VC (Vitamin C) and VE (Vitamin E) permeability improvement method based on multi-mechanism collaboration and application

Abstract

The invention relates to the technical field of daily chemical industry, and discloses a VC and VE permeability improving method based on multi-mechanism cooperation and application. The invention relates to a biomimetic channel cleaning agent, which is prepared from the following raw material components in parts by weight: 10.0 to 20.0 parts of ascorbic acid, 0.5 to 2.0 parts of tocopheryl acetate, 3.0 to 8.0 parts of dual-responsiveness amphiphilic block copolymers, 0.3 to 1.5 parts of biomimetic channel dredging agents, 30.0 to 45.0 parts of dipropylene glycol, 2.0 to 5.0 parts of ethyoxyl diethylene glycol, 3.0 to 6.0 parts of PEG-7 glyceryl cocoate, 0.5 to 1.0 part of preservatives and the balance of water. A release switch sensitive to pH value and specific enzyme is constructed through a phenylboronic acid monomer containing an enzyme digestion connecting arm, ascorbic acid is mounted on a carrier through a boric acid ester bond, ineffective loss of active ingredients on the skin surface is effectively avoided, and bioavailability and targeting are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of daily chemical technology, specifically to a method and application for improving the penetration rate of vitamin C and vitamin E based on multi-mechanism synergy. Background Technology

[0002] Ascorbic acid and tocopherol are recognized classic antioxidants in the fields of daily chemical products and skin care. Vitamin C has the effects of scavenging free radicals, promoting collagen synthesis, and inhibiting melanin production, while Vitamin E can protect cell membranes from oxidative damage. The combination of the two usually has a significant synergistic effect. However, the outermost layer of human skin, the stratum corneum, is a dense physical barrier composed of dead keratinocytes and the lipid bilayer (mainly composed of ceramides, cholesterol, and free fatty acids) that strictly limits the transdermal absorption of exogenous substances. In addition, vitamin C is not only easily oxidized and degraded, but as a water-soluble molecule, it is also difficult to penetrate the hydrophobic stratum corneum; although Vitamin E is lipid-soluble, its large molecular structure and high viscosity also make it difficult for it to independently cross the skin barrier to reach deep active tissues.

[0003] To address these issues, existing technologies primarily employ physical encapsulation or chemical modification strategies. Chemical modification mainly involves the synthesis of vitamin derivatives, which, while improving stability, often reduces bioactivity or conversion rate. Physical encapsulation technologies are more prevalent, primarily including carrier systems such as liposomes, nanoemulsions, and polymeric micelles.

[0004] Among these, micelles formed by amphiphilic block copolymers have been extensively studied due to their excellent modifying and drug-loading capabilities. Conventional techniques typically use polyethylene glycol as the hydrophilic segment and general-purpose hydrophobic polymers such as polylactic acid or polycaprolactone as the hydrophobic segment. In water, the hydrophobic segment self-assembles to form a core to encapsulate lipid-soluble drugs, while the hydrophilic segment forms a shell to maintain dispersion stability. Water-soluble drugs are usually dissolved in the external medium or encapsulated using reverse micelle technology. To further enhance permeability, existing techniques often add chemical penetration enhancers to the formulation for physical mixing, attempting to assist carrier penetration by perturbing the lipids of the stratum corneum.

[0005] The hydrophobic core of conventional polymeric micelle carriers is typically formed by the random entanglement of polymer segments through disordered hydrophobic interactions. This physical entanglement structure is relatively loose and lacks long-range order. When the carrier comes into contact with the skin surface, the significant differences in molecular configuration and size between the chemical structure of its hydrophobic side chains and the endogenous lipids in the stratum corneum prevent the carrier from effectively embedding or fusing into the lipid bilayer structure of the stratum corneum.

[0006] This structural mismatch leads to several key problems. First, the carrier struggles to form tight intermolecular interactions with stratum corneum lipids, relying primarily on passive diffusion through intercellular spaces, resulting in low transmembrane penetration efficiency and most active ingredients remaining only on the skin surface. Furthermore, the loose core structure of the carrier, lacking structured assembly with penetration-enhancing molecules, results in poor binding of the load, leading to premature leakage of active ingredients during diffusion. External moisture and oxygen can easily penetrate the loose core, causing discoloration and formulation failure due to vitamin C oxidation. Existing methods of simply physically mixing penetration enhancers do not address the compatibility issue between the carrier's structure and the skin barrier, failing to achieve a synergistic penetration effect. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method and application for improving the penetration rate of VC and VE based on multi-mechanism synergy, solving the problem of poor compatibility between the carrier structure and the skin barrier in existing technologies.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a composition for enhancing the penetration rate of vitamin C and vitamin E based on a multi-mechanism synergy, comprising the following raw material components by weight: Ascorbic acid 10.0-20.0 parts, tocopheryl acetate 0.5-2.0 parts, dual-responsive amphiphilic block copolymer 3.0-8.0 parts, biomimetic channel facilitator 0.3-1.5 parts, dipropylene glycol 30.0-45.0 parts, ethoxydiethylene glycol 2.0-5.0 parts, PEG-7 glyceryl cocoate 3.0-6.0 parts, preservative 0.5-1.0 parts, and the balance being water; The dual-responsive amphiphilic block copolymer is methoxy polyethylene glycol-b-poly(long-chain alkyl acrylate-co-phenylboronic acid monomer containing enzyme-cleaved linker arms); The biomimetic channel-clearing agent is selected from plant sphingosine or ceramide NP.

[0009] Preferably, the structural characteristics of the dual-responsive amphiphilic block copolymer satisfy: The molecular weight of the methoxy polyethylene glycol is 2000 Da-5000 Da; The long-chain alkyl acrylate is hexadecyl acrylate or octadecyl acrylate; The phenylboronic acid monomer containing the enzyme-cleaved linker arm is methacryloylglycylphenylalanylaminophenylboronic acid, which contains a glycine-phenylalanine short peptide linker arm that is sensitive to enzymes specific to the skin epidermis. The molar ratio of the long-chain alkyl acrylate to the phenylboronic acid monomer containing the enzyme-cleaved linker arm is 3:1 to 5:1.

[0010] Preferably, the dual-responsive amphiphilic block copolymer and the biomimetic channel facilitator satisfy a molecular size matching relationship: the number of alkyl carbon atoms in the side chain of the long-chain alkyl acrylate is defined as n, and the number of hydrophobic alkyl carbon atoms in the main chain of the biomimetic channel facilitator is defined as m, and n and m satisfy the following relationship: .

[0011] Preferably, the pH of the composition is 4.0-4.5, the ascorbic acid is covalently attached to the dual-responsive amphiphilic block copolymer via borate ester bonds, and the tocopheryl acetate is physically embedded in the hydrophobic microregions of the dual-responsive amphiphilic block copolymer.

[0012] A method for increasing the penetration rate of VC and VE based on multi-mechanism synergy includes the following steps: S1: Using methoxy polyethylene glycol as a macromolecular chain transfer agent, a copolymerization reaction was initiated between long-chain alkyl acrylates and phenylboronic acid monomers containing enzyme-cleaved linker arms to prepare a dual-responsive amphiphilic block copolymer. S2: Construct a precursor solution by dissolving the dual-responsive amphiphilic block copolymer in a dipropylene glycol aqueous solution matrix with a pH of 4.8-5.2, first adding ascorbic acid to react and form borate ester bonds, and then adding tocopheryl acetate and stirring homogenizing. S3: Co-assembly, add biomimetic channel-opening agent to the precursor solution obtained in step S2, heat to 45-55℃ and stir at a constant temperature, then cool to 25℃ at a rate of 1-2℃ / min. S4: Add ethoxydiethylene glycol, PEG-7 glyceryl cocoate and preservative to the system obtained in step S3, adjust the final pH to 4.0-4.5, filter and fill to obtain the final product.

[0013] According to the above technical solution: First, a dual-responsive amphiphilic block copolymer with both long-chain alkyl side chains and enzyme-cleaved linker arms is synthesized. A multi-stage pH control process is used to achieve specific covalent attachment of ascorbic acid and physical solubilization of tocopheryl acetate under weakly acidic conditions. A biomimetic channel-transfer agent matching the size of the polymer side chain is introduced. The carrier and the channel-transfer agent are driven to form a dense, ordered chain segment interdigitated assembly structure through thermal induction and controlled cooling annealing. The composition prepared by this method significantly improves transmembrane permeation efficiency through a synergistic molecular chaperone mechanism, while establishing a release logic based on a dual pH-enzyme environment response, thereby achieving high-precision site-specific release of active ingredients in the active epidermal layer of skin rich in specific enzymes and maximizing bioavailability.

[0014] Preferably, in step S1, the copolymerization reaction is a reversible addition-fragmentation chain transfer radical polymerization reaction; the reaction solvent is 1,4-dioxane or tetrahydrofuran, the initiator is azobisisobutyronitrile; the reaction temperature is 65-75℃, and the reaction time is 12-24 hours; after the reaction, unreacted monomers are removed by dialysis purification, and the molecular weight cutoff of the dialysis bag is 3500 Da.

[0015] Preferably, in step S2, the temperature for dissolving the dual-responsive amphiphilic block copolymer and adding ascorbic acid is controlled at 35-40°C. During the reaction of adding ascorbic acid, monitor the pH value of the system. If the pH is lower than 4.5, maintain the pH between 4.5 and 5.0 by adding alkali solution.

[0016] Preferably, in step S3, the mass ratio of the dual-responsive amphiphilic block copolymer to the biomimetic channel facilitator is controlled at 5:1 to 10:1; the isothermal stirring time is 45-60 minutes, so that the alkyl chain of the biomimetic channel facilitator and the hydrophobic side chain of the dual-responsive amphiphilic block copolymer undergo interdigital assembly.

[0017] Preferably, in step S4, the filtration uses a polyethersulfone microporous filter membrane with a pore size of 0.22 μm or 0.45 μm.

[0018] An application of a multi-mechanism synergistic composition for enhancing the penetration of vitamin C and vitamin E in the preparation of cosmetics with firming, anti-wrinkle, or skin brightening effects.

[0019] This invention provides a method and application for increasing the penetration rate of vitamin C and vitamin E based on multi-mechanism synergy. It has the following beneficial effects: 1. This invention utilizes a phenylboronic acid monomer containing an enzyme-cleaving linker to construct a release switch sensitive to pH and specific enzymes. Ascorbic acid is attached to a carrier via a borate ester bond and only dissociates and releases upon entering the active epidermal layer of the skin, which has a specific pH environment and contains specific enzymes. This mechanism effectively avoids the ineffective loss of active ingredients on the skin surface, significantly improving bioavailability and targeting.

[0020] 2. This invention enables ordered interdigitation between the hydrophobic side chains of the copolymer and the carbon chain length of the biomimetic channel facilitator by limiting the matching relationship between the two. While increasing the fluidity of stratum corneum lipids, the biomimetic channel facilitator acts as a molecular chaperone to protect the carrier structure and allow it to pass through the stratum corneum barrier intact, thereby achieving efficient penetration of water-soluble and lipid-soluble components.

[0021] 3. This invention blocks the easily oxidized structure of ascorbic acid at the molecular level by forming reversible borate ester bonds, while simultaneously utilizing the hydrophobic microdomains of block copolymers to physically solubilize tocopheryl acetate. This strategy, combining covalent bonding and physical encapsulation, effectively solves the technical challenges of easy oxidation and discoloration of vitamin C and poor solubility of vitamin E in water-based systems without relying on large amounts of surfactants. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the process steps of the improvement method of the present invention. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. 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.

[0024] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Unless otherwise specified, all reagents are commercially available analytical grade or higher quality products: L-Ascorbic Acid: Purity ≥99%, CAS No.: 50-81-7; DL-alpha-Tocopheryl Acetate: Purity ≥98%, CAS No.: 7695-91-2; Hexadecyl Acrylate: Purity ≥95%, CAS No.: 13402-02-3; Octadecyl Acrylate: Purity ≥97%, CAS No.: 4813 -57-4; Butyl Acrylate: Purity ≥99%, CAS No.: 141-32-2; Phytosphingosine: Purity ≥95%, CAS No.: 554-62-1; Ceramide NP: Purity ≥95%, CAS No.: 100403-19-8; Methoxylated Polyethylene Glycol (mPEG-OH): Number Average Molecular Weight (Mn) 2000 and 5000 respectively, CAS No.: 9004-74-4; S-1-Dodecyl-S'-(α,α'-Dimethyl-α''-Acetic Acid) Trithiocarbonate (DDMAT): Purity ≥97%, CAS No.: 46164 2-78-4 (chain transfer agent); Glycyl-L-phenylalanine: purity ≥98%, CAS No.: 721-66-4; 3-Aminophenylboronicacid: purity ≥98%, CAS No.: 30418-59-8; Methacrylicacid: purity ≥99%, CAS No.: 79-41-4; 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl): purity ≥98%, CAS No.: 25952-53-8; N-hydroxysuccinimide (NHS): purity ≥98%, CA S No.: 6066-82-6; AIBN: Purity ≥98%, CAS No.: 78-67-1; Dipropylene Glycol: Purity ≥99%, CAS No.: 25265-71-8; Diethylene glycol monoethylether: Purity ≥99%, CAS No.: 111-90-0; PEG-7 Glyceryl Cocoate: Cosmetic grade, CAS No.: 68201-46-7; Phenoxyethanol: Purity ≥99%, CAS No.: 122-99-6.

[0025] Synthetic Example 1: Preparation of phenylboronic acid monomer (monomer M2) containing an enzyme-cleaved linker arm Glycyl-L-phenylalanine (Gly-Phe, 10.0 mmol) was dissolved in dry dimethylformamide (DMF), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl, 12.0 mmol) and N-hydroxysuccinimide (NHS, 12.0 mmol) were added. The mixture was stirred and activated for 2 hours in an ice bath at 0 °C.

[0026] Add 10.0 mmol of 3-aminophenylboronic acid in DMF solution to the above system dropwise, and then allow the mixture to return to room temperature for 24 hours after the addition is complete.

[0027] After the reaction was completed, most of the solvent was removed by rotary evaporation. The residue was extracted with ethyl acetate, washed successively with dilute hydrochloric acid, saturated sodium bicarbonate solution and saturated brine, dried over anhydrous sodium sulfate, and concentrated to obtain the intermediate Gly-Phe-NH-C6H4-B(OH)2.

[0028] The above intermediate was redissolved in dichloromethane, and triethylamine (15.0 mmol) was added. Methacrylamide (12.0 mmol) was then slowly added dropwise at 0 °C.

[0029] After the addition was complete, the reaction was carried out at room temperature for 12 hours. The reaction solution was washed with water, dried, and separated by column chromatography (eluent: dichloromethane / methanol = 20:1). After vacuum drying, a pale yellow solid powder was obtained, which is the phenylboronic acid monomer containing the enzyme-cleaved linker arm (monomer M2: methacryloylglycylphenylalanylaminophenylboronic acid).

[0030] Synthesis Example 2: Preparation of dual-responsive amphiphilic block copolymer A-1 (corresponding to C16 side chain) Chain transfer agent preparation: Methoxy polyethylene glycol (mPEG-OH, Mn=2000, 1.0 mmol), DDMAT (1.2 mmol) and dicyclohexylcarbodiimide (DCC, 1.5 mmol) were reacted in dichloromethane for 48 hours, and the macromolecular chain transfer agent mPEG2000-CTA was obtained by precipitation and purification.

[0031] Copolymerization reaction: In a reaction flask equipped with a condenser and a nitrogen inlet and outlet, mPEG2000-CTA (0.5 mmol), hexadecyl acrylate (monomer M1, n=16, 20.0 mmol), monomer M2 (5.0 mmol) prepared in Synthesis Example 1, and azobisisobutyronitrile (AIBN, 0.1 mmol) were added.

[0032] Note: The molar ratio of M1 to M2 is 4:1. Add anhydrous 1,4-dioxane (40 mL) as a solvent and purge with nitrogen for 45 minutes to remove oxygen. Place in a 70°C oil bath and stir magnetically for 18 hours. After the reaction is complete, add the reaction solution dropwise into excess cold diethyl ether to precipitate, and filter to collect the solid.

[0033] The solid was dissolved in a small amount of tetrahydrofuran, placed in a dialysis bag with a molecular weight cutoff of 3500 Da, dialyzed against deionized water for 48 hours, and then freeze-dried to obtain a dual-responsive amphiphilic block copolymer A-1.

[0034] Synthesis Example 3: Preparation of dual-responsive amphiphilic block copolymer A-2 (corresponding to C18 side chain) Chain transfer agent preparation: methoxy polyethylene glycol (mPEG-OH) with Mn=5000 was selected and mPEG5000-CTA was prepared in the same manner as in Synthesis Example 2.

[0035] Copolymerization reaction: mPEG5000-CTA (0.2 mmol), octadecyl acrylate (monomer M1, n=18, 12.0 mmol), monomer M2 (4.0 mmol) prepared in Synthesis Example 1, and AIBN (0.04 mmol) were added to the reaction flask.

[0036] Note: The molar ratio of M1 to M2 is 3:1; anhydrous tetrahydrofuran (30 mL) is added, and nitrogen is purged for 30 minutes to remove oxygen; the mixture is placed in an oil bath at 65°C and reacted at a constant temperature for 24 hours; the post-treatment steps are the same as in Synthesis Example 2, to obtain the dual-responsive amphiphilic block copolymer A-2.

[0037] Example 1 Please see the appendix Figure 1 This embodiment provides a composition for improving the penetration rate of VC and VE based on multi-mechanism synergy.

[0038] The raw material composition by weight is as follows: 10.0 parts ascorbic acid, 0.5 parts tocopheryl acetate, 3.0 parts dual-responsive amphiphilic block copolymer A-1 (prepared from synthetic example 2, n=16), 0.3 parts phytosphingosine (bionic channel facilitator, m≈18), 30.0 parts dipropylene glycol, 2.0 parts ethoxydiethylene glycol, 3.0 parts PEG-7 glyceryl cocoate, 0.5 parts phenoxyethanol (preservative), and 50.7 parts deionized water (total 100 parts).

[0039] Preparation methods include: Step S1: Prepare dual-responsive amphiphilic block copolymer A-1 according to the method of Synthesis Example 2.

[0040] Step S2: In a mixing tank, dipropylene glycol and deionized water are mixed, and the pH of the matrix is ​​adjusted to 4.8 with 10% NaOH solution. 3.0 parts of copolymer A-1 are added, and the mixture is heated to 35°C and stirred to dissolve. 10.0 parts of ascorbic acid are slowly added, maintaining the pH between 4.5 and 5.0, and the mixture is stirred for 40 minutes to form borate ester bonds. Subsequently, 0.5 parts of tocopheryl acetate are added, and the mixture is homogenized at 800 rpm for 15 minutes to obtain the precursor solution.

[0041] Step S3: Dissolve 0.3 parts of phytosphingosine in a small amount of dipropylene glycol and add the precursor solution. Heat the system to 45°C and stir at a constant temperature for 60 minutes. Then turn on the circulating water cooling and control the cooling rate at 1°C / min to cool down to 25°C.

[0042] Step S4: Add ethoxydiethylene glycol, PEG-7 glyceryl cocoate, and phenoxyethanol, and stir until homogeneous. Adjust the final pH to 4.0 with NaOH solution. Filter using a 0.22 μm polyethersulfone membrane and fill into vials.

[0043] Example 2 This embodiment provides a composition for increasing the penetration rate of vitamin C and vitamin E based on a multi-mechanism synergy.

[0044] The raw material composition by weight is as follows: 15.0 parts ascorbic acid, 1.2 parts tocopheryl acetate, 5.5 parts dual-responsive amphiphilic block copolymer A-2 (prepared from synthetic example 3, n=18), 0.9 parts ceramide NP (bionic channel facilitator, m≈18), 37.5 parts dipropylene glycol, 3.5 parts ethoxydiethylene glycol, 4.5 parts PEG-7 glyceryl cocoate, 0.8 parts phenoxyethanol, and 31.1 parts deionized water (total 100 parts).

[0045] Preparation methods include: Step S1: Prepare dual-responsive amphiphilic block copolymer A-2 according to the method of Synthesis Example 3.

[0046] Step S2: Mix dipropylene glycol and deionized water, and adjust the pH to 5.0. Add 5.5 parts of copolymer A-2 and heat to 38°C to dissolve. Add 15.0 parts of ascorbic acid, monitor the pH to ensure it does not fall below 4.5, and stir the reaction. Then add 1.2 parts of tocopheryl acetate and homogenize at 900 rpm.

[0047] Step S3: Add 0.9 parts of ceramide NP. Heat the system to 50°C and stir at that temperature for 50 minutes. Then cool to 25°C at a rate of 1.5°C / min.

[0048] Step S4: Add the remaining excipients and adjust the final pH to 4.2. Filter using a 0.45μm polyethersulfone membrane and fill to obtain the final product.

[0049] Example 3 This embodiment provides a composition for increasing the penetration rate of vitamin C and vitamin E based on a multi-mechanism synergy.

[0050] The raw material composition by weight is as follows: 20.0 parts ascorbic acid, 2.0 parts tocopheryl acetate, 8.0 parts dual-responsive amphiphilic block copolymer A-1 (prepared from synthetic example 2, n=16), 1.5 parts phytosphingosine (bionic channel facilitator, m≈18), 45.0 parts dipropylene glycol, 5.0 parts ethoxydiethylene glycol, 6.0 parts PEG-7 glyceryl cocoate, 1.0 part phenoxyethanol, and 11.5 parts deionized water (total 100 parts).

[0051] Preparation method: Step S1: Prepare dual-responsive amphiphilic block copolymer A-1 according to the method of Synthesis Example 2.

[0052] Step S2: Mix dipropylene glycol and deionized water, and adjust the pH to 5.2. Add 8.0 parts of copolymer A-1 and heat to 40°C to dissolve. Add 20.0 parts of ascorbic acid, and add alkali solution dropwise to maintain the pH at around 4.8. The reaction time is 45 minutes. Then add 2.0 parts of tocopheryl acetate and stir homogenously at 1000 rpm.

[0053] Step S3: Add 1.5 parts of phytosphingosine. Heat the system to 55°C and stir at that temperature for 45 minutes. Then cool to 25°C at a rate of 2°C / min.

[0054] Step S4: Add the remaining excipients and adjust the final pH to 4.5. Filter using a 0.45μm polyethersulfone membrane and fill to obtain the final product.

[0055] To verify the technical effects of the present invention, the following comparative examples were provided.

[0056] Comparative Example 1 Compared with Example 1, the difference is that in the copolymerization reaction in step S1, equimolar amounts of butyl acrylate (n=4) were used to replace hexadecyl acrylate (n=16) as the hydrophobic monomer M1, and a comparative copolymer with severely mismatched side chain lengths was prepared; the other raw material types, amounts and preparation process parameters were the same.

[0057] Comparative Example 2 Compared with Example 1, the difference is that in the copolymerization reaction in step S1, an equimolar amount of 3-methacrylamidophenylboronic acid (without glycine-phenylalanine dipeptide linker) is used to replace the phenylboronic acid monomer M2 containing the enzyme-cleaved linker; the other raw material types, amounts and preparation process parameters are the same.

[0058] Comparative Example 3 The difference compared to Example 1 is as follows: In step S1, an equimolar amount of methyl methacrylate is used to replace the phenylboronic acid monomer M2 containing the enzyme-cleaved linker arm to prepare a contrast copolymer without phenylboronic acid groups; In step S2, no pH adjustment is performed to promote the formation of borate ester bonds, and ascorbic acid is dissolved in the matrix only by physical stirring; the other raw material types, amounts, and preparation process parameters are the same.

[0059] Comparative Example 4 Compared with Example 1, the difference is that: in step S3, phytosphingosine is not added, and the corresponding reduction in mass is made up by dipropylene glycol; the other raw material types, amounts and preparation process parameters are the same.

[0060] Comparative Example 5 Compared with Example 1, the difference is that: dual-responsive amphiphilic block copolymer A-1 and phytosphingosine are not added, and ascorbic acid and tocopheryl acetate are directly dissolved in a mixed solvent composed of dipropylene glycol, ethoxydiethylene glycol, PEG-7 glyceryl cocoate and water; all other aspects are the same.

[0061] Test Example 1: Antioxidant Stability Test Experimental Description: This test example is used to determine the chemical stability of the active ingredient ascorbic acid in the compositions prepared in each example and comparative example under accelerated aging conditions. High-performance liquid chromatography (HPLC) was used to quantitatively analyze the retention rate of ascorbic acid. The specific steps are as follows: Sample preparation: Take fresh composition samples prepared in Examples 1-3 and Comparative Examples 1-5 respectively, dispense them into 20mL brown glass vials, and seal them with nitrogen gas.

[0062] Accelerated aging conditions: The sealed sample was stored in a constant temperature and humidity chamber at 45°C and 75% relative humidity, away from light.

[0063] Sampling time points: Samples were collected and tested at the beginning of the experiment (Day 0), Day 14, and Day 28.

[0064] Sample determination: Accurately measure 0.5 g of the sample to be tested, place it in a 50 mL volumetric flask, add the mobile phase (0.1% phosphoric acid solution: methanol = 95:5) to dilute to the mark, sonicate for 5 minutes, and filter through a 0.45 μm microporous membrane to obtain the test solution.

[0065] Chromatographic conditions: C18 column (4.6 mm × 250 mm, 5 μm); mobile phase: 0.1% phosphoric acid aqueous solution-methanol (95:5, v / v); flow rate: 1.0 mL / min; detection wavelength: 245 nm; column temperature: 25 ℃; injection volume: 10 μL.

[0066] Data Calculation: Record the chromatographic peak area of ​​ascorbic acid and calculate the retention rate according to the following formula: .

[0067] Table 1: Ascorbic acid retention rate data of each example and comparative example under accelerated aging conditions at 45°C Table 1 shows that after 28 days of storage at 45°C, the retention rate of ascorbic acid in Examples 1 to 3 remained above 91%, significantly higher than that in Comparative Examples 3 and 5. This result verifies the contribution of the covalent loading strategy to the stability of the active ingredient. In the systems of Examples 1-3, the vicinal diol structure in the ascorbic acid molecule, which is highly susceptible to oxidation, underwent a dehydration condensation reaction with the phenylboronic acid group on the side chain of the dual-responsive amphiphilic block copolymer, forming a reversible borate bond. This chemical bonding altered the electron distribution of ascorbic acid, thereby blocking its oxidation reaction pathway. In contrast, although Comparative Example 3 contained a polymer carrier, the lack of phenylboronic acid groups in the monomer structure meant that ascorbic acid existed only in a physically mixed form and could not form covalent protection; Comparative Example 5 completely lacked carrier protection, resulting in ascorbic acid being directly exposed to the aqueous medium and rapidly degrading under the influence of heat and oxygen.

[0068] The retention rates of Examples 1-3 were also superior to those of Comparative Examples 1 and 4, indicating that molecular size matching and the addition of the biomimetic channel-conducting agent play a role in maintaining the microstructural stability of the system. In the example systems, the number of carbon atoms n in the hydrophobic side chain of the dual-responsive amphiphilic block copolymer and the number of carbon atoms m in the hydrophobic alkyl chain of the biomimetic channel-conducting agent satisfy the following condition: The size matching facilitates the formation of a tight interdigitated chain structure within the hydrophobic microregion, creating a dense hydrophobic barrier that limits the diffusion rate of external water and oxygen molecules to the core. In contrast, Comparative Example 1, due to its large difference in carbon chain length (|nm|=14), cannot form effective interdigitated assembly, resulting in a loose aggregate structure. Comparative Example 4 lacks a biomimetic channel facilitator and the auxiliary assembly effect of molecular chaperones, both of which lead to a decrease in the physical shielding effectiveness against the active ingredient, thus manifesting as a reduction in retention rate data.

[0069] Comparative Example 2 exhibited a retention rate of 92.03% similar to that of the Example in the stability test. This is because, although Comparative Example 2 lacked the glycine-phenylalanine dipeptide linker, it still retained the phenylboronic acid group, which can form a borate ester bond with ascorbic acid. This indicates that, under various physicochemical stability test dimensions, the presence of the phenylboronic acid group is the dominant factor determining the chemical stability of ascorbic acid. The difference between this comparative example and the Example will mainly lie in the subsequent steps involving specific enzymatic cleavage and release. However, under the static storage conditions described in this test example, the chemical protection mechanism of both is consistent, and the data results are in line with the expectations of the technical solution design.

[0070] Test Example 2: In vitro transdermal permeability test Experimental Description: This test example uses a modified Franz vertical diffusion cell apparatus to evaluate the in vitro transdermal permeability and dermal retention of the active ingredients ascorbic acid and tocopheryl acetate in the compositions prepared in each example and comparative example.

[0071] Skin preparation: Skin from the back of Bama miniature pigs was selected, subcutaneous adipose tissue and connective tissue were removed, and the skin was washed with physiological saline to prepare skin sections with a thickness of approximately 1.0 mm. The skin sections were immersed in physiological saline for equilibration for 30 minutes, and then fixed between the supply and receiving chambers of the Franz diffusion cell, with the stratum corneum facing the supply chamber.

[0072] Apparatus setup: The effective permeation area of ​​the diffusion cell is 1.77 cm², and the volume of the receiving chamber is 12 mL. The receiving solution is phosphate-buffered saline (PBS, pH 7.4) containing 0.5% Tween-80 to ensure the solubility of the transdermal components and to simulate the subcutaneous physiological environment. The receiving chamber is placed on a thermostatic magnetic stirrer, with the temperature controlled at 32 ± 0.5 °C and the stirring speed at 300 rpm.

[0073] Dosage and sampling: Add 1.0 g of the sample to be tested to the supply chamber and seal to prevent evaporation. At 4, 8, 12 and 24 hours after administration, aspirate 1.0 mL of the receiving solution from the side arm of the receiving chamber and immediately replenish with an isothermal and equal volume of fresh blank receiving solution.

[0074] Skin extraction: After the 24-hour permeability test, the skin slices were removed, and excess sample was washed off with deionized water. The skin was then minced and subjected to ultrasonic extraction in methanol for 30 minutes. The supernatant was collected by centrifugation as the retained skin sample.

[0075] Content determination: The concentrations of ascorbic acid and tocopheryl acetate in the receiving solution and cortical extract were determined by high performance liquid chromatography. The 24-hour cumulative permeation and 24-hour cortical retention were calculated according to Fick's first diffusion law.

[0076] Table 2: In vitro transdermal penetration and skin retention test data for each embodiment and comparative example Table 2 shows that the cumulative penetration of ascorbic acid and the dermal retention of tocopheryl acetate in Examples 1 to 3 were significantly better than those in Comparative Examples 1, 4, and 5. Compared with Comparative Example 5, which contained only a physical mixed solvent, the ascorbic acid penetration of the Example groups increased by more than 4 times, confirming the effectiveness of the dual-responsive amphiphilic block copolymer carrier system in overcoming the stratum corneum barrier. Meanwhile, the data for Example 2 were slightly better than those for Examples 1 and 3, which is completely consistent with the number of carbon atoms in the hydrophobic side chain (n=18) and the number of carbon atoms in the biomimetic channel facilitator (m=18) in Example 2. The data from Comparative Example 2 are similar to those from the Example 1, indicating that the highly matched molecular sizes facilitate the formation of a more compact transport configuration. The data from Comparative Example 2 are close to those from the Example 1, indicating that in a single receiving solution environment at pH 7.4, changes in the connecting arm structure do not significantly affect the overall passive diffusion and permeation performance; the difference is mainly reflected in the subsequent enzyme response release stage.

[0077] Comparing the data differences between the examples and Comparative Example 1 reveals the crucial role of the molecular size matching relationship between the hydrophobic side chains of the carrier and the biomimetic channel-conducting agent. The systems of the examples meet the requirements. Under certain conditions, the alkyl chains of the biomimetic channel facilitator can embed into the hydrophobic core of the copolymer, resulting in ordered interdigitated chain segment assembly. This structure stabilizes the carrier on the one hand, and reduces transmembrane resistance by utilizing the principle of similarity and compatibility between the biomimetic channel facilitator and stratum corneum lipids on the other.

[0078] In Comparative Example 1, the use of butyl acrylate (n=4) resulted in a carbon chain length difference of 14 between it and phytosphingosine (m=18), preventing the formation of interdigitated structures. This size mismatch prevented the biomimetic channel-conducting agent from effectively anchoring to the carrier, leading to phase separation during penetration and failing to exert a synergistic molecular chaperone effect, thus significantly reducing the delivery efficiency of the active ingredient.

[0079] Comparing the data of the examples and Comparative Example 4, it can be seen that in the absence of a biomimetic channel-opening agent (Comparative Example 4), although the dual-responsive amphiphilic block copolymer is still present as a carrier, its permeation and retention both decrease significantly.

[0080] This indicates that single polymer micelles still face significant resistance when traversing the dense stratum corneum. The biomimetic channel-conducting agent, phytosphingosine / ceramide, not only acts as a physical solubilizer in the system, but more importantly, as a structural analog of stratum corneum lipids, it can temporarily disrupt the ordered arrangement of the stratum corneum lipid bilayer, increasing lipid fluidity. In the examples, this molecule with permeation-enhancing function was assembled onto the carrier surface through hydrophobic interactions, essentially equipping the carrier with navigation and ice-breaking components, thereby achieving the efficient co-delivery of the water-soluble component ascorbic acid and the lipid-soluble component tocopheryl acetate.

[0081] Test Example 3: Release Characteristic Test Experimental Description: This test case uses the dialysis bag method to simulate the physiological microenvironment of different layers of the skin, and measures the ascorbic acid release behavior of each embodiment and comparative example under different pH values ​​and enzyme presence conditions. The aim is to verify the response mechanism and site-specific release capability of the technical solution to environmental stimuli.

[0082] Preparation of release media: Three different release media were prepared to simulate the skin environment: Medium A: Simulates the product storage environment and skin surface: Citrate-disodium hydrogen phosphate buffer, adjusted to pH 5.0.

[0083] Medium B: Simulates physiological body fluid environment: phosphate buffer, adjusted to pH 7.4.

[0084] Medium C: Simulating the active epidermal environment: Add cathepsin B to PBS buffer at pH 7.4 to a final concentration of 50 U / mL.

[0085] Sample loading: Take 5.0 g of each of the samples prepared in Example 1, Example 2, Comparative Example 2 and Comparative Example 3, weigh them accurately, place them in a regenerated cellulose dialysis bag with a molecular weight cutoff of 3500 Da, and tie the bag tightly.

[0086] Release experiment: The dialysis bag containing the sample was immersed in a stoppered conical flask containing 200 mL of the above different release media (media A, B, C).

[0087] Isothermal oscillation: Place the conical flask in an isothermal water bath shaker, set the temperature to 37±0.5℃ and the oscillation frequency to 100rpm.

[0088] Sampling and determination: At 24 hours (T=24h) of release, 5.0 mL of solution was taken from the release medium and immediately filtered through a 0.22 μm microporous membrane. The concentration of ascorbic acid in the filtrate was determined using the high performance liquid chromatography method described in Test Example 1, and the cumulative release rate of ascorbic acid over 24 hours was calculated based on the total feed amount.

[0089] Table 3: Cumulative release rate of ascorbic acid in each group of samples under different environmental conditions over 24 hours Table 3 reveals the fundamental regulatory role of environmental pH in the release behavior of ascorbic acid. In medium A (pH 5.0), the cumulative release rates of Examples 1, 2, and Comparative Example 2 remained at a low level of below 7.2%, while the release rate of Comparative Example 3, which used a physical mixing method, reached as high as 92.14%. This difference confirms the effectiveness of the borate ester bonding strategy in this technical solution. Under weakly acidic conditions, the five-membered ring borate ester structure formed by the vicinal diol structure in the ascorbic acid molecule and the phenylboronic acid group in the polymer side chain is in a thermodynamically stable state. This chemical bond restricts the free diffusion of ascorbic acid out of the dialysis bag, thereby achieving a "lock-in" effect in a non-targeted environment.

[0090] When the ambient pH value increased to 7.4 in medium B, the release rate of Examples 1, 2 and Comparative Example 2 increased to the range of 30%-36%. This is because the increased alkalinity of the environment caused the hydrolysis equilibrium of the borate ester bond to shift towards dissociation, resulting in the shedding and release of some ascorbic acid molecules, demonstrating a response to the pH gradient.

[0091] Comparing the data differences between the Examples and Comparative Example 2 in medium C clarifies the decisive role of the enzyme-cleaved linker arm in achieving high-precision site-specific release. In medium C containing cathepsin B, the cumulative release rates of Examples 1 and 2 showed a jump, reaching 88.92% and 91.05%, respectively, significantly higher than their release levels in a simple pH 7.4 environment (medium B). This is because the phenylboronic acid monomer in the examples contains a glycine-phenylalanine dipeptide linker arm, and this specific peptide bond structure can be specifically recognized and cleaved by cathepsin B. The breaking of the linker arm causes the phenylboronic acid group, along with the attached ascorbic acid, to detach from the polymer backbone, transforming into a smaller molecule state, thereby accelerating the diffusion process across the dialysis membrane.

[0092] Conversely, the release rate of Comparative Example 2 (34.89%) in medium C was not significantly different from its release rate of 33.21% in medium B. Because the polymer side chain of Comparative Example 2 lacks specific enzymatic linker arms, its phenylboronic acid groups are directly or via non-enzyme-sensitive segments attached to the main chain, and therefore cannot be cleaved by cathepsin B. Thus, even in a simulated environment with high enzyme activity, the release behavior of Comparative Example 2 is only controlled by the effect of pH on the hydrolysis equilibrium of the borate ester bond and cannot respond to enzyme signals.

[0093] The above results indicate that the active ingredient will only be released explosively when specific pH and enzyme conditions are met simultaneously, thus ensuring that the delivery system maintains structural integrity and load stability before reaching the enzyme-rich active epidermal layer.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-mechanism synergistic based VC, VE permeability enhancing composition, characterized in that, The composition comprises the following raw material components by weight parts: Ascorbic acid 10.0-20.0 parts, tocopheryl acetate 0.5-2.0 parts, double-responsive amphiphilic block copolymer 3.0-8.0 parts, biomimetic channel dredging agent 0.3-1.5 parts, dipropylene glycol 30.0-45.0 parts, ethoxydiglycol 2.0-5.0 parts, PEG-7 glyceryl cocoate 3.0-6.0 parts, preservative 0.5-1.0 parts, and the balance of water; The double-responsive amphiphilic block copolymer is methoxypolyethylene glycol-b-poly(long chain alkyl acrylate-co-enzyme-cleavable linker-containing phenylboronic acid monomer); The biomimetic channel dredging agent is selected from phytosphingosine or ceramide NP.

2. The multi-mechanism synergistic based VC, VE permeability enhancing composition of claim 1, wherein: The structural characteristics of the double-responsive amphiphilic block copolymer satisfy: The molecular weight of the methoxypolyethylene glycol is 2000 Da-5000 Da; The long chain alkyl acrylate is hexadecyl acrylate or octadecyl acrylate; The enzyme-cleavable linker-containing phenylboronic acid monomer is methacryloylglycylphenylalanylamino phenylboronic acid, which contains a glycine-phenylalanine short peptide linker sensitive to skin epidermal layer-specific enzymes; The molar ratio of the long chain alkyl acrylate to the enzyme-cleavable linker-containing phenylboronic acid monomer is 3:1 to 5:

1.

3. The multi-mechanism synergistic based VC, VE permeability enhancing composition of claim 2, wherein: The dual-responsive amphiphilic block copolymer and the biomimetic channeling agent satisfy a molecular size matching relationship: defining the number of alkyl carbon atoms of the side chain of the long chain alkyl acrylate as n, defining the number of alkyl carbon atoms of the main chain of the biomimetic channeling agent as m, n and m satisfy the following relationship: .

4. The multi-mechanism synergistic based VC, VE permeability enhancing composition of claim 1, wherein: The pH value of the composition is 4.0-4.5, the ascorbic acid is covalently attached to the double-responsive amphiphilic block copolymer through a boronate ester bond, and the tocopheryl acetate is physically embedded in the hydrophobic microdomains of the double-responsive amphiphilic block copolymer.

5. A method for improving the permeability of VC and VE based on multi-mechanism synergy, characterized in that: A VC, VE permeability enhancing composition based on multi-mechanism synergy according to any one of claims 1-4, comprising the following steps: S1: using methoxypolyethylene glycol as a macromolecular chain transfer agent, initiating copolymerization of long chain alkyl acrylate and enzyme-cleavable linker-containing phenylboronic acid monomer to prepare a double-responsive amphiphilic block copolymer; S2: constructing a precursor solution, dissolving the double-responsive amphiphilic block copolymer in a dipropylene glycol aqueous solution matrix with a pH of 4.8-5.2, adding ascorbic acid to form a boronate ester bond, and then adding tocopheryl acetate and homogenizing and stirring; S3: synergistically assembling, adding a biomimetic channel dredging agent to the precursor solution obtained in step S2, warming to 45-55°C for constant temperature stirring, and then cooling to 25°C at a rate of 1-2°C / min; S4: adding ethoxydiglycol, PEG-7 glyceryl cocoate, and a preservative to the system obtained in step S3, adjusting the final pH to 4.0-4.5, and filtering and filling to obtain the product.

6. The method of claim 5, wherein the method is characterized by: In the S1 step, the copolymerization reaction is a reversible addition-fragmentation chain transfer radical polymerization reaction; the reaction solvent is 1,4-dioxane or tetrahydrofuran, and the initiator is azobisisobutyronitrile; the reaction temperature is 65-75°C, and the reaction time is 12-24 hours; after the reaction, the unreacted monomers are removed by dialysis purification, and the dialysis bag has a molecular weight cut-off of 3500 Da.

7. The method of claim 5, wherein the method is characterized by: In the S2 step, the temperature for dissolving the double-responsive amphiphilic block copolymer and adding ascorbic acid is controlled at 35-40°C; During the ascorbic acid adding reaction process, the pH value of the system is monitored, and if the pH value is lower than 4.5, alkali is added to maintain the pH value between 4.5 and 5.

0.

8. The method of claim 5, wherein the method is characterized by: In the S3 step, the mass ratio of the double-responsive amphiphilic block copolymer to the biomimetic channeling agent is controlled to be 5:1 to 10:1; the constant temperature stirring time is 45-60 minutes, so that the alkyl chain of the biomimetic channeling agent and the hydrophobic side chain of the double-responsive amphiphilic block copolymer are inserted and assembled.

9. The method of claim 5, wherein the method is characterized by: In the S4 step, the filtration adopts a polyether sulfone microporous filter membrane with a pore size of 0.22 μm or 0.45 μm.

10. A multi-mechanism synergistic VC, VE permeability enhancing composition application according to any one of claims 1-4, characterized in that, The application in the preparation of cosmetics with the effects of firming, anti-wrinkling or skin lightening.

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