CN110804178B

CN110804178B - Nano drug-loaded system with glutathione responsiveness and preparation method and application thereof

Info

Publication number: CN110804178B
Application number: CN201910989546.7A
Authority: CN
Inventors: 吴钧; 孟亚彬; 顾志鹏; 周洋
Original assignee: National Sun Yat Sen University
Current assignee: National Sun Yat Sen University
Priority date: 2019-10-17
Filing date: 2019-10-17
Publication date: 2020-08-07
Anticipated expiration: 2039-10-17
Also published as: CN110804178A

Abstract

The invention discloses a nano drug-loaded system with glutathione responsiveness and a preparation method and application thereof. The invention provides a preparation method of a polyester amide polymer PEA with glutathione responsiveness, which comprises the following steps: phenylalanine or salt thereof, dihydric alcohol and p-toluenesulfonic acid are put into a solvent to react under the reflux condition to obtain a graft polymer Phe-6; dissolving cystine or cysteine or derivatives thereof and a polymer Phe-6 in chloroform, adding triethylamine, and stirring for 15-120 min under the condition of ice-water bath to obtain a mixed solution; dropwise adding equimolar diacid chloride diluted by chloroform into the mixed solution, and carrying out an amide reaction for 10-120 min. The glutathione sensitive polymer can lead the drug-loaded nanoparticles to be quickly disintegrated and the encapsulated drug to be quickly released, has high drug-loaded quantity and high responsiveness, has the characteristics of high-efficiency tumor targeting and high-efficiency inhibition of tumor cell growth, reduces the toxicity of chemotherapeutic drugs to normal tissues, and is green and safe.

Description

Nano drug-loaded system with glutathione responsiveness and preparation method and application thereof

Technical Field

The invention belongs to the technical field of biomedical materials. More particularly, relates to a nano drug delivery system with glutathione responsiveness, and a preparation method and application thereof.

Background

In recent years, malignant tumors become serious diseases threatening physical and psychological health of people, and have a remarkable rising trend, thereby having great influence on human health. Chemotherapy is one of the most commonly used treatments in oncology, and the quality of the effect depends largely on whether sufficient concentrations of the chemotherapeutic agent reach the entire tumor site. Conventional anticancer drug preparations often result in unsatisfactory therapeutic effects and serious toxic and side effects such as rapid clearance in the systemic circulation and similar cytotoxicity to cancer cells and healthy cells due to poor water solubility and poor selectivity.

Docetaxel (DTX) is one of a plurality of chemotherapeutic preparations, is a first-line non-specific antitumor chemotherapeutic medicament with a wider cell cycle in clinical application, and is used for treating various cancers, such as breast cancer, head and neck cancer, gastric cancer, prostate cancer, non-small cell lung cancer and the like. DTX is an antimitotic chemotherapeutic agent that causes cell cycle arrest in the G2/M phase and further leads to apoptosis by promoting microtubule stabilization. However, docetaxel can cause various adverse reactions including anaphylaxis, bone marrow suppression, skin reaction, fluid retention, peripheral neuropathy, alopecia, heart diseases, fatigue and other side effects when used for treating tumors. DTX requires a specific solvent system, such as a solution of ethanol and tween 80, but such a solvent system can cause allergy, poor uptake by tumor tissues, and physical side effects. Therefore, finding a way to increase the circulation time of DTX in vivo and reduce the toxicity of the drug to normal cells while ensuring the killing effect on tumor cells becomes a key bottleneck.

The nano delivery system relies on high permeability and retention Effect (EPR) of solid tumors to improve pharmacokinetic characteristics and target site accumulation, and is expected to thoroughly change the diagnosis and treatment of tumors. Under the situation of rapid development of medical polymers, it is the goal of biomaterials to achieve multiple functionalities on the basis of improving the biocompatibility of medical polymers. In recent years, many different natural polymer materials, especially amino acids, have been reported in the literature, and the last decades have witnessed the vigorous development of amino acid-based nanocarriers due to their superiority in synthetic polymers, such as structure tunability and good biocompatibility, and various reactive groups, such as thiol (-SH), amino (-NH)₂) And carboxyl (-COOH), provides a greater opportunity for developing targeted nano-drug delivery systems. At present, the development of a biocompatible, multifunctional and biodegradable amino acid polymer nanocarrier library is urgently needed to reduce the risk of diseases and improve human health.

In recent years, many polyesteramide copolymers (diblock or multiblock copolymers) have been synthesized based on amino acids, but they are all based on the reaction of an amino acid with a diol, diacid (or diacid chloride) to form a copolymer, and it is difficult to prepare a polymer nanocarrier with versatility. For example, the chinese patent with application No. CN 201310284253.1 discloses a block copolymer of polyesteramide and polyethylene glycol and a preparation method thereof. The triblock or multiblock copolymer with amphiphilic property is obtained by condensation reaction of polyesteramide with amino acid unit structure and polyethylene glycol with amino at the end of molecular chain. The segmented copolymer has good biocompatibility and biodegradability, and is suitable for preparing nanoparticles for encapsulating oil-soluble drugs. However, although the copolymer drug delivery system improves the water solubility of the tumor drug, the copolymer drug delivery system has the defect that the encapsulated tumor drug cannot be quickly released to tumor cells, has poor stability in the long circulation process of blood, and cannot efficiently enter the tumor cells in the circulation process.

Disclosure of Invention

The invention aims to solve the technical problem in the delivery of the anti-tumor drug and provides a nano drug-carrying system with glutathione responsiveness, which is suitable for the delivery of the anti-tumor drug. The invention synthesizes a novel functional polymer which is based on cystine and phenylalanine, has high biocompatibility, is biodegradable and has redox responsiveness from cystine, fatty diacid and fatty diol which are abundantly present in a body and contain disulfide bonds, and realizes the high-efficiency transfer of hydrophobic antitumor drugs represented by DTX and the positioning controllable release of the hydrophobic antitumor drugs in tumor cells. The nano drug-loaded system has good biological safety, biodegradability and long circulation stability, has the characteristics of high-efficiency tumor targeting and high-efficiency inhibition of tumor cell growth, and can effectively solve the problems of poor solubility, poor targeting property, poor responsiveness, slow release speed and poor systemic circulation stability of a nano drug carrier.

The first purpose of the invention is to provide a preparation method of a polyester amide Polymer (PEA) with glutathione responsiveness.

The second purpose of the invention is to provide the application of the polyester amide Polymer (PEA) in serving as or preparing an anti-tumor drug carrier.

The third purpose of the invention is to provide a preparation method of the glutathione-responsive drug delivery carrier.

The fourth purpose of the invention is to provide a drug delivery nano-system based on the polyesteramide polymer and having glutathione responsiveness.

The fifth purpose of the invention is to provide a preparation method of a nano drug delivery system for delivering anti-tumor drugs.

The above purpose of the invention is realized by the following technical scheme:

a preparation method of a polyester amide polymer PEA with glutathione responsiveness comprises the following steps:

s1, reacting phenylalanine or salt thereof, dihydric alcohol and p-toluenesulfonic acid in a solvent under a reflux condition to obtain a graft polymer Phe-6;

s2, dissolving cystine or cysteine or derivatives thereof and the polymer Phe-6 in chloroform, adding triethylamine, and stirring for 15-120 min under the condition of ice-water bath to obtain a mixed solution; dropwise adding equimolar diacid chloride diluted by chloroform into the mixed solution, and carrying out an amide reaction for 10-120 min to obtain the polyester amide polymer PEA with the glutathione responsiveness.

The invention starts from cystine containing disulfide bonds, fatty diacid and fatty diol which are greatly existed in a human body, synthesizes a novel functional high molecular polyesteramide polymer PEA based on cystine and phenylalanine, which has high biocompatibility, is biodegradable and has redox responsiveness, simultaneously improves the solubility of the drug, greatly improves the availability of the hydrophobic drug, and also can greatly improve the circulation time of nanoparticles in blood, thereby improving the drug accumulation at a tumor part.

In a preferred embodiment of the present invention, the degree of polymerization of the polymer PEA is 2-60, and the molecular weight is 2000-51000. The degree of polymerization and molecular weight of the polymer PEA affect the magnitude of GSH response characteristics, the particle size when self-assembled into nanoparticles, and the like. When the polymerization degree of the polymer PEA is 2-60 and the molecular weight is 2000-51000, the GSH response characteristic is strongest, and the polymer PEA is uniform in particle size and proper in size when self-assembled into nanoparticles, so that the EPR effect and the GSH response of the drug-loaded nanoparticles can be fully exerted, and the anti-tumor effect is greatly enhanced by 8.

In a preferred embodiment of the present invention, the mole ratio of polymer Phe-6 to cystine in S2 is 9: 1-1: 9; preferably 1-6: 1, as 1: 1. 2: 1. 3: 1. 4: 1. 5: 1. 6:1, etc. When the reaction material is cysteine, the mole ratio of polymer Phe-6 to cysteine salt is 2 times of the mole ratio of polymer Phe-6 to cystine. The mole ratio of polymer Phe-6 to cystine can significantly affect the yield, stability and GSH response characteristics of the synthesized polymer PEA, and experiments show that the mole ratio of polymer Phe-6 to cystine salt is 9: 1-1: 9, preferably 1-6: 1, the polymer PEA has high yield, high stability and obvious GSH response characteristic, and can rapidly crack disulfide bonds under the condition of high-concentration GSH in tumor cytoplasm, so that the polymer PEA drug-loaded nanoparticles are rapidly disintegrated and released.

The cysteine is selected from L-cysteine, D-cysteine or L, D-cysteine, the reaction raw material can also be selected from other cystine derivatives, cysteine derivatives and the like besides cystine and cysteine, wherein the cysteine derivative is one or more of cysteine, homocysteine, methyl cysteine, cysteine hydrochloride and cysteine sulfate, the cystine salt can be selected from hydrochloride or sulfate, and the reaction raw material phenylalanine can also be selected from other phenylalanine salts, such as phenylalanine hydrochloride, lithium phenylalanine, sodium phenylalanine, potassium phenylalanine or rubidium phenylalanine and the like.

In a preferred embodiment of the present invention, the diacid chloride described in S2 is diluted with chloroform by a factor of 10 or more, so as to prevent the addition of high concentration of diacid chloride, which may result in a violent reaction to produce more dark brown by-products, resulting in lower product yield and purity, and poor stability of nanoparticles.

In a preferred embodiment of the present invention, the molar ratio of phenylalanine, glycol and p-toluenesulfonic acid in S1 is 2-4: 1: 1-3, preferably 2-3: 1: 2-3; more preferably 2.2: 1: 2.6.

in the preferred embodiment of the invention, the dihydric alcohol is selected from one or more of 1, 4-butanediol, 1, 6-hexanediol, 1, 8-octanediol or 1, 10-decanediol; the binary acyl chloride is selected from one or more of self-diacid chloride, oxalyl chloride, succinyl chloride or suberoyl chloride.

In a preferred embodiment of the invention, after Phe-6 is obtained in S1, the Phe-6 is poured into boiling water to be stirred and dissolved so as to remove unreacted solvent, then the product is precipitated at 0-10 ℃, unreacted monomers are filtered out, the operation is repeated for 3-4 times, and vacuum drying is carried out at 50-100 ℃ for 12-24 hours so as to obtain a white powdery graft polymer (Phe-6), so that the purity and stability of the Phe-6 are further improved while the yield of the polymer is not reduced.

In a preferred embodiment of the invention, after the polyester amide PEA is obtained in S2, the polyester amide PEA is dripped into a boiling water bath to be stirred to remove chloroform and unreacted binary acyl chloride, and after the stirring is repeated for 3-4 times, the polyester amide PEA is dried in vacuum at 50-100 ℃ for 12-24 hours, so that the purity and the stability of the polyester amide PEA are further improved while the yield of a polymer is not reduced.

In the preferred embodiment of the present invention, the reflux conditions in S1 are: magnetically stirring and refluxing for 24-36 h at 120-140 ℃. The reaction conditions of the polymer PEA are strictly controlled in the preparation process, the reflux temperature and the reflux time obviously influence the performance effect of the obtained polymeric material, if the reflux temperature is too high or the reflux time is too long, the generation rate of functional bonds in the material is accelerated, the molecular weight distribution of the material is widened, and the stability of the obtained product is reduced; and the reflux temperature is too low or the reflux time is too short, so that a sufficient and effective functional structure cannot be formed in the drug delivery system, and the drug delivery and drug release performance of the drug delivery system are affected.

In a preferred embodiment of the present invention, the solvent in S1 is one or more selected from toluene and/or benzene. The reaction needs to be carried out under anhydrous conditions, and the presence of water reacts with the diacid chloride, reducing the yield.

In a preferred embodiment of the invention, the amount of S2 diacid chloride added is the sum of the molar amounts of polymer Phe-6 and cystine salt. If the addition amount of the diacid chloride is too high, more byproducts can be generated, so that the product yield and purity are lower, and the stability of the nanoparticles is poorer.

In a preferred embodiment of the present invention, the ice-water bath conditions in S2 are: 0 to 4 ℃. The reaction is carried out in an ice-water bath, and the reaction is too violent due to too high temperature, so that more byproducts are produced.

The invention also relates to application of the polyester amide polymer PEA prepared by the method in serving as or preparing an anti-tumor drug nano delivery carrier.

The invention also relates to a preparation method of the glutathione-responsive drug delivery carrier, which comprises the following steps:

dissolving the polymer PEA prepared by the method in an organic solvent to obtain a PEA solution, then dropwise adding the PEA solution into an aqueous solution containing a stabilizer under the stirring condition to enable the aqueous solution to be self-assembled into nanoparticles, wherein the concentration of the PEA solution is 10-50 mg/m L, or dissolving the polymer PEA prepared by the method and the stabilizer in the organic solvent, and dropwise adding the obtained mixed solution into water to self-assemble into the nanoparticles.

In a preferred embodiment of the present invention, the mass of the stabilizer is 0 to 75% of the mass of the polymer PEA, preferably 15 to 30%.

In some of these embodiments, the stabilizer is DSPE-PEG, preferably DSPE-PEG 2000.

The invention also relates to a nano drug-carrying system with glutathione responsiveness, which comprises the polymer PEA prepared by the method and an anti-tumor drug.

The invention also relates to a preparation method of the nano drug-loaded system with the glutathione responsiveness, which comprises the following steps:

respectively dissolving the anti-tumor drug and the polymer PEA prepared by the method in an organic solvent to respectively prepare solutions with the concentration of 5-60 mg/m L, respectively dropwise adding the PEA and the anti-tumor drug solution into an aqueous solution containing a stabilizer under the stirring condition to enable the solutions to be self-assembled into drug-carrying nanoparticles, or respectively dissolving the polymer PEA, the anti-tumor drug and the stabilizer prepared by the method in the organic solvent, wherein the mass ratio of the polymer PEA to the anti-tumor drug is 1: 0.05-0.50, and dropwise adding the obtained mixed solution into water to self-assemble into the drug-carrying nanoparticles.

The nano drug delivery system has the advantages of easily available raw materials, pure and mature preparation process, easy operation, no need of expensive instruments, moderate size and good biocompatibility of the prepared nano compound, realizes controllable drug loading of the hydrophobic drug, improves the solubility of the drug, greatly improves the availability of the hydrophobic drug, and can also greatly improve the circulation time of the nanoparticles in blood, thereby improving the drug accumulation of tumor parts and improving the treatment effect.

In some embodiments, the mass ratio of the polymeric PEA to the antineoplastic agent is 1: 0.08-0.25, preferably 1: 0.3. if the mass ratio of the polymer PEA to the antitumor drug is too large, the drug loading rate is low, the number of the formed nanoparticles is small, and if the mass ratio of the polymer PEA to the antitumor drug is too small, the encapsulation rate is low, so that the drug waste is caused, and the obtained nanoparticles are unstable and easy to precipitate.

In a preferred embodiment of the invention, the organic solvent is selected from one or more of dimethyl sulfoxide (DMSO), N-Dimethylformamide (DMF) or Tetrahydrofuran (THF); dimethyl sulfoxide (DMSO) is preferred.

In a preferred embodiment of the invention, the mass of the stabilizer is 15-30% of the total mass of the polymer PEA and the antitumor drug.

In a preferred embodiment of the present invention, the concentration of the antitumor drug and the polymer PEA is preferably 20-50 mg/m L.

In the invention, the particle size of the drug-loaded nanoparticles is 60-200 nm. The drug-loaded nanoparticles have the particle size of below 200nm, have higher specific surface area and high drug loading amount, are excellent drug-loaded systems and can enhance the curative effect of drugs; moreover, the drug-loaded nanoparticles can enhance the targeting property of the drug at tumor parts by utilizing the EPR effect.

In a preferred embodiment of the invention, the obtained drug-loaded nanoparticle solution is placed in an ultrafiltration tube with cut-off molecular weight (MWCO ═ 100kD), ultrafiltration is carried out at 3000-8000 rpm for 15-25 min, then washing is carried out with ultrapure water, then ultrafiltration is carried out, and the process is repeated for 2-3 times to remove unencapsulated DTX and to make the content of organic solvent below one thousandth, so as to obtain purified drug-loaded nanoparticles.

In the present invention, there is no particular limitation on the antitumor drug to be carried, and the carried drug includes a hydrophilic drug and a hydrophobic drug. Wherein, the hydrophilic drugs include, but are not limited to, doxorubicin hydrochloride, gemcitabine hydrochloride, irinotecan hydrochloride, fluorouracil or lentinan and other drugs. The hydrophobic drugs include, but are not limited to, Paclitaxel (PTX), docetaxel, methotrexate, camptothecin, doxorubicin, curcumin and other drugs.

Different polymer structures have varying degrees of impact on drug loading and delivery performance. In the nano drug delivery system prepared by the invention, the factors such as the microenvironment of tumor cells, the structure of a polymer, a functional domain, hydrophilicity and hydrophobicity and the like are fully considered, the physicochemical property of a polyesteramide carrier material is adjusted by controlling the preparation conditions, the special microenvironment of the tumor cells is combined, a biodegradable polyesteramide high molecular carrier (polyesteramide polymer PEA) with proper particle size, proper hydrophilicity and high glutathione responsiveness is prepared, and then the biodegradable polyesteramide high molecular carrier is compounded with a hydrophobic anticancer drug to form a nano structure, so that the high-efficiency loading and controllable release of the anticancer drug can be realized, good biological safety and good internal circulation stability are shown, meanwhile, as the drug-loaded nano particles have Glutathione (GSH) responsiveness, disulfide bonds are rapidly broken under the existence of high-concentration Glutathione (GSH) of the tumor cells, the rapid disintegration of the polymer nano particles and the rapid release of the encapsulated drug can be caused, the utilization of the tumor cells to the anti-cancer drugs is enhanced, so that the relative uptake rate of normal cells to the anti-cancer drugs is smaller in different degrees, and the purpose of reducing the toxicity of chemotherapeutic drugs to normal tissues is achieved while the killing effect of the tumor cells is enhanced.

Compared with the prior art, the invention has the following beneficial effects:

the material of the invention is derived from amino acid with good biocompatibility, and the safety is guaranteed; the preparation method is simple, the polyester amide polymer PEA anti-tumor drug delivery system improves the solubility of the drug, greatly improves the availability of the hydrophobic drug, and also can greatly improve the circulation time of the nanoparticles in blood, thereby improving the drug accumulation of tumor parts, and the drug loading is high, the glutathione responsiveness is high, green and safe, and easy to realize; reduces the toxicity of the chemotherapy drugs to normal tissues and widens the application range of the chemotherapy drugs in the aspect of tumor resistance.

Drawings

FIG. 1 is a characterization of the polymer PEA prepared in example 1: wherein A is the nuclear magnetic hydrogen spectrum analysis of the polymer PEA; b is the PEA infrared spectrum analytic graph of the polymer.

Fig. 2 is a physical property characterization of PEA nanoparticles (glutathione-responsive drug delivery vehicles) prepared in example 2: and (3) distributing the nano carrier particles and carrying out transmission electron microscopy.

FIG. 3 is a characterization of the biocompatibility of the PEA nanoparticles (glutathione-responsive drug delivery vehicle) prepared in example 2; wherein (A) is a toxicity test of the material to cells; (B) is a hemolysis experiment.

FIG. 4 is a characterization of the redox responsiveness of PEA @ DTX of PEA nanoparticles and drug-loaded nanoparticles prepared in examples 2 and 3; wherein (A) is the oxidation-reduction potential change of the carrier measured by cyclic voltammetry; (B) is the release curve of the nano-drug carrier under different conditions.

FIG. 5 is a graph showing the apoptosis results of CT26 cells acted on by PEA @ DTX of drug-loaded nanoparticles prepared in example 3.

FIG. 6 shows the tumor-inhibiting effect of drug-loaded nanoparticles PEA @ DTX prepared in example 3 on CT26 tumor mice.

Detailed Description

The invention is further illustrated by the following figures and specific examples (cystine as representative), which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

Example 1 preparation of a polyester amide Polymer PEA having glutathione responsiveness

1. A preparation method of a polyester amide polymer PEA with glutathione responsiveness comprises the following steps:

(1) weighing 54.5g of phenylalanine, 17.7g of 1, 6-hexanediol and 68.49g of p-toluenesulfonic acid, mixing and dissolving in a 500m L toluene-containing flask, and magnetically stirring and refluxing for 24h at 140 ℃, wherein the molar ratio of the phenylalanine to the 1, 6-hexanediol to the p-toluenesulfonic acid is 2.2: 1: 2.6;

(2) pouring the solid product obtained by the reaction into boiling water, magnetically stirring to dissolve the solid product so as to remove the unreacted benzene solvent, then placing the product in a refrigerator at 4 ℃ to precipitate the product, filtering out unreacted phenylalanine monomer and p-toluenesulfonic acid, repeating the steps for 3 times, and drying in vacuum for 1d to obtain a white powdery graft polymer (Phe-6);

(3) dissolving the obtained graft polymer (Phe-6) and cystine (Cys) in chloroform, adding a certain amount of triethylamine, rapidly stirring for 30min under the condition of ice-water bath to fully mix, and slowly dropwise adding equimolar adipoyl chloride diluted by chloroform into the solution to react for 15min under the condition; wherein the molar ratio of Cys to Phe-6 is 1: 1. 1: 2. 1: 3. 1: 4. 1: 5. 1: 6. 1: 9. 9: 1. 8: 1. 7: 1. 6: 1. 5: 1. 4: 1. 3: 1. 2: 1; and adipoyl chloride is added in a molar amount of Phe-6 plus Cys;

(4) slowly dripping the crude polyesteramide product obtained by the reaction into a boiling water bath, quickly stirring to remove chloroform and unreacted adipoyl chloride, repeating for 3 times, and drying for 1d in vacuum to obtain a series of polyesteramide polymers PEA with glutathione responsiveness.

2. Results

This example uses a 400M superconducting nuclear magnetic resonance spectrometer (Ascend. TM.400) and a Brookfield infrared spectrometer (VERTEX70) to characterize the structure of the polymer PEA prepared in example 1.

As shown in FIG. 1, the peaks at 1.5and 2.0ppm in FIG. 1 (A) correspond to the peaks of hydrogen above adipoyl chloride; the peaks at 3.0and 3.65ppm are the hydrogen peaks on cystine dimethyl ester dihydrochloride and the peak at 7.2ppm corresponds to the hydrogen on the benzene ring, the nuclear magnetic hydrogen spectrum shows that the polymer is composed of these three monomers. Further structural information is characterised by infrared, see fig. 1 (B) with Cys: Phe-6 ═ 1:1, 1:2, 1:3, 1:4, 1: 5and 1:6, and without Cys: Phe-6 ═ 1:9, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, the results of Cys: Phe-6 ═ 1:1, 1:2, 1:3, 1:4, 1: 5and 1:6) are shown, and the synthetic polymers (Cys: Phe-6 ═ 1:1, 1:2, 1:3, 1:4, 1: 5and 1:6) are tested by infrared, 3317-^-1The left and right are stretching vibration of N-H in the polymer amido bond, 3317cm^-1Is the secondary amine peak in the polymer amide; 3000-3100cm^-1，1455cm^-1And 700cm^-1Is a characteristic absorption peak of a benzene ring in Phe-6; and 1735cm^-1And 1200cm^-1Respectively stretching and vibrating C ═ O and C-O-C on an ester bond; 1648cm^-1And 1535cm^-1The absorption bands of the amide I and the amide II respectively have the same absorption peak, which indicates that the synthesized substance is the same substance. The above results indicate that the polymer PEA was successfully synthesized.

In addition, when the molar ratio of Cys to Phe-6 is 1-9: 1-9, the obtained polymer PEA has a stable structure and good comprehensive performance; when the molar ratio of Cys to Phe-6 is 1: 1-6, the prepared polymer PEA has a stable structure and better biocompatibility, and can entrap drugs with different hydrophilicity and hydrophobicity, and the prepared polyesteramide has the characteristics of small particle size and high stability; and the polymer PEA has high GSH rapid reduction responsiveness, and has good application prospect in the aspect of being used as a tumor drug delivery carrier.

The degree of polymerization of the polyesteramide polymer PEA in the embodiment is 2-60; the molecular weight is 2000-51000.

In this example, the reaction conditions of the preparation of the PEA polymer need to be strictly controlled, after the polymer (Phe-6) and the cystine (Cys) are dissolved in chloroform, a certain amount of triethylamine is added, the mixture is magnetically stirred for a certain time to be fully mixed, and insoluble substances need to be filtered and removed. The binary acyl chloride is diluted by at least 10 times with chloroform before being added, and then is slowly dripped into the solution, so as to prevent the violent reaction of the high-concentration binary acyl chloride from generating more byproducts (black brown), which causes lower product yield and purity and poorer stability of nanoparticles. The reaction is carried out in an ice-water bath, and the reaction is too violent due to too high temperature, so that more byproducts are produced. In addition, the reaction needs to be carried out under anhydrous conditions, and the presence of water reacts with the diacid chloride, resulting in a decrease in yield.

Example 2 preparation of a Polyesteramide Polymer PEA nanoparticle having glutathione responsiveness (i.e., glutathione-responsive drug delivery vehicle)

1. The preparation process comprises the following steps:

(1) dissolving the different polyester amide polymers PEA prepared in the example 1 in DMSO to prepare a solution of 50mg/m L, and dissolving DSPE-PEG2000 in water to prepare a solution with the concentration of 0.5mg/m L by taking the DSPE-PEG2000 as a surface stabilizer for later use;

(2) slowly dripping the PEA oil phase into an aqueous solution containing DSPE-PEG2000 at the rotating speed of 1000rpm, and self-assembling the compound in the aqueous solution by a nano precipitation method to form a nano system, wherein the mass of the DSPE-PEG2000 is 30% of that of PEA;

(3) placing the obtained nanoparticle solution in an ultrafiltration tube with cut-off molecular weight (MWCO ═ 100kD), and carrying out ultrafiltration for 2 times at 3000rpm, each time for 15min, so that the DMSO content is below one thousandth, and finally obtaining PEA nanoparticles.

2. Results

(1) The nano particles are characterized by an instrument and a transmission electron microscope, and the result is shown in figure 2, the particle size of the prepared nano particles is 100nm, the nano particles are round-like, and the size of the nano particles is relatively uniform.

(2) In addition, as shown in fig. 3, the nano-particles are subjected to a fine toxicity experiment and a hemolysis experiment, which shows that the nano-particles have better biocompatibility, and the prepared nano-particles have better application prospect when being used as a drug carrier. FIG. 3 shows that the prepared nanoparticles have better biocompatibility and can be used in animal bodies.

(3) FIG. 4 (A) is a graph in which the redox potential of the carrier is measured using cyclic voltammetry, and the redox potential thereof is increased as the ratio of cystine is increased, thereby illustrating that the introduction of cystine causes the redox potential of the carrier to be changed, thereby illustrating that the reaction retains the activity of cystine. The nano particles are proved to have redox responsiveness from the side, and the activity of cystine is not influenced by the preparation process.

Example 3 preparation of a Polyesteramide Polymer PEA nanoparticle having glutathione responsiveness (i.e., glutathione-responsive drug delivery vehicle)

The other conditions are the same as example 2, the polyester amide polymer PEA is dissolved in N, N-Dimethylformamide (DMF), the concentrations of the polyester amide polymer PEA are controlled to be 5mg/m L, 10mg/m L and 60mg/m L respectively, and the finally obtained polyester amide polymer PEA nanoparticles have GSH responsiveness and can rapidly release drugs under the condition of high-concentration GSH (tumor site).

Example 4 preparation of a Polymer Nanocarrier System with glutathione responsiveness

1. The preparation process comprises the following steps:

(1) respectively dissolving DTX and the different polyester amide polymers PEA prepared in the example 1 in DMSO to prepare solutions (50mg/m L) with the same concentration, dissolving DSPE-PEG2000 in water by taking the DSPE-PEG2000 as a surface stabilizer to prepare solutions with the concentration of 0.5mg/m L for later use;

(2) mixing two solutions with equal concentration according to the mass ratio of the polymer PEA to the antitumor drug of 1: 0.05, 1: 0.08, 1: 0.25, 1: 0.50, slowly dripping the mixture into an aqueous solution containing DSPE-PEG2000 at the rotating speed of 1000rpm after mixing in different proportions, and self-assembling the compound in the aqueous solution to form a nano system by a nano precipitation method, wherein the mass of the DSPE-PEG2000 is 30 percent of that of PEA;

(3) placing the obtained nanoparticle solution in an ultrafiltration tube with molecular weight cut-off (MWCO ═ 100kD), and carrying out ultrafiltration for 2 times at 3000rpm, each time for 15min, so as to remove unencapsulated DTX and enable the DMSO content to be less than one thousandth, and finally obtaining PEA @ DTX NPs drug-loaded nanoparticles.

2. Results

(1) Fig. 4 (B) is a graph showing the release profile of the nano-drug carrier, and as shown in fig. 4 (B), the release of the drug becomes faster and the cumulative amount of the released drug increases as the concentration of GSH increases. The drug-loaded nanoparticles have obvious GSH responsiveness, and can quickly release drugs under the condition of high-concentration GSH (tumor part), thereby being beneficial to playing the anti-tumor effect and reducing the toxic and side effects.

(2) Under the same conditions of the polyester amide polymer PEA and other conditions, the mass ratio of the polyester amide polymer PEA to the DTX is used as a single variable, the observation finds that the stability and the drug loading capacity of the nanoparticles have obvious influence along with the mass ratio of a polymer material to the DTX, when the DTX content is gradually increased, the drug loading capacity is increased firstly and then gradually reduced, the stability of the nanoparticles is reduced, and the mass ratio of the polymer to the DTX is 1: the case of 0.3 is preferred. The nano drug-loaded system prepared by the invention has high drug-loaded capacity, tumor microenvironment responsiveness and the capacity of gathering at a tumor part through an EPR effect and entering tumor cells to induce apoptosis; can obviously reduce the toxic and side effects of the chemotherapy drugs and improve the anti-tumor effect.

Example 5 preparation of a Polymer Nanocarrier System with glutathione responsiveness

The preparation process comprises the following steps:

(1) dissolving doxorubicin hydrochloride, the polyesteramide polymer PEA prepared in example 1 (the molar ratio of Cys to Phe-6 is 1:1 respectively) and a surface stabilizer DSPE-PEG2000 in DMSO to obtain a mixed solution; controlling the mass ratio of the polymer PEA to the antitumor drug to be 1: 0.25; wherein the mass of the DSPE-PEG2000 is 15 percent of that of PEA;

(2) slowly dripping the mixed solution into water at the rotating speed of 1000rpm to self-assemble medicine-carrying nano-particles;

(3) placing the obtained nanoparticle solution into an ultrafiltration tube with cut-off molecular weight (MWCO ═ 100kD), and carrying out ultrafiltration for 2 times at 3000rpm, each time for 15min, so as to remove unencapsulated DTX and ensure that the DMSO content is less than one per thousand, and finally obtaining the drug-loaded nanoparticles loaded with the doxorubicin hydrochloride.

Example 6 evaluation of antitumor Effect of drug-loaded nanoparticles PEA @ DTX

(1) The cell effect evaluation of the nano drug-loaded system prepared in example 4 on mouse colon cancer (CT26) cells is performed, and fig. 5 is a graph of drug-loaded nanoparticle PEA @ DTX inducing CT26 cell apoptosis, and compared with free DTX, the drug-loaded nanoparticle PEA @ DTX has stronger capacity of inducing CT26 cell apoptosis.

(2) The in vivo antitumor effect evaluation was performed on the nano drug-loaded system prepared in example 4. The in vivo tumor inhibition effect is as shown in figure 6, the drug-loaded nanoparticles have better tumor inhibition effect, and the nano drug-loaded system prepared by the invention has certain application potential in the field of tumor treatment.

The above results demonstrate that the present invention prepares block copolymers having different chemical structures and amphiphilic properties based on the reaction of cystine having glutathione responsiveness and hydrophobic phenylalanine having physiological activity with diols and acid chlorides. The copolymer has GSH responsiveness and better hydrophobicity, can directly guide anticancer drug molecules into a cancer area and can quickly release the drug at a cancer part while improving drug loading and prolonging blood circulation time, thereby achieving the purposes of quickly inhibiting the growth of cancer and reducing the toxic and side effects of the drug.

In the above embodiments, the antitumor drug may be selected from docetaxel, doxorubicin hydrochloride, camptothecin, gemcitabine hydrochloride, irinotecan hydrochloride, fluorouracil, lentinan, curcumin, and other antitumor drugs, and the same results are obtained. In practical application, corresponding antitumor drugs and polymer PEA can be selected according to specific cancer types to synthesize a nano drug delivery system according to the method disclosed by the invention, so that the effectiveness, controllability and safety of the treatment effect of the antitumor drugs are enhanced.

The applicant declares that the above detailed description is a preferred embodiment described for the convenience of understanding the present invention, but the present invention is not limited to the above embodiment, i.e. it does not mean that the present invention must be implemented by means of the above embodiment. It will be apparent to those skilled in the art that any modification of the present invention, equivalent substitutions of selected materials and additions of auxiliary components, selection of specific modes and the like, which are within the scope and disclosure of the present invention, are contemplated by the present invention.

Claims

1. A preparation method of polyester amide PEA with glutathione responsiveness is characterized by comprising the following steps:

s2, dissolving cystine salt or cysteine or derivatives thereof and the polymer Phe-6 in chloroform, adding triethylamine, and stirring for 15-120 min under the condition of ice-water bath to obtain a mixed solution; dropwise adding equimolar diacid chloride diluted by chloroform into the mixed solution, and carrying out an amide reaction for 10-120 min to obtain the polyester amide PEA with glutathione responsiveness.

2. The preparation method according to claim 1, wherein the mole ratio of Phe-6 of the polymer S2 to cystine salt is 1-9: 1 to 9.

3. The method according to claim 1, wherein the diacid chloride of S2 is diluted 10 times or more with chloroform.

4. The preparation method according to claim 1, wherein S1 molar ratio of the phenylalanine, the diol and the p-toluenesulfonic acid is 2-4: 1:1 to 3.

5. The preparation method according to claim 4, wherein the diol is one or more selected from 1, 4-butanediol, 1, 6-hexanediol, 1, 8-octanediol and 1, 10-decanediol;

the binary acyl chloride is selected from one or more of self-diacyl chloride, oxalyl chloride, succinyl chloride or suberoyl chloride;

after Phe-6 is obtained in S1, pouring the Phe-6 into boiling water, stirring and dissolving to remove unreacted solvent, then putting the product at 0-10 ℃ for precipitation, filtering unreacted monomers, repeating the reaction for 3-4 times, and performing vacuum drying at 50-100 ℃ for 12-24 hours to obtain a white powdery graft polymer (Phe-6);

and S2, after obtaining the polyesteramide PEA, dropwise adding the polyesteramide PEA into a boiling water bath, stirring to remove chloroform and unreacted binary acyl chloride, repeating for 3-4 times, and then drying in vacuum at 50-100 ℃ for 12-24 hours.

6. The use of the polyester amide polymer PEA prepared by the method of any one of claims 1 to 5 as or in the preparation of an antitumor drug nano delivery carrier.

7. A preparation method of a glutathione-responsive drug delivery carrier is characterized by comprising the following steps:

dissolving the PEA polymer prepared by the method of any one of claims 1 to 5 in an organic solvent to obtain a PEA solution, and then dropwise adding the PEA solution into an aqueous solution containing a stabilizer under the stirring condition to enable the PEA solution to be self-assembled into nanoparticles, wherein the concentration of the PEA solution is 10-50 mg/m L;

or, dissolving the PEA polymer prepared by the method of any one of claims 1 to 5and a stabilizer in an organic solvent, and dropwise adding the obtained mixed solution into water to self-assemble nanoparticles;

the mass of the stabilizer is 0-75% of that of the polymer PEA.

8. A nano drug delivery system with glutathione responsiveness, which is characterized by comprising the polymer PEA prepared by the method of any one of claims 1-5 and an anti-tumor drug.

9. The method for preparing the nano drug-loaded system of claim 8, which comprises the following steps:

respectively dissolving an anti-tumor drug and the polymer PEA prepared by the method of any one of claims 1 to 5 in an organic solvent to prepare solutions with the concentration of 5 to 60mg/m L, respectively dripping the PEA and the anti-tumor drug solution into an aqueous solution containing a stabilizer under the stirring condition, and self-assembling the solutions into drug-loaded nanoparticles;

or the polymer PEA, the anti-tumor drug and the stabilizer prepared by the method of any one of claims 1 to 5 are dissolved in an organic solvent, and the mass ratio of the polymer PEA to the anti-tumor drug is 1: 0.05-0.50, and dropwise adding the obtained mixed solution into water to self-assemble the drug-loaded nanoparticles.

10. The method according to claim 9, wherein the organic solvent is one or more selected from the group consisting of dimethylsulfoxide, N-dimethylformamide, and tetrahydrofuran;

the stabilizer is DSPE-PEG₂₀₀₀(ii) a The mass of the stabilizer is 15-30% of the total mass of the polymer PEA and the antitumor drug;

the concentration of the anti-tumor drug and the polymer PEA is 20-50 mg/m L;

the particle size of the drug-loaded nanoparticles is 60-200 nm.