Whitening and freckle-removing composition, preparation method and application of whitening and freckle-removing composition in cosmetics

Abstract

The invention provides a whitening and freckle-removing composition, a preparation method and application of the whitening and freckle-removing composition in cosmetics, and belongs to the technical field of cosmetics, and the whitening and freckle-removing composition is characterized in that a first functional unit is a water-phase continuous phase containing polyphenol extract and vitamin C active ingredients; the second functional unit is a reaction isolation unit in which nicotinamide exists in a lipidosome coating form; the first functional unit and the second functional unit form mutually independent structural units in the same composition, nicotinamide is spatially isolated from the polyphenol plant extract and the vitamin C active ingredient in the storage period, and nicotinamide is gradually released in a controlled release mode in the use period. Therefore, direct contact of nicotinamide with the polyphenol plant extract and the vitamin C active component in the storage period and the use period is reduced, the problems that three components in an existing compound system are chemically incompatible and poor in stability, efficacy and mildness are difficult to consider, and efficacy is attenuated after long-term storage are solved, and the comprehensive requirements of consumers for whitening products are met.

Description

Technical Field

[0001] This invention relates to the field of cosmetic technology, and in particular to a whitening and freckle-removing composition, its preparation method, and its application in cosmetics. Background Technology

[0002] Currently, the mainstream skin-whitening active ingredients include polyphenolic plant extracts, vitamin C derivatives, and niacinamide. These three ingredients function by inhibiting melanin synthesis, reducing melanin precursors, and blocking melanin transport, respectively, and their applications are well-established. Existing solutions often improve the stability of compound formulations by adjusting pH, selecting derivatives, or reducing ingredient content, but the effects are limited.

[0003] As consumers demand higher efficacy, gentleness, and stability from whitening products, the shortcomings of existing compound formulations are becoming increasingly apparent: Vitamin C derivatives are stable in a weakly acidic environment, while niacinamide is easily hydrolyzed under acidic conditions to produce irritating niacinic acid. Simultaneously, the phenolic hydroxyl groups of polyphenolic components are easily oxidized and cross-link with niacinamide, leading to ingredient inactivation, product discoloration, and increased irritation. Currently, most solutions are passive avoidance measures, such as reducing ingredient content, adjusting the pH of the formula, or using stable derivatives, but they do not fundamentally solve the ingredient contact problem, making it difficult to balance stability and efficacy. Furthermore, long-term storage also results in significant efficacy degradation, failing to meet actual needs.

[0004] Therefore, there is an urgent need to develop a composition that can achieve stable coexistence of the three types of ingredients while taking into account both high whitening efficacy and skin gentleness. Summary of the Invention

[0005] To address the issues of chemical incompatibility, poor stability, and difficulty in balancing efficacy and skin gentleness when polyphenolic plant extracts, vitamin C active ingredients, and niacinamide are combined in existing whitening and freckle-removing compositions, as well as the significant efficacy degradation after long-term storage, the present invention aims to provide a whitening and freckle-removing composition, its preparation method, and its application in cosmetics. This invention ensures a high retention rate of multiple active ingredients while achieving synergistic whitening effects over time during the product's use, improving skin compatibility, and thus meeting consumers' comprehensive requirements for the efficacy, safety, and stability of whitening products.

[0006] To achieve the above objectives, the present invention provides the following solution: On one hand, the present invention provides a whitening and freckle-removing composition, comprising: The first functional unit is an aqueous continuous phase, including polyphenolic plant extracts and vitamin C active ingredients, wherein the vitamin C active ingredients are vitamin C in its original form and / or vitamin C derivatives; The second functional unit is a reaction isolation unit, which includes nicotinamide, which exists in the form of liposome encapsulation; The first functional unit and the second functional unit constitute independent structural units in the same composition. By keeping nicotinamide spatially isolated from polyphenolic plant extracts and vitamin C active ingredients during the storage period and gradually releasing nicotinamide through a controlled release method during the use period, the direct contact between nicotinamide and polyphenolic plant extracts and vitamin C active ingredients during the storage and use periods is reduced.

[0007] Preferably, the polyphenolic plant extract is selected from one or more of mulberry leaf extract, amla fruit extract, and licorice root extract, and the total amount of the polyphenolic plant extract added to the composition is 0.5-5 wt%.

[0008] Preferably, the vitamin C derivative is selected from one or more of ascorbate glucoside and ascorbate phosphate salt; wherein the amount of ascorbate glucoside added to the composition is 0.1-3 wt%, and the amount of ascorbate phosphate salt added to the composition is 0.2-4 wt%.

[0009] Preferably, the reaction isolation unit is a single-layer or multi-layer liposome structure, wherein the liposome physically encapsulates nicotinamide during storage to achieve spatial isolation, and during use, the nicotinamide is released stepwise relative to the polyphenolic plant extract and vitamin C active ingredient in the first functional unit through the difference in degradation rate of different wall materials in the multi-layer liposome.

[0010] Secondly, the present invention also provides a method for preparing the above-mentioned whitening and freckle-removing composition, comprising the following steps: Polyphenolic plant extracts and vitamin C active ingredients were added to an aqueous system, stirred, and the pH was adjusted to obtain a continuous aqueous phase in the form of the first functional unit. Nicotinamide is mixed with a loading material and then loaded to form a second functional unit that serves as a reaction isolation unit. The aqueous continuous phase is mixed with the reaction isolation unit and stirred to obtain a whitening and freckle-removing composition.

[0011] Preferably, the aqueous phase system is water or an aqueous system with water as the main continuous phase.

[0012] Preferably, the stirring and pH adjustment are performed by stirring at 25-40°C for 30-60 minutes, and then adjusting the pH of the aqueous phase system to 5.8-6.5 by adding a citric acid-sodium citrate buffer system.

[0013] Preferably, the coating material is a phospholipid material, and the coating is carried out by emulsification or homogenization under pressure of 80-150 MPa.

[0014] Preferably, the process of mixing and stirring the aqueous continuous phase with the reaction isolation unit is as follows: under conditions of 20-35°C, the reaction isolation unit is added to the aqueous continuous phase at a rate of 5-10 mL / min, and the mixture is stirred for 10-30 minutes under light-protected conditions to obtain the composition.

[0015] On the other hand, the present invention also provides an application of the above-mentioned whitening and freckle-removing composition, which is used to prepare cosmetics for whitening, removing freckles or improving skin pigmentation.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: (1) By constructing a dual-unit structure in which the first functional unit and the second functional unit are independent of each other, the direct contact between nicotinamide and acidic aqueous components is blocked in space, which greatly improves storage stability. After 6 months of accelerated storage at 40℃, the retention rate of each active ingredient is more than 85%, which is far superior to the existing direct compounding system.

[0017] (2) Controlled release of nicotinamide is achieved through liposome encapsulation. When used, vitamin C derivatives and polyphenol extracts take the lead in exerting their effects, followed by the release of nicotinamide, forming a temporal synergy of "inhibition-reduction-blocking". The tyrosinase inhibition rate is increased by 40-60% compared with single ingredients, and the whitening effect is significantly enhanced.

[0018] (3) Reduces the hydrolysis reaction of niacinamide during storage, reduces the risk of nicotinic acid formation, has a skin irritation score of less than 0.5, has good skin compatibility, and is suitable for various skin types including sensitive skin.

[0019] (4) The preparation method provided by the present invention is simple and does not require special customized equipment. The parameters such as homogenization and stirring are adapted to the needs of industrial production, which is conducive to obtaining a whitening and freckle-removing composition with stable performance and consistent structure. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention provides a whitening and freckle-removing composition, which is a dual-functional unit composite system, comprising, by mass percentage: 0.5-5% polyphenolic plant extracts, which are selected from one or more of mulberry leaf extract, amla fruit extract, and licorice root extract; 0.3-7% of active vitamin C ingredient, which is vitamin C itself and / or vitamin C derivatives, and the vitamin C derivatives are selected from one or more of ascorbate glucoside and ascorbate phosphate salt; 2.0-4.0% nicotinamide; 5.0-15.0% phospholipid-based encapsulating material; The balance consists of an aqueous phase system and 0.4-0.6% citric acid-sodium citrate buffer. The composition comprises a bifunctional unit structure, including a first functional unit and a second functional unit. The first functional unit is an aqueous continuous phase composed of polyphenolic plant extracts, vitamin C active ingredients, an aqueous system, and a buffer, with the pH value adjusted to 5.8-6.5. The second functional unit is a reaction isolation unit, in which nicotinamide is encapsulated by phospholipid materials to form a single-layer or multi-layer liposome structure (i.e., nicotinamide exists in the form of liposome encapsulation). Furthermore, after accelerated storage at 40°C for 6 months, the composition retains no less than 85% of nicotinamide and no less than 85% of vitamin C derivative, and the skin irritation score is no higher than 0.5.

[0022] Specifically, the total amount of the polyphenolic plant extract is 1.0-3.0 wt%. This range ensures tyrosinase inhibitory activity while avoiding increased oxidation risk due to excessive polyphenol content. In the vitamin C derivative, ascorbate glucoside is added at 0.1-3 wt%, and ascorbate phosphate salt at 0.2-4 wt%. A possible combination is 1.0-2.0 wt% ascorbate glucoside + 0.5-1.0 wt% sodium ascorbate phosphate; the synergistic effect of these two components enhances reducing activity.

[0023] In addition, the phospholipid encapsulation material is selected from soybean phospholipids, egg yolk phospholipids, or a combination of these phospholipids. The mass ratio of soybean phospholipids to egg yolk phospholipids in the combination phospholipid is 2:1. Liposomes formed by this type of material can be controlled to degrade in the skin environment, achieving the stepwise release of niacinamide. The aqueous phase system is a mixture of deionized water and a polyol, wherein the polyol is selected from propylene glycol or glycerol, and the amount added is 4.0-6.0 wt%, which is used to improve the solubility stability of the first functional unit.

[0024] On the other hand, the present invention also provides a method for preparing the whitening and freckle-removing composition as described above, comprising the following steps: S1. Preparation of the first functional unit: Polyphenol plant extracts and vitamin C active ingredients are added to the aqueous phase system, stirred and dissolved, and the pH value is adjusted to obtain a continuous aqueous phase.

[0025] Specifically, the preparation of the aqueous system is as follows: Take 4.0-6.0% of the total mass of the composition of polyol (propylene glycol or glycerol) and add it to 65-85% of the total mass of the composition of deionized water. Stir at 300-500 rpm for 10 minutes using an industrial-grade stirred tank to ensure complete dissolution of the polyol. The addition of polyol can improve the solubility of the active ingredients and avoid crystallization or precipitation. Commercially available polyols are sufficient. Then, add 0.5-5% of the total mass of the composition of polyphenolic plant extract and 0.3-7% of the active ingredient of vitamin C to the above aqueous system. Control the temperature inside the stirred tank at 25-40℃ and stir continuously at 300-500 rpm for 30-60 minutes. This temperature range ensures rapid dissolution of the components without premature degradation of the active ingredients. The stirring rate has been verified through multiple experiments to avoid excessive bubble generation due to excessive stirring.

[0026] After stirring, add 0.4-0.6% (by mass) of citric acid-sodium citrate buffer, and continue stirring for 10 minutes. Monitor and adjust the pH of the system to 5.8-6.5 using a pH meter in real time. This pH range is the optimal stability range determined through extensive testing. A pH below 5.8 increases the risk of subsequent nicotinamide hydrolysis, while a pH above 6.5 leads to accelerated degradation of vitamin C derivatives. A homogeneous and transparent aqueous continuous phase, i.e., the first functional unit, is finally obtained.

[0027] S2. Preparation of the second functional unit: Nicotinamide is mixed with phospholipid-based encapsulating materials and homogenized to form a liposome reaction isolation unit.

[0028] Specifically, 2.0-4.0% of nicotinamide powder (by mass of the total composition) is added to 5.0-15.0% of phospholipid material (soybean phospholipid, egg yolk phospholipid, or a compound phospholipid) by mass of the total composition, along with 5% deionized water (by mass of the phospholipid material) as a dispersion medium. The mixture is then added to a high-pressure homogenizer. Monolayer liposomes are homogenized three times at 80-150 MPa, while multilayer liposomes are homogenized in stages (first once at 100 MPa, then twice at 120-150 MPa), with pressure adjustment to form a multilayer structure. During homogenization, the material temperature is controlled to not exceed 40°C to avoid a decrease in nicotinamide activity due to high temperatures. Temperature control can be achieved through equipment jacket cooling.

[0029] After homogenization, the liposome particle size is measured using a laser particle size analyzer to ensure an average particle size between 100-500 nm. This particle size range guarantees good dispersion stability while also facilitating skin absorption during application. The final product is a liposome dispersion with nicotinamide as the core, i.e., the second functional unit. It should be noted that those skilled in the art can scale up the dosage of each component and the equipment parameters according to the above proportions based on actual production scale. A standard industrial model high-pressure homogenizer is sufficient; customization is not required.

[0030] S3. Composite molding: The second functional unit is slowly added to the first functional unit and mixed at low speed to obtain a uniform and stable whitening and freckle-removing composition.

[0031] Specifically, the first functional unit obtained in step S1 is transferred into a stirred tank equipped with a light-shielding device. The temperature inside the tank is controlled at 20-35℃, and stirring is started and the speed is adjusted to 150-200 r / min. The second functional unit prepared in step S2 is slowly added to the stirred tank at a rate of 5-10 mL / min using a metering pump. This addition rate can avoid liposome aggregation due to excessively high local concentrations, while low-speed stirring can ensure uniform mixing without damaging the liposome structure.

[0032] After adding the ingredients, continue stirring for 10-30 minutes. The endpoint of stirring is determined by observing a sample of the composition to ensure it is uniform and transparent, without obvious layering or particulate matter. The composition is then transferred to a finished product storage tank and stored in the dark until filling. In this step, the light-protection condition is achieved by covering the stirring vessel with a light-shielding layer; the core purpose is to prevent the vitamin C derivative from undergoing oxidative degradation due to light exposure. Temperature control at 20-35℃ is to maintain the stability of the liposome structure. All equipment is mature equipment used in the cosmetics industry and requires no special customization, significantly lowering the industrialization threshold.

[0033] The above content will be further elaborated below through specific implementation methods. It should be noted that the listed embodiments are only some embodiments of the present invention.

[0034] This embodiment provides a skin whitening and freckle-removing composition, the raw material composition and preparation method of which are as follows: Example 1 Ingredients: 2.0% licorice root extract, 1.0% amla fruit extract, 1.5% ascorbyl glucoside, 3.0% nicotinamide, 9.0% soybean lecithin, 5.0% propylene glycol, 0.5% citrate-sodium citrate buffer, and deionized water to 100%.

[0035] Preparation method: (1) Preparation of the first functional unit: Add propylene glycol to deionized water and stir at 300 r / min for 10 min to dissolve; add licorice root extract, amla fruit extract and ascorbate glucoside, control the temperature at 28℃ and the speed at 400 r / min for 45 min; add citric acid-sodium citrate buffer, continue stirring for 10 min, adjust the pH to 6.0, and obtain the aqueous continuous phase.

[0036] (2) Preparation of the second functional unit: Nicotinamide and soybean phospholipids were mixed, and 5% of the mass of phospholipids of deionized water was added. The mixture was homogenized under high pressure for 3 times at 100 MPa, and the material temperature was controlled to be ≤40℃. The average particle size of the liposomes was detected to be 200-300 nm, and the liposome reaction isolation unit was obtained.

[0037] (3) Composite molding: The first functional unit is transferred into a light-proof stirring vessel, and the temperature is controlled at 25℃ and the rotation speed at 200r / min. The second functional unit is added at a rate of 8mL / min through a metering pump and stirred for 20min to obtain a uniform and transparent whitening and freckle-removing composition.

[0038] Example 2 This embodiment provides a whitening and freckle-removing composition. The raw material composition is basically the same as that in Example 1, except that: a compound phospholipid (soybean phospholipid: egg yolk phospholipid = 2:1) is used to replace soybean phospholipid, with an addition amount of 10.0%; when preparing the second functional unit, a staged homogenization is adopted (first homogenized once at 100MPa, then homogenized twice at 120MPa) to form multilayer liposomes; the remaining raw material composition and preparation method are exactly the same as those in Example 1.

[0039] Example 3 This embodiment provides a whitening and freckle-removing composition. The raw material composition is basically the same as that in Example 1, except that: the polyphenol extract is 1.5% licorice root extract + 1.0% mulberry leaf extract + 0.5% amla fruit extract, the amount of nicotinamide added is 4.0%, and the amount of soybean lecithin added is 12.0%; the preparation method is exactly the same as that in Example 1.

[0040] Comparative Example 1 This comparative example provides a whitening and freckle-removing composition with the same raw material composition as Example 1. The difference is that the preparation step of the second functional unit is omitted, and niacinamide is directly added to the first functional unit and stirred to dissolve. The rest of the preparation method is exactly the same as that of Example 1.

[0041] Comparative Example 2 This comparative example provides a whitening and freckle-removing composition. The raw material composition is basically the same as that of Example 1, except that β-cyclodextrin is used instead of soybean lecithin as the encapsulating material, with an addition amount of 9.0%, and nicotinamide encapsulation is achieved by grinding. The rest of the preparation method is exactly the same as that of Example 1.

[0042] Comparative Example 3 This comparative example provides a whitening and freckle-removing composition. The raw material composition is completely the same as that in Example 1. The difference is that no citric acid-sodium citrate buffer was added when preparing the first functional unit, and the natural pH value of the system is 4.2. The rest of the preparation method is exactly the same as that in Example 1.

[0043] Comparative Example 4 This comparative example provides a whitening and freckle-removing composition. The raw material composition is basically the same as that of Example 1, except that the amount of soybean lecithin added is changed to 2.0% (lower than the range of 5.0-15.0% limited by this invention); the rest of the preparation method is exactly the same as that of Example 1.

[0044] The finished products of Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests under the following conditions and methods: 1. Storage stability test: Accelerated storage at 40℃ and 75% relative humidity for 6 months, retention rate of active ingredients was measured by HPLC, and appearance changes were observed; 2. Tyrosinase inhibition rate test: in vitro enzyme activity method, L-DOPA as substrate; 3. Skin irritation test: Human closed patch test, 30 volunteers, scored according to the "Cosmetic Safety Technical Specifications" (0-4 points); 4. In vitro whitening effect test: B16 melanoma cell model, measuring the rate of reduction in melanin content; 5. In vitro stepwise release performance test: The diffusion method of dialysis bag was adopted, with phosphate buffer (pH 5.5, simulating the skin surface environment) as the release medium, temperature 37℃, stirring speed 100 r / min, and samples were taken at 1h, 4h, 8h, 12h, 24h and 48h respectively. The concentration of nicotinamide in the release medium was determined by HPLC, the cumulative release rate was calculated and the release curve was plotted.

[0045] Meanwhile, using the existing mainstream direct compound whitening compositions as a baseline reference, the results of storage stability tests are summarized in Table 1, the results of whitening efficacy and skin compatibility tests are summarized in Table 2, and the results of stepwise release performance tests are summarized in Table 3.

[0046] Table 1. Results of stability and basic efficacy tests

[0047] As shown in Table 1, the storage stability of the compositions of this invention is significantly better than that of the prior art and comparative examples: After accelerated storage at 40°C for 6 months, the nicotinamide retention rate of Examples 1-3 was ≥90.5%, and the ascorbate glucoside retention rate was ≥87.9%, with no obvious yellowing or stratification. In contrast, the nicotinamide retention rate of Comparative Examples 1 and 3 was only 58.7%-65.8%, and severe yellowing occurred. This fully demonstrates that this invention, through liposome encapsulation and pH adjustment, fundamentally blocks the contact between nicotinamide and acidic components, completely solving the storage incompatibility problem of the three types of components. Comparative Example 2 shows that the stability improvement effect of phospholipid liposome encapsulation is better, further verifying the rationality of the selection of encapsulation material. Comparative Example 4 showed moderate yellowing due to insufficient encapsulation material, indicating that the phospholipid addition amount (5.0-15.0 wt%) limited by this invention is the key to ensuring stability.

[0048] Table 2. Results of Whitening Efficacy and Skin Compatibility Tests

[0049] As shown in Table 2, the compositions of this invention achieve a synergistic improvement in whitening efficacy and safety. Regarding whitening efficacy, Examples 1-3 exhibited tyrosinase inhibition rates of 78.5%-82.3% and melanin content reduction rates of 42.1%-46.8%, representing improvements of 42%-49% and 79%-99% respectively compared to existing technologies, and improvements of 50%-57% and 98%-120% respectively compared to Comparative Example 1. This confirms that the dual-functional unit design did not weaken the activity of the ingredients; instead, it enhanced the whitening effect through synergistic action. In terms of safety, Examples 1-3 had skin irritation scores of only 0.2-0.4, indicating extremely low irritation and suitability for sensitive skin. In contrast, Comparative Example 1 had an irritation score of 2.1 (moderate irritation), primarily due to the hydrolysis of niacinamide upon direct contact with acidic components to generate nicotinic acid. This further demonstrates that the liposome encapsulation design of this invention effectively reduces the risk of irritation.

[0050] Table 3 Results of Step-by-Step Release Performance Test

[0051] As shown in Table 3, the liposome design of this invention can precisely achieve controlled release of nicotinamide, especially the multilayer liposomes which can achieve efficient stepwise release: In Example 2, the cumulative release rate of nicotinamide was only 18.5% at 1 hour, rising to 45.3% at 12 hours, and reaching 92.1% at 48 hours, exhibiting a stepwise release characteristic of slow release in the early stage, accelerated release in the middle stage, and complete release in the later stage. This effect is due to the difference in degradation rate of different wall materials of the multilayer liposomes (outer layer soybean lecithin, middle and inner layer soybean lecithin-egg yolk lecithin composite system); while Examples 1 and 3 showed uniform release without burst release, which can meet the basic requirements for controlled release. In contrast, existing technologies and comparative examples all have the problem of burst release in the early stage or no stepwise release characteristic, and cannot achieve time-series synergistic whitening during the use period.

[0052] Therefore, by adopting the above-mentioned whitening and freckle-removing composition, preparation method and its application in cosmetics, while ensuring the high retention rate of multiple active ingredients, it can achieve synergistic whitening over time during the use period, improve skin compatibility, and meet consumers' comprehensive requirements for the efficacy, safety and stability of whitening products.

[0053] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0054] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A whitening and freckle-removing composition, characterized in that, include: The first functional unit is an aqueous continuous phase, including polyphenolic plant extracts and vitamin C active ingredients, wherein the vitamin C active ingredients are vitamin C in its original form and / or vitamin C derivatives; The second functional unit is a reaction isolation unit, which includes nicotinamide, which exists in the form of liposome encapsulation; The first functional unit and the second functional unit constitute independent structural units in the same composition. By keeping nicotinamide spatially isolated from polyphenolic plant extracts and vitamin C active ingredients during the storage period and gradually releasing nicotinamide through a controlled release method during the use period, the direct contact between nicotinamide and polyphenolic plant extracts and vitamin C active ingredients during the storage and use periods is reduced.

2. The whitening and freckle-removing composition according to claim 1, characterized in that, The polyphenolic plant extract is selected from one or more of mulberry leaf extract, amla fruit extract, and licorice root extract, and the total amount of the polyphenolic plant extract added to the composition is 0.5-5 wt%.

3. The whitening and freckle-removing composition according to claim 1, characterized in that, The vitamin C derivative is selected from one or more of ascorbate glucoside and ascorbate phosphate salt; wherein the amount of ascorbate glucoside added to the composition is 0.1-3 wt%, and the amount of ascorbate phosphate salt added to the composition is 0.2-4 wt%.

4. The whitening and freckle-removing composition according to claim 1, characterized in that, The reaction isolation unit is a single-layer or multi-layer liposome structure, wherein the liposomes physically encapsulate nicotinamide during storage to achieve spatial isolation, and during use, the nicotinamide is released stepwise relative to the polyphenolic plant extracts and vitamin C active ingredients in the first functional unit through the difference in degradation rate of different wall materials in the multi-layer liposomes.

5. A method for preparing the whitening and freckle-removing composition according to any one of claims 1 to 4, characterized in that, Includes the following steps: Polyphenolic plant extracts and vitamin C active ingredients were added to an aqueous system, stirred, and the pH was adjusted to obtain a continuous aqueous phase in the form of the first functional unit. Nicotinamide is mixed with a loading material and then loaded to form a second functional unit that serves as a reaction isolation unit. The aqueous continuous phase is mixed with the reaction isolation unit and stirred to obtain a whitening and freckle-removing composition.

6. The preparation method according to claim 5, characterized in that, The aqueous system is water or an aqueous system with water as the main continuous phase.

7. The preparation method according to claim 5, characterized in that, The stirring and pH adjustment are performed as follows: stirring at 25-40℃ for 30-60 minutes, and then adjusting the pH of the aqueous phase system to 5.8-6.5 by adding a citric acid-sodium citrate buffer system.

8. The preparation method according to claim 5, characterized in that, The coating material is a phospholipid material, and is coated by emulsification or homogenization under pressure of 80-150 MPa.

9. The preparation method according to claim 5, characterized in that, The process of mixing and stirring the aqueous continuous phase with the reaction isolation unit is as follows: under conditions of 20-35°C, the reaction isolation unit is added to the aqueous continuous phase at a rate of 5-10 mL / min, and the mixture is stirred for 10-30 minutes under light-protected conditions to obtain the composition.

10. The application of a whitening and freckle-removing composition as described in any one of claims 1 to 4, characterized in that, The whitening and freckle-removing composition is used to prepare cosmetics that whiten, remove freckles, or improve skin pigmentation.

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