A vitamin c dipeptide conjugate, and a preparation method thereof

Abstract

The present application relates to the technical field of cosmetic raw materials and external preparation, and discloses a vitamin C dipeptide conjugate, a preparation method and application thereof, which comprises the following steps: dissolving 3-O-ethyl vitamin C and a divalent linking group precursor in anhydrous ethanol, adding an alkaline catalyst to complete condensation activation to obtain a mother nucleus activation solution; introducing a dipeptide modified with a linking arm to complete condensation reaction to generate a conjugate precursor; after removing a protective group, the conjugate is separated and dried through chromatography elution; the present application uses a low molecular weight dipeptide to be bonded to a mother nucleus hydroxyl group, effectively improves the physicochemical stability of skeleton delocalized electron orbit, and simultaneously perfectly adapts a tyrosinase catalytic pocket in a specific spatial orientation, directly induces catalytic inhibition feedback, and synergistically enhances the transmembrane transport efficiency and target response speed.

Description

Technical Field

[0001] This invention relates to a vitamin C dipeptide conjugate and its preparation method, belonging to the technical field of cosmetic raw materials and topical preparations. Background Technology

[0002] Ascorbic acid, a classic whitening ingredient in topical formulations, has an olefinic hydroxyl group that serves as an active site for scavenging free radicals and inhibiting tyrosinase. However, external light, temperature, and oxygen can easily cause it to undergo oxidative degradation and discoloration. To maintain its physicochemical stability under normal conditions, existing technologies typically employ chemical modification methods, introducing groups into the parent nucleus hydroxyl group to shield the active reaction site. While this shielding mechanism improves stability, it also introduces significant drawbacks. Because the modified derivative occupies the active hydroxyl group, its molecular spatial configuration cannot precisely match the catalytic pocket of tyrosinase, resulting in a substantial decrease in direct catalytic activity. After transdermal absorption, such ingredients must rely on specific epidermal hydrolases to gradually cleave and break the groups, releasing the free parent nucleus to exert their effects. This conversion process leads to metabolic delays, and due to differences in the expression levels of specific enzymes among individuals, the overall conversion rate is low, limiting the immediate effectiveness of the formulation.

[0003] To overcome the aforementioned conversion limitations, the common approach is to increase the initial concentration of the derivative in the multiphase system or to use exogenous stabilizers. However, increasing the solute loading can easily disrupt the solid-liquid dynamic equilibrium of the fluid medium, leading to solute crystallization under low temperature or shear stress. Simultaneously, the introduction of excessive stabilizers often increases the risk of epidermal barrier damage, weakening the transdermal tolerance of the formulation. This indicates an inherent and irreconcilable conflict between site shielding for antioxidant effects, catalytic matching for immediate efficacy, and constraints on fluid stability. Analysis shows that existing technologies mainly suffer from the following shortcomings: 1. Modified derivatives lack direct catalytic activity to inhibit tyrosinase, relying excessively on the conversion efficiency of in vivo hydrolases; 2. The product has poor amphiphilicity, making it difficult to cross the highly polar epidermal barrier, resulting in insufficient local retention; 3. The formulation matrix still faces the risk of discoloration and degradation under continuous shear stress, leading to a short formulation lifespan.

[0004] Therefore, how to construct a molecular configuration that combines direct catalytic pocket-matching activity with excellent transdermal penetration capability, and resolve the contradiction between improving physicochemical stability and preserving direct activity and transdermal rate, has become the technical problem to be solved by this invention. Summary of the Invention

[0005] To address the problems mentioned in the background section, the technical solution of this invention is as follows: A vitamin C dipeptide conjugate and its preparation method, comprising the following steps: Step S1: In a light-protected environment with nitrogen flow, 3-O-ethyl vitamin C is completely dissolved in anhydrous ethanol with a divalent linker precursor at a molar ratio of 1.0:1.1, and an alkaline catalyst is added. The mixture is then condensed and activated at an activation temperature of 15°C to 25°C and a constant stirring speed of 200 r / min to 400 r / min for 1.5 h to 2.5 h to obtain a core activation solution containing an activation intermediate with an oxygen atom at the 2-position. Step S2: By adjusting the alkalinity of the system, a weakly alkaline reaction environment with a pH of 7.2 to 7.5 is established. The linker-modified dipeptide is introduced into the core activation solution at a molar ratio of 1.0:1.0. The intermolecular condensation reaction is carried out at a reaction temperature of 30°C to 40°C for 5 to 8 hours to generate a coupling precursor. The linker-modified dipeptide is formed by covalently bonding a low molecular weight dipeptide to the linker. The low molecular weight dipeptide is selected from proline-proline dipeptide, proline-hydroxyproline dipeptide, and hydroxyproline-hydroxyproline dipeptide. Step S3: Add a deprotecting agent to the coupling precursor and react at a normal pressure cooling temperature of 0°C to 5°C to release the terminal functional groups of the low molecular weight dipeptide and obtain a crude product solution. Introduce the crude product solution into a macroporous resin chromatography column to complete chromatographic adsorption and elution separation. Collect the target eluent containing the vitamin C dipeptide conjugate and perform vacuum concentration and freeze drying on the target eluent to obtain the vitamin C dipeptide conjugate.

[0006] Preferably, in step S1, the mass ratio of anhydrous ethanol to 3-O-ethyl vitamin C is 5:1 to 8:1; the alkaline catalyst is selected from triethylamine, N,N-diisopropylethylamine, pyridine and 4-dimethylaminopyridine, and the molar ratio of the alkaline catalyst to 3-O-ethyl vitamin C is 0.05:1 to 0.15:1.

[0007] Preferably, in step S1, the 3-O-ethyl vitamin C is replaced by an equimolar ratio of vitamin C; the divalent linker precursor is selected from succinyl chloride, glutaryl chloride, and adipicoyl chloride; the linker generated by the reaction of the divalent linker precursor is selected from succinyl, glutaryl, and adipicoyl, and the linker is covalently bonded to the hydroxyl group of the 3-O-ethyl vitamin C core via an ester bond, and covalently bonded to the amino terminus of the dipeptide modified by the linker via an amide bond.

[0008] Preferably, in step S2, a condensing agent is added to the intermolecular condensation reaction system, and the condensing agent is selected from 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N,N'-dicyclohexylcarbodiimide.

[0009] Preferably, in step S3, the macroporous resin chromatography column is filled with polystyrene-type nonpolar macroporous adsorption resin; the elution separation is carried out by gradient flow elution using an ethanol solution with a volume percentage concentration of 20% to 50% as the eluent, and the target eluent is collected and dried under reduced pressure at a temperature of 45°C to 55°C and a sealed vacuum of -0.08MPa to -0.09MPa.

[0010] Preferably, after obtaining the vitamin C dipeptide conjugate in step S3, the method further includes step S4 of formulating the vitamin C dipeptide conjugate into a topical multiphase cosmetic formulation: Step S4: Dissolve the vitamin C dipeptide conjugate in an aqueous matrix at a mass percentage of 0.5% to 3.0%, and uniformly mix the aqueous matrix and oil matrix at a mixing temperature of 40°C to 50°C. The mixture is then subjected to high-pressure mechanical shearing and homogenization emulsification by a high-pressure mechanical shearing homogenization unit to generate an emulsion system.

[0011] Preferably, the aqueous phase matrix is ​​prepared by mixing glycerol, butylene glycol, sodium hyaluronate and deionized water; the oil phase matrix is ​​prepared by mixing squalane, jojoba seed oil, potassium cetyl phosphate and ethylhexyl palmitate.

[0012] Preferably, the high-pressure mechanical shearing and homogenization emulsification in step S4 includes the following sub-steps: Step S41: The oil phase matrix is ​​heated to 75°C to 85°C, and the aqueous phase matrix is ​​heated to 75°C to 85°C. The heated oil phase matrix is ​​introduced into the heated aqueous phase matrix under constant speed stirring to generate a primary emulsion; Step S42: The primary emulsion is introduced into a high-pressure mechanical shearing homogenization unit, and circulated and sheared 3 times under a homogenization pressure of 50MPa to 80MPa to compress the particle size of the dispersed phase. Then, the temperature is lowered to 40°C to 45°C and an aqueous solution of vitamin C dipeptide conjugate is mixed in. The mixture is stirred evenly until it reaches room temperature.

[0013] Preferably, in step S4, after the emulsion system is generated, a buffer solution with a mass ratio of citric acid to sodium citrate of 1:2.5 to 1:3.2 is added dropwise to the emulsion system. The pH value of the topical multiphase cosmetic formulation is stabilized within a preset range of 5.5 to 6.2 by means of the acid-base buffer balance of the buffer solution, and the viscosity of the emulsion system is adaptively adjusted and maintained within a preset viscosity range of 3000 mPa·s to 5000 mPa·s.

[0014] The application of a vitamin C dipeptide conjugate involves adding a vitamin C dipeptide conjugate and the vitamin C dipeptide conjugate obtained by its preparation method as an active ingredient in whitening, antioxidant, or anti-aging cosmetics.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. The compound represented by general formula I of this invention adopts a specific core single-point modification configuration. By coupling one of its 2- or 3-position hydroxyl groups to a dipeptide fragment, the other unsubstituted hydroxyl group remains in a free state. While maintaining the physicochemical antioxidant properties of the molecule, the molecular spatial configuration forms a specific spatial match with the catalytic pocket of tyrosinase. This matching state directly induces non-competitive catalytic inhibition feedback, so that the complex does not need to rely on the hydrolysis release process of specific hydrolytic enzymes in the body to exhibit blocking efficacy, reduce the in vivo transformation barrier of conventional derivatives, improve the direct response speed of the target, and ensure the bioavailability efficiency of the formulation system in complex matrix conditions.

[0016] 2. This invention introduces a specific amphiphilic unit into a specific hydroxyl site of the parent nucleus. By extending the linker arm and synergizing with low molecular weight dipeptides containing proline or hydroxyproline, the overall oil-water partition coefficient of the molecule is optimized. This amphiphilic dynamic variable weakens the cell membrane polarity barrier, induces highly efficient endocytosis and vesicle transport channels, and enables the complex to achieve high-density intracellular accumulation and transmembrane transport within a short period after administration. It spontaneously crosses the stratum corneum barrier of the epidermis, solving the physical transport problem of limited penetration and insufficient deep local retention of conventional low-lipid-soluble active ingredients. Thus, a long-lasting and stable transdermal transport delivery link is established in the matrix layer of topical multiphase formulations.

[0017] 3. This invention introduces specific substituents into the parent nucleus hydroxyl group to shield the active olefin reaction center, reducing the frequency of direct contact between this reaction site and water, oxygen molecules, and metal ions. This synergistically enhances the stability of delocalized electronic orbitals in the molecular skeleton. This spatial barrier mechanism maintains an excellent anti-dissociation state in complex acid-base formulation matrices and can spontaneously resist oxidative degradation and system discoloration even in continuous thermal shear stress environments. It avoids the physicochemical compromise point of discoloration and failure in traditional ascorbic acid systems. While ensuring the physical appearance of the matrix is ​​pure and stable, it constructs a long-term, high-retention, anti-differentiation state, extending the lifespan of the formulation. Attached Figure Description

[0018] Figure 1 This is a flowchart of the vitamin C dipeptide conjugate condensation process of the present invention; Figure 2 This diagram illustrates the external application of the dipeptide conjugate of the present invention.

[0019] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] A vitamin C dipeptide conjugate and its preparation method, comprising the following steps: Step S1: In a light-protected environment with nitrogen flow, 3-O-ethyl vitamin C is completely dissolved in anhydrous ethanol with a divalent linker precursor at a molar ratio of 1.0:1.1, and an alkaline catalyst is added. The mixture is then condensed and activated at an activation temperature of 15°C to 25°C and a constant stirring speed of 200 r / min to 400 r / min for 1.5 h to 2.5 h to obtain a core activation solution containing an activation intermediate with an oxygen atom at the 2-position. Step S2: By adjusting the alkalinity of the system, a weakly alkaline reaction environment with a pH of 7.2 to 7.5 is established. The linker-modified dipeptide is introduced into the core activation solution at a molar ratio of 1.0:1.0. The intermolecular condensation reaction is carried out at a reaction temperature of 30°C to 40°C for 5 to 8 hours to generate a coupling precursor. The linker-modified dipeptide is formed by covalently bonding a low molecular weight dipeptide to the linker. The low molecular weight dipeptide is selected from proline-proline dipeptide, proline-hydroxyproline dipeptide, and hydroxyproline-hydroxyproline dipeptide. Step S3: Add a deprotecting agent to the coupling precursor and react at a normal pressure cooling temperature of 0°C to 5°C to release the terminal functional groups of the low molecular weight dipeptide and obtain a crude product solution. Introduce the crude product solution into a macroporous resin chromatography column to complete chromatographic adsorption and elution separation. Collect the target eluent containing the vitamin C dipeptide conjugate and perform vacuum concentration and freeze drying on the target eluent to obtain the vitamin C dipeptide conjugate.

[0022] Preferably, in step S1, the mass ratio of anhydrous ethanol to 3-O-ethyl vitamin C is 5:1 to 8:1; the alkaline catalyst is selected from triethylamine, N,N-diisopropylethylamine, pyridine and 4-dimethylaminopyridine, and the molar ratio of the alkaline catalyst to 3-O-ethyl vitamin C is 0.05:1 to 0.15:1.

[0023] Preferably, in step S1, the 3-O-ethyl vitamin C is replaced by an equimolar ratio of vitamin C; the divalent linker precursor is selected from succinyl chloride, glutaryl chloride, and adipicoyl chloride; the linker generated by the reaction of the divalent linker precursor is selected from succinyl, glutaryl, and adipicoyl, and the linker is covalently bonded to the hydroxyl group of the 3-O-ethyl vitamin C core via an ester bond, and covalently bonded to the amino terminus of the dipeptide modified by the linker via an amide bond.

[0024] Preferably, in step S2, a condensing agent is added to the intermolecular condensation reaction system, and the condensing agent is selected from 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N,N'-dicyclohexylcarbodiimide.

[0025] Preferably, in step S3, the macroporous resin chromatography column is filled with polystyrene-type nonpolar macroporous adsorption resin; the elution separation is carried out by gradient flow elution using an ethanol solution with a volume percentage concentration of 20% to 50% as the eluent, and the target eluent is collected and dried under reduced pressure at a temperature of 45°C to 55°C and a sealed vacuum of -0.08MPa to -0.09MPa.

[0026] Preferably, after obtaining the vitamin C dipeptide conjugate in step S3, the method further includes step S4 of formulating the vitamin C dipeptide conjugate into a topical multiphase cosmetic formulation: Step S4: Dissolve the vitamin C dipeptide conjugate in an aqueous matrix at a mass percentage of 0.5% to 3.0%, and uniformly mix the aqueous matrix and oil matrix at a mixing temperature of 40°C to 50°C. The mixture is then subjected to high-pressure mechanical shearing and homogenization emulsification by a high-pressure mechanical shearing homogenization unit to generate an emulsion system.

[0027] Preferably, the aqueous phase matrix is ​​prepared by mixing glycerol, butylene glycol, sodium hyaluronate and deionized water; the oil phase matrix is ​​prepared by mixing squalane, jojoba seed oil, potassium cetyl phosphate and ethylhexyl palmitate.

[0028] Preferably, the high-pressure mechanical shearing and homogenization emulsification in step S4 includes the following sub-steps: Step S41: The oil phase matrix is ​​heated to 75°C to 85°C, and the aqueous phase matrix is ​​heated to 75°C to 85°C. The heated oil phase matrix is ​​introduced into the heated aqueous phase matrix under constant speed stirring to generate a primary emulsion; Step S42: The primary emulsion is introduced into a high-pressure mechanical shearing homogenization unit, and circulated and sheared 3 times under a homogenization pressure of 50MPa to 80MPa to compress the particle size of the dispersed phase. Then, the temperature is lowered to 40°C to 45°C and an aqueous solution of vitamin C dipeptide conjugate is mixed in. The mixture is stirred evenly until it reaches room temperature.

[0029] Preferably, in step S4, after the emulsion system is generated, a buffer solution with a mass ratio of citric acid to sodium citrate of 1:2.5 to 1:3.2 is added dropwise to the emulsion system. The pH value of the topical multiphase cosmetic formulation is stabilized within a preset range of 5.5 to 6.2 by means of the acid-base buffer balance of the buffer solution, and the viscosity of the emulsion system is adaptively adjusted and maintained within a preset viscosity range of 3000 mPa·s to 5000 mPa·s.

[0030] The application of a vitamin C dipeptide conjugate is characterized in that a vitamin C dipeptide conjugate or a vitamin C dipeptide conjugate obtained by the same preparation method is added as an active ingredient to whitening, antioxidant or anti-aging cosmetics.

[0031] Example 1: This example combines Figures 1 to 2 Regarding a vitamin C dipeptide conjugate, its preparation method and application instructions, such as... Figure 1 As shown, the reactant 3-O-ethyl vitamin C and the divalent linker precursor were dissolved in anhydrous ethanol at a molar ratio of 1.0:1.1, and an alkaline catalyst was added. The mixture was then placed in a light-protected environment with a nitrogen atmosphere and subjected to a constant stirring speed of 200-400 rpm for 1.5-2.5 hours to undergo condensation activation, generating a core activation solution containing an activated intermediate at the 2-position oxygen atom. This core activation solution, along with a linker-modified dipeptide formed by the covalent bonding of a low-molecular-weight dipeptide with a linker arm, was then fed into the intermolecular condensation reaction node. The alkalinity was adjusted to establish a pH of 7.2-7.5. Under conditions of a weakly alkaline environment, a dipeptide molar ratio of 1.0:1.0, and a reaction temperature of 30-40℃ for 5-8 hours, a coupling precursor is generated. This coupling precursor, together with the deprotection reagent, participates in a cold cleavage deprotection reaction. The terminal functional groups of the low molecular weight dipeptide are separated at a cold cleavage temperature of 0-5℃ under normal pressure, and a crude product solution is output. This crude product solution is transferred to the chromatography adsorption and elution separation process. The target eluent containing the coupling compound is collected by introducing it into a macroporous resin chromatography column, and then successively subjected to vacuum concentration and freeze-drying treatment aimed at removing solvent and solidifying the product, finally outputting the vitamin C dipeptide coupling compound.

[0032] like Figure 2As shown, a vitamin C dipeptide conjugate is used as the core system of the target active molecule. This core system incorporates a 3-O-ethyl vitamin C core as the parent compound for the condensation activation reaction, a divalent linker precursor providing covalently bonded linker arms, and a dipeptide modified with linker arms as the introductory end of a low molecular weight dipeptide. In its process flow system, the 2-position oxygen atom activation intermediate, which is the product of anhydrous ethanol incubation condensation, flows to the coupling precursor molecule generation node for intermolecular condensation in a weakly alkaline environment. This node further flows to the crude product solution end-group freeing node for deprotection at ambient pressure and cold shear temperature, and then flows to the target eluent chromatography separation node for macroporous resin adsorption gradient elution and feedback flow to the upper... The oxygen atom at position 2 activates the intermediate. Simultaneously, in the formulation transfer system, the aqueous and oil phase matrix mixing node, which serves as the base for topical multiphase cosmetic formulation, flows to the high-pressure mechanical shearing homogenization unit for implementing cyclic flow shearing and compression of particle size. It then flows to the topical multiphase cosmetic formulation stabilization node for implementing acid-base buffering balance and viscosity adjustment. Finally, it flows to the whitening, anti-oxidation, and anti-aging cosmetic node for application as an active ingredient in topical formulations and feeds back to the aforementioned aqueous and oil phase matrix mixing node. The target eluent chromatography separation node is unidirectionally connected to the whitening, anti-oxidation, and anti-aging cosmetic node, and the aqueous and oil phase matrix mixing node is unidirectionally connected to the coupling precursor molecule generation node.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A vitamin C dipeptide conjugate and its preparation method, characterized in that, Includes the following steps: Step S1: In a light-protected environment with nitrogen flow, 3-O-ethyl vitamin C is completely dissolved in anhydrous ethanol with a divalent linker precursor at a molar ratio of 1.0:1.1, and an alkaline catalyst is added. The mixture is then condensed and activated at an activation temperature of 15°C to 25°C and a constant stirring speed of 200 r / min to 400 r / min for 1.5 h to 2.5 h to obtain a core activation solution containing an activation intermediate with an oxygen atom at the 2-position. Step S2: By adjusting the alkalinity of the system, a weakly alkaline reaction environment with a pH of 7.2 to 7.5 is established. The linker-modified dipeptide is introduced into the core activation solution at a molar ratio of 1.0:1.

0. The intermolecular condensation reaction is carried out at a reaction temperature of 30°C to 40°C for 5 to 8 hours to generate a coupling precursor. The linker-modified dipeptide is formed by covalently bonding a low molecular weight dipeptide to the linker. The low molecular weight dipeptide is selected from proline-proline dipeptide, proline-hydroxyproline dipeptide, and hydroxyproline-hydroxyproline dipeptide. Step S3: Add a deprotecting agent to the coupling precursor and react at a normal pressure cooling temperature of 0°C to 5°C to release the terminal functional groups of the low molecular weight dipeptide and obtain a crude product solution. Introduce the crude product solution into a macroporous resin chromatography column to complete chromatographic adsorption and elution separation. Collect the target eluent containing the vitamin C dipeptide conjugate and perform vacuum concentration and freeze drying on the target eluent to obtain the vitamin C dipeptide conjugate.

2. The vitamin C dipeptide conjugate according to claim 1, and its preparation method, characterized in that, In step S1, the mass ratio of anhydrous ethanol to 3-O-ethyl vitamin C is 5:1 to 8:1; the alkaline catalyst is selected from triethylamine, N,N-diisopropylethylamine, pyridine and 4-dimethylaminopyridine, and the molar ratio of the alkaline catalyst to 3-O-ethyl vitamin C is 0.05:1 to 0.15:

1.

3. The vitamin C dipeptide conjugate of claim 1, a preparation method thereof, characterized in that, In step S1, 3-O-ethyl vitamin C is replaced by an equivalent molar ratio of vitamin C; the divalent linker precursor is selected from succinyl chloride, glutaryl chloride, and adipicoyl chloride; the linker generated from the reaction of the divalent linker precursor is selected from succinyl, glutaryl, and adipicoyl groups, and the linker is covalently bonded to the hydroxyl group of the 3-O-ethyl vitamin C core via ester bonds, and covalently bonded to the amino terminus of the dipeptide modified by the linker via amide bonds.

4. The vitamin C dipeptide conjugate of claim 1, a preparation method thereof, characterized in that, In step S2, a condensing agent is added to the intermolecular condensation reaction system. The condensing agent is selected from 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N,N'-dicyclohexylcarbodiimide.

5. The vitamin C dipeptide conjugate of claim 1, a preparation method thereof, characterized in that, In step S3, the macroporous resin chromatography column is filled with polystyrene-type nonpolar macroporous adsorption resin; the elution separation is carried out by gradient flow elution using an ethanol solution with a volume percentage concentration of 20% to 50% as the eluent, and the target eluent is collected and dried under reduced pressure at a temperature of 45°C to 55°C and a sealed vacuum of -0.08MPa to -0.09MPa.

6. The vitamin C dipeptide conjugate of claim 1, a preparation method thereof, characterized in that, After obtaining the vitamin C dipeptide conjugate in step S3, the process further includes step S4, which involves formulating the vitamin C dipeptide conjugate into a topical multiphase cosmetic formulation: Step S4: The vitamin C dipeptide conjugate is dissolved in an aqueous matrix at a mass percentage of 0.5% to 3.0%, and the aqueous matrix and oil matrix are uniformly mixed at a mixing temperature of 40°C to 50°C. High-pressure mechanical shearing and homogenization emulsification are then completed by a high-pressure mechanical shearing homogenization unit to generate an emulsion system.

7. The vitamin C dipeptide conjugate according to claim 6, a method for preparing the same, characterized by, The aqueous phase matrix is ​​prepared by mixing glycerol, butylene glycol, sodium hyaluronate and deionized water; the oil phase matrix is ​​prepared by mixing squalane, jojoba seed oil, potassium cetyl phosphate and ethylhexyl palmitate.

8. The vitamin C dipeptide conjugate according to claim 6, a method for preparing the same, characterized by, The high-pressure mechanical shearing and homogenization emulsification in step S4 includes the following sub-steps: Step S41: Heat the oil phase matrix to 75°C to 85°C and the aqueous phase matrix to 75°C to 85°C. Under constant stirring, the heated oil phase matrix is ​​introduced into the heated aqueous phase matrix to generate a primary emulsion. Step S42: The primary emulsion is introduced into a high-pressure mechanical shearing homogenization unit and circulated and sheared three times under a homogenization pressure of 50MPa to 80MPa to compress the particle size of the dispersed phase. Then, the temperature is lowered to 40°C to 45°C and an aqueous solution of vitamin C dipeptide conjugate is mixed in. The mixture is stirred evenly until it reaches room temperature.

9. The vitamin C dipeptide conjugate of claim 7, wherein the vitamin C dipeptide conjugate is prepared by the method of claim 1. In step S4, after the emulsion system is generated, a buffer solution with a mass ratio of citric acid to sodium citrate of 1:2.5 to 1:3.2 is added dropwise to the emulsion system. The pH value of the topical multiphase cosmetic formulation is stabilized within a preset range of 5.5 to 6.2 by means of the acid-base buffer balance of the buffer solution, and the viscosity of the emulsion system is adaptively adjusted and maintained within a preset viscosity range of 3000 mPa·s to 5000 mPa·s.

10. Use of a vitamin C dipeptide conjugate, characterized in that The vitamin C dipeptide conjugate of claim 1 and the vitamin C dipeptide conjugate obtained by its preparation method are added as active ingredients to whitening, antioxidant or anti-aging cosmetics.

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