An embolism microsphere and a preparation method thereof, and a drug-loaded embolism microsphere

Abstract

The application relates to an embolization microsphere and a preparation method thereof, and a drug-loaded embolization microsphere, and belongs to the technical field of embolization microspheres. The embolization microsphere comprises a three-dimensional network structure formed by cross-linking polymerization of a multi-hydroxy water-soluble high-molecular polymer, a water-soluble cross-linking agent, a first water-soluble monomer and a second water-soluble monomer; wherein the first water-soluble monomer comprises a sulfonic acid group or a carboxylic acid group and at least one polymerizable double bond, and the second water-soluble monomer comprises a cis-adjacent diol group and at least one polymerizable double bond. The embolization microsphere contains the sulfonic acid group or the carboxylic acid group and the cis-adjacent diol group, so that the embolization microsphere can simultaneously load a positively charged drug and a drug containing a boric acid structure, thereby solving the drug resistance problem caused by long-term use of a single type of drug and effectively improving the treatment effect on tumors.

Description

Technical Field

[0001] This application relates to the field of embolization microsphere technology, and particularly to an embolization microsphere and its preparation method, and a drug-loaded embolization microsphere. Background Technology

[0002] Currently available embolization microspheres mainly use polyvinyl alcohol as the backbone material. By grafting monomers with polymerizable double bonds onto the molecular chain of polyvinyl alcohol, and then polymerizing and crosslinking these monomers with monomers containing ionic functional groups, charged embolization microspheres are formed, thereby achieving drug-carrying function and thus realizing the dual effects of embolization and chemotherapy.

[0003] However, existing embolization microspheres typically only load a limited number of positively charged drugs, and these positively charged drugs, such as anthracyclines, are prone to drug resistance with long-term use. Therefore, the limitation of drug loading and the development of drug resistance result in the poor therapeutic efficacy of existing drug-loaded embolization microspheres for tumors. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides an embolization microsphere and its preparation method, as well as a drug-loaded embolization microsphere, to improve the problem that existing embolization microspheres can only load one type of drug and are prone to drug resistance, resulting in poor therapeutic effects on tumors. In a first aspect, embodiments of this application provide an embolization microsphere comprising a three-dimensional network structure formed by crosslinking and polymerization of a multi-hydroxyl water-soluble polymer, a water-soluble crosslinking agent, a first water-soluble monomer, and a second water-soluble monomer; wherein the first water-soluble monomer comprises a sulfonic acid group or a carboxylic acid group and at least one polymerizable double bond, and the second water-soluble monomer comprises a cis-ortho-diol group and at least one polymerizable double bond. In the above-described technical solution, the embolization microspheres of this application are obtained by cross-linking and copolymerizing a first water-soluble monomer including sulfonic acid groups or carboxylic acid groups and a second water-soluble monomer including cis-vicinal diol groups. The introduction of sulfonic acid groups or carboxylic acid groups allows the embolization microspheres to load positively charged drugs through electrostatic interactions, while the introduction of cis-vicinal diol groups allows the embolization microspheres to load drugs containing boric acid structures through reversible esterification reactions, thereby improving the drug resistance problem caused by prolonged use of a single type of drug. Therefore, these embolization microspheres can be combined with embolization therapy and chemotherapy with two types of drugs to synergistically improve the therapeutic effect on tumors.

[0005] Secondly, embodiments of this application provide a method for preparing the embolic microspheres provided in the first aspect of this application, comprising the following steps: S1: Grafting a water-soluble crosslinking agent onto a multi-hydroxyl water-soluble polymer yields a modified polymer aqueous solution; S2: Mix the modified polymer aqueous solution, the first water-soluble monomer, the second water-soluble monomer, and the initiator to obtain an aqueous solution; S3: Add the aqueous solution to the oil solution, mix to form a water-in-oil reverse suspension polymerization system, and obtain embolization microspheres after the reaction.

[0006] In the above-described technical solution, this application uses a multi-hydroxyl water-soluble polymer as the backbone material. First, hydroxyl groups are used for graft modification with a crosslinking agent to introduce crosslinkable reaction sites. Then, it undergoes crosslinking copolymerization with a first water-soluble monomer containing sulfonic acid or carboxylic acid groups and a second water-soluble monomer containing cis-vicinal diol groups, simultaneously introducing sulfonic acid or carboxylic acid groups and cis-vicinal diol groups into the embolic microspheres. The introduction of sulfonic acid or carboxylic acid groups allows the embolic microspheres to load positively charged drugs through electrostatic interactions, while the introduction of cis-vicinal diol groups allows the embolic microspheres to load boric acid-containing drugs through reversible esterification reactions, thereby improving drug resistance problems caused by prolonged use of a single drug. Therefore, these embolic microspheres can be combined with embolization therapy and chemotherapy with two types of drugs to synergistically improve the therapeutic effect on tumors.

[0007] Thirdly, embodiments of this application provide a drug-loaded embolization microsphere, comprising the embolization microsphere provided in the first aspect of this application and a loaded drug; wherein the loaded drug comprises at least one of a first class of drugs or a second class of drugs; the first class of drugs comprises positively charged drugs, and the second class of drugs comprises drugs containing boric acid structures.

[0008] In the above technical solution, since the embolization microspheres simultaneously contain sulfonic acid groups or carboxylic acid groups and cis-vicinal diol groups, the sulfonic acid groups or carboxylic acid groups can load the first type of drug, i.e., positively charged drugs, through electrostatic interaction, while the cis-vicinal diol groups can form dynamic covalent bonds through reversible esterification reactions to load the second type of drug, i.e., drugs containing boric acid structures. Thus, the drug-loaded embolization microspheres can be efficiently applied to tumor treatment. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a process flow diagram of a method for preparing embolization microspheres provided in an embodiment of this application.

[0011] Figure 2 This is a drug release curve of the drug-loaded embolized microspheres in Example 1 of this application.

[0012] Figure 3 The image shows the cell viability test results provided in the embodiments of this application. Detailed Implementation

[0013] The following detailed description, with appropriate reference to the accompanying drawings, discloses the embolization microspheres, methods for preparing the embolization microspheres, and embodiments of drug-loaded embolization microspheres of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0014] It should be noted that the terms "and / or" in this application, such as "feature 1 and / or feature 2", refer to the three cases where it can be "feature 1" alone, "feature 2" alone, or "feature 1" plus "feature 2".

[0015] In addition, in the description of this application, unless otherwise stated, "one or more" means two or more; the range of "numerical value a to numerical value b" includes the two endpoints "a" and "b"; and "unit of measurement" in "numerical value a to numerical value b + unit of measurement" represents the "unit of measurement" of both "numerical value a" and "numerical value b".

[0016] Currently available embolic microspheres primarily use polyvinyl alcohol (PVA) as the microsphere's framework material. This is achieved by grafting monomers with polymerizable double bonds onto the PVA molecular chain, followed by polymerization and cross-linking of these monomers with ionic functional groups to form charged embolic microspheres. This allows for drug loading, enabling both embolization and chemotherapy. However, existing drug-loaded embolic microspheres typically only load positively charged drugs. Furthermore, these positively charged drugs, such as anthracyclines, are prone to developing resistance with long-term use, including cross-resistance between drugs within the same class and cross-resistance to vincristine and vinblastine, leading to poor therapeutic effects on tumors. Therefore, there is an urgent need to combine these microspheres with other treatment modalities to enhance long-term effective treatment of tumor cells.

[0017] Boron neutron capture therapy (BNCT) is an effective treatment for tumors. In BNCT, a compound containing the isotope boron-10, which has a strong affinity for cancer cells, is introduced into the body. The boron-10 rapidly accumulates within the cancer cells, and then thermal neutrons, slowed by normal tissue, react with the boron-10 in a nuclear reaction, releasing alpha particles and lithium atoms, thereby killing the tumor cells. Alpha particles are highly lethal rays that can effectively kill tumor cells, but their killing radius is only about 10 μm, equivalent to the diameter of a cell. Therefore, they can only kill tumor cells that have undergone nuclear reactions, without affecting surrounding normal tissues and cells. However, for this treatment method to achieve good therapeutic effects, the following two conditions must be met: (1) the concentration of the drug in the tumor after administration must be 3-4 times that in normal tissue; (2) the concentration of boron in the tumor tissue must reach 20 μg / g. To meet these two conditions, a suitable method is also needed to deliver the boron drug to the vicinity of the tumor tissue. The drug commonly used in BNCT treatment is 1,4-dihydroxyboronylphenylalanine (BPA), which contains a special boric acid group. As a boron carrier, BPA can enrich boron-10 in large quantities, which is beneficial for achieving radiotherapy of tumor cells through BNCT.

[0018] In addition, bortezomib is a revolutionary proteasome inhibitor-type antitumor drug containing a unique borate group. It exerts its inhibitory effect by reversibly binding to the threonine hydroxyl group of the β5 subunit of the proteasome, specifically inhibiting the chymotrypsin-like activity of the 26S proteasome, blocking the ubiquitin-proteasome pathway, leading to the accumulation of faulty proteins, activating apoptosis signals (such as inducing NOXA expression), inhibiting the NF-κB pathway, downregulating anti-apoptotic proteins (such as BCL-2), enhancing the sensitivity of tumor cells to chemotherapy, and achieving chemotherapeutic effects on tumor cells.

[0019] Therefore, there is a need for embolic microspheres that can simultaneously load positively charged drugs as well as bortezomib and / or 1,4-dihydroxyboronylalanine to improve the efficacy of tumor treatment.

[0020] Based on this, the first aspect of the present application provides an embolization microsphere, comprising a three-dimensional network structure formed by crosslinking and polymerization of a multi-hydroxyl water-soluble polymer, a water-soluble crosslinking agent, a first water-soluble monomer, and a second water-soluble monomer; wherein the first water-soluble monomer comprises a sulfonic acid group or a carboxylic acid group and at least one polymerizable double bond, and the second water-soluble monomer comprises a cis-ortho-diol group and at least one polymerizable double bond. In this application, a sulfonic acid group or a carboxylic acid group and a cis-vicinal diol group are simultaneously introduced into the embolization microspheres by copolymerizing a multi-hydroxyl water-soluble polymer with a first water-soluble monomer and a second water-soluble monomer. The sulfonic acid group or carboxylic acid group carries a negative charge and can load positively charged drugs, such as anthracyclines, through electrostatic interactions. The two hydroxyl groups of the cis-vicinal diol group are located on adjacent carbon atoms and are in a cis configuration. They can undergo a reversible esterification reaction with the boric acid group in a boric acid-containing compound to form a dynamic covalent bond, thereby loading boric acid-containing drugs, such as bortezomib and / or 1,4-dihydroxyborophenylalanine. When bortezomib is loaded, it can synergistically achieve different therapeutic effects in chemotherapy; when 1,4-dihydroxyborophenylalanine is loaded, it can introduce boron neutron capture therapy for radiotherapy, achieving a synergistic therapeutic effect of chemotherapy and radiotherapy. Therefore, this embolization microsphere can combine embolization therapy with the chemotherapy and radiotherapy effects of two drugs carrying boric acid groups, improve the drug resistance problem caused by long-term use of a single drug, and synergistically improve the therapeutic effect on tumors.

[0021] Figure 1 For a process flow diagram of a method for preparing embolic microspheres provided in this application embodiment, please refer to [link / reference]. Figure 1 The preparation method of the embolic microspheres includes the following steps: S1: Grafting a water-soluble crosslinking agent onto a multi-hydroxyl water-soluble polymer yields a modified polymer aqueous solution.

[0022] Among them, by grafting water-soluble crosslinking agents onto the polymer molecular chain, active groups that can participate in polymerization can be introduced into the polymer molecular chain, which not only retains water solubility, but also provides connection sites for subsequent crosslinking and copolymerization with the first and second water-soluble monomers.

[0023] In some embodiments, the multi-hydroxyl water-soluble polymer includes at least one of polyvinyl alcohol, sodium alginate, sodium hyaluronate, sodium carboxymethyl cellulose, or water-soluble chitosan. These polymers contain a large number of hydroxyl groups, have good water solubility, are compatible with aqueous systems, can undergo grafting reactions with crosslinking agents to achieve crosslinking and curing, and also have good biocompatibility.

[0024] In some embodiments, the water-soluble crosslinking agent includes at least one aldehyde, acetal, or hemiacetal group and at least one polymerizable double bond. The aldehyde, acetal, or hemiacetal group in the water-soluble crosslinking agent enables it to undergo acetalization / hemiacetalization reactions with the hydroxyl groups in the polyhydroxy water-soluble polymer to form a stable grafted crosslinking structure; while the polymerizable double bond enables it to undergo free radical copolymerization of the modified polymer and the two water-soluble monomers under the action of a subsequent initiator, thereby forming a stable three-dimensional network structure.

[0025] Further, the water-soluble crosslinking agent includes at least one of N-(2,2-dimethoxy)-2-methacrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, N-(2,2-dimethoxy)-2-acrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-methacrylamide, N-(2,2-dimethoxy)-2-methacrylate, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylate, N-(2,2-dimethoxy)-2-acrylate, or N-(1-hydroxy-2,2-dimethoxyethyl)-2-methacrylate.

[0026] In some embodiments, the water-soluble crosslinking agent accounts for 2% to 6% of the mass percentage of the polyhydroxy water-soluble polymer. Using a suitable amount of water-soluble crosslinking agent is beneficial for producing a moderate degree of crosslinking, thus imparting good mechanical strength and compressive elasticity to the embolic microspheres.

[0027] As an example, the water-soluble crosslinking agent accounts for any one of the following mass percentages of the polyhydroxy water-soluble polymer: 2%, 3%, 4%, 5%, 6%, or a range between any two of these values.

[0028] In some embodiments, step S1 includes: dissolving a polyhydroxy water-soluble polymer in water to obtain a polymer aqueous solution; sequentially adding a water-soluble crosslinking agent and an acid catalyst to the polymer aqueous solution, and reacting at 20°C to 30°C for 10 to 15 hours to obtain a modified polymer aqueous solution. By first dissolving the polyhydroxy water-soluble polymer in water to expose the reaction sites (i.e., hydroxyl groups), and then sequentially adding a water-soluble crosslinking agent and an acid catalyst to catalyze the grafting reaction under an acidic environment, the water-soluble crosslinking agent is effectively grafted onto the polymer molecular chain, introducing active sites (i.e., polymerizing double bonds) for subsequent polymerization to form microspheres.

[0029] For example, the reaction temperature can be 20℃, 22℃, 25℃, 28℃, 30℃, etc.; the reaction time can be 10h, 12h, 14h, 15h, etc.

[0030] Furthermore, the mass percentage of the polyhydroxyl water-soluble polymer in the polymer aqueous solution is 15% to 25%, for example, 15%, 18%, 20%, 22%, 25%, etc. A moderate concentration of the polyhydroxyl water-soluble polymer is beneficial for the complete dissolution of the polymer and provides a sufficient number of hydroxyl reaction sites, while maintaining a suitable viscosity in the reaction system, which is conducive to improving the efficiency and uniformity of the grafting reaction.

[0031] Furthermore, the temperature at which the polyhydroxy water-soluble polymer dissolves in water is 90℃~100℃, such as 90℃, 92℃, 95℃, 100℃, etc.

[0032] Furthermore, the acid catalyst includes at least one of hydrochloric acid, sulfuric acid, nitric acid, or p-toluenesulfonic acid. Even further, the acid catalyst is hydrochloric acid.

[0033] Furthermore, the acid catalyst accounts for 20% to 40% of the mass percentage of the polyhydroxy water-soluble polymer, for example, 20%, 25%, 30%, 35%, 40%, etc.

[0034] S2: Mix the modified polymer aqueous solution, the first water-soluble monomer, the second water-soluble monomer, and the initiator to obtain an aqueous solution; wherein the first water-soluble monomer includes a sulfonic acid group or a carboxylic acid group and at least one polymerizable double bond, and the second water-soluble monomer includes a cis-ortho-diol group and at least one polymerizable double bond.

[0035] In some embodiments, the first water-soluble monomer includes at least one of sodium 2-acrylamido-2-methylpropanesulfonate, sodium allyl sulfonate, sodium methpropylene sulfonate, or sodium methacrylate. Sodium 2-acrylamido-2-methylpropanesulfonate, sodium allyl sulfonate, and sodium methpropylene sulfonate contain sulfonic acid groups, while sodium methacrylate contains carboxylic acid groups, and all have good water solubility, polymerization activity, and biocompatibility.

[0036] In some embodiments, the first water-soluble monomer accounts for 5% to 15% of the mass percentage of the modified polymer aqueous solution. A suitable proportion of the first water-soluble monomer is beneficial for introducing more sulfonic acid groups or carboxylic acid groups into the embolization microspheres, while also helping to maintain the structural stability of the embolization microspheres.

[0037] As an example, the mass percentage of the first water-soluble monomer in the modified polymer aqueous solution is any one of 5%, 8%, 10%, 12%, 15%, or a range between any two of these values.

[0038] In some embodiments, the second water-soluble monomer includes at least one of mannitol acrylate, tarottyl acrylate, gulottyl acrylate, galactitol acrylate, sorbitol acrylate, idutol acrylate, or allitol acrylate. These monomers all contain cis-ortho-diol groups and polymerizable double bonds, and exhibit good water solubility and biocompatibility.

[0039] In some embodiments, the second water-soluble monomer accounts for 5% to 15% of the mass percentage of the modified polymer aqueous solution. A suitable proportion of the second water-soluble monomer is beneficial for introducing more cis-o-diol groups into the embolic microspheres after polymerization, while also helping to maintain the structural stability of the embolic microspheres.

[0040] As an example, the mass percentage of the second water-soluble monomer in the modified polymer aqueous solution is any one of 5%, 8%, 10%, 12%, 15%, or a range between any two of these values.

[0041] In some embodiments, step S2 further includes adding a chain regulator with at least two polymerizable double bonds. When two drug-loaded monomers are present simultaneously, steric hindrance exists, affecting the drug loading of the embolic microspheres. In this embodiment, by adding a chain regulator to participate in free radical copolymerization, the two polymerizable double bonds can covalently bond with the first and second water-soluble monomers respectively to form bridges, adjusting the spacing of the covalent crosslinking between the first and second water-soluble monomers, thereby adjusting the steric hindrance between the two water-soluble monomers, increasing the drug loading rate of each of the two water-soluble monomers, and thus increasing the drug loading of the embolic microspheres.

[0042] In some embodiments, the chain regulator comprises an acrylate compound having at least two polymerizable double bonds. This type of chain regulator exhibits good polymerization activity and water solubility, while easily adjusting the spacing of the covalent crosslinking of the first and second water-soluble monomers according to the molecular chain segment length, thereby regulating the strength and elasticity of the embolic microspheres.

[0043] Furthermore, the chain modifier includes at least one of ethylene glycol diacrylate, propylene glycol diacrylate, butanediol diacrylate, or pentanediol diacrylate. These chain modifiers all contain flexible alkane segments and two polymerizable double bonds. The different lengths of the alkane segments and the different distances between the two polymerizable double bonds have varying effects on the structure and drug loading of the embolic microspheres. By selecting a suitable chain modifier, the drug loading can be effectively increased while maintaining the structural strength and elasticity of the embolic microspheres.

[0044] In some embodiments, the chain regulator constitutes a mass percentage of 2.5% to 7.5% of the modified polymer aqueous solution, for example, any single value or a range between any two values ​​from 2.5%, 3.5%, 5.5%, to 7.5%. A suitable proportion of the chain regulator facilitates the provision of sufficient crosslinking sites, effectively modulates the steric hindrance of the first and second water-soluble monomers, and reduces the impact on the overall strength and elasticity of the embolic microspheres.

[0045] In some embodiments, the chain regulator accounts for 25% to 55% of the mass percentage of the first water-soluble monomer, for example, any one of 25%, 35%, 45%, 55%, or a range between any two of these values.

[0046] In some embodiments, the chain regulator accounts for 25% to 55% of the mass percentage of the second water-soluble monomer, for example, any one of 25%, 35%, 45%, 55%, or a range between any two of these values.

[0047] When the proportion of chain regulator is within an appropriate range, it is beneficial to effectively regulate the steric hindrance of the first and second water-soluble monomers, while reducing the impact on the copolymerization of the monomers themselves, thereby balancing steric regulation and drug loading efficiency.

[0048] In some embodiments, the initiator includes at least one of ammonium persulfate, sodium persulfate, or potassium persulfate.

[0049] In some embodiments, the initiator accounts for 0.1% to 0.6% of the mass percentage of the modified polymer aqueous solution, for example, any one of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6% or a range between any two of these values.

[0050] S3: The aqueous solution is added to the oil solution, and after mixing, an oil-in-water reverse suspension polymerization system is formed. After the reaction, embolic microspheres are obtained.

[0051] In this process, an aqueous solution serves as the dispersed phase, an oil solution serves as the continuous phase, and a modified polymer in the aqueous solution serves as the basic framework. The first water-soluble monomer provides sulfonic acid groups or carboxylic acid groups, and the second water-soluble monomer provides cis-ortho-diol groups. Under the action of an initiator, the modified polymer, the first water-soluble monomer, and the second water-soluble monomer undergo free radical copolymerization. At the same time, a crosslinking agent achieves inter-chain crosslinking, ultimately forming embolic microspheres.

[0052] In some embodiments, the reaction is carried out under stirring conditions, with a reaction temperature of 50°C to 80°C, a reaction time of 3 h to 15 h, and a stirring rate of 200 rpm to 800 rpm.

[0053] As an example, the reaction temperature can be any one value or a range between any two values ​​from 50°C, 60°C, 70°C, and 80°C; the time can be any one value or a range between any two values ​​from 3h, 5h, 10h, 12h, and 15h; and the stirring rate can be any one value or a range between any two values ​​from 200rpm, 300rpm, 500rpm, 600rpm, and 800rpm.

[0054] In some embodiments, the method for preparing an oil phase solution includes: dissolving an oily dispersant in an oily solvent to obtain an oil phase solution.

[0055] The oily dispersant includes at least one of Tween-60, Tween-80, Span-60, Span-80, OP-10, OP-20 or cellulose acetate butyrate, and the oily solvent includes at least one of butyl acetate, ethyl acetate, methyl acetate or propyl acetate.

[0056] Furthermore, the mass percentage of the oily dispersant in the oil phase solution is 2% to 6%, for example, any value or a range between any two values ​​from 2%, 3%, 4%, 5%, to 6%.

[0057] Furthermore, the dissolution temperature of the oily dispersant is 30℃~50℃, for example, any one value or any range between two values ​​of 30℃, 35℃, 40℃, 45℃, and 50℃.

[0058] This application also provides a drug-loaded embolization microsphere, including the embolization microsphere provided in the first aspect of this application and a loaded drug; the loaded drug includes at least one of a first class of drugs or a second class of drugs; the first class of drugs includes positively charged drugs; the second class of drugs includes drugs with boric acid structures.

[0059] In some embodiments, the positively charged drug includes at least one of anthracyclines, camptothecins, vincristines, or nucleoside analogs.

[0060] Among them, anthracycline drugs may include at least one of doxorubicin, arubicin, epirubicin, idarubicin, and pentorubicin; camptothecin drugs may include at least one of irinotecan and topotecan; vinca alkaloid drugs may include at least one of vinorelbine and vindesine; and nucleoside analogues may include at least one of gemcitabine and capecitabine.

[0061] In some embodiments, the boric acid-containing drug includes at least one of bortezomib, ixazomib, or 1,4-dihydroxyboronylphenylalanine.

[0062] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0063] Example 1 This embodiment provides an embolization microsphere, the preparation method of which includes the following steps: (1) Prepare an aqueous solution of the modified polymer 100g of polyvinyl alcohol (a water-soluble polyhydroxy polymer) was added to 500mL of water, heated to 95℃ and stirred to dissolve, thus obtaining an aqueous polymer solution. 3.00g of N-(2,2-dimethoxy)-2-methylacrylamide (a water-soluble crosslinking agent) was added to the aqueous polymer solution, stirred evenly, and then 30mL of hydrochloric acid (an acid catalyst) was added. The mixture was stirred continuously at 25℃ for 15h to obtain a modified polymer aqueous solution.

[0064] (2) Prepare aqueous solution 10g of 2-acrylamide-2-methylpropanesulfonic acid (first water-soluble monomer), 10g of mannitol acrylate monomer (second water-soluble monomer), 0.3g of potassium persulfate (initiator) and 100g of modified polymer aqueous solution were stirred and mixed evenly to obtain an aqueous solution.

[0065] (3) Prepare oil phase solution Add 20g of cellulose acetate butyrate (oil-based dispersant) to 500mL of butyl acetate (oil-based solvent), stir at 35℃ to dissolve and form a homogeneous solution, thus obtaining an oil phase solution.

[0066] (4) Preparation of embolic microspheres Under stirring conditions of 500 rpm, an aqueous phase solution was slowly added dropwise to the oil phase solution to form a water-in-oil reverse suspension polymerization system. After the addition was completed, the reaction system was heated to 65°C, and a certain amount of the catalyst tetramethylethylenediamine was added dropwise to the reaction system to carry out the reverse suspension polymerization reaction. After 8 hours, the reaction ended, stirring and heating were stopped, the reaction system was allowed to stand and separate into layers, the oil phase was separated, the microspheres were collected and repeatedly washed and sieved to obtain embolization microspheres.

[0067] Example 2 This embodiment provides an embolization microsphere, the preparation method of which differs from that of Example 1 in that: In step (2), 5g of ethylene glycol diacrylate (chain regulator) was also added.

[0068] Example 3 This embodiment provides an embolization microsphere, the preparation method of which differs from that of Example 2 in that: The chain regulator is propylene glycol diacrylate.

[0069] Example 4 This embodiment provides an embolization microsphere, the preparation method of which differs from that of Example 2 in that: The chain regulator is butanediol diacrylate.

[0070] Example 5 This embodiment provides an embolization microsphere, the preparation method of which differs from that of Example 2 in that: The chain regulator is pentylene glycol diacrylate.

[0071] Performance testing and results analysis 1. Mechanical properties Blank embolic microspheres with a particle size range of 100μm to 300μm from Examples 1 to 5 were used to test the strength, elasticity, and catheter permeability of the microspheres. The test results are shown in Table 1. The specific test methods are as follows: (1) Strength and elasticity: Lay it flat on a glass slide, place it under the probe of the texture analyzer (TA.XT PlusC), and select HoldCompression mode for testing.

[0072] (2) Catheter passability: Mix the embolized microspheres in physiological saline, draw up the fully mixed microsphere solution with a syringe, connect a 2.6F microcatheter, and inject at a rate of 1 mL / min to observe whether the microspheres pass through smoothly.

[0073] Table 1. Test results of mechanical properties of embolized microspheres

[0074] As shown in Table 1, the embolic microspheres prepared in Examples 1-5 all exhibit high strength and elasticity, with a strength greater than 70g and a compressive elasticity greater than 40%. Furthermore, a comparison of Examples 1 and Examples 2-5 shows that the strength and elasticity of the embolic microspheres can be adjusted by regulating the length of the alkane segment in the chain regulator; as the alkane segment of the chain regulator shortens, the strength and elasticity of the microspheres increase accordingly.

[0075] 2. Drug loading capacity Two mL of embolic microspheres with a particle size of 100 μm–150 μm were mixed with 8 mL of doxorubicin solution (Dox, 20 mg / mL) and stirred at 25 °C for 1 min. The residual amount of doxorubicin in the supernatant was determined by high-performance liquid chromatography (HPLC), and the doxorubicin loading of the embolic microspheres was calculated. The microspheres were then mixed with 8 mL of bortezomib solution (Bor, 20 mg / mL) and stirred at 25 °C for 1 min. The residual amount of bortezomib in the supernatant was determined by HPLC, and the bortezomib loading of the embolic microspheres was calculated. The test results are shown in Table 2.

[0076] Table 2. Drug loading test results of embolization microspheres

[0077] As shown in Table 2, the embolic microspheres in Examples 1 to 5 can simultaneously load doxorubicin and bortezomib, meaning they can simultaneously load two types of drugs with high drug loading capacity and efficiency. A comparison of Examples 1 and Examples 2 to 4 shows that as the alkane segment of the chain regulator lengthens, the steric hindrance between the two drug-loadable monomers decreases, thus increasing the drug loading capacity of both drugs.

[0078] 3. Drug release performance The drug-loaded microspheres corresponding to Example 1 were placed in a dialysis bag, which was then placed into a centrifuge tube. 20 mL of physiological saline was added to the centrifuge tube, which was then sealed and placed on a constant-temperature shaker (37.0°C) at 100 rpm. Samples were taken at various time points, and 0.1 mL of the solution was diluted at each time point. The concentrations of doxorubicin and bortezomib solutions were tested using high-performance liquid chromatography (HPLC), and the cumulative release of the drug-loaded embolic microspheres was calculated. The cumulative release rate was calculated using the following formula: ; In the formula, Q represents the cumulative drug release rate (%), and M represents the cumulative drug release rate (%). D Where n is the quantity of drug loaded, and C is the number of times the drug is retrieved. n Let V be the concentration of the sample taken in the nth sampling, V be the total volume of the released liquid, and C be the concentration of the sample taken in the nth sampling. i V represents the sample concentration of the i-th sampling. i Let C0 and V0 be the sample volume of the i-th sampling, where C0 and V0 are both 0.

[0079] Figure 2 This is a drug release curve of the drug-loaded embolic microspheres in Example 1 of this application, from... Figure 2 It can be seen that both doxorubicin and bortezomib in the drug-loaded embolized microspheres can be released slowly, with a cumulative release rate of 79% over 16 days.

[0080] 4. Cell viability test Cell viability was determined using the MTT assay. Cells were divided into three groups: complete culture medium (blank group), embolization microspheres from Example 1 (EM group), pure doxorubicin (1 μg / mL, Dox group), pure bortezomib (1 μg / mL, Bor group), embolization microspheres loaded with doxorubicin (Dox content 1 μg / mL, Dox@EM group), embolization microspheres loaded with bortezomib (Bor content 1 μg / mL, Bor@EM group), and embolization microspheres loaded with both doxorubicin and bortezomib (Dox content 1 μg / mL, Bor content 1 μg / mL, Dox+Bor@EM group). Each group had three parallel wells, and the sonication conditions were 0.6 W / cm². 2 60s. HepG2 liver cancer cells spread at 8×10 3 The cells were seeded in 96-well plates. After cell adhesion, the control and experimental groups were treated for 24 h. The culture medium was removed and the cells were cultured in MTT solution (0.5 mg / mL) at 37 °C for 4 h. The methyl sulfoxide crystals were dissolved in 100 μL of dimethyl sulfoxide and the absorbance was measured at 490 nm using a Bio-Tek Cytation 5 microplate reader.

[0081] Figure 3 The image showing the cell viability test results provided in the embodiments of this application is created by... Figure 3 It can be seen that the embolization microspheres loaded with both doxorubicin and bortezomib (Dox+Bor@EM group) have a greater tumor cell killing effect than those loaded with doxorubicin alone (Dox@EM group) or bortezomib alone (Bor@EM group).

[0082] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. An embolizing microsphere, characterized by, It includes a three-dimensional network structure formed by cross-linking polymerization of a multi-hydroxyl water-soluble polymer, a water-soluble crosslinking agent, a first water-soluble monomer, and a second water-soluble monomer; wherein the first water-soluble monomer includes a sulfonic acid group or a carboxylic acid group and at least one polymerizable double bond, and the second water-soluble monomer includes a cis-ortho-diol group and at least one polymerizable double bond. The embolization microspheres also include a chain regulator with at least two polymerizable double bonds, wherein the chain regulator, the first water-soluble monomer, and the second water-soluble monomer are covalently cross-linked and polymerized to form the three-dimensional network structure.

2. The embolizing microspheres according to claim 1, characterized in that, The first water-soluble monomer includes at least one of sodium 2-acrylamido-2-methylpropanesulfonate, sodium allyl sulfonate, sodium methpropylene sulfonate, or sodium methacrylate; And / or, the second water-soluble monomer includes at least one of mannitol acrylate, tarottol acrylate, gulottol acrylate, galactose acrylate, sorbitol acrylate, idutol acrylate, or allotol acrylate; And / or, the polyhydroxy water-soluble polymer includes at least one of polyvinyl alcohol, sodium alginate, sodium hyaluronate, sodium carboxymethyl cellulose, or water-soluble chitosan; And / or, the water-soluble crosslinking agent comprises at least one aldehyde group, acetal or hemiacetal group and at least one polymerizable double bond.

3. The embolic microspheres according to claim 2, characterized in that, The water-soluble crosslinking agent comprises at least one aldehyde, acetal, or hemiacetal group and at least one polymerizable double bond, wherein the water-soluble crosslinking agent comprises at least one of N-(2,2-dimethoxy)-2-methacrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, N-(2,2-dimethoxy)-2-acrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-methacrylamide, N-(2,2-dimethoxy)-2-methacrylate, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylate, N-(2,2-dimethoxy)-2-acrylate, or N-(1-hydroxy-2,2-dimethoxyethyl)-2-methacrylate.

4. The embolic microspheres according to claim 1, characterized in that, The chain regulator is an acrylate compound with at least two polymerizable double bonds.

5. The embolic microspheres according to claim 4, characterized in that, The chain regulator includes at least one of ethylene glycol diacrylate, propylene glycol diacrylate, butanediol diacrylate, or pentanediol diacrylate.

6. A method for preparing embolic microspheres as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Grafting a water-soluble crosslinking agent onto a multi-hydroxyl water-soluble polymer yields a modified polymer aqueous solution; S2: Mix the modified polymer aqueous solution, a chain regulator with at least two polymerizable double bonds, a first water-soluble monomer, a second water-soluble monomer, and an initiator to obtain an aqueous solution; S3: The aqueous solution is added to the oil solution, and after mixing, an oil-in-water reverse suspension polymerization system is formed. After the reaction, embolic microspheres are obtained.

7. The preparation method according to claim 6, characterized in that, The water-soluble crosslinking agent accounts for 2% to 6% of the mass of the polyhydroxy water-soluble polymer; And / or, the first water-soluble monomer accounts for 5% to 15% of the mass percentage of the modified polymer aqueous solution; And / or, the second water-soluble monomer accounts for 5% to 15% of the mass percentage of the modified polymer aqueous solution.

8. The preparation method according to claim 6, characterized in that, The chain regulator accounts for 2.5% to 7.5% of the mass percentage of the modified polymer aqueous solution; And / or, the chain regulator accounts for 25% to 55% of the mass percentage of the first water-soluble monomer; And / or, the chain regulator accounts for 25% to 55% of the mass percentage of the second water-soluble monomer.

9. A drug-loaded embolic microsphere, characterized in that, The invention comprises a drug-loaded microsphere as described in any one of claims 1 to 5; the drug-loaded microsphere comprises at least one of a Class I drug or a Class II drug. The first category of drugs includes positively charged drugs; The second category of drugs includes drugs containing boric acid structures.

10. The drug-loaded embolic microspheres according to claim 9, characterized in that, The positively charged drug includes at least one of anthracyclines, camptothecins, vincristines, or nucleoside analogs.

11. The drug-loaded embolic microspheres according to claim 9, characterized in that, The boric acid-containing drug includes at least one of bortezomib, ixazomib, or 1,4-dihydroxyboronylphenylalanine.

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