Disulfide bond mediated beta-cyclodextrin monomer, preparation method thereof and method for preparing gel film by using disulfide bond mediated beta-cyclodextrin monomer

Abstract

The invention provides a disulfide bond mediated beta-cyclodextrin monomer, a preparation method thereof and a method for preparing a gel film by using the disulfide bond mediated beta-cyclodextrin monomer. The disulfide bond mediated beta-cyclodextrin monomer is prepared by combining a disulfide bond with redox response capability with beta-CD (cyclodextrin) capable of improving hydrophobic drug loading capability. The prepared disulfide bond mediated beta-cyclodextrin monomer and a polymeric monomer are copolymerized to obtain the gel film. The gel film obtained by the invention has high light transmittance, excellent mechanical properties and good hydrophobic drug loading capacity, does not affect the curative effect of drugs, can stabilize the drugs, has reduction responsive release capacity, and can completely release the drugs.

Description

Technical Field

[0001] The invention relates to a disulfide bond-mediated beta-cyclodextrin monomer, a preparation method thereof and a method for using the monomer to prepare a gel film, and belongs to the technical field of functional polymer composite materials. Background Art

[0002] Hydrogels are hydrophilic three-dimensional cross-linked polymer networks that are biocompatible, flexible, and porous. They are often widely discussed as drug delivery systems and have wide applications in materials science, life sciences, and other fields.

[0003] There are currently two main drug loading methods for hydrogel drug delivery systems: (a) coupling the drug to the gel network through chemical bonds; and (b) physical encapsulation. However, the first method requires chemical modification of the drug, which is not considered a feasible approach because it may lead to the loss of active groups, thereby reducing the efficacy of the drug. However, the hydrogel drug delivery system synthesized according to the second method may again show the situation of drug burst release, and the stability of the drug will also be reduced. However, the application of hydrogels is limited because most drugs have low solubility in water and hydrophobic drugs are generally incompatible with hydrogels. One of the main strategies to expand the compatibility of hydrogels with hydrophobic APIs is to introduce molecules that can form complexes or nanoparticles in the matrix to encapsulate the drug molecules. β-cyclodextrin (β-CD) is the most commonly used starch cyclic oligomer, which is characterized by seven D-pyranose units linked together by α-1,4 glycosidic bonds to form a large molecule. The resulting molecule has a conical cavity with a distinct hydrophobic inner cavity and a hydrophilic outer surface. Adding β-CD to the gel network can effectively improve hydrophobic drug delivery and can also be used as a stabilizer to improve the stability of drug molecules and improve the permeability of drugs through biological barriers; however, there are problems such as reduced drug efficacy and incomplete drug release or sudden drug release.

[0004] Chinese patent document CN103800949A discloses a drug carrier for corneal contact lenses with bionic properties, which is polymerized by a cyclodextrin derivative containing double bonds, phosphorylcholine, hydroxyethyl methacrylate and an initiator, wherein the average functionality of the double bonds in the cyclodextrin derivative containing double bonds is 1.1 to 1.5, the mass of phosphorylcholine is 0.1 to 1% of the total mass of the cyclodextrin derivative containing double bonds and hydroxyethyl methacrylate; the mass ratio of hydroxyethyl methacrylate to the cyclodextrin derivative containing double bonds is 1 to 20:1, and the initiator is ammonium sulfate and tetramethylethylenediamine. The performance of the product obtained by this invention meets the basic requirements of corneal contact lenses and can control the release of eye drops. However, for drugs with high inclusion constants with cyclodextrin, this method ignores the problem that the drug cannot be completely released after being encapsulated by cyclodextrin.

[0005] Chinese patent document CN113248656A discloses a multifunctional pHEMA-based corneal contact lens hydrogel material, a preparation method and an application thereof. The preparation of the hydrogel material comprises the following steps: the synthesis of acryloyl quaternary ammonium salt chitosan, and the preparation of a multifunctional pHEMA-based corneal contact lens hydrogel material. The multifunctional pHEMA-based corneal contact lens hydrogel material prepared by the invention is ternary copolymerized by HEMA, acryloyl quaternary ammonium salt chitosan and acryloyl β-cyclodextrin. The novel corneal contact lens material has the properties of good surface hydrophilicity, can reduce the adsorption of tear protein on the material surface, can reduce bacterial infection and reduce the occurrence of ocular inflammation, high drug loading and prolonged drug release time. However, for drugs with high inclusion constants with cyclodextrin, this method ignores the problem that the drug cannot be completely released after being encapsulated by cyclodextrin.

[0006] Therefore, it is of great significance to develop a new gel delivery system that can solve the above problems at the same time. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a disulfide bond-mediated β-cyclodextrin monomer, a preparation method thereof and a method for preparing a gel film thereof. The present invention combines a disulfide bond having redox responsiveness with β-CD that can improve the hydrophobic drug loading capacity to prepare a disulfide bond-mediated β-cyclodextrin monomer. The prepared disulfide bond-mediated β-cyclodextrin monomer is copolymerized with a polymerized monomer to obtain a gel film. The gel film obtained by the present invention has high light transmittance, excellent mechanical properties, good hydrophobic drug loading capacity, does not affect the efficacy of the drug, can stabilize the drug, has reduction-responsive release ability, and can completely release the drug.

[0008] The technical solution of the present invention is as follows:

[0009] A disulfide bond-mediated β-cyclodextrin monomer having the following structure:

[0010]

[0011] The method for preparing the above disulfide bond-mediated β-cyclodextrin monomer comprises the steps of:

[0012] (1) dissolving dithioglycolic acid in anhydride, reacting, and then concentrating in vacuo; adding organic solvent B, hydroxyethyl methacrylate (HEMA), and 4-dimethylaminopyridine (DMAP), reacting, and purifying to obtain an intermediate;

[0013] (2) dissolving 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), N-hydroxysuccinimide (NHS) and the intermediate in an organic solvent C, reacting and purifying to obtain an NHS ester functional monomer;

[0014] (3) The organic solution of the NHS ester functional monomer and the monoamino-substituted β-cyclodextrin is fully mixed, and the disulfide bond-mediated β-cyclodextrin monomer is obtained through reaction and purification.

[0015] Preferably according to the present invention, in step (1), the acid anhydride is one of acetic anhydride or propionic anhydride; and the molar amount of dithioglycolic acid and the volume ratio of the acid anhydride are 1-2 mol / L.

[0016] Preferably, according to the present invention, in step (1), the reaction temperature after dithioglycolic acid is dissolved in acid anhydride is room temperature, the reaction time is 3-4 hours, and the reaction is carried out under stirring conditions.

[0017] Preferably, in step (1), vacuum concentration is performed to remove remaining acetic anhydride and impurities such as small molecules.

[0018] Preferably, in step (1), the organic solvent B is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone; and the molar ratio of dithioglycolic acid to the volume ratio of the organic solvent B is 0.5-1 mol / L.

[0019] Preferably, in step (1), the molar ratio of dithioglycolic acid to hydroxyethyl methacrylate is 1:1-3; and the mass of 4-dimethylaminopyridine is 0.1wt%-0.8wt% of the mass of hydroxyethyl methacrylate.

[0020] Preferably according to the present invention, in step (1), the reaction temperature after adding organic solvent B, hydroxyethyl methacrylate (HEMA) and 4-dimethylaminopyridine (DMAP) is room temperature, the reaction time is 10-14 hours, and the reaction is carried out under stirring conditions.

[0021] According to the preferred embodiment of the present invention, in step (1), the purification method comprises the steps of: adding a saturated sodium bicarbonate aqueous solution to the reaction solution to adjust the pH to 1-3; adding an organic solvent B for extraction, and drying the obtained organic phase over anhydrous sodium sulfate and purifying it with a silica gel column to obtain an intermediate. Further preferably, the organic solvent B is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone.

[0022] Preferably according to the present invention, in step (2), the molar ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), N-hydroxysuccinimide (NHS) and dithioglycolic acid in step (1) is 1:1-3:1-3.

[0023] Preferably, in step (2), the organic solvent C is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone; and the molar ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) to the volume ratio of the organic solvent C is 0.1-1 mol / L.

[0024] Preferably according to the present invention, in step (2), the reaction temperature is room temperature, the reaction time is 10-14 hours, and the reaction is carried out in an inert gas atmosphere with stirring; further preferably, the inert gas is nitrogen or argon.

[0025] Preferably according to the present invention, in step (2), the purification method is silica gel chromatography column purification.

[0026] Preferably according to the present invention, in step (3), the monoamino-substituted β-cyclodextrin is mono(6-ethylenediamino-6-deoxy)β-cyclodextrin.

[0027] Preferably according to the present invention, in step (3), the concentration of the organic solution of monoamino-substituted β-cyclodextrin is 0.1-0.5 g / ml; wherein the organic solvent used is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone.

[0028] Preferably, according to the present invention, in step (3), the molar ratio of the NHS ester functional monomer to the monoamino-substituted β-cyclodextrin is 4-6:1.

[0029] Preferably, according to the present invention, in step (3), the reaction temperature is room temperature, the reaction time is 2-4 days, and the reaction is carried out under stirring conditions.

[0030] According to the preferred embodiment of the present invention, in step (3), the purification method is as follows: adding an organic solvent to the reaction solution for precipitation, then washing with the organic solvent and drying to obtain a disulfide bond-mediated β-cyclodextrin monomer. Preferably, the organic solvent is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone.

[0031] The method for preparing a gel film using the above disulfide bond-mediated β-cyclodextrin monomer comprises the steps of:

[0032] The disulfide bond-mediated beta-cyclodextrin monomer, polymerization monomer and initiator are fully dispersed in an organic solvent A; the solvent and unreacted monomer are removed through thermal curing or photocuring to obtain a gel film.

[0033] According to the present invention, the polymerizable monomer is preferably one or a combination of two or more of β-hydroxyethyl methacrylate (HEMA), N,N-dimethylacrylamide, acrylic acid, methacrylic acid, methyl acrylate (MA) or methyl methacrylate.

[0034] Preferably according to the present invention, the mass ratio of disulfide bond-mediated β-cyclodextrin monomer to polymerized monomer is 1:1-12, preferably 1:1.5-9.

[0035] Preferably, according to the present invention, the organic solvent A is one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide or dimethyl sulfoxide; and the mass ratio of the polymerization monomer to the organic solvent A is 0.1-2:1.

[0036] Preferably according to the present invention, the initiator is one of azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO) or 2-hydroxy-2-methyl-1-phenyl-1-propanone; the mass of the initiator is 0.2%-1% of the total mass of the disulfide bond-mediated β-cyclodextrin monomer and the polymerized monomer.

[0037] Preferably, according to the present invention, the thermal curing temperature is 60-100° C., and the thermal curing time is 8-24 hours; and the light curing is curing under ultraviolet light for 4-8 hours.

[0038] According to the present invention, the disulfide bond-mediated β-cyclodextrin monomer, polymerization monomer, and initiator need to be fully dispersed in the organic solvent A, otherwise a complete gel film with high light transmittance cannot be obtained.

[0039] The invention also provides a gel film prepared by the method.

[0040] The present invention also provides the application of the gel film as a delivery carrier for loading and delivering hydrophobic drugs.

[0041] Preferably according to the present invention, the hydrophobic drug is curcumin.

[0042] According to a preferred embodiment of the present invention, the application method is as follows: the gel film is placed in a drug solution and soaked at room temperature for 20-30 hours to obtain a drug-loaded gel film.

[0043] Preferably according to the present invention, the gel film is used as an ocular drug delivery carrier to deliver hydrophobic drugs.

[0044] Preferably, according to the present invention, when the gel film is used as a delivery carrier to load and deliver hydrophobic drugs, the drug can be responsively and completely released under reducing conditions. Preferably, the reducing conditions are provided by reduced glutathione; more preferably, the reducing conditions are provided by a PBS buffer of reduced glutathione.

[0045] The reaction route of the disulfide bond-mediated β-cyclodextrin monomer of the present invention is exemplified as follows:

[0046]

[0047] The technical features and beneficial effects of the present invention are as follows:

[0048] 1. In the preparation process of the polymerizable disulfide bond-mediated β-cyclodextrin monomer of the present invention, a nucleophilic substitution reaction is performed between an NHS ester functional monomer and a monoamine-substituted β-CD to obtain a disulfide bond-mediated β-CD cyclodextrin monomer. The NHS ester functional monomer generates an active intermediate in a weakly alkaline system; then the amino group of the monoamine-substituted β-CD nucleophilically attacks the intermediate to form an amide structure. In the preparation of the disulfide bond-mediated β-cyclodextrin monomer of the present invention, the reaction activity is high, the operation is easy, and the yield and purity of the target product are high; the preparation method of the present invention as a whole, each step and each condition work together to achieve the preparation of the disulfide bond-mediated β-cyclodextrin monomer with high yield and high purity.

[0049] 2. The present invention uses disulfide bond-mediated β-cyclodextrin monomers containing polymerizable groups, polymerizable monomers such as β-hydroxyethyl methacrylate (HEMA), and initiators as raw materials, and obtains disulfide bond-mediated β-cyclodextrin gel film through thermal curing or photocuring. The above method of the present invention is simple, easy to operate, short in steps, and energy-saving and environmentally friendly.

[0050] 3. The gel film obtained by the present invention has good light transmittance, and still maintains a light transmittance of about 80% at 630nm; and due to the introduction of β-CD, the stress and strain of the gel film are improved by about 1 times, and it has good tensile resistance. The amount of disulfide bond-mediated β-cyclodextrin monomer containing polymerizable groups in the present invention has a certain influence on the light transmittance and tensile resistance of the obtained gel film. Only the disulfide bond-mediated β-cyclodextrin monomer containing polymerizable groups used in the present invention can achieve high light transmittance and tensile resistance of the gel film.

[0051] 4. The present invention introduces β-cyclodextrin into the gel network structure, so that the gel's loading capacity for poorly soluble drugs is greatly improved, and the drug efficacy is not affected, while the drug can be stabilized. Due to the redox characteristics of the disulfide bond, that is, the disulfide bond can be broken under reducing conditions, the drug that forms an inclusion complex with β-cyclodextrin can be responsively released under reducing conditions, solving the problem of inability to release or incomplete release that may occur after the drug forms an inclusion complex with β-CD. The amount of disulfide bond-mediated β-cyclodextrin monomers containing polymerizable groups in the present invention has a certain influence on the drug loading capacity and drug release performance of the resulting gel film. Only the disulfide bond-mediated β-cyclodextrin monomers containing polymerizable groups used in the present invention can achieve the above-mentioned effects of the present invention.

[0052] 5. The gel film obtained by the present invention is safe and has good biocompatibility, and is suitable for use as a corneal contact lens material and can be used as an eye drug delivery carrier to relieve eye symptoms. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the disulfide bond-mediated β-cyclodextrin monomer prepared in Example 1;

[0054] Figure 2 This is a test diagram of the equilibrium swelling degree of the gel film prepared in Example 2-6;

[0055] Figure 3 This is a test chart of light transmittance of the gel film prepared in Example 2-6;

[0056] Figure 4 The stress-strain curve test diagram of the gel film prepared in Example 2-6;

[0057] Figure 5 This is a test diagram of drug loading rate of the gel film prepared in Example 2-6;

[0058] Figure 6 The drug release test diagram of the gel film prepared in Example 2-6;

[0059] Figure 7 This is a diagram showing the cytotoxicity test of the gel film prepared in Example 2-6. DETAILED DESCRIPTION

[0060] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0061] Meanwhile, the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0062] Example 1

[0063] The preparation method of disulfide bond-mediated β-cyclodextrin monomer comprises the following steps:

[0064] Dissolve dithioglycolic acid (1.8 g, 10 mmol) in 8 mL of acetic anhydride, stir at room temperature for 3.5 hours, and concentrate in vacuo to remove the remaining acetic anhydride and small molecule impurities; add 15 mL of dichloromethane, hydroxyethyl methacrylate (HEMA 1.9 g, 10 mmol), and 4-dimethylaminopyridine (DMAP 12 mg, 10 mmol) and stir at room temperature for 12 hours, add 30 mL of saturated sodium bicarbonate aqueous solution, adjust the solution pH to 2 with 1 M HCl aqueous solution, extract with dichloromethane, dry the obtained organic phase with anhydrous sodium sulfate, and purify with silica gel column (the eluent is a mixed solvent of methanol and dichloromethane, wherein the volume ratio of methanol: dichloromethane is 1:20) to obtain an intermediate.

[0065] The above intermediate, 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC, 1.55 g, 10 mmol), and N-hydroxysuccinimide (NHS, 1.15 g, 10 mmol) were dissolved in 15 mL of dichloromethane, stirred at room temperature for 12 hours under a nitrogen atmosphere, and purified by silica gel column chromatography (the eluent was a mixed solvent of ethyl acetate and petroleum ether, wherein the volume ratio of ethyl acetate to petroleum ether was 1:4) to obtain an NHS ester functional monomer.

[0066] NHS ester functional monomer (3.93 g, 10 mmol) was added to a dimethyl sulfoxide (the volume of dimethyl sulfoxide was 6 ml) solution containing monoamino-substituted β-cyclodextrin (EDA-β-CD, 2.9 g, 2 mmol, synthesized according to the method described in the literature Synthesis and Characterization of b-Cyclodextrin Based Functional Monomers and its Copolymers with N-isopropylacrylamide, DOI: 10.1002 / mabi.200300052), stirred at room temperature for 3 days, and precipitated with acetone, washed with acetone, and dried to obtain a disulfide bond-mediated β-cyclodextrin monomer.

[0067] The total yield of disulfide-bond-mediated β-cyclodextrin monomer was 86%.

[0068] Figure 1 This is the H NMR spectrum of disulfide bond-mediated β-cyclodextrin monomer. Figure 1It can be seen that the absorption peaks at 2.55 and 2.70 ppm in the spectrum of EDA-β-CD are attributed to -CH2 at the ortho position of the primary amine and the secondary amine, respectively, and the absorption peaks at 3.68-3.83 ppm, 3.25-3.51 ppm and 4.95 ppm are attributed to β-CD. The -CH2 at the ortho position of the disulfide bond in the NHS ester functional monomer appears at 3.62 and 3.78 ppm, which coincides with the absorption peak of β-CD in the previous report, making it difficult to determine whether the disulfide bond is grafted to β-CD. The absorption peaks of CH2=CH2 appear at 5.53 ppm and 6.05 ppm, without interference from other peaks. In the spectrum of the final product, the absorption peaks of CH2=CH2 at 5.53 ppm and 6.05 ppm and the three major absorption peaks of β-CD (3.68-3.83 ppm, 3.25-3.51 ppm and 4.95 ppm) can be observed, so it can be determined that the disulfide bond is successfully grafted to β-CD.

[0069] Embodiment 2-6

[0070] The preparation method of disulfide bond-mediated β-CD gel film comprises the following steps:

[0071] (1) Preparation of polymerization solution: According to the formula in Table 1, weigh the disulfide bond-mediated β-cyclodextrin monomers and disperse them in a solvent, dimethyl sulfoxide (DMSO), by ultrasonic dispersion to obtain a transparent uniform solution; add the polymerization monomer HEMA and initiator AIBN (the mass of the initiator is 0.2 wt% of the total mass of the monomers) in the formula amount, and dissolve them by ultrasonic dispersion to obtain a polymerization solution;

[0072] (2) Preparation of disulfide bond-mediated β-CD gel film: Use a dropper to draw the above polymerization solution and drop it into the groove of the lower mold of the flat mold, and press the matching upper mold of the mold to ensure that there are no bubbles inside. Place the mold in an oven, increase the oven temperature from room temperature to 80°C, and heat cure for 12 hours.

[0073] (3) Demolding: After curing is completed, open the mold, remove the cured flat membrane, immerse it in distilled water to extract the unreacted monomers and solvent, and take it out to obtain a disulfide bond-mediated β-CD gel film with a thickness of 0.2 mm; and store it in distilled water.

[0074] Table 1 Preparation formula of disulfide bond-mediated β-CD gel film

[0075]

[0076] Test example

[0077] The gel films prepared in Examples 2-6 were tested for equilibrium swelling, light transmittance, mechanical properties, drug loading capacity and drug release capacity. The test methods are as follows:

[0078] (1) Equilibrium swelling degree

[0079] Place the gel film in distilled water until swelling equilibrium is reached, and weigh it (Ws, mg); dry it in an oven at 105 degrees Celsius for 24 hours to obtain a dry gel, and weigh it (Wd, mg). The equilibrium swelling degree of the sample is calculated as follows:

[0080]

[0081] (2) Light transmittance test

[0082] The gel film was placed in distilled water until swelling equilibrium was reached, and then the sample was cut into a 10mm*30mm rectangle and attached to the inner wall of a 10mm*10mm*45mm quartz cuvette. The light transmittance of the material was measured using a UV-visible spectrophotometer with distilled water as a blank. The measuring range was 200nm~800nm ​​and the slit width was 2nm.

[0083] (3) Mechanical properties

[0084] After the gel film was placed in distilled water until swelling equilibrium, the sample was cut into a 10mm*30mm rectangle and the surface water was wiped off with filter paper to test the tensile strength. During the experiment, the temperature was maintained at 25°C, the humidity was 60%, and the material stretching speed was 20mm / min.

[0085] (4) Drug loading test

[0086] The gel film was placed in a 1 mg / mL curcumin ethanol solution for 24 hours, and the absorbance difference at 426 nm before and after the solution was measured to calculate the drug loading of the gel film. The film was dried and set aside for drug release testing. Drug loading = m (loaded drug mass) / n (mass of dry gel).

[0087] (5) Drug release

[0088] The dried drug-loaded gel was placed in a PBS buffer solution with a pH of 7.4 and 5 mM GSH (glutathione) to simulate the in vivo release environment. Samples were taken at fixed time points to measure the absorbance of the solution and calculate the cumulative release of the drug.

[0089] (6) Cytotoxicity

[0090] The gel film was placed in distilled water until swelling equilibrium was reached, and then the sample was cut into a 10 mm*10 mm rectangle. After incubation with mouse fibroblasts at 37°C for 12 hours, the cell viability was determined using an ELISA reader.

[0091] Results and Discussion

[0092] Figure 2This is a test diagram of the equilibrium swelling degree of the disulfide bond-mediated β-CD gel film prepared in Example 2-6. The equilibrium swelling degree of the gel is positively correlated with the content of disulfide bond-mediated β-cyclodextrin monomer (SS-β-CD) containing polymerizable groups in the gel. When the SS-β-CD content increases from 0 to 40%, the equilibrium swelling degree of the gel film increases from 57.5% to 119.5%, indicating that SS-β-CD can effectively enhance the swelling capacity of the hydrogel. Generally speaking, materials with higher water absorption capacity are more suitable for use as corneal contact lens materials, making them more comfortable to wear.

[0093] Figure 3 The light transmittance test diagram of the disulfide bond-mediated β-CD gel film prepared in Example 2-6. It can be seen from the figure that the gel film prepared by the present invention has good light transmittance. As the content of SS-β-CD increases, the light transmittance of the gel film gradually decreases, but the gel film with a SS-β-CD content of 40% still shows a light transmittance of about 80% at 630nm, indicating that the gel film has good light transmittance and can be used as an eye drug delivery carrier to relieve eye symptoms.

[0094] Figure 4 The tensile stress-strain relationship of SS-β-CD gel films with different concentrations is shown. It is not difficult to see that the Young's modulus generally shows a trend of increasing with the increase of SS-β-CD content, and the ability to resist deformation is enhanced. As the SS-β-CD content increases from 0 to 30%, the fracture stress and elongation of the gel film increase from the original 0.125MPa and 169.9% to 0.239MPa and 281.2%, showing stronger fracture stress and strain, which may be related to the hydrogen bonds formed by β-CD and the host-guest interaction of β-CD (other smaller polymer fragments are interspersed in the cavity of β-CD). However, when the SS-β-CD content increases to 40%, its elongation decreases to 244%. This is because the addition of SS-β-CD is about 35%, resulting in a decrease in crosslinking density, a weakening of hydrogen bonding forces and other forces, and a slight weakening of the tensile properties of the gel. In summary, these results show that gel films containing SS-β-CD all exhibit tensile properties superior to those of pure HEMA gel films.

[0095] Figure 5The drug loading rate test diagram of the disulfide bond-mediated β-CD gel film prepared in Example 2-6 is shown. It can be seen that as the SS-β-CD content increases, the loading amount of curcumin shows an increasing trend. For every 10% increase in the content of SS-β-CD, the drug loading per gram of dry gel increases by an average of 3.85 mg. The reason for this phenomenon is that curcumin forms an inclusion complex with β-CD. It is calculated that the proportion of curcumin and β-CD forming an inclusion complex is 32.3% (the percentage of drugs that form a complex with β-CD to all β-CD). Using the disulfide bond-mediated β-CD gel film obtained by the present invention, the present invention increases the loading amount of curcumin by about 7 times. It shows that the present invention has good loading efficiency for hydrophobic drugs and can be used to solve the delivery problem of hydrophobic drugs.

[0096] Figure 6 The drug release test diagram of the disulfide bond-mediated β-CD drug-loaded gel film prepared in Example 2-6. Under the control group (without GSH), the drug release rate of the gel film decreases with the increase of SS-β-CD content, and at the end of the test, some drugs cannot be released. The proportion of drugs that cannot be released is proportional to the content of SS-β-CD, which is consistent with Figure 5 The conclusion obtained (curcumin and β-CD form an inclusion complex) is consistent. Except for the gel film without SS-β-CD, the average release rate of other gel films has increased to varying degrees under redox conditions (containing 5mM GSH), and the degree of increase is proportional to the SS-β-CD content. Figure 6 It shows that under redox conditions, the drug-loaded gels that could not completely release the drug under non-redox conditions all released the drug completely. This is because the GSH in the buffer reduces the disulfide bonds in the gel network to sulfhydryl groups, the drug-loaded β-CD falls and releases the drug into the buffer, and the gel structure is destroyed, resulting in faster solvent exchange. Under the combined action of the two, the drug is released faster and is proportional to the content of disulfide bonds in the gel network.

[0097] Figure 7 The cytotoxicity test diagram of the disulfide bond-mediated β-CD content gel film prepared in Example 2-6. The results show that after being treated with hydrogels containing 0%, 10%, 20%, 30% and 40% SS-β-CD, the cell survival rates are 97.926%, 97.104%, 99.023%, 99.023%, 96.647% and 95.917%, respectively. The toxicity of the hydrogel is not obvious, and the experiment proves that the gel material has good biocompatibility.

Claims

1. A disulfide bond-mediated β-cyclodextrin monomer, characterized in that: Has the following structure:

2. The method for preparing the disulfide bond-mediated β-cyclodextrin monomer according to claim 1, comprising the steps of: (1) dissolving dithioglycolic acid in anhydride, reacting, and then concentrating in vacuo; adding organic solvent B, hydroxyethyl methacrylate (HEMA), and 4-dimethylaminopyridine (DMAP), reacting, and purifying to obtain an intermediate; (2) dissolving 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), N-hydroxysuccinimide (NHS) and the intermediate in an organic solvent C, reacting and purifying to obtain an NHS ester functional monomer; (3) The organic solution of the NHS ester functional monomer and the monoamino-substituted β-cyclodextrin is fully mixed, and the disulfide bond-mediated β-cyclodextrin monomer is obtained through reaction and purification.

3. The method for preparing disulfide bond-mediated β-cyclodextrin monomer according to claim 2, characterized in that: In step (1), one or more of the following conditions are included: i. The acid anhydride is one of acetic anhydride or propionic anhydride; the molar amount of dithioglycolic acid and the volume ratio of the acid anhydride is 1-2 mol / L; ii. The reaction temperature after dithioglycolic acid is dissolved in acid anhydride is room temperature, the reaction time is 3-4 hours, and the reaction is carried out under stirring conditions; iii. The organic solvent B is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone; the molar amount of dithioglycolic acid and the volume ratio of the organic solvent B are 0.5-1 mol / L; iv. the molar ratio of dithioglycolic acid to hydroxyethyl methacrylate is 1:1-3; the mass of 4-dimethylaminopyridine is 0.1wt%-0.8wt% of the mass of hydroxyethyl methacrylate; v. The reaction temperature after adding organic solvent B, hydroxyethyl methacrylate (HEMA) and 4-dimethylaminopyridine (DMAP) is room temperature, the reaction time is 10-14 hours, and the reaction is carried out under stirring conditions; vi. The purification method comprises the steps of: adding a saturated sodium bicarbonate aqueous solution to the reaction solution to adjust the pH to 1-3; adding an organic solvent B for extraction, and drying the obtained organic phase over anhydrous sodium sulfate and purifying it with a silica gel chromatography column to obtain an intermediate; preferably, the organic solvent B is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone.

4. The method for preparing disulfide bond-mediated β-cyclodextrin monomer according to claim 2, characterized in that: In step (2), one or more of the following conditions are included: i. The molar ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC), N-hydroxysuccinimide (NHS) and dithioglycolic acid in step (1) is 1:1-3:1-3; ii. The organic solvent C is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone; the molar amount of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and the volume ratio of the organic solvent C is 0.1-1 mol / L; iii. The reaction temperature is room temperature, the reaction time is 10-14 hours, and the reaction is carried out under an inert gas atmosphere and stirring conditions; further preferably, the inert gas is nitrogen or argon; iv. The purification method is silica gel column purification.

5. The method for preparing disulfide bond-mediated β-cyclodextrin monomer according to claim 2, characterized in that: In step (3), one or more of the following conditions are included: i. Monoamino-substituted β-cyclodextrin is mono(6-ethylenediamino-6-deoxy)β-cyclodextrin; ii. The concentration of the organic solution of monoamino-substituted β-cyclodextrin is 0.1-0.5 g / ml; wherein the organic solvent used is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone; iii. the molar ratio of the NHS ester functional monomer to the monoamino-substituted β-cyclodextrin is 4-6:1; iv. The reaction temperature is room temperature, the reaction time is 2-4 days, and the reaction is carried out under stirring; v. The purification method is as follows: adding an organic solvent to the reaction solution for precipitation, then washing with the organic solvent and drying to obtain a disulfide bond-mediated β-cyclodextrin monomer; preferably, the organic solvent is one or a combination of two or more of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, cyclopentanone or cyclohexanone.

6. A method for preparing a gel film using the disulfide bond-mediated β-cyclodextrin according to claim 1, comprising the steps of: The disulfide bond-mediated beta-cyclodextrin monomer, polymerization monomer and initiator are fully dispersed in an organic solvent A; the gel film is obtained by heat curing or light curing and removing the solvent and unreacted monomer.

7. The method for preparing a gel film according to claim 6, characterized in that: Includes one or more of the following conditions: i. The polymerizable monomer is one or a combination of two or more of β-hydroxyethyl methacrylate (HEMA), N,N-dimethylacrylamide, acrylic acid, methacrylic acid, methyl acrylate (MA) or methyl methacrylate; ii. The mass ratio of disulfide bond-mediated β-cyclodextrin monomer to polymerized monomer is 1:1-12, preferably 1:1.5-9; iii. The organic solvent A is one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide or dimethyl sulfoxide; the mass ratio of the polymerization monomer to the organic solvent A is 0.1-2:1; iv. The initiator is one of azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO) or 2-hydroxy-2-methyl-1-phenyl-1-propanone; the mass of the initiator is 0.2%-1% of the total mass of the disulfide bond-mediated β-cyclodextrin monomer and the polymerized monomer; v. The thermal curing temperature is 60-100°C, and the thermal curing time is 8-24 hours; the light curing is curing under ultraviolet light for 4-8 hours.

8. A gel film prepared by the method of claim 6 or 7.

9. The use of the gel film according to claim 8, characterized in that: It is used as a delivery vehicle to load and deliver hydrophobic drugs.

10. The use of the gel film according to claim 9, comprising one or more of the following conditions: i. The hydrophobic drug is curcumin; ii. The application method is as follows: placing the gel film in a drug solution and soaking it at room temperature for 20-30 hours to obtain a drug-loaded gel film; iii. the gel film is used as an ocular drug delivery carrier to deliver hydrophobic drugs; iv. When the gel film is used as a delivery carrier to load and deliver hydrophobic drugs, responsive and complete release of the drugs can be achieved under reducing conditions; preferably, the reducing conditions are provided by reduced glutathione; further preferably, the reducing conditions are provided by PBS buffer of reduced glutathione.

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