KR20060113612A - Cosmetic composition with high concentration of stable pure vitamin c in aqueous system - Google Patents

Abstract

A cosmetic composition comprising highly concentrated pure vitamin C is provided to be able to maintain physicochemically stable state in an aqueous system and be used to skin without any skin irritation. The water in oil emulsion type of cosmetic composition comprises 3-20 wt.% of pure L-ascorbic acid, 0.5-20 wt.% of polar solvent, 0.1-10 wt.% of surfactant, 0.1-30 wt.% of silicone oil, other additives and water. The composition is characterized in that a base where the pure vitamin C is highly concentrated is added to a hydrophilic part, thereby obtaining the water in oil emulsion type.

Description

Cosmetic composition with high concentration of stable pure vitamin C in aqueous system

The present invention relates to an emulsified cosmetic composition containing a high concentration of pure vitamin C, which is stable even in aquatic systems. Vitamin C is a representative water-soluble vitamin and is a powerful bio-oxidant in skin, blood, and tissues. It has an antioxidant action that prevents skin aging by blocking the oxidation by. In addition, vitamin C enhances the body's immune function, promotes the production of collagen, which is a component of skin, cartilage, capillaries, and muscles, prevents wrinkles, maintains healthy skin, and regenerates damaged skin tissue. It also helps to promote the formation of histamine, known to cause allergic reactions.

It has an indirect sunscreen effect by vitamin C. Like conventional sunscreens, it does not absorb UV light directly, but it has a function of sufficiently reducing erythema and edema caused by UVB.

In addition, vitamin C has an effect of improving skin pigmentation by inhibiting tyrosinase activity, which is a major enzyme of melanin formation in the skin, and reducing oxidized melanin formed by oxidation to reduce melanin. .

Vitamin C having these various biological functions has the advantage of being stored once absorbed into the skin, thus maintaining its efficacy for a long time even after discontinuing use.

However, vitamin C has a problem in that it is very unstable in a structure similar to gamma-lactone and is easily decomposed by being sensitive to air, particularly oxygen, heat, and external environment such as light. This phenomenon is mainly due to the oxidation reaction of vitamin C, the sugar-like structure that is easily oxidized to radical in the form of dehydro-L-ascorbic acid by dissociating hydrogen ions which are electron transfer process. (Sugar like structure). Very small amount is dissolved in the non-aqueous solution, while a large amount is dissolved in the aqueous solution, but a sufficient amount of vitamin C cannot be stabilized due to the rapid oxidation, and thus a small amount is used in medicine, food, cosmetics, or a non-aqueous system. system).

In Korean Patent Registration No. 10-158102, it was synthesized and stabilized with a glucosyl L-ascorbic acid derivative. In Korean Patent Registration No. 10-230653, a derivative obtained by reacting L-ascorbic acid and 3-aminopropane acid. In Korea Patent Publication No. 10-2002-23574, a water-soluble polyhydric alcohol-type non-aqueous emulsion that is dissolved in vitamin C using polyhydric alcohol and then emulsified in water and ethanol is disclosed in US Patent No. 4,983,382. A method of using an organic solvent together as a medium, US Patent No. 5,981,578 describes a method of simultaneously applying a non-aqueous solution containing ascorbic acid and other products such as a lotion or lotion containing water.

However, in the patent, the derivative of vitamin C used has a problem of skin absorption and difficulty in hydrolysis of the active part, so that it is weaker than pure vitamin C in terms of physiological activity. Due to the difficulty, the skin delivery process is inefficient, resulting in low efficiency of expression and stickiness in usability.

The present invention overcomes the problems described above with emulsions containing pure vitamin C, which are stable over a long period of time with excellent usability, such as common cosmetic emulsions.

In addition, it has the advantages of excellent skin safety and skin absorption, which are characteristic of general water-in-oil emulsions.

The present inventors are very unstable to heat, light, oxygen, etc., causing discoloration and discoloration in the air, causing problems of skin safety and formulation stability, and the stability problem of vitamin C, which has a problem in that the titer is drastically reduced. By stabilizing in an (aqueous system) it was possible to develop a cosmetic excellent in the above problems and a feeling of non-sticky when applying skin. Accordingly, the present invention is to provide a cosmetic composition containing a high concentration of pure vitamin C while being stable in an aqueous system.

The present invention is to provide an aqueous emulsion cosmetic composition consisting of 3 to 20% by weight of pure vitamin C, 0.5 to 20% by weight of a polar solvent, 0.1 to 10% by weight of surfactant, 0.1 to 30% by weight of silicone oil and other additives and water. .

The cosmetic composition of the present invention is characterized in that a stable aqueous emulsion formulation is prepared by adding a base stabilized at a high concentration of pure vitamin C to a hydrophilic part.

Vitamin C used in the cosmetic composition of the present invention is clear and clean skin, and contains 3 to 20% by weight based on the total weight of the cosmetic composition. If the vitamin C exceeds 20% by weight, skin irritation such as peeling phenomenon is concerned due to the low pH, and less than 3% by weight of the skin improvement effect is less.

Experimental Example 1 Preparation of Stable High Concentration Vitamin C Base

Specific manufacturing examples are as follows.

20 wt% L-Ascorbic Acid, other additives, and 3.0% by weight of sodium hyaluronate (1%) at room temperature with a composition as shown in Table 1 were dissolved by mixing in purified water with an azimixer and 3.5 wt% of Sodium Hydroxide (20%). Mix slowly while adding.

The composition ratio of the cosmetic composition of Examples 1-2 is weight%.

ingredient Example 1 Example 2 Purified water TO 100 TO 100 L-Ascorbic Acid 20.0 20.0 Gelling agent 0.5 - Sodium Hyaluronate (1%) 3.0 - Sodium Hydroxide (20%) 3.5 -

 Examples 1 and 2 were stored at room temperature, 37 ° C., 45 ° C., daylight, and measured pure vitamin C residual ratios using discoloration, odor stability, and HPLC, and are shown in Tables 2 and 3.

Measurement period Example 1 Example 2 Room temperature 37 ℃ 45 ℃ daylight Room temperature 37 ℃ 45 ℃ daylight 1 week ○ ○ ○ ○ ○ ○ ○ ○ 2 weeks ○ ○ ○ ○ ○ X X X 1 month ○ ○ ○ ○ X X X X 2 months ○ ○ ○ ○ X X X X 3 months ○ ○ ○ ○ X X X X

  Discoloration, deodorant stability results (discoloration, no odor: ○, discoloration, odor: X)

         Residual L-Ascorbic Acid (Vitamin C)

Measurement period Example 1 Example 2 Room temperature 37 ℃ 45 ℃ daylight Room temperature 37 ℃ 45 ℃ daylight 1 week 99.75% 99.88% 99.64% 99.67% 99.34% 99.23% 99.22% 95.56% 2 weeks 99.35% 99.33% 99.29% 98.89% 99.18% 98.28% 97.32% 90.87% 1 month 98.61% 98.22% 98.18% 98.12% 62.45% 58.04% 45.78% 33.22% 2 months 98.40% 98.87% 98.13% 98.28% 45.68% 39.35% 35.56% 22.78% 3 months 98.50% 98.26% 98.07% 98.09% 36.90% 31.65% 28.06% 12.12%

  In order to more accurately investigate the oxidation stability of L-Ascorbic Acid (Vitamin C), the composition prepared in the above Experiment 1 was subjected to the residual rate of L-Ascorbic Acid according to the change over time in room temperature, thermostat (37 ℃, 45 ℃) and sunlight. Was measured by HPLC.

As a column for quantitative analysis of L-Ascorbic Acid by HPLC, Phenomenex 00G-4252-EO Luan 5u C18 (2) 100A (size 250 * 4.60 mm) was used. It was detected at 240 nm ultraviolet absorbance spectrometer at / min. In addition, 0.025 M potassium hydrogen phosphate solution (pH 2.5) was used for the mobile phase.

 As shown in Table 2 and Table 3, when comparing Examples 1 and 2 of the present invention, Example 1 did not cause discoloration and discoloration even under severe conditions, and in Example 2 in vitamin C residual ratio, It shows a higher residual rate than the stability standard (95% or more) required by the functional cosmetics law.

Experimental results of discoloration, discoloration, and L-Ascorbic Acid residual ratio in the cream and skin formulations, which are representative formulations, according to the stabilization and temperature, are as follows.

Experimental Example 2 Preparation of Cream and Soft Cosmetics Containing 3% of Vitamin C

 Formulation Example 1 (Water-in-oil Cream) Composition (% by weight) Oil Part Hydrogenated Lauryl Olive Esters 1.0 Trioctanine 5.0 Dimethicone 8.0 Hydrogenated Polyisobutene 1.5 Cyclopentasiloxane 1.0 Dibutylhydrotoluene 0.1 Dimethicone Copolyol 1.0 Lauryl Fiji-9 Polydimethylsiloxyethyldimethicone 1.0 Water part glycerin 3.0 Dipropylene glycol 2.0 Example 1 15.0 antiseptic Quantity Plant extract 5.0 antiseptic a very small amount Purified water To 100

Formulation Example 1 is a water-in-oil emulsion type cream composition is as follows. The oil parts and the water parts are heated to 80 ° C., respectively, to be uniformly dissolved, and then the water parts are slowly poured into the oil parts, mixed and mixed to form a desired viscosity, followed by cooling to room temperature.

 Formulation Example 2 (Flexible Cosmetic) Composition (% by weight) Water part Betaine 3.0 Natto gum 3.0 Cellulose gum 0.08 Plant extract 3.0 Distilled water To 100 Alcohol Part ethanol 5.0 Polyoxyethylene Cured Castor Oil 0.5 Tocopherol Acetate 0.2 antiseptic Quantity Example 1 15.0

Formulation Example 2 is prepared by dissolving each component of the water part and the alcohol part and mixing and mixing the alcohol part into the water part gradually, followed by the final addition of Example 1.

Measurement period Formulation Example 1 Formulation Example 2 Room temperature 37 ℃ 45 ℃ daylight Room temperature 37 ℃ 45 ℃ daylight 1 week ○ ○ ○ ○ ○ ○ ○ ○ 2 weeks ○ ○ ○ ○ ○ ○ ○ ○ 1 month ○ ○ ○ ○ ○ ○ ○ ○ 2 months ○ ○ ○ ○ ○ ○ ○ ○ 3 months ○ ○ ○ ○ ○ ○ ○ ○

Table 4 Discoloration and malodor stability results of Formulation Examples 1 and 2

 (Discoloration, no odor: ○ discoloration, odor: X)

 Table 5 Measurement of L-Ascorbic Acid (Vitamin C) Retention Rate of Formulation Examples 1,2

Measurement period Formulation Example 1 (3% Vitamin) Formulation Example 2 (3% Vitamin) Room temperature 37 ℃ 45 ℃ daylight Room temperature 37 ℃ 45 ℃ daylight 1 week 99.95% 99.78% 99.64% 99.68% 99.34% 99.23% 99.22% 95.56% 2 weeks 99.61% 99.24% 98.89% 98.24% 99.30% 98.28% 97.32% 90.87% 1 month 98.42% 98.47% 98.03% 98.12% 99.05% 99.04% 99.78% 98.22% 2 months 98.25% 98.15% 97.67% 97.38% 97.98% 98.35% 97.56% 96.78% 3 months 97.80% 97.67% 97.07% 97.09% 97.60% 96.65% 96.06% 96.12%

As shown in (Table 4) and (Table 5), the formulation examples 1 and 2 of the present invention did not discolor or deteriorate even under severe conditions, and showed a higher residual rate in the vitamin C residual rate than Example 2. The results are higher than the stability criteria (95% or more) required by the Functional Cosmetics Act.

Experimental conditions in (Table 4) and (Table 5) were tested under the same conditions as in (Table 2) and (Table 3).

Experimental Example 3 Measurement of Skin Irritability

50 healthy male and female experimenters applied the samples of each of the above examples to the lower arm of the arm under the closed patch test method, and then covered with a plastic cap for blocking from the outside once a day, then 1 day, 3 days, and 7 days later. The degree of stimulation was observed according to the following judgment method. Criteria for the degree of stimulation are shown in Table 6 below.

Judgment Skin irritation degree 0 No irritation One Minimal irritation (only detectable) 2 Slight irritation (erythema) 3 Severe irritation (erythema, edema) 4 Severe irritation (erythema, edema)

The stimulus degree of each subject was measured, and the average stimulus degree was calculated by dividing by the number of subjects. The result shown in following (Table 7) is an average value of the stimulus computed by the said determination method.

Skin irritation degree (%) 1 day later 3 days later 7 days later Formulation Example 1 0.5 0.5 0.8 Formulation Example 2 0.6 0.7 0.5

It can be seen that there is no skin irritation in all samples of Formulation Example 1 and Formulation Example 2. This result is a result confirming that the formulation can be provided in a state with almost no skin irritation even in the general formulation containing 3% vitamin C provided in the present invention.

The experimental examples, formulation examples of the present invention have been described above.

As can be seen from the above, the vitamin C stabilization method provided by the present invention is characterized by maintaining a long period of physicochemically stable state in an aqueous system containing 80% or more of water. It can be used safely without skin irritation.

Claims (3)

Cosmetic composition containing L-Ascorbic Acid (Vitamin C) in formulations containing more than 70% water The cosmetic composition according to claim 1, wherein L-Ascorbic Acid (vitamin C) is used in an amount of 3 to 10% by weight. The gelling agent used in claim 1 is all water-soluble polymers present in the form of gels at room temperature, and include agar, alginate, Arabic, carrageenan, furcellaran, gelatin, getti, guar, karaya, larch, locust bean ), Pectin, starch, tragacanth and derivatives thereof, dextran, xanthan gum and derivatives thereof prepared by microbial fermentation synthesis method Cosmetic composition for stabilizing vitamin C (L-Ascorbic Acid) using 0.01 to 30% by weight based on the weight