stirring. As a sample solution of specified concentration, 0.1%, 0.01%,
A 0.001% DNA-K or HP-DNANa solution was used. 6 ml of the test liquid was placed in an Ostwald viscometer placed in a constant temperature water bath at 37 ° C., and the viscosity of the test liquid was measured after 1 minute, 5 minutes, 10 minutes, 20 minutes, and 40 minutes. As a control, the measurement was performed in the same manner as above, except that the sample solution having the specified concentration was replaced with pure water. In this test, the final concentration of the sample is 1/8 of the concentration of the sample. With the viscosity after 1 minute being 100, each result is shown in Table 2 as an index.
4 shows.

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

[0029]

[Table 5]

As is clear from the results of Tables 2 to 5, the specimen using the predetermined concentration of DNA-K or HP-DNA-Na showed a slight change in viscosity with time as compared with the specimen containing no DNA. Therefore, it can be seen that the sample containing DNA clearly suppresses the activity of hyaluronidase.

[0031]

EFFECTS OF THE INVENTION The oil-in-water cream base of the present invention exhibits a strong creamy form without the addition of a surfactant conventionally used for emulsification, and can be stored for a long period of time. It has excellent stability without physical change, and it is safe for the skin because it does not use a surfactant.
In addition, it retains water in the intercellular spaces of the human body, forms a jelly-like matrix in the tissues to retain cells, maintains the lubricity and flexibility of the skin, and exerts external force (mechanical obstacle).
Also, since it suppresses the activity of hyaluronidase that decomposes hyaluronic acid that prevents bacterial infection, it has excellent effects such as preventing rough skin and fine wrinkles and maintaining a moist feeling.

[Procedure amendment]

[Submission date] November 16, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-in-water cream base which is highly safe to the skin and has good stability, for use in cosmetics or pharmaceuticals such as a skin external preparation.

[0002]

2. Description of the Related Art Conventionally, when a cream base for cosmetics or pharmaceuticals, that is, an emulsion is prepared, it is emulsified with a surfactant, but the surfactant has a problem in safety. Efforts are being made to reduce the blending amount as much as possible. For this reason, emulsification without using a surfactant has been earnestly studied, but until now, an emulsion having a high stability and a functional aspect could not be obtained.

Therefore, as one measure, instead of a surfactant, a colloidal hydrous silicate that has been conventionally used as a thickener or an emulsification aid is used to raise the yield value of the aqueous phase and increase the emulsion. Attempts have been made to stabilize the. However, even if this colloidal hydrous silicate was used, there were still problems in stability and sensory aspects.
As a solution to this problem, the applicant of the present invention has disclosed in Japanese Patent Laid-Open No. 3-8390.
No. 9 and Japanese Patent Application No. 3-221290 have been proposed. Japanese Unexamined Patent Publication No. 3-83909 is a cream base containing synthetic bentonite and silicone oil. By adding silicone oil, the blending amount of synthetic bentonite is reduced, and the squeaky feeling of the same substance is reduced, and its increase. The viscous action and the fineness of the bentonite particles maintain the stability of the emulsion. Moreover, Japanese Patent Application No. 3-221290 is a cream base containing a fatty acid dextrin and a colloidal hydrous silicate, and the fatty acid portion enhances the affinity with an oil component,
The affinity for the aqueous component is increased by the dextrin part,
It improves the stability of the emulsion.

On the other hand, a rotary homogenizer has been widely used as a conventional emulsification method for cosmetics and the like. Recently,
Although a high-pressure type homogenizer has appeared and the emulsifying power has also increased, the microfluidizer described in US Pat. No. 4,533,254 is superior among them. However, even with this microfluidizer, the conventional formulation has problems in separation and stability.

On the other hand, hyaluronidase is an enzyme that is widely distributed in the living body and is also present in the skin, and as its name implies, it decomposes hyaluronic acid. Hyaluronic acid is β-D-N
-A linear high molecular polysaccharide in which acetylglucosamine and β-D-glucuronic acid are alternately bonded, and is a kind of mucopolysaccharide. The action of hyaluronic acid in connective tissue is to retain water in the intercellular spaces, form a jelly-like matrix in the tissue to retain cells, maintain skin lubricity and flexibility, and apply external force ( Mechanical damage) and bacterial infections. In addition, it is said that hyaluronic acid in the skin decreases with age, resulting in aging such as wrinkles and bulkiness. Therefore, suppressing the activity of hyaluronidase that decomposes this hyaluronic acid, the stability of hyaluronic acid used in the formulation, the hyaluronic acid of the formulation after application to the skin and the hyaluronic acid present in the skin It is believed to contribute to stability. Hyaluronidase is also known as an inflammatory enzyme, and suppressing this activity is known to suppress inflammation and also allergies.

Deoxyribonucleic acid (hereinafter referred to simply as "D
NA) is a substance contained in all living organisms, and this DNA is a linear polymer of deoxyribonucleotides, and each nucleotide has a sugar 3 '.
And a polydeoxyribonucleotide linked by a 5'carbon phosphodiester bond. The bases that make up DNA are usually the purines adenine and guanine,
And pyrimidine thymine and cytosine. This DNA is currently used as an injection drug, a health drug, an anticancer drug, a radiation protection agent and a therapeutic agent, or as a diet for preventing aging as a health food, or as a cosmetic, a skin activating agent, a sunscreen cream, etc. ing.

[0007]

The object of the present invention is to obtain an excellent evaluation in terms of sensory aspects without using a surfactant to enhance safety, and to have a hyaluronidase inhibitory action. Moreover, it is to provide a stable oil-in-water cream base.

[0008]

The inventors of the present invention repeatedly conducted various experiments to solve the above-mentioned problems, and as a result, D
The present invention has been completed by finding that NA has a remarkably high hyaluronidase inhibitory activity and that the above-mentioned problems can be solved by the following formulation.

That is, the present invention is an oil-in-water cream base containing deoxyribonucleic acid and emulsified by a microfluidizer.

Although DNA is contained in all living organisms, the DNA extraction method from the living organisms that has been used so far is generally from salmon, herring or cod etc. Extracting. D from this fish
The NA extraction method is to grind testicular tissues such as mature agar,
Make a porridge, mix it with water, and add sodium acetate and sodium hydroxide or sodium hydroxide alone to heat and separate the proteins while separating the proteins.
Is separated and neutralized, alcohol, copper chloride,
It is a method of precipitating and separating DNA by precipitating DNA with lead acetate or the like, or adding picric acid, iron colloid and the like. Since this method uses an alkali, DNA is likely to be decomposed and coloring or the like may occur. Therefore, it was repeatedly washed with an aqueous solution of sodium citrate instead of alkali, extracted with salt, and then the DNA was precipitated with alcohol, the protein was removed with sodium dodecyl sulfate and sodium chloride, and the DNA was again precipitated with alcohol. The method of refining is better. Also,
Since some DNAs are commercially available in a purified state, they may be used. In addition, DNA is usually
Although present in the form of sodium salt or free acid, DNA such as potassium, magnesium and iron salts can also achieve the object of the present invention.

The blending amount of DNA depends on the formulation because it is influenced by the components of the aqueous phase, and also depends on the type and grade of the DNA. As a general range, it is 0.05 to 10.0 with respect to the aqueous phase. %.

As the emulsifying method, a general method can be applied, but it has been found that stability and safety are particularly improved by emulsifying using the microfluidizer described in US Pat. No. 4,533,254. When using a Microfluidizer, the processing pressure that exerts this function is 700 kg /
It is natural to process at cm ² or more. The average particle size of the cream is preferably 0.3 micron or less.
If the average particle size exceeds 0.3 micron, the cream tends to separate, which is not preferable. Microfluid
The diizer flattenes the emulsion-forming liquid mixture.
The leading edge turns into multiple sheet-like flows by the fiss
To collide at high speed into a low-pressure turbulent zone
Therefore, emulsification that enables emulsion formation
It is a device. Of course, only microfluidizer
A stable emulsion for any material without an emulsifier
It is not possible to obtain a microfluidizer according to the present invention.
Stable emergy when combining ingredients of such prescription
Is what you get. See the US patent for details.
Have been described. With Microfluidizer
Easily reduce the average diameter of dispersed droplets to 0.01 μm to 0.2 μm
can do.

As other raw materials contained in the oil-in-water cream base, the raw materials used in general cream bases can be utilized to formulate the formulation. All polyhydric alcohols can be used, but glycerin was the most dominant. The oil phase is preferably 40% or less.

The oil-in-water cream base of the present invention comprises the above-obtained DNA, a pharmaceutical raw material such as a skin external preparation, or other cosmetic raw material, for example, liquid oil such as squalane, jojoba oil, beeswax, cetyl alcohol. Etc., solid oils, various activators, humectants such as glycerin, 1,3-butylene glycol, etc. and various chemicals, and general cream base materials are mixed and emulsified with a microfluidizer to form various dosage forms. Can be prepared into a lotion, a cream, a milky lotion, a pack, and the like, and can be prepared into cosmetics of various usage forms according to the purpose.

[0015]

The following is a description of examples of practical use, but the present invention is not limited to these examples. In addition, "part" in an Example shows a "weight part" unless there is particular limitation.

Example 1 (Preparation of cream) A and B consisting of the following components were dissolved by heating, and then A and B were mixed with stirring and treated with a microfluidizer (M-110Y). A cream was prepared by treating with a pressure of 1600 kg / cm ² . A Squalane 10.0 parts Octyldodecyl myristate 10.0 parts Gelow 5.0 parts Beeswax 5.0 parts Silicone 0.5 parts B Purified water 56.1 parts Deoxyribonucleic acid sodium (manufactured by Yuki Fines, Inc., "HP-DNANa "referred to as) 0.2 parts colloidal hydrous silicate (Kunimine Industries Co. Sumecton SA) 0.5 parts glycerin 10.0 parts Po Rie Chi glycol (molecular weight 4,000) 2.0 parts of methyl p-hydroxybenzoate 0.2 Part sodium hyaluronate 0.5 part

Example 2 (Preparation of Cream) A and B consisting of the following components were dissolved by heating, respectively, and then A and B were mixed with stirring and treated with a microfluidizer (M-110Y). A cream was prepared by treating with a pressure of 1600 kg / cm ² . A squalane 10.0 parts Octyldodecyl myristate 10.0 parts Beeswax 1.0 parts Batyl alcohol 3.5 parts Stearyl alcohol 2.5 parts Stearyl acid 0.5 parts Silicon 0.5 parts B Purified water 48. 3 parts Deoxyribonucleic acid potassium (manufactured by Yukifinez Co., Ltd., hereinafter referred to as “HP-DNA-K”) 0.5 part Colloidal hydrous silicic acid (Sumikton SA manufactured by Kunimine Industries Co., Ltd.) 0.5 part 2% crystalline cellulose aqueous solution 10 .0 parts glycerin 10.0 parts Po Rie Chi glycol (molecular weight 4,000) 1.0 parts Po Rie Chi glycol (molecular weight 1,540) 1.0 parts methyl parahydroxybenzoate 0.2 parts 0.5 part of sodium hyaluronate

Comparative Example 1 The same procedure as in Example 1 was carried out except that the microfluidizer used in Example 1 was replaced by a tabletop homomixer (LR-1, manufactured by Mizuho Kogyo Co., Ltd.).

Comparative Example 2 The procedure of Example 1 was repeated except that the microfluidizer used in Example 2 was replaced by a tabletop homomixer (LR-1, manufactured by Mizuho Kogyo Co., Ltd.).

The above Examples 1-2 and Comparative Examples 1 to each of the cream obtained in two states, the average particle diameter, the stored state in the state and 50 ° C. After centrifugation, evaluate its properties by the following method did. The evaluation of these characteristics is shown in Table 1 below. Cream state: The state of the cream immediately after production was visually evaluated. Average particle diameter: Particle size distribution measuring instrument (Shimadzu Corporation, SAL
D-2000). State after centrifugation: After centrifuging at 6000 rpm for 30 minutes, the state of the cream was visually evaluated. Storage state at 50 ° C .: The cream was placed in a 50 ° C. constant temperature bath, and changes with time of the cream were observed.

[0021]

[Table 1]

As is clear from the results in Table 1, the creams (Examples 1 and 2) emulsified with the microfluidizer using the formulation of the present invention exhibited a strong creamy form,
It can be seen that the average particle size is also 0.1 micron or less, it does not separate even when subjected to a centrifuge, and it is stable for 3 months or more even when stored at 50 ° C. On the other hand, also in the formulation of the present invention, the creams (Comparative Examples 1 and 2 ) which were not emulsified by the microfluidizer were separated by centrifugation, and
It separates at 1 ° C for 1 day, which is not preferable as a cream base . From the above, in order to obtain the desired cream base without using a surfactant, it is necessary to use DNA and treat with a microfluidizer.

Hyaluronidase activity inhibition test (test method) 0.4% sodium hyaluronate 0.1M
After leaving 6 g of (pH 6.0) phosphate buffer solution in a constant temperature water bath at 37 ° C. for 5 minutes, 1.0 ml of a sample solution having a specified concentration was added and stirred, and 0.01% hyaluronidase (manufactured by Sigma) was added.
A test solution was prepared by adding 1 ml of 0.1 M (pH 6.0) phosphate buffer solution (type I-S, made by beef testis) and immediately stirring. As a sample solution of specified concentration, 0.1%, 0.01%,
A 0.001% DNA-K or HP-DNANa solution was used. 6 ml of the test liquid was placed in an Ostwald viscometer placed in a constant temperature water bath at 37 ° C., and the viscosity of the test liquid was measured after 1 minute, 5 minutes, 10 minutes, 20 minutes, and 40 minutes. As a control, the measurement was performed in the same manner as above, except that the sample solution having the specified concentration was replaced with pure water. In this test, the final concentration of the sample is 1/8 of the concentration of the sample. With the viscosity after 1 minute being 100, each result is shown in Table 2 as an index.
4 shows.

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

[0027]

[Table 5]

As is clear from the results of Tables 2 to 5, the specimen using the predetermined concentration of DNA-K or HP-DNA-Na showed a slight change in viscosity with time as compared with the specimen containing no DNA. Therefore, it can be seen that the sample containing DNA clearly suppresses the activity of hyaluronidase.

[0029]

EFFECTS OF THE INVENTION The oil-in-water cream base of the present invention exhibits a strong creamy form without the addition of a surfactant conventionally used for emulsification, and can be stored for a long period of time. It has excellent stability without physical change, and it is safe for the skin because it does not use a surfactant.
In addition, it retains water in the intercellular spaces of the human body, forms a jelly-like matrix in the tissues to retain cells, maintains the lubricity and flexibility of the skin, and exerts external force (mechanical obstacle).
Also, since it suppresses the activity of hyaluronidase that decomposes hyaluronic acid that prevents bacterial infection, it has excellent effects such as preventing rough skin and fine wrinkles and maintaining a moist feeling.

Claims (1)

[Claims] 1. An oil-in-water cream base which comprises deoxyribonucleic acid and is emulsified by a microfluidizer.