Antioxidant composition based on pH response type microcapsules as well as preparation method and application of antioxidant composition

Abstract

The invention discloses an antioxidant composition based on pH response type microcapsules as well as a preparation method and application of the antioxidant composition. Wherein the antioxidant composition contains ferulic acid, L-ascorbic acid-2-glucoside and tocopheryl acetate, and the mass ratio of the ferulic acid to the L-ascorbic acid-2-glucoside to the tocopheryl acetate is 1 to (3 to 5) to (5 to 10). A composition of ferulic acid, L-ascorbic acid-2-glucoside and tocopheryl acetate in a specific ratio is used as a core material, and a chitosan-sodium alginate compound is used as a wall material. The microcapsule can effectively protect the stability of antioxidant active ingredients in the storage period, and can specifically respond to a weak acidic pH environment of skin to release active matters so as to realize intelligent delivery. Components of the core material have a synergistic anti-oxidation effect, so that the final effect of the product is remarkably improved. The cosmetic composition containing the microcapsules has the advantages of being high in stability, remarkable in effect, good in skin feeling and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of daily skin care products, and relates to an antioxidant composition, in particular to a microcapsule composition containing specifically encapsulated antioxidant active ingredients, a preparation method thereof and application thereof in cosmetics, which can intelligently release active ingredients in response to skin pH. BACKGROUND

[0002] At present, antioxidant ingredients (such as ferulic acid, vitamin C, vitamin E, etc.) on the market are the core efficacy ingredients in cosmetics to resist free radicals and delay skin aging. However, most antioxidant ingredients are extremely easy to be inactivated due to light, oxygen and high temperature during preparation and storage, resulting in discoloration of the product and decline of efficacy. For example, ferulic acid is easily decomposed by light, and L-ascorbic acid is extremely unstable in aqueous solution.

[0003] The invention with publication number CN109939055A discloses a sustained antioxidant cosmetic composition, which comprises the following components: water, butylene glycol, beta-glucan, ascorbic acid, betaine, trehalose, yeast fermentation product filtrate, nicotinamide, salvia miltiorrhiza extract, panthenol, hexylene glycol, caprylhydroxamic acid, phloretin, sodium hyaluronate, glutathione, gamma-polyglutamic acid sodium, mannitol, squalane, hydrogenated lecithin, bisabolol, ginger extract, tocopherol, ferulic acid.

[0004] The existing technology often uses microencapsulation technology to protect these active ingredients. For example, the patent application with publication number WO2025007794A1 discloses a microcapsule for relieving irritation of high-concentration vitamin C ethyl ether, which is successfully prepared by a complex coacervation microcapsule wrapping process. In this process, retinol is creatively used as a curing crosslinking agent to enhance the stability of the microcapsule, and it is also accidentally found that it has a synergistic effect on the whitening and antioxidant efficacy of vitamin C ethyl ether.

[0005] However, traditional microcapsules (such as gelatin / arabic gum microcapsules) may release the contents too early in the cosmetic matrix, or release in non-target areas, and cannot achieve precise delivery. The weakly acidic environment (pH about 4.5-6.0) on the surface of the skin is the key to maintaining the health of the skin barrier. If the microcapsule can quickly release active substances in the weakly acidic environment of the skin, and remain stable under neutral conditions (such as during product storage), it will greatly improve the stability and use efficiency of the product.

[0006] Therefore, it is a technical problem to be solved in the field to develop a microcapsule system that can intelligently respond to skin pH, efficiently protect and synergistically enhance antioxidant activity. SUMMARY

[0007] The present application aims to provide a pH-responsive antioxidant microcapsule, a microcapsule composition capable of releasing in response to the pH environment of the skin, which can significantly improve the stability of the internal antioxidant components and achieve synergistic antioxidant effect. The present application also aims to provide a preparation method of the pH-responsive antioxidant microcapsule.

[0008] The present application further aims to provide a cosmetic composition comprising the above-mentioned microcapsule.

[0009] The present application achieves the above-mentioned aims by providing a pH-responsive antioxidant microcapsule, which is composed of a core material and a wall material: The core material is an antioxidant active composition, which is composed of ferulic acid, L-ascorbic acid-2-glucoside (AA2G) and tocopheryl acetate in a mass ratio of 1:(3-5):(5-10). This specific ratio has been proven to produce excellent antioxidant synergistic effect.

[0010] The wall material is a composite wall material formed by electrostatic complexation of chitosan and sodium alginate, wherein the mass ratio of chitosan to sodium alginate is 1:(1.5-2.5). This composite wall material can remain stable under neutral conditions, rapidly swell and release the core material under weakly acidic environment.

[0011] Preferably, the mass ratio of ferulic acid, L-ascorbic acid-2-glucoside and tocopheryl acetate is 1:(4-5):(8-9).

[0012] Preferably, the mass ratio of chitosan to sodium alginate is 1:(2.0-2.5).

[0013] In a second aspect, the present application provides a method for preparing the above-mentioned pH-responsive antioxidant microcapsule, which comprises the following steps: (1) Preparation of core material solution: dissolve ferulic acid, AA2G and tocopheryl acetate in a proportion in an appropriate amount of ethanol-water mixed solvent, and stir uniformly.

[0014] (2) Preparation of wall material solution: dissolve sodium alginate in deionized water to prepare a 1.0%-2.0% (w / v) solution; dissolve chitosan in 1% (v / v) acetic acid solution to prepare a 0.5%-1.5% (w / v) solution.

[0015] (3) Preparation of primary emulsion: slowly add the core material solution to the sodium alginate solution under high-speed shearing (8000-12000 rpm) to form a primary emulsion.

[0016] (4) Forming by sharp-hole-coagulation bath method: drop the above-mentioned primary emulsion into a chitosan acetic acid solution containing calcium chloride (2%-5%, w / v) through a sharp-hole device to form microcapsules by ionic cross-linking and electrostatic adsorption. After the dropping is completed, continue to stir gently for 20-40 minutes.

[0017] (5) Post-treatment: filter the microcapsules, wash with deionized water, and dry in a fluidized bed at an inlet air temperature of 40-50°C to obtain the pH-responsive antioxidant microcapsules.

[0018] In a third aspect, the present application provides a cosmetic composition comprising a cosmetically acceptable carrier and an effective amount of the above-mentioned pH-responsive antioxidant microcapsules.

[0019] The amount of the microcapsules added to the composition is 0.1%-10.0% (w / w). Preferably, the amount of the pH-responsive antioxidant microcapsules added to the composition is 0.5%-5.0% (w / v); more preferably, 1.0%-3.0% (w / v).

[0020] The pH value of the composition ranges from weak acidity to the pH value of human skin. Preferably, the pH value of the cosmetic composition ranges from 4.5 to 6.0, more preferably, from 5.0 to 5.5.

[0021] Preferably, the cosmetic composition is a serum, an emulsion, a cream, or a mask. In a preferred embodiment of the present application, the serum contains glycerol, butylene glycol, and sodium hyaluronate.

[0022] The present application has the following advantages: (1) Excellent stability: the easily-inactivated antioxidant components are isolated from the external environment by the composite wall material, significantly improving the storage stability of the antioxidant components in the cosmetic formulation. Accelerated test shows that the retention rate of the active ingredients of the microencapsulated antioxidant composition of the present application is more than 90% after 8 weeks of storage at 40°C / 75% RH (relative humidity), and the product has no obvious discoloration.

[0023] (2) pH-responsive intelligent release: the chitosan-sodium alginate wall material system is sensitive to pH. It is stable under storage conditions (neutral pH); when applied to the skin (weakly acidic pH), the wall material network structure relaxes, rapidly releasing the active substances, improving the utilization efficiency and immediate effect of the ingredients.

[0024] (3) Synergistic antioxidant effect: through a large number of experiments, a specific mass ratio (1:3-5:5-10) of ferulic acid, AA2G, and tocopherol acetate is screened out. This group shows a clear synergistic effect in the DPPH free radical scavenging experiment, and its antioxidant capacity is significantly higher than that of any single component or simple mixture.

[0025] (4) Excellent use skin feel: the particle size of the microcapsules is controllable (50-200 μm), and the microcapsules are uniformly dispersed in the serum. When applied, the microcapsules are broken by slight rubbing, providing a unique technological and skin feel. DETAILED DESCRIPTION

[0026] The technical solutions will be described clearly and completely by the embodiments of the present application. Obviously, the described embodiments are only some preferred embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0027] Embodiment 1: A pH-responsive antioxidant microcapsule is prepared by the following steps: (1) Core material liquid: take ferulic acid 1.0 g, AA2G 4.0 g, and tocopherol acetate 8.0 g, add 20 mL of 50% ethanol aqueous solution, dissolve and mix evenly; (2) Wall material liquid A: take sodium alginate 2.0 g, dissolve in 100 mL of deionized water; (3) Wall material liquid B: take chitosan 1.0 g, dissolve in 100 mL of 1% acetic acid solution to obtain chitosan acetic acid solution; (4) Coagulation bath: prepare 500 mL of chitosan acetic acid solution containing 3% calcium chloride (w / v); (5) Under high-speed shearing at 10000 rpm, slowly add the core material liquid into the wall material liquid A, emulsify for 5 minutes to form an O / W primary emulsion; (6) Using a sharp hole with an inner diameter of 0.5 mm, drop the primary emulsion into the coagulation bath at a constant speed, and gently stir for 30 minutes.

[0028] (7) Filter, wash with water, and dry in a fluidized bed at 45°C to obtain white powder-like pH-responsive antioxidant microcapsules.

[0029] It is determined that the average particle size of the pH-responsive antioxidant microcapsule is 125 μm, and the encapsulation efficiency is 92.5%.

[0030] Embodiment 2: An antioxidant essence containing microcapsules is prepared by the following steps: (1) Prepare the essence according to the following formula: Glycerin 5.0% Butylene glycol 4.0% Sodium hyaluronate 0.1% (2) Antioxidant microcapsules prepared in Embodiment 1 3.0% Carbomer 0.2% Triethanolamine appropriate amount (adjust pH to 5.5) Preservative appropriate amount.

[0031] It should be added drop by drop during stirring and measured by pH meter at any time until the viscosity of the system is stable and the pH value reaches the preset 5.5. Usually this amount is very small (may be only about 0.1%).

[0032] Deionized water is added to 100%.

[0033] Preparation process: after dissolving the water phase raw materials, carbomer gel is added, neutralized to pH 5.5 with triethanolamine, and finally microcapsules are added under low speed stirring, homogenized to obtain.

[0034] Comparative Example 1 The control group essence without microcapsules is prepared according to the following steps: This comparative example aims to provide a comparative sample which does not contain the microcapsules of the present application, and the types and total amount of active ingredients are exactly the same as the total amount of core material in the microcapsules contained in Example 2, in order to fairly compare the protection effect of microencapsulation technology.

[0035] (1) Control group formula: Glycerol: 5.0%, Butanediol: 4.0%, Sodium hyaluronate: 0.1%, Ferulic acid: 0.069% (calculated from the total content of ferulic acid in the essence of Example 2 microcapsules), L-ascorbic acid-2-glucoside (AA2G): 0.276% (calculated from the total content of AA2G in the essence of Example 2 microcapsules), Tocopheryl acetate: 0.552% (calculated from the total content of tocopheryl acetate in the essence of Example 2 microcapsules), Carbomer: 0.2%, Triethanolamine: appropriate amount (adjust pH to 5.5), Preservative: appropriate amount, same as above, Deionized water: added to 100%.

[0036] (2) Preparation process: Dissolve glycerol, butanediol and sodium hyaluronate in part of deionized water and stir evenly to obtain the water phase; Add ferulic acid, AA2G and tocopheryl acetate directly into the above water phase and stir until evenly dispersed (or pre-dissolve with a small amount of cosolvent if necessary); then, Add carbomer, homogenize at high speed, neutralize with triethanolamine and adjust pH to 5.5, finally supplement the remaining water and homogenize to obtain.

[0037] Note: This process intentionally avoids any microencapsulation step, exposing the active ingredients directly to the water phase of the formula, to simulate the conventional addition method.

[0038] Comparative Example 2 The preparation method is the same as Example 1, but the wall material is gelatin-arabic gum.

[0039] Core material: exactly the same as Example 1, a composition of ferulic acid, AA2G and tocopheryl acetate in a mass ratio of 1:4:8; Wall material liquid: Liquid A: prepare a gelatin aqueous solution with a concentration of 2.0% (w / v) and keep it in a 40℃ water bath; Liquid B: prepare an arabic gum aqueous solution with a concentration of 2.0% (w / v); Wall material ratio: the mass ratio of gelatin to arabic gum is 1:1.

[0040] Preparation process: Add the core material to liquid A and homogenize to form a primary emulsion. Mix liquid B with liquid A under stirring, adjust the pH of the mixed system to about 4.0 with dilute acetic acid to initiate the complex coacervation reaction. Then, cool it to below 10℃ and add glutaraldehyde for solidification and crosslinking. After filtration, washing and drying, it is obtained.

[0041] Test 1: stability test The microcapsule-containing serum prepared in Example 2 and the same amount of active ingredient serum without microcapsules (control) were placed in a constant temperature and humidity chamber at 40℃ and 75% relative humidity, and samples were taken at 0 weeks, 4 weeks and 8 weeks, respectively, to detect the contents of AA2G, tocopheryl acetate and ferulic acid, and observe the color change of the product.

[0042] The results are shown in Table 1 below: The above research results show that the microcapsule-containing sample can greatly improve the retention rate of the core material components, especially the retention rates of the active ingredients ferulic acid and tocopheryl acetate after 8 weeks are significantly higher than those of the control group, directly proving the excellent protection of the microencapsulation technology on the active ingredients.

[0043] Test 2: in vitro release test The microcapsules of Example 1 and Comparative Example 2 were respectively placed in release media with pH=5.5 and pH=7.4 and shaken at 37℃, and the ferulic acid concentration in the medium was measured at different time points to calculate the cumulative release rate.

[0044] The pH-responsive release data of Table 2 are shown below: According to the above data, at pH 5.5 (simulating the skin environment), the release rate of the microcapsules of the application (Example 1) reached 85% at 2 hours, while that of Comparative Example 2 was only 28%. This directly and quantitatively proves that the application responds more quickly and releases more efficiently.

[0045] Test 3: Synergistic antioxidant test To demonstrate the synergistic effect of the specific ratio of the core material of the present application, the following sample solutions with a total mass of 13.0 mg were prepared for testing: Sample A (composition of the present application): Ferulic acid 1.0 mg, AA2G 4.0 mg, Tocopherol acetate 8.0 mg.

[0046] Sample B (ferulic acid single component control): Ferulic acid 13.0 mg.

[0047] Sample C (AA2G single component control): AA2G 13.0 mg.

[0048] Sample D (tocopherol acetate single component control): Tocopherol acetate 13.0 mg.

[0049] Sample E (equimass average physical mixture control): Ferulic acid 3.25 mg, AA2G 3.25 mg, Tocopherol acetate 6.5 mg.

[0050] The concentration (IC 50 value) required for each sample to scavenge 50% of free radicals was determined by DPPH method. The results are shown in Table 3 below: As can be seen from the above table, the specific mass ratio (1:4:8) of ferulic acid, AA2G and tocopherol acetate provided by the present application produces an unexpected synergistic antioxidant effect, which is significantly higher than that of any single component and other proportions of mixtures.

[0051] In the description of the present application, the term "comprising", "containing" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "comprising a reference structure" does not exclude the presence of another identical element in the process, method, article or device including the element. It should be noted that in this paper, the relationship terms such as "first", "second" and the like are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations.

[0052] The above embodiments are merely specific implementations of the present application, and the protection scope of the present application is not limited thereto, and any person skilled in the art can conceive of changes or replacements within the technical scope disclosed by the present application without creative labor, and such changes or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims in the present application.

Claims

1. An antioxidant composition based on pH-responsive microcapsules, characterized in that, The antioxidant composition comprises ferulic acid, L-ascorbic acid-2-glucoside and tocopheryl acetate, and the mass ratio of ferulic acid, L-ascorbic acid-2-glucoside and tocopheryl acetate is 1:(3-5):(5-10).

2. A pH-responsive antioxidant microcapsule, characterized in that, The core material and the wall material are used to form the antioxidant microcapsule. The core material is a composition of ferulic acid, L-ascorbic acid-2-glucoside and tocopheryl acetate in a specific ratio, and the wall material is a chitosan-sodium alginate complex.

3. The antioxidant microcapsule according to claim 2, wherein the mass ratio of ferulic acid, L-ascorbic acid-2-glucoside and tocopheryl acetate in the core material is 1:(4-5):(8-9). The mass ratio of chitosan to sodium alginate in the wall material is 1:(1.5-2.5), and the chitosan and the sodium alginate form a complex wall material through electrostatic complexation. The method comprises the following steps:

4. The method for preparing pH-responsive antioxidant microcapsules according to any one of claims 2-3, wherein, (1) dissolving the components of the core material in a solvent to form a core material solution; (2) preparing a sodium alginate aqueous solution and a chitosan acid solution as wall material solutions, respectively; (3) mixing and emulsifying the core material solution and the sodium alginate aqueous solution to form a primary emulsion; (4) adding the primary emulsion dropwise into a chitosan acid solution containing calcium ions to form the microcapsule through ionic crosslinking and electrostatic adsorption; (5) collecting, washing and drying the microcapsule. In step (4), the concentration of calcium chloride in the chitosan acid solution containing calcium ions is 2%-5% (w / v).

5. The method of claim 4, wherein the pH-responsive antioxidant microcapsules are prepared by the steps of: The antioxidant microcapsule according to any one of claims 2-3 is used in a cosmetically acceptable carrier in an effective amount.

6. A cosmetic composition characterized in that, The antioxidant microcapsule is added to the composition in an amount of 0.1%-10.0% (w / v).

7. The cosmetic composition according to claim 6, characterized by The dosage form of the cosmetic composition is a serum, a lotion, a cream or a mask. The pH value of the composition is in the range of 4.5-6.

0. The antioxidant microcapsule is added to the composition in an amount of 0.5%-5.0% (w / v).

8. The cosmetic composition according to claim 6, characterized by The antioxidant microcapsule is added to the composition in an amount of 1.0%-3.0% (w / v).

9. The cosmetic composition according to claim 8, characterized by The pH value of the composition is in the range of 5.0-5.

5. The serum contains one or more of glycerol, butylene glycol and sodium hyaluronate.

10. Use of the antioxidant microcapsule according to any one of claims 2-3 in the preparation of a cosmetic for skin antioxidant, skin lightening or skin anti-aging. ​

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