An embolization microsphere with an interpenetrating polymer network structure and a preparation method thereof

Abstract

The present invention belongs to the technical field of medical devices, and particularly relates to an embolic microsphere with an interpenetrating polymer network structure and a preparation method thereof. The embolic microsphere is formed by the entanglement and interpenetration of molecular chains between a polyvinyl alcohol polymer network formed by the free radical polymerization cross-linking of modified polyvinyl alcohol molecules and a polyamino acid network formed by the reaction of polyamino acids with a carbodiimide cross-linking agent and a cross-linking monomer to form a three-dimensional mechanical interlocking structure; wherein, the polyvinyl alcohol polymer network and the polyamino acid network do not form a chemical bond. In the present invention, an interlocking structure is formed by cross-linking polyvinyl alcohol and a degradable polyamino acid. Polyvinyl alcohol serves as an elastic skeleton, having good elasticity and recoverability, reducing the risk of fragmentation during delivery. After the degradable polymer degrades, the polyvinyl alcohol skeleton still plays an embolic role, reducing the risk of vascular recanalization. At the same time, the polyamino acid network has active functional groups, which can degrade and slowly release drugs.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and particularly relates to an embolic microsphere with an interpenetrating polymer network structure and a preparation method thereof. Background Art

[0002] Transcatheter arterial embolization is a procedure in which an embolic agent is controllably injected into the blood supply vessels of a diseased organ through an arterial or venous catheter, causing the blood vessels to occlude and interrupting blood supply, with the aim of achieving treatment goals such as controlling bleeding, treating tumors, and vascular diseases. As a dedicated medical device in the field of embolization therapy, the importance and application value of embolic microspheres are increasingly prominent in the field of interventional medicine. In current clinical applications, drug-loaded embolic microspheres can bind to chemotherapy drugs and slowly release them at the lesion site, realizing a combined embolization and chemotherapy treatment plan, which is beneficial to increasing the local concentration of chemotherapy drugs, reducing the drug dosage during the treatment cycle, and alleviating the burden on patients.

[0003] According to the different materials, embolic microspheres are mainly divided into two categories: biopolymer embolic microspheres and synthetic polymer embolic microspheres. Biopolymer embolic microspheres are mainly made of natural biopolymer materials such as gelatin and agarose. These materials have excellent biocompatibility and degradability and can be gradually absorbed in the body. Synthetic polymer embolic microspheres are made of synthetic polymer materials such as polyvinyl alcohol and polylactic acid. These synthetic materials have high mechanical strength and stability and can exist in the body for a long time, making them suitable for treatment scenarios that require long-term embolization maintenance, such as the treatment of embolized tumors. However, biopolymer embolic microspheres cannot continue to block blood vessels after reaching the expected degradation period, which may lead to the recurrence of vascular recanalization diseases, and there is currently no commercially available drug-loaded and degradable embolic microsphere, and its treatment method is single. Although there are many synthetic polymer embolic microspheres already on the market at home and abroad, such as Hepasphere microspheres, DCBead microspheres, Jialisheng microspheres, and Keruichi microspheres; the drug release driving force of these products is the drug concentration gradient difference inside and outside the microspheres, and the release process also needs to overcome the electrostatic binding force and hydrophilic-hydrophobic interaction between the drug and the polymer main chain. The drug release rate of the microspheres usually does not exceed 50%, and the drug utilization rate is low.

[0004] Based on the above problems, this application document proposes an embolic microsphere with an interpenetrating polymer network structure and a preparation method thereof to improve the above problems. Summary of the Invention

[0005] The object of the present invention is to provide an embolic microsphere with an interpenetrating polymer network structure and a preparation method thereof. An interlocking structure is formed by crosslinking polyvinyl alcohol and a biodegradable polyamino acid. Polyvinyl alcohol serves as an elastic skeleton, having good elasticity and restorability, reducing the risk of fragmentation during transportation. After the biodegradable polymer degrades, the polyvinyl alcohol skeleton still plays an embolic role, reducing the risk of vascular recanalization. At the same time, the polyamino acid network has active functional groups, can degrade and slowly release drugs, and the drugs and active monomers can be excreted, reducing damage to normal tissues.

[0006] The technical solution adopted by the present invention is specifically as follows:

[0007] An embolic microsphere with an interpenetrating polymer network structure is formed by the entanglement and interpenetration of molecular chains between a polyvinyl alcohol polymer network formed by radical polymerization crosslinking of modified polyvinyl alcohol molecules and a polyamino acid network formed by the reaction of a polyamino acid with a carbodiimide crosslinking agent and a crosslinking monomer to form a three-dimensional mechanical interlocking structure;

[0008] Among them, no chemical bond is formed between the polyvinyl alcohol polymer network and the polyamino acid network.

[0009] In a preferred embodiment, the polyamino acid is at least one of polylysine, polyarginine, polyglutamic acid, and polyaspartic acid.

[0010] In a preferred embodiment, when the polyamino acid contains polylysine or / and polyarginine, the crosslinking monomer is a compound containing at least 2 carboxyl groups; optionally, the crosslinking monomer is at least one of malic acid, citric acid, succinic acid, terephthalic acid, glutaric acid, maleic acid, and polyethylene glycol dicarboxylic acid.

[0011] In a preferred embodiment, when the polyamino acid contains polyglutamic acid or / and polyaspartic acid, the crosslinking monomer is a compound containing at least 2 primary amine groups; optionally, the crosslinking monomer is at least one of 2,2'-(ethylenedioxy)bis(ethylamine), ethylenediamine, nonameric arginine, polyarginine, and polylysine.

[0012] A preparation method of an embolic microsphere with an interpenetrating polymer network structure includes the following steps:

[0013] Step 1: Prepare a modified polymerization monomer and a prepolymer solution. Add concentrated hydrochloric acid to an aqueous solution of polyvinyl alcohol, stir for 10 - 30 min, then add acrolein dimethyl acetal or N-acrylamidoacetaldehyde dimethyl acetal and stir to obtain a first mixed solution. Dropwise add an inorganic base solution to the first mixed solution to terminate the reaction, concentrate the first mixed solution to obtain a polyvinyl alcohol solution, and add the polyamino acid and a free radical initiator to the polyvinyl alcohol solution after stirring and dissolving at room temperature to obtain a prepolymer solution;

[0014] Step 2: Prepare the semi-polymerized microsphere intermediate. Add the prepolymer solution into the butyl acetate solution to obtain an inverse emulsion. Heat it to 40 - 80 °C and stir. Add a radical amplification agent into the inverse emulsion and stir. After stirring, filter to obtain the semi-polymerized microsphere intermediate, and wash the semi-polymerized microsphere intermediate with a non-polar solution and a polar organic solution in sequence. After washing, conduct drying;

[0015] Step 3: Prepare the crude fully polymerized microspheres. Dissolve the crosslinking monomer, carbodiimide crosslinking agent, and crosslinking assistant in three aqueous solutions respectively to obtain a crosslinking monomer solution, a carbodiimide crosslinking agent solution, and a crosslinking assistant solution. Mix the crosslinking monomer solution, the carbodiimide crosslinking agent solution, and the semi-polymerized microsphere intermediate, and stir for 15 - 60 min to obtain a second mixed solution. Add the crosslinking assistant solution into the second mixed solution and stir for 2 - 12 h to obtain a crude mixed solution. After the crude mixed solution is cooled to room temperature, conduct solid-liquid separation to obtain the crude fully polymerized microspheres;

[0016] Step 4: Prepare the finished embolization microspheres. Disperse the crude fully polymerized microspheres in an aqueous solvent, stir for 5 - 30 min, then filter and discard the filtrate. Repeat this cleaning and filtering process 3 - 5 times; then disperse the crude fully polymerized microspheres evenly in an aqueous solvent again, stir for 5 - 30 min, then filter and discard the filtrate. Repeat this cleaning and filtering process 3 - 5 times; then disperse the crude fully polymerized microspheres in dehydrating agents with gradient concentrations in sequence for dehydration and impurity removal. Stir for 10 - 60 min respectively, then filter and discard the filtrate. After dehydration, conduct drying treatment to obtain the finished embolization microspheres;

[0017] Among them, the dehydrating agents with gradient concentrations refer to multiple dehydrating agents with gradually increasing concentrations.

[0018] In a preferred embodiment, in Step 1, the dosage ratio of the concentrated hydrochloric acid: polyvinyl alcohol: polyamino acid: free radical initiator is (0.6 - 1.4) mL: 1 g: (0.01 - 0.5) g: (0.01 - 0.1) g, and the free radical initiator is one of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, sodium persulfate, ammonium persulfate, and potassium persulfate.

[0019] In a preferred embodiment, in Step 1, the concentration of the polyvinyl alcohol aqueous solution is 5% - 15%, and in the prepolymer solution, the average degree of polymerization of polyvinyl alcohol is 200 - 2000, and the degree of alcoholysis is 60% - 95%.

[0020] In a preferred embodiment, in the second step, the dosage ratio of the prepolymer solution: butyl acetate: free radical amplifier: non-polar washing solution: polar organic washing solution is 1 g: (5-10) mL: (0.01-0.05) g: (1-5) mL: (1-10) mL. The free radical amplifier is N, N, N', N'-tetramethylethylenediamine. The non-polar washing solution is one or more of ethyl acetate, petroleum ether, and liquid paraffin. The polar organic washing solution is one or more of methanol, ethanol, isopropanol, and acetone.

[0021] In a preferred embodiment, in the third step, the dosage ratio of the crosslinking monomer: carbodiimide crosslinking agent: crosslinking aid: semi-polymerized microsphere intermediate is (1-5) mmol: (1-10) mmol: (1-20) mmol: 1 g. The carbodiimide crosslinking agent is a water-soluble compound containing a carbodiimide structure. The crosslinking aid is one of N-hydroxysuccinimide and sodium N-hydroxythiosuccinimide.

[0022] In a preferred embodiment, in the fourth step, the aqueous solvent is one of purified water, water for injection, sodium chloride solution, and phosphate buffer solution. The organic phase reagent is one of ethyl acetate, petroleum ether, and isopropanol. The dehydrating agent is a mixture of one or more of ethanol, isopropanol, acetone, and tetrahydrofuran and purified water or water for injection.

[0023] The technical effects achieved by the present invention are as follows:

[0024] In the present invention, a crosslinked network is formed step by step from polyvinyl alcohol and degradable polyamino acids. The two polymer networks are crosslinked and penetrated with each other to form a mechanical interlocking structure. The polyvinyl alcohol crosslinked network serves as the elastic skeleton of the embolization microspheres, having good elasticity and compression recovery performance, enabling the embolization microspheres to be intactly transported to the target organ or blood vessel, reducing the risk of ectopic embolization caused by fragmentation during the transportation of the microspheres. At the same time, polyvinyl alcohol molecules have biological inertness, which is beneficial for the permanent residence of the embolization microspheres at the target position. After the degradable polymer degrades, the microspheres with a polyvinyl alcohol skeleton can still play the role of embolization, reducing the risk of blood vessel recanalization.

[0025] The degradable polymer network composed of polyamino acids in the present invention has active functional groups and can be slowly degraded in the physiological environment, thereby realizing the loading and slow release of drugs. After being used for the chemoembolization treatment of malignant tumors and achieving the expected therapeutic effect, the active functional groups and chemotherapeutic drugs can be excreted from the body to reduce the continuous damage to normal tissues, solving the problem that the drugs and active monomers of the existing embolization microspheres cannot be permanently retained and excreted. Moreover, the drug release process is controlled by degradation, with high drug release efficiency and controllable cycle. Brief Description of the Drawings

[0026] Figure 1 is a schematic diagram of the interpenetrating polymer network structure of the present invention;

[0027] Figure 2 are the microscopic pictures before and after drug loading of the microspheres in the second embodiment of the present invention.

[0028] Figure 3 is the appearance change of the embolization microspheres before and after loading doxorubicin solution in the second embodiment of the present invention.

[0029] Figure 4 are the drug release curves in each embodiment and comparative example of the present invention;

[0030] Figure 5 are the electron microscope pictures of the freeze-dried sample (a) of the polyvinyl alcohol / polyamino acid interpenetrating network structure microspheres and its local surface (b) in the second embodiment of the present invention.

[0031] Figure 6 are the electron microscope pictures of the freeze-dried sample (a) of the polyvinyl alcohol microspheres and its local surface (b) in the third comparative example of the present invention Detailed Embodiments

[0032] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following detailed description of the specific embodiments of the present invention will be made with reference to the accompanying drawings of the specification.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0034] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation manner of the present invention. The phrase "in a preferred embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that mutually excludes other embodiments.

[0035] Please refer to Figure 3 As shown, the present invention provides an embolization microsphere with an interpenetrating polymer network structure. The embolization microsphere with an interpenetrating polymer network structure has a spherical shape and mainly consists of a polyvinyl alcohol polymer network formed by the free radical polymerization crosslinking of modified polyvinyl alcohol molecules and a polyamino acid network formed by the reaction of polyamino acids with a carbodiimide crosslinking agent and a crosslinking monomer through the entanglement and interpenetration of molecular chains to form a three-dimensional mechanical interlocking structure;

[0036] Among them, the polyvinyl alcohol polymer network and the polyamino acid network do not form a chemical bond. The particle size range of the embolization microspheres with an interpenetrating polymer network structure is 50-2000 μm, and the water content of the embolization microspheres with an interpenetrating polymer network structure after swelling is greater than or equal to 80%.

[0037] In this embodiment, the three-dimensional mechanical interlocking structure can be understood by referring to the structure form of knitted fabric (as Figure 1 shown), but it should be clear that this schematic diagram is only used to show that no chemical reaction will occur between the polyvinyl alcohol polymer network and the polyamino acid network. The actual polymer network structure is a microscopic structure and cannot be directly observed, and in actual situations, the two networks are not composed in such an orderly and regular manner.

[0038] It should be noted that the polyamino acid is one or more of polylysine, polyarginine, polyglutamic acid, and polyaspartic acid. Among them, when the polyamino acid contains polylysine or / and polyarginine, the crosslinking monomer is a compound containing at least 2 carboxyl groups (optionally, the crosslinking monomer is at least one of malic acid, citric acid, succinic acid, terephthalic acid, glutaric acid, maleic acid, polyethylene glycol dicarboxylic acid); when the polyamino acid contains polyglutamic acid or / and polyaspartic acid, the crosslinking monomer is a compound containing at least 2 primary amine groups (optionally, the crosslinking monomer is at least one of 2,2'-(ethylenedioxy)bis(ethylamine), ethylenediamine, nonameric arginine, polyarginine, and polylysine).

[0039] In this embodiment, through the above scheme setting, compared with single-material embolization microspheres, the interpenetrating polymer network composite material usually consists of 2 or more polymer networks entangled and penetrating each other. It can mix thermodynamically incompatible polymers to form a kinetically stable alloy-like substance without losing the inherent characteristics of the original polymers. The polyamino acid material is formed by polymerizing biologically essential amino acid molecules. Its side chains contain a large number of active groups that can be used for crosslinking or binding to drugs, and the peptide bonds in the main chain can be degraded into essential amino acids in the human body without toxic side effects. As the polyamino acid degrades, the drug molecules bound to its side chains can be released from the polymer network, and the drug release resistance is small. Therefore, based on the interpenetrating polymer network, polyamino acids can be combined with synthetic polymer materials to endow the embolization microspheres with the functions of permanent embolization and efficient drug release.

[0040] The preparation method of the embolization microspheres with an interpenetrating polymer network structure includes the following steps:

[0041] Step1: Modification of polymerization monomers and preparation of prepolymer solution, and its preparation process is as follows:

[0042] Add concentrated hydrochloric acid to the aqueous solution of polyvinyl alcohol, stir at room temperature for 10 - 30 min, then quickly add acrolein dimethyl acetal or N - acrylamidoacetaldehyde dimethyl acetal, and continue stirring for 3 - 12 h to obtain a first mixed solution. Dropwise add an inorganic base solution to the first mixed solution to terminate the reaction and adjust the pH of the first mixed solution to 6 - 7. After the pH value adjustment is completed, concentrate the first mixed solution to 1 / 3 - 2 / 3 of the maximum reaction volume by ultrafiltration or evaporation to obtain a polyvinyl alcohol solution. Dissolve polyamino acid and a free - radical initiator by stirring at room temperature respectively and then add them to the polyvinyl alcohol solution to obtain a prepolymer solution;

[0043] Among them, the average degree of polymerization of polyvinyl alcohol in the aqueous solution of polyvinyl alcohol is 200 - 2000, the concentration is 5% - 15%, and the degree of alcoholysis is 60% - 95%. The free - radical initiator is one of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, sodium persulfate, ammonium persulfate, potassium persulfate. The dosage ratio of the concentrated hydrochloric acid: polyvinyl alcohol: polyamino acid: free - radical initiator is (0.6 - 1.4) mL: 1 g: (0.01 - 0.5) g: (0.01 - 0.1) g;

[0044] Here, by premixing polyamino acid and polyvinyl alcohol solution, the two components of polyvinyl alcohol and polyamino acid in the finished microspheres can be evenly dispersed, avoiding the problems of phase separation or uneven component distribution in the finished microspheres.

[0045] Step2: In the reverse - phase emulsion system, initiate the free - radical polymerization of the prepolymer solution by a free - radical initiator to prepare a semi - polymerized microsphere intermediate, and its preparation process is as follows;

[0046] Add the prepolymer solution prepared in Step1 to the butyl acetate solution to obtain a reverse - phase emulsion. Heat it to 40 - 80 °C and stir evenly. Add a free - radical amplifier to the reverse - phase emulsion and continue stirring for 2 - 8 h. After stirring is completed, filter to obtain a semi - polymerized microsphere intermediate, and wash the semi - polymerized microsphere intermediate with a non - polar solution and a polar organic solution in sequence. After washing is completed, perform a drying treatment to obtain a dried semi - polymerized microsphere intermediate;

[0047] Among them, the free - radical amplifier is N, N, N', N' - tetramethylethylenediamine; the non - polar solution is one or more of ethyl acetate, petroleum ether, liquid paraffin; the polar organic solution is one or more of methanol, ethanol, isopropanol, acetone. The dosage ratio of the prepolymer solution: butyl acetate: free - radical amplifier: non - polar solution for washing: polar organic solution for washing is 1 g: (5 - 10) mL: (0.01 - 0.05) g: (1 - 5) mL: (1 - 10) mL;

[0048] Here, by sequentially washing the semi-polymerized microsphere intermediate (wet material) with a non-polar solution and a polar organic solution, non-polar and polar impurities in the microspheres can be fully removed. At the same time, since the polyamino acid component is insoluble in the non-polar solution and the polar organic solution, the content and uniform distribution of each component in the intermediate can be ensured, and the loss of unpolymerized components can be avoided.

[0049] Step3: In an aqueous homogeneous system, polyamino acid molecules and crosslinking monomers are crosslinked and polymerized by a carbodiimide crosslinking agent, and a crude product of fully polymerized microspheres is prepared. The preparation process is as follows:

[0050] Dissolve the crosslinking monomer, carbodiimide crosslinking agent, and crosslinking aid in three aqueous solutions with a pH of 5-9 respectively to obtain a crosslinking monomer solution with a concentration of 0.1 g / mL, a carbodiimide crosslinking agent solution with a concentration of 0.05 g / mL, and a crosslinking aid solution with a concentration of 0.05 g / mL. Mix the crosslinking monomer solution, carbodiimide crosslinking agent solution, and semi-polymerized microsphere intermediate, stir at 25-40 °C for 15-60 min to obtain a second mixed solution, add the crosslinking aid solution to the second mixed solution, and continue stirring for 2-12 h to obtain a crude product mixed solution. After the crude product mixed solution is cooled to room temperature, solid-liquid separation is carried out to obtain a crude product of fully polymerized microspheres;

[0051] Among them, the carbodiimide crosslinking agent is a water-soluble compound containing a carbodiimide structure; optionally, the carbodiimide crosslinking agent is one of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide methyl p-toluenesulfonate, the crosslinking aid is one of N-hydroxysuccinimide and sodium N-hydroxythiosuccinimide, the aqueous solution is one of purified water, water for injection, physiological sodium chloride solution, and phosphate buffer solution, and the dosage ratio of the crosslinking monomer: carbodiimide crosslinking agent: crosslinking aid: semi-polymerized microsphere intermediate is (1-5) mmol: (1-10) mmol: (1-20) mmol: 1 g;

[0052] Through the free radical polymerization reactions in Step1 and Step2 above, the polyvinyl alcohol network can be polymerized without affecting the reactivity of polyamino acids. At the same time, the carbodiimide crosslinking reaction in Step3 can polymerize the polyamino acid network without changing the physical and chemical properties of the polyvinyl alcohol network. By these two specific polymerization methods, the side reaction interference caused by the simultaneous progress of multiple polymerization methods in other preparation methods is avoided, and the polymerization efficiency and product performance are improved.

[0053] Step4: Wash, remove impurities, and dry the crude product of fully polymerized microspheres in sequence to prepare the finished embolization microspheres. The preparation process is as follows:

[0054] The crude product of the fully polymerized microspheres is uniformly dispersed in an aqueous solvent, stirred for 5 - 30 min, then filtered and the filtrate is discarded. The fully polymerized microspheres are subjected to the first washing and filtering treatment, and the first washing and filtering treatment is repeated 3 - 5 times; then the crude product of the fully polymerized microspheres is uniformly dispersed in an aqueous solvent again, stirred for 5 - 30 min, then filtered and the filtrate is discarded. The fully polymerized microspheres are subjected to the second washing and filtering treatment, and the second washing and filtering treatment is repeated 3 - 5 times; then the crude product of the fully polymerized microspheres is successively dispersed in dehydrating agents with gradient concentrations for dehydration. After stirring for 10 - 60 min respectively, it is filtered and the filtrate is discarded. The fully polymerized microspheres are subjected to dehydration and impurity removal treatment. After dehydration is completed, drying treatment is carried out to obtain the finished product of embolization microspheres (i.e., embolization microspheres with an interpenetrating polymer network structure).

[0055] Among them, the dehydrating agents with gradient concentrations refer to multiple dehydrating agents with gradually increasing concentrations. The aqueous solvent is one of purified water, water for injection, sodium chloride solution, and phosphate buffer solution. The organic phase reagent is one of ethyl acetate, petroleum ether, and isopropanol. The dehydrating agent is one or more of ethanol, isopropanol, acetone, and tetrahydrofuran mixed with purified water or water for injection.

[0056] Furthermore, the finished product of embolization microspheres prepared by the above steps is spherical in shape. After complete swelling, the water content is not less than 80%. Using the polyvinyl alcohol cross-linked network as the elastic skeleton of the microspheres, it has good elasticity and compression recovery performance, enabling the microspheres to be transported to the target organ or blood vessel intact, reducing the risk of ectopic embolization caused by fragmentation during the transportation of the microspheres. At the same time, the polyvinyl alcohol molecule has biological inertness, which is beneficial for the permanent residence of the embolization microspheres at the target position. After the biodegradable polymer degrades, the microspheres with the polyvinyl alcohol skeleton can still play an embolization role, reducing the risk of blood vessel recanalization; among them, the polyamino acid network can load ionic chemotherapy drugs and gradually release the drugs under physiological conditions, achieving long-term and high-release-rate drug release. When the expected therapeutic effect is achieved, the active functional groups and chemotherapy drugs can be excreted from the body to reduce the continuous damage to normal tissues, solving the problem that the drugs and active monomers of the existing embolization microspheres cannot be excreted after permanent residence.

[0057] The following are the examples of the present invention

[0058] Example 1

[0059] Step 1: Add 100 g of polyvinyl alcohol (PVA) to 700 mL of water and heat until the PVA is completely dissolved to obtain a polyvinyl alcohol solution with a concentration of 14.3%. Among them, the average degree of polymerization of polyvinyl alcohol is 1500, and the degree of alcoholysis is 80%. Slowly add 70 mL of concentrated hydrochloric acid to the polyvinyl alcohol solution, stir at room temperature for 30 min, then quickly add 1.06 g of acrolein dimethyl acetal, and continue to stir for 6 h to obtain a first mixed solution. Dropwise add a sodium hydroxide solution to the first mixture to terminate the reaction and adjust the pH of the first mixed solution to 6 - 7. Concentrate the first mixed solution to 1 / 3 of the maximum reaction volume (about 400 mL) by ultrafiltration to obtain a polyvinyl alcohol solution. Then dissolve 50 g of polylysine and 4.5 g of potassium persulfate in 200 mL of water at room temperature and add them to the polyvinyl alcohol solution to obtain a prepolymer solution. Among them, the dosage ratio of concentrated hydrochloric acid: polyvinyl alcohol: polylysine: potassium persulfate is 0.7 mL: 1 g: 0.5 g: 0.045 g;

[0060] Step 2: Slowly add 400 g of the prepolymer solution prepared in Step 1 to 3 L of butyl acetate solution to obtain a reverse emulsion. Heat to 55 °C and stir evenly. Quickly add 6 g of N, N, N', N'-tetramethylethylenediamine to the above reverse emulsion and continue to stir for 3 h. After stirring, filter to obtain a semi-polymerized microsphere intermediate. Wash the semi-polymerized microsphere intermediate with 1.2 L of ethyl acetate, 1.2 L of isopropanol, and 1.5 L of acetone in sequence. After washing, perform a drying treatment to obtain a dried semi-polymerized microsphere intermediate. Among them, the dosage ratio of prepolymer solution: butyl acetate: N, N, N', N'-tetramethylethylenediamine: ethyl acetate: isopropanol: acetone is 1 g: 7.5 mL: 0.015 g: 3 mL: 3 mL: 3.75 mL;

[0061] Step 3: Dissolve 13.4 g of malic acid, 19.2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 23.0 g of N-hydroxysuccinimide in three aqueous solutions with a pH of 7 respectively to obtain a malic acid solution with a concentration of 0.1 g / mL, a 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with a concentration of 0.05 g / mL, and an N-hydroxysuccinimide solution with a concentration of 0.05 g / mL. Mix the malic acid solution, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with 100 g of the semi-polymerized microsphere intermediate and add 200 mL of the aqueous solution. Stir at 30 °C for 30 min to obtain a second mixed solution. Add the N-hydroxysuccinimide solution to the second mixed solution and continue stirring and reacting for 6 h to obtain a crude product mixed solution. After the crude product mixed solution is cooled to room temperature, solid-liquid separation is carried out to obtain the completely polymerized microsphere crude product. Among them, the dosage ratio of malic acid: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride: N-hydroxysuccinimide: semi-polymerized microsphere intermediate is: 1 mmol: 1 mmol: 2 mmol: 1 g;

[0062] Step 4: Uniformly disperse the completely polymerized microsphere crude product in physiological saline with a concentration of 0.9%. After stirring for 30 min, filter and discard the filtrate, and perform the first cleaning and filtering treatment on the completely polymerized microspheres. Repeat the first cleaning and filtering treatment 3 times; then uniformly disperse the completely polymerized microspheres in ethyl acetate. After stirring for 30 min, filter and discard the filtrate, and perform the second cleaning and filtering treatment on the completely polymerized microspheres. Repeat the second cleaning and filtering treatment 3 times; then sequentially disperse the completely polymerized microspheres in ethanol aqueous solutions with concentrations of 30%, 70%, and 100% for gradient dehydration. After stirring for 30 min respectively, filter and discard the filtrate, and perform dehydration and impurity removal treatment on the completely polymerized microspheres. After dehydration is completed, perform drying treatment to obtain the finished embolization microspheres (i.e., embolization microspheres with an interpenetrating polymer network structure).

[0063] Example 2

[0064] Step 1: Add 100 g of polyvinyl alcohol (PVA) to 700 mL of water and heat it until the PVA is completely dissolved to obtain a PVA solution with a concentration of 14.3%. Among them, the average degree of polymerization of PVA is 1500 and the degree of alcoholysis is 80%. Slowly add 70 mL of concentrated hydrochloric acid to the PVA solution, stir at room temperature for 30 min, then quickly add 1.06 g of acrolein dimethyl acetal, and continue to stir for 6 h to obtain a first mixed solution. Dropwise add sodium hydroxide solution to the first mixture to terminate the reaction and adjust the pH of the first mixed solution to 6 - 7. Concentrate the first mixed solution to 1 / 3 of the maximum reaction volume by ultrafiltration to obtain a PVA solution. Then dissolve 50 g of polyglutamic acid and 3.8 g of dimethyl 2,2'-azobis(2-methylpropionate) in 200 mL of water at room temperature and add them to the PVA solution to obtain a prepolymer solution. Among them, the dosage ratio of concentrated hydrochloric acid:PVA:polyglutamic acid:dimethyl 2,2'-azobis(2-methylpropionate) is 0.7 mL:1 g:0.5 g:0.038 g;

[0065] Step 2: Slowly add 400 g of the prepolymer solution prepared in Step 1 to 3 L of butyl acetate solution to obtain an inverse emulsion. Heat it to 55 °C and stir evenly. Quickly add 6 g of N,N,N',N'-tetramethylethylenediamine to the above inverse emulsion and continue to stir for 3 h. After stirring, filter to obtain a semi-polymerized microsphere intermediate. Wash the semi-polymerized microsphere intermediate with 1.2 L of ethyl acetate, 1.2 L of isopropanol, and 1.5 L of acetone in sequence. After washing, perform a drying treatment to obtain a dried semi-polymerized microsphere intermediate. Among them, the dosage ratio of prepolymer solution:butyl acetate:N,N,N',N'-tetramethylethylenediamine:ethyl acetate:isopropanol:acetone is 1 g:7.5 mL:0.015 g:3 mL:3 mL:3.75 mL;

[0066] Step 3: Dissolve 6 g of ethylenediamine, 19.2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 23.0 g of N-hydroxysuccinimide in three aqueous solutions with a pH of 7 respectively to obtain an ethylenediamine solution with a concentration of 0.1 g / mL, a 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with a concentration of 0.05 g / mL, and an N-hydroxysuccinimide solution with a concentration of 0.05 g / mL. Mix the ethylenediamine solution, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with 100 g of the semi-polymerized microsphere intermediate and add 200 mL of the aqueous solution. Stir at 30 °C for 30 min to obtain a second mixture. Add the N-hydroxysuccinimide solution to the second mixture and continue stirring and reacting for 6 h to obtain a crude mixture. After the crude mixture is cooled to room temperature, solid-liquid separation is carried out to obtain the completely polymerized microsphere crude product. Among them, the dosage ratio of ethylenediamine: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride: N-hydroxysuccinimide: semi-polymerized microsphere intermediate is: 1 mmol: 1 mmol: 2 mmol: 1 g;

[0067] Step 4: Uniformly disperse the completely polymerized microsphere crude product in physiological saline with a concentration of 0.9%. After stirring for 30 min, filter and discard the filtrate, and perform the first cleaning and filtering treatment on the completely polymerized microspheres. Repeat the first cleaning and filtering treatment 3 times; then uniformly disperse the completely polymerized microspheres in ethyl acetate. After stirring for 30 min, filter and discard the filtrate, and perform the second cleaning and filtering treatment on the completely polymerized microspheres. Repeat the second cleaning and filtering treatment 3 times; then sequentially disperse the completely polymerized microspheres in ethanol aqueous solutions with concentrations of 60%, 80%, and 100% for gradient dehydration. After stirring for 30 min respectively, filter and discard the filtrate, and perform dehydration and impurity removal treatment on the completely polymerized microspheres. After dehydration is completed, perform a drying treatment to obtain the finished embolization microspheres (i.e., embolization microspheres with an interpenetrating polymer network structure).

[0068] Example 3

[0069] Step1: Add 50 g of polyvinyl alcohol (PVA) to 350 mL of water and heat until the PVA is completely dissolved to obtain a polyvinyl alcohol solution with a concentration of 14.3%. Among them, the average degree of polymerization of polyvinyl alcohol is 1500, and the degree of alcoholysis is 80%. Slowly add 35 mL of concentrated hydrochloric acid to the polyvinyl alcohol solution, stir at room temperature for 30 min, then quickly add 0.83 g of N - acrylamidoacetaldehyde dimethyl acetal, and continue to stir for 6 h to obtain the first mixture. Dropwise add sodium hydroxide solution to the first mixture to terminate the reaction and adjust the pH of the first mixture to 6 - 7. Concentrate the first mixture to 1 / 3 of the maximum reaction volume by ultrafiltration to obtain a polyvinyl alcohol solution. Then dissolve 5 g of polylysine and 1.4 g of azobisisobutyronitrile in 100 mL of water at room temperature and add them to the polyvinyl alcohol solution to obtain a prepolymer solution. Among them, the dosage ratio of concentrated hydrochloric acid: polyvinyl alcohol: polylysine: azobisisobutyronitrile is 0.7 mL: 1 g: 0.5 g: 0.028 g;

[0070] Step2: Slowly add 200 g of the prepolymer solution prepared in Step1 to 1.5 L of butyl acetate solution to obtain a reverse emulsion. Heat to 55 °C and stir evenly. Quickly add 3 g of N, N, N', N' - tetramethylethylenediamine to the above - mentioned reverse emulsion, and continue to stir for 3 h. After stirring, filter to obtain a semi - polymerized microsphere intermediate. Wash the semi - polymerized microsphere intermediate successively with 0.6 L of ethyl acetate, 0.6 L of isopropanol, and 0.75 L of acetone. After washing, perform a drying treatment to obtain a dried semi - polymerized microsphere intermediate. Among them, the dosage ratio of prepolymer solution: butyl acetate: N, N, N', N' - tetramethylethylenediamine: ethyl acetate: isopropanol: acetone is 1 g: 7.5 mL: 0.015 g: 3 mL: 3 mL: 3.75 mL;

[0071] Step 3: Dissolve 1.66 g of terephthalic acid, 1.92 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 2.30 g of N-hydroxysuccinimide in three aqueous solutions with a pH of 7 respectively to obtain a terephthalic acid solution with a concentration of 0.1 g / mL, a 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with a concentration of 0.05 g / mL, and an N-hydroxysuccinimide solution with a concentration of 0.05 g / mL. Mix the terephthalic acid solution, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with 50 g of semi-polymerized microsphere intermediate, and stir at 30 °C for 30 min to obtain a second mixed solution. Add the N-hydroxysuccinimide solution to the second mixed solution and continue stirring and reacting for 6 h to obtain a crude product mixed solution. After the crude product mixed solution is cooled to room temperature, solid-liquid separation is carried out to obtain the completely polymerized microsphere crude product. Among them, the dosage ratio of terephthalic acid: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride: N-hydroxysuccinimide: semi-polymerized microsphere intermediate is: 1 mmol: 1 mmol: 2 mmol: 1 g;

[0072] Step 4: Uniformly disperse the completely polymerized microsphere crude product in physiological saline with a concentration of 0.9%, stir for 30 min, then filter and discard the filtrate, and perform the first cleaning and filtering treatment on the completely polymerized microspheres, repeating the first cleaning and filtering treatment 3 times; then uniformly disperse the completely polymerized microspheres in ethyl acetate, stir for 30 min, then filter and discard the filtrate, and perform the second cleaning and filtering treatment on the completely polymerized microspheres, repeating the second cleaning and filtering treatment 3 times; then sequentially disperse the completely polymerized microspheres in ethanol aqueous solutions with concentrations of 30%, 70%, and 100% for gradient dehydration, stir for 30 min respectively, then filter and discard the filtrate, and perform dehydration and impurity removal treatment on the completely polymerized microspheres. After dehydration, drying treatment is carried out to obtain the finished embolization microspheres (i.e., embolization microspheres with an interpenetrating polymer network structure).

[0073] Example 4

[0074] Step 1: Add 100 g of polyvinyl alcohol (PVA) to 700 mL of water and heat until the PVA is completely dissolved to obtain a polyvinyl alcohol solution with a concentration of 14.3%. Here, the average degree of polymerization of the polyvinyl alcohol is 1500, and the degree of alcoholysis is 80%. Slowly add 70 mL of concentrated hydrochloric acid to the polyvinyl alcohol solution, stir at room temperature for 30 min, then quickly add 1.66 g of N - acrylamidoacetaldehyde dimethyl acetal, and continue to stir for 6 h to obtain a first mixture. Dropwise add a sodium hydroxide solution to the first mixture to terminate the reaction and adjust the pH of the first mixture to 6 - 7. Concentrate the first mixture to 1 / 3 of the maximum reaction volume by ultrafiltration to obtain a polyvinyl alcohol solution. Then dissolve 50 g of polyarginine and 3.8 g of ammonium persulfate in 200 mL of water at room temperature and add them to the polyvinyl alcohol solution to obtain a prepolymer solution. Here, the dosage ratio of concentrated hydrochloric acid: polyvinyl alcohol: polyarginine: ammonium persulfate is 0.7 mL: 1 g: 0.5 g: 0.038 g;

[0075] Step 2: Slowly add 400 g of the prepolymer solution prepared in Step 1 to 3 L of butyl acetate solution to obtain an inverse emulsion. Heat to 55 °C and stir evenly. Quickly add 6 g of N, N, N', N' - tetramethylethylenediamine to the above - mentioned inverse emulsion, and continue to stir for 3 h. After stirring, filter to obtain a semi - polymerized microsphere intermediate. Wash the semi - polymerized microsphere intermediate successively with 1.2 L of ethyl acetate, 1.2 L of isopropyl alcohol, and 1.5 L of acetone, and perform a drying treatment after washing to obtain a dried semi - polymerized microsphere intermediate. Here, the dosage ratio of prepolymer solution: butyl acetate: N, N, N', N' - tetramethylethylenediamine: ethyl acetate: isopropyl alcohol: acetone is 1 g: 7.5 mL: 0.015 g: 3 mL: 3 mL: 3.75 mL;

[0076] Step 3: Dissolve 11.8 g of succinic acid, 42.4 g of N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide methyl p-toluenesulfonate, and 43.8 g of sodium N-hydroxysulfosuccinimide in three aqueous solutions with a pH of 8 respectively to obtain a succinic acid solution with a concentration of 0.1 g / mL, an N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide methyl p-toluenesulfonate solution with a concentration of 0.05 g / mL, and a sodium N-hydroxysulfosuccinimide solution with a concentration of 0.05 g / mL. Mix the succinic acid solution, the N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide methyl p-toluenesulfonate solution with 100 g of the semi-polymerized microsphere intermediate and add 200 mL of the aqueous solution, stir at 30 °C for 30 min to obtain a second mixture. Add the sodium N-hydroxysulfosuccinimide solution to the second mixture and continue stirring and reacting for 6 h to obtain a crude mixture. After the crude mixture is cooled to room temperature, perform solid-liquid separation to obtain the completely polymerized microsphere crude product. Among them, the dosage ratio of succinic acid:N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide methyl p-toluenesulfonate:sodium N-hydroxysulfosuccinimide:semi-polymerized microsphere intermediate is: 1 mmol:1 mmol:2 mmol:1 g;

[0077] Step 4: Uniformly disperse the completely polymerized microsphere crude product in a phosphate buffer solution, stir for 30 min, then filter and discard the filtrate to perform the first washing and filtering treatment on the completely polymerized microspheres, and repeat the first washing and filtering treatment 3 times; then uniformly disperse the completely polymerized microspheres in petroleum ether, stir for 30 min, then filter and discard the filtrate to perform the second washing and filtering treatment on the completely polymerized microspheres, and repeat the second washing and filtering treatment 3 times; then sequentially disperse the completely polymerized microspheres in tetrahydrofuran aqueous solutions with concentrations of 30%, 70%, and 100% for gradient dehydration. After stirring for 30 min each time, filter and discard the filtrate to perform dehydration and impurity removal treatment on the completely polymerized microspheres. After dehydration is completed, perform a drying treatment to obtain the finished embolization microspheres (i.e., embolization microspheres with an interpenetrating polymer network structure).

[0078] The following are the comparative examples of the present invention

[0079] Comparative Example 1

[0080] This comparative example is based on Example 1 and adjusts the addition order of the polyamino acid. Specifically, it includes the following steps:

[0081] Step 1: Add 100 g of polyvinyl alcohol (PVA) to 700 mL of water, heat it until the polyvinyl alcohol is completely dissolved, and obtain a polyvinyl alcohol solution with a concentration of 14.3%. Among them, the average degree of polymerization of polyvinyl alcohol is 1500, and the degree of alcoholysis is 80%. Slowly add 70 mL of concentrated hydrochloric acid to the polyvinyl alcohol solution, stir at room temperature for 30 min, then quickly add 1.06 g of acrolein dimethyl acetal, and continue to stir for 6 h to obtain the first mixed solution. Dropwise add sodium hydroxide solution to the first mixture to terminate the reaction, and adjust the pH of the first mixed solution to 6 - 7. Concentrate the polyvinyl alcohol solution to 1 / 3 of the maximum reaction volume (about 400 mL) by ultrafiltration to obtain a polyvinyl alcohol solution. Then dissolve 4.5 g of potassium persulfate in 200 mL of water at room temperature and add it to the polyvinyl alcohol solution to obtain a prepolymer solution;

[0082] Step 2: Slowly add 400 g of the prepolymer solution prepared in Step 1 to 3 L of butyl acetate solution to obtain an inverse emulsion. Heat it to 55 °C and stir evenly. Quickly add 6 g of N,N,N',N'-tetramethylethylenediamine to the above inverse emulsion, and continue to stir for 3 h. After stirring, filter to obtain a semi-polymerized microsphere intermediate. Wash the semi-polymerized microsphere intermediate with 1.2 L of ethyl acetate, 1.2 L of isopropanol, and 1.5 L of acetone in sequence. After washing, perform a drying treatment to obtain a dried semi-polymerized microsphere intermediate;

[0083] Step 3: Dissolve 50 g of polylysine in an aqueous solution to obtain a polylysine solution with a concentration of 0.25 g / mL, mix it with 100 g of the semi-polymerized microsphere intermediate and add 200 mL of aqueous solution, and stir at 30 °C for 1 h to obtain a second mixed solution. Dissolve 13.4 g of malic acid, 19.2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 23.0 g of N-hydroxysuccinimide in three portions of aqueous solution with a pH of 7 respectively to obtain a malic acid solution with a concentration of 0.1 g / mL, a 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with a concentration of 0.05 g / mL, and an N-hydroxysuccinimide solution with a concentration of 0.05 g / mL. Mix the malic acid solution, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with the second mixed solution, and stir at 30 °C for 30 min to obtain a third mixed solution. Add the N-hydroxysuccinimide solution to the third mixed solution, and continue to stir and react for 6 h to obtain a crude product mixed solution. After the crude product mixed solution cools to room temperature, perform solid-liquid separation to obtain a completely polymerized microsphere crude product;

[0084] Step 4: Uniformly disperse the completely polymerized crude microspheres in physiological saline with a concentration of 0.9%, stir for 30 min, then filter and discard the filtrate, conduct the first washing and filtering treatment on the completely polymerized microspheres, and repeat the first washing and filtering treatment 3 times; then uniformly disperse the completely polymerized microspheres in ethyl acetate, stir for 30 min, filter and discard the filtrate, conduct the second washing and filtering treatment on the completely polymerized microspheres, and repeat the second washing and filtering treatment 3 times; then sequentially disperse the completely polymerized microspheres in ethanol aqueous solutions with concentrations of 30%, 70%, and 100% for gradient dehydration, stir for 30 min respectively, filter and discard the filtrate, conduct dehydration and impurity removal treatment on the completely polymerized microspheres, and conduct drying treatment after dehydration is completed to obtain the finished embolization microspheres (i.e., embolization microspheres with an interpenetrating polymer network structure).

[0085] Comparative Example 2

[0086] This comparative example is based on Example 2, and the cleaning reagent in Step 2 and the drying method in Step 4 are replaced. Specifically, it includes the following steps:

[0087] Step 1: Add 100 g of polyvinyl alcohol (PVA) to 700 mL of water, heat until the polyvinyl alcohol is completely dissolved to obtain a polyvinyl alcohol solution with a concentration of 14.3%. Among them, the average degree of polymerization of polyvinyl alcohol is 1500, and the degree of alcoholysis is 80%. Slowly add 70 mL of concentrated hydrochloric acid to the polyvinyl alcohol solution, stir at room temperature for 30 min, then quickly add 1.06 g of acrolein dimethyl acetal, continue to stir for 6 h to obtain the first mixed solution. Dropwise add sodium hydroxide solution to the first mixture to terminate the reaction, and adjust the pH of the first mixed solution to 6 - 7. Concentrate the first mixed solution to 1 / 3 of the maximum reaction volume by ultrafiltration to obtain a polyvinyl alcohol solution. Then dissolve 50 g of polyglutamic acid and 3.8 g of dimethyl azobisisobutyrate in 200 mL of water at room temperature and add them to the polyvinyl alcohol solution to obtain a prepolymer solution;

[0088] Step 2: Slowly add 400 g of the prepolymer solution prepared in Step 1 to 3 L of butyl acetate solution, heat to 55 °C and stir evenly to obtain a reverse-phase emulsion; quickly add 6 g of N, N, N', N'-tetramethylethylenediamine to the above reverse-phase emulsion, continue to stir for 3 h. After stirring is completed, filter to obtain semi-polymerized microsphere intermediates, and wash the semi-polymerized microsphere intermediates with 1.2 L of ethyl acetate, 1.2 L of petroleum ether, and 1.5 L of water in sequence. After washing is completed, conduct drying treatment to obtain dry semi-polymerized microsphere intermediates;

[0089] Step 3: 6 g of ethylenediamine, 19.2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 23.0 g of N-hydroxysuccinimide are respectively dissolved in three aqueous solutions with a pH of 7 to obtain a glutaric acid solution with a concentration of 0.1 mg / mL, a 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution with a concentration of 0.05 mg / mL, and an N-hydroxysuccinimide solution with a concentration of 0.05 mg / mL. The glutaric acid solution, the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride solution are mixed with 100 g of the semi-polymerized microsphere intermediate and 200 mL of aqueous solution is added. Stir at 30 °C for 30 min to obtain a second mixed solution. The N-hydroxysuccinimide solution is added to the second mixed solution and stirring reaction continues for 6 h to obtain a crude product mixed solution. After the crude product mixed solution is cooled to room temperature, solid-liquid separation is carried out to obtain the completely polymerized microsphere crude product;

[0090] Step 4: The completely polymerized microsphere crude product is uniformly dispersed in physiological saline with a concentration of 0.9%. After stirring for 30 min, filtration is carried out and the filtrate is discarded. The completely polymerized microspheres are subjected to the first washing and filtration treatment, and the first washing and filtration treatment is repeated 3 times; then the completely polymerized microspheres are uniformly dispersed in ethyl acetate. After stirring for 30 min, filtration is carried out and the filtrate is discarded. The completely polymerized microspheres are subjected to the second washing and filtration treatment, and the second washing and filtration treatment is repeated 3 times. Finally, a drying treatment is carried out to obtain the finished embolization microspheres (i.e., embolization microspheres with an interpenetrating polymer network structure).

[0091] Comparative Example 3

[0092] In this comparative example, microspheres were prepared according to the method described in Example 3 of the patent with the publication number CN115869457A, and their properties were tested as a comparative example.

[0093] The following are the test examples of the present invention

[0094] Test Example 1

[0095] Elasticity test: The compression performance of the embolization microspheres was tested using a mechanical property analysis instrument. Specifically, in this test example, a texture analyzer was used. The microsphere sample was laid flat in a single layer on the sample stage, and the microspheres were compressed with the texture analyzer probe. The particle size of the microspheres was determined according to the distance between the sample stage and the point when the probe sensed 10 g. According to the size of the compression deformation of the tested microspheres, the probe was moved down by the corresponding distance and held for 10 s. The elasticity quantification value was defined as the ratio of the probe sensing stress when compressed to the corresponding deformation and held for 10 s to the probe sensing stress when just compressed to the corresponding deformation.

[0096] Test Example 2

[0097] Strength test: Use a mechanical property analysis instrument to test the strength of the embolization microspheres. Specifically, in this test example, a texture analyzer is used. A single layer of microsphere samples is laid flat on the sample stage, and the microspheres are compressed with the texture analyzer probe. Continuously increase the compression deformation of the microspheres until the microspheres are broken, and obtain the maximum deformation when the compression does not cause breakage.

[0098] Test Example III

[0099] Drug loading test: In a light-shielded environment, weigh 100 mg of doxorubicin and dissolve it in 4 mL of water for injection to obtain a 25 mg / mL doxorubicin solution. Immerse 500 mg of dry embolization microspheres in the doxorubicin solution and shake for 5 min to allow the microspheres to be fully loaded with the drug. Let it stand, take the supernatant and transfer it to a 100 mL volumetric flask, add 10 mL of water for injection to wash the microspheres, let it stand, take the supernatant and transfer it to the volumetric flask, repeat 3 times, and make up the volume. Use HPLC to measure the concentration of doxorubicin in the supernatant, and then calculate the amount of doxorubicin in the supernatant. Do three groups of parallel samples.

[0100] Actual drug loading rate = (total drug dosage - remaining drug dosage in supernatant) / total drug dosage * 100%

[0101] Test Example IV

[0102] Drug release test: Add the three groups of drug-loaded microspheres to 100 mL of physiological saline respectively, and perform drug release in a constant temperature shaker at 37 °C and 150 r / min under light-shielded conditions. Take 4 mL of supernatant at the specified time points and supplement 4 mL of supernatant, and use HPLC to test the concentration of doxorubicin in the supernatant, and calculate the drug release amount and cumulative drug release rate.

[0103] Cumulative drug release rate = (cumulative drug release amount / drug loading amount) * 100%

[0104] In Examples 1 to 4 and Comparative Examples 1 to 3, the test results of the embolization microspheres are shown in the following table:

[0105]

[0106] Please refer to Figures 2 to 6 And the embolization microsphere test table. Combining Example 1 and Comparative Example 1, it can be seen that by adjusting the addition order of the polyamino acid, the polyethylene glycol polymer network and the polyamino acid network cannot form an interpenetrating three-dimensional mechanical interlocking structure, and the drug loading performance and drug release curve of the embolization microspheres are greatly affected;

[0107] Combining Example 2 and Comparative Example 2, it can be seen that by adjusting the cleaning reagent and drying method, the cleaning cleanliness is reduced and the moisture cannot be completely dried, which in turn affects the drug loading performance and drug release curve of the embolization microspheres;

[0108] In summary, through data comparison, it can be seen that the overall performance of the embolization microsphere products prepared in Examples 1 to 4 is better than that of the embolization microsphere products in Comparative Examples 1 to 3. The embolization microsphere products prepared in Examples 1 to 4 have a polyvinyl alcohol cross-linked network as the elastic skeleton of the microspheres, with good elasticity and compression recovery performance, enabling the microspheres to be transported intact to the target organ or blood vessel, reducing the risk of ectopic embolization caused by fragmentation during microsphere transportation. At the same time, polyvinyl alcohol molecules have biological inertness, which is beneficial for the permanent residence of the embolization microspheres at the target position. After the biodegradable polymer degrades, the microspheres with a polyvinyl alcohol skeleton can still play an embolization role, reducing the risk of blood vessel recanalization. Combining the embolization microsphere products prepared in Examples 1 to 4, it can be seen that the embolization microsphere products in Example 1 have a higher drug release rate, but their drug release period is relatively short, while the drug release rate of the embolization microsphere products prepared in Example 2 is slightly lower, but its drug release period is significantly increased. The comprehensive performance of the embolization microsphere products prepared in Example 2 is significantly better than that of the embolization microsphere products prepared in Example 1, Example 3, and Example 4, taking into account both the drug release period and the drug release rate. In Example 2, the biodegradable polymer network composed of polyamino acids has active functional groups and can slowly degrade in a physiological environment, thereby realizing drug loading and slow release, and can be used for chemoembolization treatment of malignant tumors. When the expected therapeutic effect is achieved, the active functional groups and chemotherapeutic drugs can be excreted from the body to reduce the continuous damage to normal tissues, solving the problem that the drugs and active monomers of existing embolization microspheres permanently remain and cannot be excreted. Moreover, the drug release process is controlled by degradation, with high drug release efficiency and controllable period. At the same time, by adjusting and optimizing the dosage ratios of ethylenediamine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and N-hydroxysuccinimide, not only the purpose of optimizing the cross-linking degree, adjusting the cross-linking density, and enhancing the structural stability of the microspheres is achieved, but also it helps to realize the controlled release of drugs, precisely controlling the drug release rate and release curve of the microspheres, which is particularly important for application scenarios that require precise control of drug release to meet different treatment needs.

[0109] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. The structures, devices, and operation methods not specifically described and explained in the present invention are implemented according to the conventional means in the art without special description and limitation.

Claims

1. A method for preparing embolic microspheres having an interpenetrating polymer network structure, for preparing embolic microspheres having an interpenetrating polymer network structure, characterized in that: The embolic microspheres are formed by cross-linking modified polyvinyl alcohol molecules through free radical polymerization to form a polyvinyl alcohol polymer network, and a polyamino acid network formed by the reaction of a polyamino acid with a carbodiimide cross-linking agent and a cross-linking monomer to form a three-dimensional mechanical interlocking structure through the entanglement and mutual penetration of molecular chains. Wherein, the polyvinyl alcohol polymer network and the polyamino acid network do not form a chemical bond, and the polyamino acid network can load ionic chemotherapy drugs and gradually release the drugs under physiological conditions to achieve long-term drug release; The preparation method of the embolic microspheres having an interpenetrating polymer network structure comprises the following steps: Step 1: preparing a modified polymer monomer and a prepolymer solution, adding concentrated hydrochloric acid to a polyvinyl alcohol aqueous solution, stirring for 10 to 30 minutes, then adding acrolein dimethyl acetal or N-acrylamide acetaldehyde dimethyl acetal and stirring to obtain a first mixed solution, dropping an inorganic alkali solution into the first mixed solution to terminate the reaction, concentrating the first mixed solution to obtain a polyvinyl alcohol solution, and stirring and dissolving a polyamino acid and a free radical initiator at room temperature, respectively, and then adding them to the polyvinyl alcohol solution to obtain a prepolymer solution; Step 2: preparing a semi-polymerized microsphere intermediate, adding the prepolymer solution to a butyl acetate solution to obtain a reverse emulsion, heating the prepolymer solution to 40-80° C. and stirring the solution, adding a free radical amplifier to the reverse emulsion and stirring the solution, filtering the solution to obtain a semi-polymerized microsphere intermediate after stirring, washing the semi-polymerized microsphere intermediate with a non-polar solution and a polar organic solution in turn, and drying the solution after washing; Step 3: Prepare a crude product of fully polymerized microspheres, dissolve a crosslinking monomer, a carbodiimide crosslinking agent, and a crosslinking aid in three aqueous phase solutions, respectively, to obtain a crosslinking monomer solution, a carbodiimide crosslinking agent solution, and a crosslinking aid solution, respectively, mix the crosslinking monomer solution, the carbodiimide crosslinking agent solution, and the semi-polymerized microsphere intermediate, stir for 15 to 60 minutes, obtain a second mixed solution, add a crosslinking aid solution to the second mixed solution, stir for 2 to 12 hours, obtain a crude mixed solution, cool the crude mixed solution to room temperature, perform solid-liquid separation, and obtain a crude product of fully polymerized microspheres; Step 4: Prepare the finished embolic microspheres, disperse the crude microspheres of the fully polymerized product in an aqueous phase solvent, stir for 5 to 30 minutes, filter and discard the filtrate, and repeat the cleaning and filtering process 3 to 5 times; then evenly disperse the crude microspheres of the fully polymerized product in an organic phase reagent, stir for 5 to 30 minutes, filter and discard the filtrate, and repeat the cleaning and filtering process 3 to 5 times; then disperse the crude microspheres of the fully polymerized product in gradient concentration dehydrating agents in sequence for dehydration and impurity removal, stir for 10 to 60 minutes respectively, filter and discard the filtrate, and dry after dehydration to obtain the finished embolic microspheres; The gradient concentration of dehydrating agent refers to a plurality of dehydrating agents with gradually increasing concentrations.

2. The method for preparing embolic microspheres having an interpenetrating polymer network structure according to claim 1, characterized in that: The polyamino acid is at least one of polylysine, polyarginine, polyglutamic acid and polyaspartic acid.

3. The method for preparing embolic microspheres having an interpenetrating polymer network structure according to claim 2, characterized in that: When the polyamino acid contains polylysine and / or polyarginine, the crosslinking monomer is a compound containing at least two carboxyl groups; the crosslinking monomer is at least one of malic acid, citric acid, succinic acid, terephthalic acid, glutaric acid, maleic acid, and polyethylene glycol dicarboxylic acid.

4. The method for preparing embolic microspheres having an interpenetrating polymer network structure according to claim 2, characterized in that: When the polyamino acid contains polyglutamic acid and / or polyaspartic acid, the crosslinking monomer is a compound containing at least two primary amine groups; the crosslinking monomer is at least one of 2,2'-(ethylenedioxy)bis(ethylamine), ethylenediamine, nona-arginine, polyarginine, and polylysine.

5. The method for preparing embolic microspheres having an interpenetrating polymer network structure according to claim 1, characterized in that: In the step 1, the usage ratio of the concentrated hydrochloric acid: polyvinyl alcohol: polyamino acid: free radical initiator is (0.6-1.4) mL: 1 g: (0.01-0.5) g: (0.01-0.1) g, and the free radical initiator is one of azobisisobutyronitrile, azobisisoheptanenitrile or dimethyl azobisisobutyrate, sodium persulfate, ammonium persulfate, and potassium persulfate.

6. The method for preparing embolic microspheres having an interpenetrating polymer network structure according to claim 1, characterized in that: In the step 1, the concentration of the polyvinyl alcohol aqueous solution is 5% to 15%, and in the prepolymer solution, the average polymerization degree of the polyvinyl alcohol is 200 to 2000, and the alcoholysis degree is 60% to 95%.

7. The method for preparing embolic microspheres having an interpenetrating polymer network structure according to claim 1, characterized in that: In the step 2, the ratio of the prepolymer solution: butyl acetate: free radical amplifier: non-polar solution for washing: polar organic solution for washing is 1 g: (5-10) mL: (0.01-0.05) g: (1-5) mL: (1-10) mL, the free radical amplifier is N, N, N', N'-tetramethylethylenediamine, the non-polar solution for washing is one or more of ethyl acetate, petroleum ether, and liquid paraffin, and the polar organic solution for washing is one or more of methanol, ethanol, isopropanol, and acetone.

8. The method for preparing embolic microspheres having an interpenetrating polymer network structure according to claim 1, characterized in that: In the step three, the usage ratio of the cross-linking monomer: carbodiimide cross-linking agent: cross-linking aid: semi-polymerized microsphere intermediate is (1-5) mmol: (1-10) mmol: (1-20) mmol: 1 g, the carbodiimide cross-linking agent is a water-soluble compound containing a carbodiimide structure, and the cross-linking aid is one of N-hydroxysuccinimide and N-hydroxysulfosuccinimide sodium salt.

9. The method for preparing embolic microspheres having an interpenetrating polymer network structure according to claim 1, characterized in that: In step 4, the aqueous phase solvent is one of purified water, water for injection, sodium chloride solution, and phosphate buffer solution; the organic phase reagent is one of ethyl acetate, petroleum ether, and isopropanol; and the dehydrating agent is a mixture of one or more of ethanol, isopropanol, acetone, and tetrahydrofuran with purified water or water for injection.

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