CN115010913B - PH/reduction dual-response polymer micelle and preparation method and application thereof - Google Patents

Abstract

The present application relates to the technical field of polymer micelles, in particular to a pH/reduction dual response polymer micelles and its preparation method and application. Among them, the structure of the pH/reduction dual response polymer micelles includes polyethylene glycol methyl ether methacrylate, ε-caprolactone, γ-amino-ε-caprolactone and disulfide bonds, making the polymer gel After the bundle is loaded with anticancer drugs, it can exist stably in the microenvironment of normal cells, and release the drug rapidly in the acidic and high glutathione environment of tumor cells, which solves the problem of drug control in polymer drug-loaded micelles in the prior art. There are technical issues that still need to be improved in the interpretation performance.

Description

A kind of pH/reduction dual response polymer micelles and its preparation method and application

technical field

The present application relates to the field of micelle technology, in particular to a pH/reduction dual response polymer micelle and its preparation method and application.

Background technique

Cancer treatment is an important research field in the medical field of various countries in the world. In recent years, medical workers have found through research that the microenvironmental conditions in tumor cells are significantly different from those in normal cells. For example, the pH in tumor cells is lower than that in normal cells, the pH in tumor cells is 5.0-6.0, and the pH in normal cells is 7.4; , the study also found that the concentration of glutathione in tumor cells was several times higher than that in normal tissue cells, resulting in a higher reduction response in tumor cells than in normal cells. The microenvironmental conditions of tumor cells are different from those of normal cells, that is, the microenvironment of tumor cells has a high reduction response and slightly acidic, which provides a theoretical basis for medical workers to achieve targeted delivery of anticancer drugs in tumor tissues.

Nanopolymer micelles are formed by self-assembly of amphiphilic polymers in water. The hydrophobic core of the micelles can contain insoluble drugs and improve the water solubility of hydrophobic drugs; The phagocytosis of bundles and the non-specific recognition of the reticuloendothelial system prolong the circulation time of drugs in the body; using the nanoscale EPR effect, polymer drug-loaded micelles can enhance drug permeability and retention, and promote anticancer drugs in the body. Accumulation in tumor tissue sites, thereby reducing the toxic and side effects of drugs and improving the therapeutic effect of anticancer drugs. At the same time, the polymer drug-loaded micelles can be further chemically modified, such as adding pH-responsive blocks, redox-responsive blocks, etc., so that the drug-loaded micelles can exist stably in the normal cell environment and release drugs in tumor cells, thereby Targeted delivery of anticancer drugs. However, although various nanopolymer micelles have made great progress in the delivery of anticancer drugs, their drug release performance needs to be further improved.

Contents of the invention

In view of this, the present application provides a pH/reduction dual response polymer micelle and its preparation method and application, which are used to solve the technical problem that the drug-controlled release performance of the polymer drug-loaded micelle still needs to be improved in the prior art .

The first aspect of the present application provides a pH/reduction dual-response polymer micelle, the structural formula of the polymer used to prepare the micelle is:

Wherein, x=8-23, y=36-47, z=14-19.

Preferably, the number average molecular weight of the polymer is 9000-18000 g/mol.

It should be noted that when the number-average molecular weight of the polymer is 9000-18000 g/mol, its critical micelle concentration is low, which is favorable for self-assembly to form polymer micelles.

The second aspect of the present application provides a method for preparing pH/reduction dual-response polymer micelles, comprising the following steps:

Step 1, under inert gas protection and anhydrous and oxygen-free conditions, the small molecule initiator of γ-(tert-butyl carbamate)-ε-caprolactone, ε-caprolactone, disulfide bond and the first After the catalysts are mixed, ring-opening polymerization is carried out to obtain a macromolecular initiator;

Step 2. Under nitrogen atmosphere, after mixing polyethylene glycol methyl ether methacrylate, macromolecular initiator, solvent, second catalyst and ligand, freezing-pumping-heating three times, stirring at room temperature, to obtain Catalyst complexes;

Step 3, after stirring the catalyst complex and the reducing agent, performing an oil bath reaction to obtain a reduction-responsive polymer;

Step 4, dissolving the reduction-responsive polymer and trifluoroacetic acid in dichloromethane and reacting with stirring to obtain a pH/reduction dual-response polymer;

Step 5. Dialyzing the pH/reduction dual-response polymer obtained in step 4 to obtain pH/reduction dual-response polymer micelles;

In step 1, the first catalyst is stannous octoate, and the ring-opening polymerization reaction is carried out at 100-130°C for 24-48 hours;

In step 2, the second catalyst is copper bromide, the ligand is pentamethyldiethyltriamine, and the solvent is tetrahydrofuran or toluene;

In step 3, the reducing agent is stannous octoate, the temperature of the oil bath reaction is 60-70° C., and the time is 12-24 hours.

Preferably, in step 3, after the oil bath reaction, the method further includes: after diluting the oil bath reaction product with a solvent, removing the catalyst through a neutral alumina chromatography column.

Preferably, the eluent of the neutral alumina chromatography column is tetrahydrofuran.

Preferably, calculated in parts by mass, the raw materials for the preparation of the macroinitiator include: 49.6 to 66.3 parts by mass of ε-caprolactone, 12.8 to 21.6 parts by mass of γ-(tert-butyl carbamate)-ε-caprolactone , 0.05-0.06 parts by mass of stannous octoate, and 0.8-1.2 parts by mass of small molecule initiators containing disulfide bonds.

Preferably, before obtaining the macromolecular initiator, also include: concentrating, precipitating, filtering, drying, and described precipitating is that the product after concentration is dissolved in a small amount of dichloromethane, and then this solution is transferred to 10 times of volume Precipitate in cold ether.

Preferably, calculated in parts by mass, the raw materials for the preparation of the reduction-responsive polymer include: 3.4-4.1 parts by mass of a macroinitiator, 4.8-5.9 parts by mass of polyethylene glycol methyl ether methacrylate, 0.013-0.022 parts by mass copper bromide, 0.12-0.20 parts by mass of pentamethyldiethyltriamine, and 0.26-0.38 parts of stannous octoate.

Preferably, in terms of parts by mass, the raw materials for the preparation of the pH/reduction dual response polymer include: 0.6-1.2 parts by mass of the reduction-responsive polymer, and 0.8-1.6 parts by mass of trifluoroacetic acid.

In step 3, before obtaining the reduction-responsive polymer, it also includes: concentrating, precipitating, filtering, and drying;

The precipitation is to dissolve the concentrated product in a small amount of tetrahydrofuran, and then transfer the solution to 10 times the volume of cold n-hexane for precipitation.

In step 4, before obtaining the pH/reduction dual-response polymer, it also includes: concentration, precipitation, filtration, and drying;

The precipitation is to dissolve the concentrated product in a small amount of tetrahydrofuran, and then transfer the solution to 10 times the volume of cold n-hexane for precipitation.

Preferably, the preparation method of the γ-(tert-butyl carbamate)-ε-caprolactone comprises: dissolving 4-(tert-butyloxycarbonylamino)cyclohexanone and 3-chloroperoxybenzoic acid in two In methyl chloride, react at 40-50°C for 12-24 hours to obtain γ-(tert-butyl carbamate)-ε-caprolactone.

Preferably, calculated in parts by mass, the raw materials for the preparation of γ-(tert-butylcarbamate)-ε-caprolactone include: 20.6 to 22.4 parts by mass of 4-(tert-butyloxycarbonylamino)cyclohexanone, 19.3 ~21.8 parts by mass of 3-chloroperoxybenzoic acid.

Preferably, in step 1, the preparation method of the small molecule initiator containing disulfide bonds comprises: under inert gas protection and anhydrous conditions, bis(2-hydroxyethyl) disulfide is dissolved in tetrahydrofuran, adding Triethylamine, cooled to 0°C. Add 2,4-dibromoisobutyryl bromide dropwise and stir. After the dropwise addition, react at 0°C for 1-3 hours, and then continue to react at room temperature for 12-24 hours.

Preferably, the tetrahydrofuran is tetrahydrofuran with water removed.

Preferably, calculated in parts by mass, the raw materials for the preparation of the small molecule initiator including disulfide bonds include: 5.96 to 6.41 parts by mass of bis(2-hydroxyethyl) disulfide, 6.42 to 6.58 parts by mass of triethylamine 4.88 ~4.98 parts by mass of 2,4-dibromoisobutyryl bromide.

Preferably, after the reaction is finished, it also includes concentrating and washing the small molecule initiator containing disulfide bonds;

Preferably, said concentrating includes: performing vacuum rotary evaporation on the reaction solution to remove the organic solvent;

The washing includes: washing the small molecule initiator with dilute hydrochloric acid, sodium bicarbonate solution and deionized water in sequence.

The third aspect of the present application also provides the application of a pH/reduction dual responsive polymer micelle as an anticancer drug carrier.

It should be noted that the pH/reduction dual-response polymer micelles of the present invention provided by this application are simple to prepare, have a high yield, and have a low critical micelle concentration, and self-assemble in aqueous solution to form polymer micelles. Applied to carry anticancer drugs.

Preferably, the anticancer drug is a hydrophobic anticancer drug.

The pH/reduction dual-response polymer micelle provided by the present application includes a hydrophobic block, which is suitable for loading hydrophobic drugs, can solubilize hydrophobic anticancer drugs, and improve the drug-loading capacity of the polymer micelle.

Preferably, the preparation method of the anticancer drug carrier: dissolve the pH/reduction dual response polymer and the hydrophobic anticancer drug in an organic solvent at a ratio of 3-6:1-3, stir for 4-12 hours and use Deionized water dialysis was performed for 24-72 hours, during which deionized water was changed every 3-6 hours and then freeze-dried.

It should be noted that when the ratio of the pH/reduction dual response polymer to the hydrophobic anticancer drug is 3-6:1-3, the polymer-loaded drug with uniform particle size distribution and high drug-loading capacity can be obtained. Drug micelles.

In summary, the present application provides a pH/reduction dual response polymer micelle and its preparation method and application. The structure of the pH/reduction dual response micelle includes polyethylene glycol methyl ether methacrylate, γ-amino-ε-caprolactone, ε-caprolactone and disulfide bonds, wherein polyethylene glycol methyl ether methacrylate is a hydrophilic block, compared with linear polyethylene glycol, it can Improve the stability of micelles under neutral conditions, ε-caprolactone is a hydrophobic block, which can improve the drug loading of micelles to hydrophobic drugs, and the disulfide bond is a reduction response group, and γ-amino -ε-caprolactone block can be protonated under acidic conditions, the block is converted from hydrophobicity to hydrophilicity, so that the micelles have a pH response, and, under reducing conditions, disulfide bonds are exchanged by sulfhydryl-disulfide bonds After the reaction, the cleavage will change the hydrophilic-hydrophobic balance of the polymer, resulting in the change of the micelle structure or even disintegration, so as to realize the controlled and targeted release of the drug. It exists stably in environmental conditions, and is released rapidly under the acidity and high glutathione concentration in tumor cells. There is a technical problem that the performance of polymer drug-loaded micelles drug controlled release still needs to be improved in the art.

Detailed ways

In order to make the purpose, features and advantages of the present application more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the embodiments described below are only part of the implementation of the present application. example, but not all examples. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the synthetic process roadmap of γ-(tert-butyl carbamate)-ε-caprolactone;

Fig. 2 is the synthesis process roadmap of pH/reduction dual response polymer;

Fig. 3 is the hydrogen nuclear magnetic resonance spectrogram of pH/reduction dual response polymer in embodiment 4;

Fig. 4 is the FT-IR spectrum before and after the hydrolysis reaction of the dual response polymer of pH/reduction in embodiment 4;

Fig. 5 is the gel permeation chromatogram of pH/reduction dual responsive polymer in embodiment 4;

Fig. 6 is the critical micelle concentration determination curve figure of pH/reduction dual response polymer in embodiment 4;

Fig. 7 is the graph of blank micelle particle diameter to pH in embodiment 8;

Fig. 8 is the transmission electron micrograph of the pH/reduction dual-response drug-loaded polymer micelle in Example 9;

Fig. 9 is the in vitro release curve of the pH/reduction dual response drug-loaded polymer micelles in Example 10.

Example 1

This embodiment 1 provides the preparation process of γ-(tert-butyl carbamate)-ε-caprolactone, comprising steps:

4-(tert-butyloxycarbonylamino)cyclohexanone (21.3 g, 0.1 mol) and 3-chloroperoxybenzoic acid (20.6 g, 0.12 mol) were dissolved in anhydrous dichloromethane (100 mL), and The mixture was condensed and refluxed at 43°C for 24 hours. After the reaction, dichloromethane was rotated to evaporate, and the concentrated product was added dropwise to cold ether of ten times its volume to precipitate, filtered, and vacuum-dried at room temperature for 24 hours to obtain γ -(tert-butylcarbamate)-ε-caprolactone.

Example 2

This embodiment 2 provides the preparation process of the small molecule initiator containing disulfide bond, comprising steps:

Add bis(2-hydroxyethyl) disulfide (15.425g, 100mmol) and a stirring bar into a 100mL anhydrous and anaerobic reaction bottle, seal it with a reverse rubber stopper, vacuumize and pass nitrogen three times, and in a nitrogen atmosphere Add 100ml of anhydrous tetrahydrofuran and anhydrous triethylamine (13.900mL, 100mmol) with a syringe, and cool to 0°C in an ice bath. Add 2,4-dibromoisobutyryl bromide (9.888mL, 80mmol) dropwise while stirring. After the dropwise addition, continue the reaction at 0°C for 3h, then continue the reaction at room temperature for 24h, and remove the insoluble triethyl bromide by filtration. amine salt, and the filtrate was distilled with dichloromethane. Wash with dilute hydrochloric acid solution, sodium bicarbonate solution, and deionized water three times in sequence, then dry overnight with anhydrous magnesium sulfate, filter, concentrate the filtrate by rotary evaporation, and vacuum-dry the obtained product at 40°C for 12 hours to obtain a small molecule containing a disulfide bond Initiator.

Example 3

Present embodiment 3 provides the preparation technology of macromolecular initiator, comprises steps:

Add small molecule initiator (0.244g, 0.8mmol) and γ-(tert-butyl carbamate)-ε-caprolactone (3.46g, 15.0mmol) prepared in embodiment 2 in 100ml anhydrous and oxygen-free reaction flask, Seal it with a back-mouth rubber stopper, vacuumize and blow nitrogen three times, add ε-caprolactone (5.70g, 50.0mmol) and catalyst stannous octoate (0.00916g, 0.02mmol) respectively with a syringe, and place in an oil bath at 130°C After the reaction, cool down to room temperature, dissolve the product with a small amount of dichloromethane, add the reaction solution dropwise to cold diethyl ether ten times its volume, stir to precipitate, filter with suction, and dry in vacuum at room temperature for 12 hours , to obtain the product macroinitiator.

Example 4

This embodiment 4 provides the preparation process of the pH/reduction dual response polymer, including steps:

Step 1, put into stirring bar, the macromolecular initiator (9.439g, 1mmol) and copper bromide (0.018g, 0.08mmol) prepared by embodiment 3 in the 100ml anhydrous and oxygen-free reaction flask, after the reaction flask is sealed, Vacuum-gas three times in turn, then add polyethylene glycol methyl ether methacrylate (4.75g, 10mmol), anhydrous tetrahydrofuran 20mL, ligand pentamethyldiethyltriamine (0.190mL, 0.8mmol ), after stirring for 15min, the copper bromide/pentamethyldiethyltriamine catalyst complex was formed, and then the reducing agent stannous octoate (0.324g, 0.8mmol) dissolved in 10mL of anhydrous tetrahydrofuran was added in the reaction flask with a syringe , followed by stirring for 20 min, then reacted in an oil bath at 60°C for 24 h, and when cooled to room temperature, dilute the reaction solution with tetrahydrofuran, pass through a neutral alumina column to remove the catalyst, spin the solution, and add the solution dropwise to a volume of ten Precipitate in twice the amount of frozen n-hexane, filter with suction, and finally dry in vacuum at 40°C for 12 hours to obtain a reduction-responsive polymer;

Step 2. A solution of trifluoroacetic acid (1.2 g, 10 mmol) dissolved in 5 mL of anhydrous dichloromethane was slowly added to a reduction-responsive polymer (0.8 g, 0.9 mmol) dissolved in 5 mL of anhydrous methylene chloride Butyl ester)-ε-caprolactone) solution, the reaction was stirred at room temperature for 24h, and dichloromethane was rotary evaporated after the reaction was completed. The crude product was dissolved in a small amount of tetrahydrofuran, precipitated twice in refrigerated n-hexane of ten times its volume, filtered with suction, and the residual solvent was removed by vacuum to obtain a pH/reduction dual responsive polymer.

Example 5

This embodiment 5 provides the preparation process of the pH/reduction dual response polymer, including steps:

Step 1, put stirring bar, the macroinitiator (9.439g, 1mmol) and copper bromide (0.022g, 0.1mmol) that embodiment 3 prepares in 100ml anhydrous anaerobic reaction bottle. After sealing the reaction bottle, vacuumize and nitrogen three times successively, then add polyethylene glycol methyl ether methacrylate (7.13g, 15mmol), anhydrous tetrahydrofuran 30mL, ligand pentamethyldiethyltriamine (0.238 mL, 1.0 mmol), the copper bromide/pentamethyldiethyltriamine catalyst complex was formed after stirring for 15 min. Add the reductant stannous octoate (0.405 g, 1.0 mmol) dissolved in 10 mL of anhydrous tetrahydrofuran into the reaction flask with a syringe, then stir for 20 min, then react in an oil bath at 60°C for 24 h, and when cooled to room temperature, wash with tetrahydrofuran The solution obtained after diluting the reaction was passed through a neutral alumina chromatography column to remove the catalyst, the solution was rotary evaporated, added dropwise into frozen n-hexane of ten times its volume to precipitate, filtered with suction, and finally vacuum-dried at 40°C for 12h to obtain Reduction-responsive polymers;

Step 2. A solution of trifluoroacetic acid (1.2 g, 10 mmol) dissolved in 5 mL of anhydrous dichloromethane was slowly added to a reduction-responsive polymer (1.0 g, 0.9 mmol) dissolved in 5 mL of anhydrous methylene chloride Butyl ester)-ε-caprolactone) solution. The reaction was stirred at room temperature for 24 h, and dichloromethane was rotary evaporated after the reaction was completed. The crude product was dissolved in a small amount of tetrahydrofuran, precipitated twice in refrigerated n-hexane of ten times its volume, and filtered with suction. Residual solvent was removed by vacuum to obtain a pH/reduction dual responsive polymer.

Example 6

This embodiment 6 provides a pH/reduction dual-response polymer preparation process, including steps:

Step 1, put into stirring bar, the macromolecular initiator (9.439g, 1mmol) and copper bromide (0.027g, 0.12mmol) prepared by embodiment 3 in the 100ml anhydrous and oxygen-free reaction flask, after the reaction flask is sealed, Vacuum-gas three times in sequence, then add polyethylene glycol methyl ether methacrylate (9.50g, 20mmol), anhydrous tetrahydrofuran 40mL, ligand pentamethyldiethyltriamine (0.285mL, 1.2mmol ). After stirring for 15 min, the copper bromide/pentamethyldiethyltriamine catalyst complex was formed. Add the reducing agent stannous octoate (0.486g, 1.2mmol) dissolved in 10mL of anhydrous tetrahydrofuran into the reaction flask with a syringe, then stir for 20min, then react in an oil bath at 60°C for 24h, and when cooled to room temperature, wash with tetrahydrofuran The solution obtained after diluting the reaction was passed through a neutral alumina chromatography column to remove the catalyst, the solution was rotary evaporated, added dropwise into frozen n-hexane of ten times its volume to precipitate, filtered with suction, and finally vacuum-dried at 40°C for 12h to obtain Reduction-responsive polymers;

Step 2. A solution of trifluoroacetic acid (1.2 g, 10 mmol) dissolved in 5 mL of anhydrous dichloromethane was slowly added to a reduction-responsive polymer (1.1 g, 0.9 mmol) dissolved in 5 mL of anhydrous methylene chloride Butyl ester)-ε-caprolactone) solution. The reaction was stirred at room temperature for 24 h, and dichloromethane was rotary evaporated after the reaction was completed. The crude product was dissolved in a small amount of tetrahydrofuran, precipitated twice in refrigerated n-hexane of ten times its volume, and filtered with suction. Residual solvent was removed by vacuum to obtain a pH/reduction dual responsive polymer.

Example 7

This Example 7 is to test the critical micelle concentration of the pH/reduction dual-response polymer prepared in Example 4. The test method is the fluorescent probe method, and the test steps include:

Step 1, preparing a pyrene solution, dissolving pyrene in acetone to prepare a 6×10 ^-5 M acetone solution;

Step 2. Accurately weigh 10 mg of the pH/reduction dual-response polymer prepared in Example 4, dissolve it in 5 mL of acetone, add it dropwise to 100 mL of deionized water, and volatilize the acetone to obtain a 0.1 mg/mL solution, which is then diluted to a series of concentrations ( 0.0001～0.1mg/ml). Take 20 10mL brown volumetric flasks, add 0.1mL pyrene solution to each, and then add the above-mentioned polymer solutions with different concentrations to make sample solution. The concentration of pyrene in the sample solution is 6×10 ^-7 M;

Step 3, fluorescence spectrum test: with 373nm as the emission wavelength, test the excitation spectrum of the sample solution at 300-350nm, take the _I337 / _I332 ratio and plot the logarithm of the concentration logC (Figure 6), the turning point of the curve is the critical micelle concentration value. The measured critical micelle concentration was 1.26mg/L.

Example 8

Example 8 is the self-assembly behavior of the pH/reduction dual responsive polymer prepared in Example 4 above the CMC and the particle size of blank micelles at different pHs tested by DLS.

Among them, the self-assembly behavior includes: accurately weighing 30 mg of the pH/reduction dual-response polymer prepared in Example 4, dissolving it in 30 mL of dimethyl sulfoxide, transferring it to a dialysis bag (MWCO3500) after completely dissolving, and using 1 L of deionized water Dialyze for 48 hours, and replace the dialysis medium every 4 hours to obtain a blank micellar solution with a concentration of 1 mg/mL;

The particle size of the blank micelles at different pH includes: divide the blank micellar solution into 10 parts, adjust the pH from 3 to 10 respectively, and after a period of stability, use the dynamic light scattering method to measure the particle size at each pH.

Example 9

In Example 9, the pH/reduction dual-response polymer prepared in Example 4 was tested for anticancer drug loading, and its particle size distribution and morphology were characterized.

Anticancer drug loading test includes: accurately weigh 30mg pH/reduction dual response polymer and dissolve in 30mL dimethyl sulfoxide, add 15mg paclitaxel accurately after complete dissolution, stir at room temperature for 4 hours in the dark, then transfer to dialysis bag (MWCO3500 ), dialyzed with 1L deionized water for 48 hours, and replaced the dialysis medium every 4 hours. The micellar solution was filtered through a filter head with a pore size of 0.45 μm and freeze-dried.

The particle size distribution and morphology characterization are shown in Figure 8. The particle size and particle size distribution were measured by dynamic light scattering method, and the average particle size of the pH/reduction dual-response polymer micelles loaded with anticancer drugs was obtained by laser light scattering method. It is 229.6nm, and the particle size distribution is 0.218. Its morphology was observed by TEM as spherical.

Example 10

This Example 10 is to perform a drug release test on the pH/reduction dual-response polymer micelles loaded with anticancer drugs prepared in Example 9, and the test includes steps:

Accurately weigh four parts of 5 mg of pH/reduction dual response micelles loaded with anticancer drugs prepared in Example 9, and dissolve them in 5 mL of pH 5.0, pH 7.4, pH 5.0/10mM DTT, pH 7.4/10mM DTT respectively in the buffer solution. After fully dissolving, the mixed solution was placed in a dialysis bag (MWCO3500), and then the dialysis bag was immersed in 95 mL of the above corresponding buffer solution. Set the temperature at 37 °C and the stirring speed at 100 rpm. Sample 4mL at regular intervals and add 4mL of fresh buffer. The concentration of paclitaxel in the release solution at different times was measured by ultraviolet spectrophotometry, and its in vitro release curve was drawn;

The results are shown in Fig. 9. As can be seen from Fig. 9, in a normal blood environment (pH 7.4/0mM DTT), the drug release rate is slow, the cumulative release amount is lower than 10% within 6h, and the cumulative release amount is lower than 20% within 120h. It can effectively reduce the loss of drugs in the normal blood circulation of the human body; in the pH 5.0/10mM DTT environment, the release rate of the drug-loaded micelles is rapid, with a cumulative release of about 30% within 12 hours and a cumulative release of 67% within 120 hours. There was no burst release phenomenon in the four experimental conditions, which met the requirements of slow-controlled release.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions described in each embodiment are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the application.

Claims (10)

1. a pH/reduction double response polymer micelle, is characterized in that, the structural formula of polymer in the described polymer micelle is:

Among them, x =8～23, y =36～47, z =14～19. 2. A pH/reduction dual response polymer micelle according to claim 1, characterized in that the number average molecular weight of the pH/reduction dual response polymer is 9000-18000 g/mol. 3. the preparation method of a kind of pH/reduction double responsive polymer micelles described in claim 1, is characterized in that, comprises the following steps: Step 1, under inert gas protection and anhydrous and oxygen-free conditions, γ- (tert-butyl carbamate) -ε -caprolactone, ε -caprolactone, a small molecule initiator containing a disulfide bond and the first After the catalysts are mixed, ring-opening polymerization is carried out to obtain a macromolecular initiator; Step 2. Under nitrogen atmosphere, after mixing polyethylene glycol methyl ether methacrylate, macromolecular initiator, solvent, second catalyst and ligand, freezing-pumping-heating three times, stirring at room temperature, to obtain Catalyst complexes; Step 3, after stirring the catalyst complex and the reducing agent, performing an oil bath reaction to obtain a reduction-responsive polymer; Step 4, dissolving the reduction-responsive polymer and trifluoroacetic acid in dichloromethane and reacting with stirring to obtain a pH/reduction dual-response polymer; Step 5. Dialyzing the pH/reduction dual-response polymer obtained in step 4 to obtain pH/reduction dual-response polymer micelles; In step 1, the first catalyst is stannous octoate, and the ring-opening polymerization is carried out at 100-130°C for 24-48 hours; In step 2, the second catalyst is copper bromide, the ligand is pentamethyldiethyltriamine, and the solvent is tetrahydrofuran or toluene; In step 3, the reducing agent is stannous octoate, the temperature of the oil bath reaction is 60-70 °C, and the time is 12-24 h. 4. the preparation method of a kind of pH/reduction dual response polymer micelle according to claim 3, is characterized in that, the preparation method of described γ- (tert-butyl carbamate) -ε -caprolactone comprises: Dissolve 4-(tert-butyloxycarbonylamino)cyclohexanone and 3-chloroperoxybenzoic acid in dichloromethane and react at 40~50°C for 12~24 h to obtain γ- (tert-butyl carbamate) - ε -caprolactone. 5. the preparation method of a kind of pH/reduction dual response polymer micelle according to claim 3, is characterized in that, the preparation method of the small molecular initiator containing disulfide bond comprises: under inert gas protection and without Under water conditions, dissolve bis(2-hydroxyethyl)disulfide in tetrahydrofuran, add triethylamine, cool to 0 ℃, add 2,4-dibromoisobutyryl bromide drop by drop and stir, after dropwise addition React at 0 °C for 1-3 h, then continue to react at room temperature for 12-24 h. 6. The preparation method of a pH/reduction dual response polymer micelle according to claim 3, characterized in that, calculated in parts by mass, the raw materials for the preparation of the macroinitiator include: 49.6 to 66.3 parts by mass ε - caprolactone, 12.8-21.6 parts by mass of γ- (tert-butyl carbamate) -ε -caprolactone, 0.05-0.06 parts by mass of stannous octoate, and 0.8-1.2 parts by mass of a disulfide bond-containing small molecule initiator. 7. The preparation method of a kind of pH/reduction double response polymer micelle according to claim 3, is characterized in that, the preparation raw material of described reduction response polymer comprises: 3.4～4.1 mass parts macromolecular initiator, 4.8 ~5.9 parts by mass of polyethylene glycol methyl ether methacrylate, 0.013~0.022 parts by mass of copper bromide, 0.12~0.20 parts by mass of pentamethyldiethyltriamine, and 0.26~0.38 parts of stannous octoate. 8. The preparation method of a pH/reduction dual-response polymer micelle according to claim 3, characterized in that, in parts by mass, the raw materials for preparing the pH/reduction dual-response polymer include: 0.6~1.2 Parts by mass of reduction-responsive polymer, 0.8-1.6 parts by mass of trifluoroacetic acid. 9. The pH/reduction dual response polymer micelle described in any one of claim 1-2 or the pH/reduction dual response polymer micelle that the preparation method described in any one of claim 3-8 prepares as anti- Applications of cancer drug carriers. 10. The application according to claim 9, wherein the preparation method of the anticancer drug carrier comprises: mixing pH/reduction dual responsive polymer micelles and hydrophobic anticancer drugs at a ratio of 3~6:1~3 Dissolve in an organic solvent, stir for 4 to 12 hours, then dialyze with deionized water for 24 to 72 hours, during which the deionized water is changed every 3 to 6 hours and then freeze-dried.

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