Preparation method and application of ursolic acid-based vesicle gel

Abstract

The molecular structure of the ursolic acid amine oxide surfactant is as follows: # imgabs0 #. The ursolic acid amine oxide surfactant provided by the invention can be self-assembled in an aqueous solution to form vesicles, the size of the vesicles is between 10 and 200nm, and the vesicles are uniformly dispersed in the aqueous solution. When the concentration of the ursolic acid amine oxide surfactant is greater than 60mmol. L <-1 >, the vesicles are stacked at high density, and water molecules are fixed through capillary action, surface tension and other actions, so that stable hydrogel is formed. The vesicle hydrogel is obtained from a natural product ursolic acid, is mild in property and can be applied to the fields of drug sustained release, tissue engineering, daily chemicals, medicines and the like.

Description

Technical Field

[0001] The present invention belongs to the fields of supramolecular chemistry, surfactant science and utilization of natural product chemistry, and relates to the preparation and application of ursolic acid-based vesicle gels. Background Art

[0002] Vesicle gels are a special soft matter formed by the self-assembly of amphiphilic molecules in aqueous solutions. The amphiphilic molecules self-assemble into spherical or ellipsoidal vesicles with a hollow structure. The formation of vesicle gels is closely related to the characteristics of their three-dimensional network structure. These networks not only trap a large amount of solvent, but also endow the gels with high hydration and structural tunability. Vesicle gels have been widely used in fields such as controlled release systems, tissue engineering, and biomimicry due to their unique physical properties. For example, in the field of drug delivery, the high hydration and tunable structure of vesicle gels enable them to effectively encapsulate drugs and optimize drug release by controlling the size and stability of the vesicles. In tissue engineering, vesicle gels provide an environment that mimics the extracellular matrix, supporting cell growth and tissue regeneration. In addition, the structural and functional similarities of vesicle gels play an important role in biomimicry in simulating the physical and chemical properties of cell membranes and studying cell-cell interactions and signal transduction. The design and synthesis of small molecule hydrogel agents using natural products as the main raw materials contribute to the construction of environmentally friendly and biocompatible vesicle gel systems that meet the requirements. Ursolic acid, a natural product widely present in plants, has attracted much attention due to the excellent biocompatibility and low toxicity of its derivatives. It is very suitable as a raw material for preparing biomedical materials, but its low water solubility limits its wide application. So far, there has been no report on ursolic acid vesicle gel systems. If an ursolic acid vesicle gel system can be obtained, it will greatly expand the application scope of the natural product ursolic acid and the research scope of hydrogels. Summary of the Invention

[0003] Technical problems to be solved: Using ursolic acid as a raw material, through molecular design and a series of reactions, the present invention obtains an ursolic acid-based amine oxide surfactant 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide (UA-6-AO). The present invention uses this molecule as a building block to prepare a vesicle hydrogel system, laying a foundation for the application research of ursolic acid in supramolecular hydrogels.

[0004] Technical solutions: The first object of the present invention is to provide a compound 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide, and its structural formula is shown as the following formula: The second object of the present invention is to provide a method for synthesizing the compound, which synthesizes 6-ursolic acid-based N,N-dimethyl-hexylamine oxide using ursolic acid as a raw material. Preferably, the method for synthesizing the compound comprises the following steps: S1. Ursolic acid and N-Boc-1,6-hexanediamine undergo a condensation reaction catalyzed by 2-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) to obtain a Boc-protected ursolic acid amide-based primary amine compound; S2. The Boc-protected ursolic acid amide-based primary amine compound obtained in S1 is reacted with trifluoroacetic acid to obtain an ursolic acid amide-based primary amine compound; S3. After dissolving the ursolic acid amide obtained in S2, formic acid and formaldehyde are added and reacted to obtain an ursolic acid amide-based tertiary amine compound; S4. The ursolic acid amide-based tertiary amine compound obtained in S3 is reacted with hydrogen peroxide under the catalysis of catalysts citric acid and disodium ethylenediaminetetraacetate to obtain 6-ursolic acid-based N,N-dimethyl-hexylamine oxide. Preferably, the molar ratio of ursolic acid to N-Boc-1,6-hexanediamine is 1 to 4:1 to 10, the molar ratio of the protected ursolic acid amide-based primary amine compound to trifluoroacetic acid is 1 to 5:5 to 30, the molar ratio of the ursolic acid amide-based primary amine compound, formic acid and formaldehyde is 1 to 4:1 to 10:1 to 10, and the molar ratio of the ursolic acid amide-based tertiary amine compound to hydrogen peroxide is 1 to 5:1 to 10. The third object of the present invention is to provide the application of the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide in the fields of drug sustained release, biotechnology, environmental engineering or daily chemicals. The fourth object of the present invention is to provide a vesicle hydrogel, which comprises the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide as a gel factor. Preferably, the vesicle hydrogel is formed by dissolving 6-ursolic acid-based N,N-dimethyl-hexylamine oxide in a certain amount of water. Preferably, the concentration range of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide in the vesicle hydrogel is 5 to 300 mmol·L -1 , and the vesicle size ranges from 10 to 200 nm. The fifth object of the present invention is to provide a sustained release material, which comprises 6-ursolic acid-based N,N-dimethyl-hexylamine oxide and a substance to be sustained released. Preferably, the sustained release material comprises 6-ursolic acid-based N,N-dimethyl-hexylamine oxide and at least one substance to be sustained released, and is used for preparing a long-acting delivery system. The sixth object of the present invention is to provide a medical wound dressing, which forms a hydrogel with 6-dehydroabietylamide-N,N-dimethyl-hexyloxide amine as a gel skeleton, effectively supports wound healing and has an anti-inflammatory effect. The seventh object of the present invention is to provide a hydrogel facial mask, which forms a hydrogel with 6-ursolic acid-based-N,N-dimethyl-hexyloxide amine as the main gel skeleton, combines cosmetic active ingredients, and provides skin care solutions for anti-aging, whitening and deep moisturizing. Preferably, one or more substances such as collagen, hyaluronic acid, arbutin, and niacinamide can be injected into the hydrogel facial mask. Preferably, the synthetic route of the compound 6-ursolic acid-based-N,N-dimethyl-hexyloxide amine is as follows: Preferably, in one embodiment, the specific synthesis steps of the compound are as follows: Synthesis of compound 1: Ursolic acid, triethylamine and HATU are dissolved in dichloromethane. After stirring for a period of time, N-Boc-1,6-hexanediamine is added, and the reaction is carried out at 35 °C for 5 h. After the reaction is completed, the cooled reaction product is removed of the excess thionyl chloride by vacuum distillation to obtain a yellow viscous liquid containing compound 1; Synthesis of compound 2: Under the condition of an ice bath, 5 ml of trifluoroacetic acid is slowly added dropwise to the dichloromethane solution of compound 1. After the addition is completed, the reaction is carried out at room temperature for 3 h. After the reaction is completed, saturated aqueous Na2CO3 solution is added to the mixture, and it is extracted with dichloromethane. The organic layer is washed with water 5-6 times, and then the organic layer is dried with anhydrous MgSO4. The remaining solvent in the extract is removed by vacuum distillation to obtain a yellow viscous liquid containing compound 2; Synthesis of compound 3: The mixture containing compound 2 is dissolved in ethanol, and formic acid and formaldehyde solution are slowly added dropwise in sequence at room temperature. After the addition is completed, the reaction is carried out at 80 °C for 8 h. After the reaction is completed, the pH of the product is adjusted to 11 with NaOH solution, and it is extracted with dichloromethane. The extract is dried with anhydrous sodium sulfate, and the solvent is removed under reduced pressure to obtain a yellow viscous liquid containing compound 3; Synthesis of 6-ursolic acid-based-N,N-dimethyl-hexyloxide amine: Compound 3 is dissolved in ethanol, and catalytic amounts of citric acid and disodium ethylenediaminetetraacetate are added. When the temperature rises to 55 °C, 30 wt% H2O2 is slowly added dropwise. After the addition is completed, the reaction is carried out at 80 °C for 5 h. After the reaction is completed, ethanol is removed by vacuum distillation. The product is purified by silica gel column chromatography to obtain 6-ursolic acid-based-N,N-dimethyl-hexyloxide amine, which is a white powdery solid after vacuum drying. Beneficial effects 1. In the present invention, ursolic acid can be used to obtain a 6-ursolic acid-based N,N-dimethyl-hexylamine oxide surfactant that meets the requirements of "green chemistry" through simple synthesis steps; 2. The 6-ursolic acid-based N,N-dimethyl-hexylamine oxide surfactant obtained in the present invention can self-assemble to form vesicles with a size ranging from 10 to 200 nm. When the concentration of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide in an aqueous solution is greater than 60 mmol·L -1 , the vesicles densely pack to form a gel; 3. The hydrogel agent in the present invention is derived from the natural product ursolic acid, has mild and non-toxic properties, and has important applications in the fields of drug sustained release, tissue engineering, cell culture, and daily chemicals. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is the molecular structure of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide; Figure 2 is the appearance photo of the gel formed by 6-ursolic acid-based N,N-dimethyl-hexylamine oxide; Figure 3 is the hydrogen nuclear magnetic resonance spectrum of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide; Figure 4 is the steady-state shear diagram of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide at 80 mmol·L -1 ; Figure 5 is the dynamic shear diagram (G is the storage modulus, solid symbol; G″ is the loss modulus, hollow symbol) of the gel formed by 6-ursolic acid-based N,N-dimethyl-hexylamine oxide at 80 mmol·L -1 ; Figure 6 is the in-situ cryo-transmission electron microscopy image of the gel of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide at 80 mmol·L -1 ; Figure 7 is the particle size distribution diagram of the aqueous solution of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide at 10 mmol·L -1 ; Figure 8 is the release curve of 5-fluorouracil without coating and the release curve of 5-fluorouracil coated with the gel of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide at 30 mmol·L -1 and 50 mmol·L -1 . DETAILED DESCRIPTION OF THE INVENTION The present invention will be further described below in conjunction with embodiments. The following embodiments are explanations of the present invention and the present invention is not limited to the following embodiments: Example 1 A synthesis method of a 6-ursolic acid-based N,N-dimethyl-hexylamine oxide compound, comprising the following steps: S1. Add HATU (27.6 g, 0.072 mol), ursolic acid (30 g, 0.066 mol), triethylamine (20.1 g, 0.198 mol), DMAP (0.2 g, 0.0016 mol) and 150 mL of dichloromethane into a three-necked flask in sequence, stir for 1 h, and then add compound N-Boc-1,6-hexanediamine (17.52 g, 0.088 mol), react at 35 °C for 5 h. After the reaction is completed, extract with dichloromethane. The organic layer is washed 5 times with deionized water, and then dried with anhydrous Na2SO4. After filtering off Na2SO4 by suction, rotary evaporate to remove dichloromethane and triethylamine to obtain a viscous liquid containing compound 1; S2. Dissolve compound 1 (35.7 g, 0.051 mol) in ethyl acetate, slowly add 5 ml of trifluoroacetic acid dropwise. After the addition is completed, react at room temperature for 3 h. After the reaction is completed, extract with ethyl acetate, wash 3 times with saturated Na2CO3 solution, and dry the extracted organic phase with anhydrous MgSO4. After suction filtration, rotary evaporate to remove ethyl acetate to obtain a yellow viscous liquid containing compound 2; S3. Dissolve compound 2 in ethanol, slowly add 88 wt% formic acid (13.07 g, 0.25 mol) and 30 wt% formaldehyde (25.01 g, 0.25 mol) solution dropwise in sequence at room temperature. After the addition is completed, react at 80 °C for 8 h. After the reaction is completed, adjust the pH of the product to 11 with 15 wt% NaOH solution, and extract with ether. The organic layer is dried with anhydrous sodium sulfate, and the solvent is removed under reduced pressure to obtain compound 3, which is a yellow viscous liquid; S4. React the ursolylamide-based tertiary amine compound obtained in S3 with hydrogen peroxide under the catalysis of citric acid and disodium ethylenediaminetetraacetate to obtain 6-ursolic acid-based N,N-dimethyl-hexylamine oxide. Example 2 A synthesis method of a 6-ursolic acid-based N,N-dimethyl-hexylamine oxide compound, comprising the following steps: S1. Add HATU (33.73 g, 0.088 mol), ursolic acid (20 g, 0.044 mol), triethylamine (44.67 g, 0.44 mol), DMAP (1 g, 0.0082 mol) and 200 mL of dichloromethane into a three-necked flask in sequence, stir for 1 h, and then add compound N-Boc-1,6-hexanediamine (19.03 g, 0.088 mol), react at 35 °C for 5 h. After the reaction is completed, extract with dichloromethane. The organic layer is washed 5 times with deionized water, and then dried with anhydrous Na2SO4. After filtering off Na2SO4 by suction, rotary evaporate to remove dichloromethane and triethylamine to obtain a viscous liquid containing compound 1; S2. Dissolve compound 1 (20 g, 0.020 mol) in ethyl acetate, then slowly add 20 ml of trifluoroacetic acid dropwise. After the addition is complete, react at room temperature for 3 h. After the reaction is completed, extract with ethyl acetate, wash with saturated Na2CO3 solution three times, and dry the extracted organic phase with anhydrous MgSO4. After filtration by suction, rotary evaporate to remove ethyl acetate to obtain a yellow viscous liquid containing compound 2; S3. Dissolve compound 2 in ethanol, and sequentially add 88 wt% formic acid (3.13 g, 0.06 mol) and 30 wt% formaldehyde (4.85 g, 0.06 mol) solution dropwise at room temperature. After the addition is complete, react at 80 °C for 8 h. After the reaction is completed, adjust the pH of the product to 11 with 15 wt% NaOH solution and extract with ether. Dry the organic layer with anhydrous sodium sulfate and remove the solvent under reduced pressure to obtain compound 3, which is a yellow viscous liquid; S4. React the ursolylamide tertiary amine compound obtained in S3 with hydrogen peroxide under the catalysis of citric acid and disodium ethylenediaminetetraacetate to obtain 6-ursolyl-N,N-dimethyl-hexylamine oxide. Example 3 A method for synthesizing a 6-ursolyl-N,N-dimethyl-hexylamine oxide compound, comprising the following steps: S1. Add HATU (210.81 g, 0.55 mol), ursolic acid (50 g, 0.11 mol), triethylamine (55.83 g, 0.55 mol), DMAP (2 g, 0.016 mol) and 800 mL of dichloromethane to a three-necked flask in sequence, stir for 1 h, then add compound N-Boc-1,6-hexanediamine (118.93 g, 0.55 mol), and react at 35 °C for 5 h. After the reaction is completed, extract with dichloromethane. After washing the organic layer with deionized water five times, dry it with anhydrous Na2SO4. After removing Na2SO4 by filtration by suction, rotary evaporate to remove dichloromethane and triethylamine to obtain a viscous liquid containing compound 1; S2. Dissolve compound 1 (45 g, 0.045 mol) in ethyl acetate, and then slowly add 100 ml of trifluoroacetic acid dropwise. After the addition is complete, react at room temperature for 3 h. After the reaction is completed, extract with ethyl acetate, wash three times with saturated Na2CO3 solution, and dry the extracted organic phase with anhydrous MgSO4. After filtration, evaporate the ethyl acetate by rotary evaporation to obtain a yellow viscous liquid containing compound 2; S3. Dissolve compound 2 in ethanol, and slowly add 88 wt% formic acid (7.04 g, 0.135 mol) and 30 wt% formaldehyde (10.91 g, 0.135 mol) solutions in sequence at room temperature. After the addition is complete, react at 80 °C for 8 h. After the reaction is completed, adjust the pH of the product to 11 with 15 wt% NaOH solution and extract with ether. Dry the organic layer with anhydrous sodium sulfate and remove the solvent under reduced pressure to obtain compound 3, which is a yellow viscous liquid; S4. React the ursolylamide-based tertiary amine compound obtained in S3 with hydrogen peroxide under the catalysis of citric acid and disodium ethylenediaminetetraacetate to obtain 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide. Example 4 A preparation method of ursolic acid-based vesicle gel, comprising the following steps: Take 1 mL of deionized water, add the 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide obtained in Example 1 (concentrations are 60 mM, 70 mM, 80 mM, 90 mM, 100 mM) thereto, heat the solution to 60 °C to ensure complete dissolution of the 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide, and observe the solution state after cooling. Comparative Example 1 Take 1 mL of deionized water, add the 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide obtained in Example 1 (concentration is 3 mM) thereto, heat the solution to 60 °C to ensure complete dissolution of the 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide, and observe the solution state after cooling. Comparative Example 2 Take 1 mL of deionized water, add the 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide obtained in Example 1 (concentration is 350 mM) thereto, heat the solution to 60 °C to ensure complete dissolution of the 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide, and observe the solution state after cooling. Table 1 States of solutions obtained at different concentrations of 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide It can be seen from Example 4, Comparative Example 1 and Comparative Example 2 that when the concentration of 6-ursolic acid-based-N,N-dimethyl-hexylamine oxide is lower than 5 mmol·L -1When the concentration of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide is below 5 mmol·L, a gel cannot be formed, and the viscosity of the solution is comparable to that of water; when the concentration of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide is 5 - 60 mmol·L -1 a solution with a relatively low viscosity can be formed; when the concentration of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide is 60 - 300 mmol·L -1 a semi-transparent solution with a relatively high viscosity can be formed; when the concentration of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide is higher than 300 mmol·L -1 it cannot be completely dissolved, solids precipitate out, and a gel cannot be formed. Performance Testing 1. Structure and Purity Determination of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide: Take an appropriate amount of the final product 6-dehydroabietylamide-based N,N-dimethyl-hexylamine oxide and place it in a nuclear magnetic tube, and dissolve it with the deuterated reagent DMSO. Use an Aduance III nuclear magnetic resonance spectrometer to perform 1 1H NMR testing at 25 °C. 1 The resonance frequency of 1H is 400 MHz. From the Figure 3 1H nuclear magnetic resonance spectrum of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide, it can be seen that the chemical shifts of each hydrogen are consistent with those of the target product 6-ursolic acid-based N,N-dimethyl-hexylamine oxide, indicating that the final product has been obtained. At the same time, there are no impurity peaks on the spectrum, indicating that the product reaches a very high purity; 2. Viscoelasticity Measurement of 80 mmol·L -1 6-ursolic acid-based N,N-dimethyl-hexylamine oxide solution: In the test, the cone angle of the cone plate (ETC) used is 2°, the diameter is 40 mm, and the distance between the cone plate and the platform is 53 μm. Before dynamic scanning, stress scanning is first performed to determine the linear viscoelastic region of the test sample, and the tests of the samples are all carried out within the linear viscoelastic region. From the Figure 4 steady-state shear diagram of the gel formed by 80 mmol·L -1 6-ursolic acid-based N,N-dimethyl-hexylamine oxide, it can be seen that its viscosity decreases sharply with the increase of the shear rate, indicating that the solution at this time is a non-Newtonian fluid, and its fluid behavior has a sensitive response to shear conditions. From the Figure 5 dynamic shear diagram of the gel formed by 80 mmol·L -1 6-ursolic acid-based N,N-dimethyl-hexylamine oxide, it can be seen that within the tested frequency range, the elastic modulus of the gel formed by 6-ursolic acid-based N,N-dimethyl-hexylamine oxide is always greater than the viscous modulus, indicating that the gel system has good elasticity; 3. 80 mmol·L -1Microscopic morphology measurement of the small molecule hydrogel formed by 6-ursolic acid-based N,N-dimethyl-hexylamine oxide: A cryogenic sample preparation device Cryoplunge TM3 with controllable environment was used to prepare samples, and the environmental temperature was controlled at 25 °C. The relative humidity in the device cavity was adjusted to be greater than 90%, and about 5 μL of the sample was pipetted onto the quantifoil. The droplets on the microgrid surface were absorbed by patting the sample with filter paper on both sides of Cp3 to obtain an extremely thin liquid film. Then the sample was quickly inserted into liquid ethane cooled by liquid nitrogen. The frozen sample was transferred to a sample rod cooled by liquid nitrogen, and finally observed in a transmission electron microscope at an operating voltage of 120 kV. From Figure 6 in 80 mmol·L -1 The in-situ cryo-transmission electron microscope photographs of the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide hydrogel sample show that ursolic acid-based amine oxide self-assembled into vesicular aggregates in solution. Figure 6 Some vesicles in it were deformed by extrusion, indicating that the bilayer has good flexibility; 4. Particle size measurement of the small molecule hydrogel formed by 6-ursolic acid-based N,N-dimethyl-hexylamine oxide: Pipette 3 - 3.5 mL of the sample to be measured into a 4.5 mL clean four-side light-transmitting dish, and use a dynamic light scattering nano-particle size analyzer to measure the particle size of the vesicles at a temperature of 25 °C. From Figure 7 in 10 mmol·L -1 The particle size distribution diagram of the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide aqueous solution shows that the particle size of the vesicles self-assembled by 6-ursolic acid-based N,N-dimethyl-hexylamine oxide presents a normal distribution, with an average diameter of 82.2 nm, indicating that the particle size distribution of the nano-vesicles is relatively uniform and has good stability; 5. Release performance measurement of the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide vesicle hydrogel: Use phosphate buffer to prepare 6-ursolic acid-based N,N-dimethyl-hexylamine oxide vesicle hydrogels with concentrations of 30 mmol·L -1 , 50 mmol·L -1 respectively. Add 10 mg of 5-fluorouracil (5-FU) to the vesicle hydrogel at 50 °C and stir for 1 hour. After cooling to room temperature and equilibrating for 24 hours, measure the release performance of the vesicle hydrogel. Take 5 mL of the drug-loaded vesicle gel and put it into a dialysis bag with a molecular weight cut-off of 3500, and place it in 200 mL of phosphate buffer with pH = 7.4. Dialyze for 1 h in a constant temperature culture shaker at 37 °C and 80 r / min to remove the uncoated 5-fluorouracil. Subsequently, place the dialyzed vesicle hydrogel in fresh phosphate buffer and conduct an in vitro simulated release experiment in a constant temperature culture shaker at 37 °C and 80 r / min. Measure the absorbance of the withdrawn solution at 266 nm and calculate the cumulative release percentage. FromFigure 8 The in vitro release curve shows that the release amount of free 5-fluorouracil in phosphate buffer exceeds 90% within 1 h, while the release of phosphate buffer in the vesicle hydrogel is slow and continuous, and with the increase of the concentration of 6-ursolic acid-based N,N-dimethyl-hexyloxylamine, the sustained-release effect of the vesicle hydrogel on 5-fluorouracil is better. This indicates that the 6-ursolic acid-based N,N-dimethyl-hexyloxylamine vesicle hydrogel has a certain sustained-release effect under physiological pH conditions, and the greater the concentration, the better the sustained-release effect on the drug, providing potential application value for the controlled release of drugs. Obviously, the above embodiments are only examples given for clear illustration, rather than limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A compound, characterized in that: The compound is 6-ursolic acid-based N,N-dimethyl-hexylamine oxide, and its structural formula is formula (1):

2. The preparation method of the compound according to claim 1, wherein: The preparation method includes the following steps: S1. Ursolic acid and N-Boc-1,6-hexanediamine are subjected to a condensation reaction under the catalysis of 2-(7-azabenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate to generate a Boc-protected ursolic acid amide-based primary amine compound; S2. The Boc-protected ursolic acid amide-based primary amine compound obtained in S1 is reacted with trifluoroacetic acid to remove the Boc protecting group, obtaining an ursolic acid amide-based primary amine compound; S3. After the ursolic acid amide-based primary amine compound obtained in S2 is dissolved, formic acid and formaldehyde are added for reaction to prepare an ursolic acid amide-based tertiary amine compound; S4. The ursolic acid amide-based tertiary amine compound obtained in S3 is reacted with hydrogen peroxide under the catalysis of citric acid and disodium ethylenediaminetetraacetate to obtain 6-ursolic acid-based N,N-dimethyl-hexylamine oxide.

3. A capsule hydrogel, characterized in that: The vesicle hydrogel contains the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide described in claim 1 as a gel factor.

4. The hydrogel vesicle according to claim 3, wherein: The concentration range of 6-ursolic acid-based N,N-dimethyl-hexylamine oxide in the vesicle hydrogel is 5-300 mmol·L -1 , and the vesicle size ranges from 10 to 200 nm.

5. The application of the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide described in claim 1 in the fields of drug sustained release, biotechnology, environmental engineering or daily chemical products.

6. A sustained-release material, characterized in that: The sustained release material contains the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide of claim 1 and at least one substance to be sustained released, and is used for preparing a long-acting delivery system.

7. A medical wound dressing, characterized in that: The medical wound dressing uses the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide of claim 1 as a matrix material to form a hydrogel with self-recovery function, effectively supporting wound healing and having an anti-inflammatory effect.

8. A hydrogel facial mask, characterized in that: The hydrogel facial mask uses the 6-ursolic acid-based N,N-dimethyl-hexylamine oxide of claim 1 as a main gel framework, combines cosmetic active ingredients, and provides skin care solutions for anti-aging, whitening and deep moisturizing.

9. The preparation method of the compound according to claim 2, characterized in that: The molar ratio of the ursolic acid to the N-Boc-1,6-hexanediamine is 1-4:1-10, the molar ratio of the protected ursolic acid amide-based primary amine compound to the trifluoroacetic acid is 1-5:5-30, the molar ratio of the ursolic acid amide-based primary amine compound, the formic acid and the formaldehyde is 1-4:1-10:1-10, and the molar ratio of the ursolic acid amide-based tertiary amine compound to the hydrogen peroxide is 1-5:1-10.

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