Embolism microsphere, preparation method thereof and drug-loaded embolism microsphere

Abstract

The invention provides an embolism microsphere, a preparation method of the embolism microsphere and a drug-loaded embolism microsphere, and belongs to the technical field of drug-loaded microsphere manufacturing. The embolism microsphere comprises an imidazole monomer with a double bond, a water-soluble monomer with an anionic group and a net-shaped structure formed by cross-linking polymerization of a cross-linking agent with a double bond, and the embolism microsphere comprises the anionic group and the imidazole group. A hydrophilic anion group is negatively charged, so that good hydrophilicity and elasticity can be brought to the embolism microsphere, and a cationic drug can be adsorbed through electrostatic interaction; the imidazole monomer contains an imidazole ring which can generate hydrogen-bond interaction with a cationic drug, so that the drug loading performance and the slow release capability of the embolism microsphere on the cationic drug are improved, that is, the embolism microsphere realizes the dual anchoring effect on the cationic drug loading through the ionic group and the imidazole group, the stability of the drug is enhanced, and the bioavailability of the embolism microsphere is improved. The sustained release effect of the medicine is delayed, and meanwhile, the medicine loading capacity is relatively high. In addition, because imidazole groups are introduced into the embolism microspheres, the suspension performance is improved.

Description

Technical Field

[0001] The present application relates to the technical field of drug-loaded microsphere manufacturing, and in particular to an embolic microsphere and a preparation method thereof, and a drug-loaded embolic microsphere. Background Art

[0002] Transarterial chemoembolization (TACE) is a minimally invasive treatment method that uses a catheter to deliver chemotherapy drugs and embolic materials into the hepatic artery to kill tumor cells. It is currently recognized as one of the most commonly used methods for treating liver cancer. Drug-loaded embolic microspheres, commonly used embolic materials in TACE, combine vascular embolization with sustained drug release. By delivering the microspheres into the blood vessels at the site of the disease through an interventional procedure, they can block the blood supply to the lesion, causing ischemic necrosis of the tumor. Furthermore, the drug carried by the microspheres is slowly released within the lesion to exert its therapeutic effect.

[0003] Currently, drug-loaded embolic microspheres primarily load drugs through an ion exchange mechanism. These microspheres typically carry negatively charged functional groups such as sulfonic acid (-SO3H) or carboxylic acid (-COOH), while many chemotherapy drugs, such as doxorubicin, gemcitabine, and irinotecan, contain positively charged protonated amine groups. When the microspheres are mixed with a drug solution, the drug molecules are adsorbed onto the microspheres through ion exchange, forming drug salts and achieving drug loading.

[0004] However, although existing drug-loaded embolic microspheres have good loading capacity for cationic drugs, they still have drug burst release phenomenon, which is not conducive to cancer treatment. Summary of the Invention

[0005] The purpose of the present application is to provide an embolic microsphere and a preparation method thereof, as well as a drug-loaded embolic microsphere, which has a high drug loading capacity and a slow drug release rate for cationic drugs.

[0006] In a first aspect, an embodiment of the present application provides an embolic microsphere comprising a network structure of an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, and a cross-linking agent with a double bond, wherein the embolic microsphere comprises an anionic group and an imidazole group.

[0007] In the above technical solution, the hydrophilic anionic group is negatively charged, which not only imparts good hydrophilicity and elasticity to the embolic microspheres, but also allows them to adsorb cationic drugs through electrostatic interactions. The imidazole ring in the imidazole monomer can form hydrogen bonds with the cationic drug, thereby improving the drug loading and sustained release capacity of the embolic microspheres. In other words, the embolic microspheres achieve a dual anchoring effect for the cationic drug through the ionic group and the imidazole group, enhancing the drug's stability, delaying its sustained release, and simultaneously achieving a high drug loading capacity. Furthermore, the introduction of the imidazole group improves the embolic microspheres' suspension properties.

[0008] In a second aspect, an embodiment of the present application provides a method for preparing embolic microspheres as described above, comprising: reacting raw materials including an aqueous solution, an oily solution, and a catalyst at a temperature of 50°C to 80°C for 2h to 24h, washing the resulting product with an organic solvent and deionized water, boiling it with alkaline water, and finally screening it to obtain drug-loaded embolic microspheres.

[0009] The aqueous solution includes an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, a cross-linking agent with a double bond, and an initiator; and the oil solution includes an oil solvent and a dispersant.

[0010] In the above technical solution, the preparation method of the embolic microspheres of the present application is to form an oil-in-water reaction system including an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, a cross-linking agent with a double bond, and an oil-phase solvent, and obtain the embolic microspheres by reverse suspension polymerization. The preparation method is simple. The prepared embolic microspheres include anionic groups and imidazole groups. The hydrophilic anionic groups are negatively charged, which not only can give the embolic microspheres good hydrophilicity and elasticity, but also can adsorb cationic drugs through electrostatic interaction. The imidazole monomer contains an imidazole ring, which can form hydrogen bonds with cationic drugs, thereby improving the drug loading performance and sustained release capacity of the embolic microspheres for cationic drugs. That is, the embolic microspheres achieve a dual anchoring effect on the cationic drug load through the ionic group and the imidazole group, enhancing the stability of the drug, delaying the sustained release effect of the drug, and at the same time having a high drug loading capacity. In addition, the introduction of the imidazole group improves the suspension performance of the embolic microspheres.

[0011] In a third aspect, an embodiment of the present application provides a drug-loaded embolic microsphere, which includes the above-mentioned embolic microsphere, wherein the embolic microsphere is loaded with a cationizable drug via an anionic group and an imidazole group; Optionally, the cationizable drug includes at least one of doxorubicin, aclarubicin, epirubicin, idarubicin, valrubicin, irinotecan, topotecan, vinorelbine, vindesine, gemcitabine, capecitabine, sorafenib, regorafenib, donafenib, cabozantinib, cranvatinib, sunitinib, osimertinib, and apatinib.

[0012] In the above technical solution, the hydrophilic anionic group is negatively charged, which not only imparts good hydrophilicity and elasticity to the drug-loaded embolic microspheres, but also allows them to adsorb cationic drugs through electrostatic interactions. The imidazole ring in the imidazole monomer can form hydrogen bonds with the cationic drug, thereby improving the drug loading and sustained release capacity of the drug-loaded embolic microspheres. In other words, the drug-loaded embolic microspheres achieve dual anchoring of the cationic drug through the ionic group and the imidazole group, enhancing drug stability, delaying drug sustained release, and simultaneously achieving a high drug loading capacity. Furthermore, the introduction of the imidazole group improves the suspension properties of the drug-loaded embolic microspheres. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 This is an optical microscope image of the embolic microspheres prepared in Example 1 of the present application; Figure 2 This is a synthetic route diagram of Example 1 of the present application; Figure 3 This is a synthetic route diagram of Example 6 of the present application; Figure 4 This is a synthetic route diagram of Example 7 of the present application; Figure 5 This is the synthesis path diagram of Comparative Example 2 of this application. DETAILED DESCRIPTION

[0015] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0016] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to three situations: “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0017] In addition, in the description of this application, unless otherwise specified, the meaning of "multiple" in "one or more" refers to two or more; the range of "value a to value b" includes the two end values ​​"a" and "b", and the "unit of measurement" in "value a to value b+unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0018] The following is a detailed description of an embolic microsphere and its preparation method, and a drug-loaded embolic microsphere according to an embodiment of the present application.

[0019] In a first aspect, an embodiment of the present application provides an embolic microsphere comprising a network structure of an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, and a cross-linking agent with a double bond, wherein the embolic microsphere comprises an anionic group and an imidazole group.

[0020] It should be noted that "a network structure comprising an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, and a cross-linked polymerized cross-linking agent with a double bond" does not mean that the cross-linking polymerization reaction occurs only with these three or two raw materials. It is well known in the art that the cross-linking polymerization reaction also requires the addition of some basic functional components, such as conventional components such as surfactants and initiators. Since the creativity of this application lies in the selection of the cross-linking agent and monomers, only the cross-linking agent and two monomers are limited.

[0021] In this application, the hydrophilic anionic group is negatively charged, which not only imparts good hydrophilicity and elasticity to the embolic microspheres but also allows them to adsorb cationic drugs through electrostatic interactions. The imidazole ring in the imidazole monomer can form hydrogen bonds with the cationic drug, thereby improving the drug loading and sustained-release capacity of the embolic microspheres. In other words, the embolic microspheres achieve a dual anchoring effect on the cationic drug through the ionic group and the imidazole group, enhancing the drug's stability, delaying its sustained-release effect, and simultaneously achieving a higher drug loading capacity. Furthermore, the introduction of the imidazole group improves the embolic microspheres' suspension properties.

[0022] It is understandable that the selection of the types of various corresponding raw materials is closely related to the drug loading performance of the embolic microspheres finally prepared, and based on this, the types of corresponding raw materials can be limited.

[0023] As an example, the anionic group includes at least one of a carboxylate group and a sulfonate group.

[0024] The electronegativity of the sulfonate group is greater than that of the carboxylate group. On the one hand, this makes the drug loading capacity of the embolic microspheres cross-linked and polymerized by an imidazole monomer with a double bond and a water-soluble monomer with a sulfonate group higher than that of the embolic microspheres cross-linked and polymerized by an imidazole monomer with a double bond and a water-soluble monomer with a carboxylate group; on the other hand, the sulfonate group has a stronger binding force to cationic drug molecules, and the sulfonate group is more spatially matched with the imidazole group, which makes the drug sustained-release ability of the embolic microspheres cross-linked and polymerized by an imidazole monomer with a double bond and a water-soluble monomer with a sulfonate group stronger than that of the embolic microspheres cross-linked and polymerized by an imidazole monomer with a double bond and a water-soluble monomer with a carboxylate group.

[0025] As an example, the water-soluble monomer having an anionic group includes at least one of a first water-soluble monomer and a second water-soluble monomer.

[0026] The first water-soluble monomer includes a carboxylic acid compound or a carboxylate compound having both a carboxylate radical and a double bond, and the second water-soluble monomer includes a sulfonic acid compound or a sulfonate compound having both a sulfonate radical and a double bond.

[0027] As an example, the first water-soluble monomer includes at least one of acrylic acid, methacrylic acid, acrylic anhydride, maleic acid, maleic anhydride, itaconic acid, β-(acryloyloxy)propionic acid, 2,4-hexadienoic acid, and 2,4-pentadienoic acid.

[0028] As an example, the second water-soluble monomer includes 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and / or sodium p-styrenesulfonate.

[0029] As an example, the imidazole monomer with a double bond includes a compound with a double bond and an imidazole group, wherein the imidazole group has at least one nitrogen atom that can participate in an active reaction.

[0030] The N atom that can participate in the active reaction has a lone pair of electrons and a high electronegativity, which can be used to generate hydrogen bonds with cationic drugs.

[0031] As an example, the imidazole monomer having a double bond includes vinyl imidazole and / or N-acryloyl-L-histidine.

[0032] As an example, the cross-linking agent with a double bond includes at least one of a short-chain cross-linking agent and a long-chain cross-linking agent formed by acrylamide and its derivatives, acrylate and its derivatives.

[0033] The present application can regulate the spatial structure of the embolic microspheres by adjusting the length of the cross-linking agent, thereby adjusting the drug release performance of the microspheres.

[0034] When a short-chain cross-linker is selected, the distance between the groups of the embolic microspheres becomes shorter, the structure of the embolic microspheres formed by cross-linking is dense, and the cationic drug molecules can form hydrogen bonds with multiple imidazole rings, which makes the embolic microspheres have a stronger drug sustained-release effect and a slower drug loading speed, and the drug loading capacity is basically unchanged.

[0035] When a long-chain cross-linker is selected, the distance between the embolic microsphere groups becomes longer, the structure of the embolic microspheres formed by cross-linking becomes loose, the contact between the cationic drug molecules and the imidazole ring becomes less, and they tend to form hydrogen bonds with one imidazole group. Since the loose structure enables the cationic drug molecules to diffuse more quickly, the drug release rate of the embolic microspheres is accelerated, the drug loading rate is also slightly accelerated, and the drug loading amount remains basically unchanged.

[0036] As an example, long chain crosslinkers include high molecular weight polyethylene glycol diacrylate ((C2H4O) n C6H6O3, n≥5), at least one of glycerol 1,3-diglycerol glycol diacrylate and its derivatives.

[0037] As an example, short chain crosslinkers include N,N'-methylenebisacrylamide, N,N'-ethyleneacrylamide, low molecular weight polyethylene glycol diacrylate ((C2H4O) n C6H6O3, n=1~4) and at least one of its derivatives.

[0038] Optionally, the molar ratio of the imidazole monomer with a double bond, the water-soluble monomer with an anionic group, and the cross-linking agent with a double bond is 1: (0.25-2.5): (0.02-0.5).

[0039] As an example, the molar ratio of the imidazole monomer with a double bond, the water-soluble monomer with an anionic group, and the cross-linking agent with a double bond can be 1:0.25:0.02, 1:0.5:0.02, 1:1:0.02, 1:1.5:0.02, 1:2:0.02, 1:2.5:0.02, 1:0.5:0.1, 1:0.5:0.5, 1:1:0.1, 1:1:0.5, 1:2:0.1 or 1:2:0.5.

[0040] The present application can adjust the number of groups and spatial structure of the microspheres by adjusting the material ratio, thereby regulating the drug loading and release performance of the embolic microspheres. The increase of imidazole monomers with double bonds and water-soluble monomers with anionic groups can both improve the drug loading capacity and drug sustained release effect of the prepared embolic microspheres; among them, the increase of imidazole monomers with double bonds has a more significant effect on improving the drug sustained release effect of the embolic microspheres than the increase of water-soluble monomers with anionic groups. This is because when the embolic microspheres release drugs, the "anchoring effect" of the imidazole ring on the cationic drug molecules can enhance the stability between the groups and the drug molecules, resulting in the sustained release ability of the embolic microspheres becoming stronger with the increase of imidazole rings; the increase of water-soluble monomers with anionic groups has a more significant effect on improving the drug loading capacity of the embolic microspheres than the increase of imidazole monomers with double bonds. This is because when the embolic microspheres are loaded with drugs, the ion exchange mechanism of the anionic group for the cationic drug is dominant, so the anionic group has a greater effect on the drug loading capacity of the microspheres, while the imidazole ring has a smaller effect on it.

[0041] In a second aspect, an embodiment of the present application provides a method for preparing the above-mentioned embolic microspheres, comprising: reacting raw materials including an aqueous solution, an oily solution, and a catalyst at a temperature of 50° C. to 80° C. for 2 h to 24 h; The aqueous solution includes an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, a cross-linking agent with a double bond, and an initiator; and the oil solution includes an oil solvent and a dispersant.

[0042] In the present application, the preparation method of embolic microspheres is to form an oil-in-water reaction system including an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, a cross-linking agent with a double bond, and an oil-phase solvent, and then obtain the embolic microspheres by reverse suspension polymerization. The preparation method is simple. The prepared embolic microspheres include anionic groups and imidazole groups. The hydrophilic anionic groups are negatively charged, which not only can give the embolic microspheres good hydrophilicity and elasticity, but also can adsorb cationic drugs through electrostatic interaction. The imidazole monomer has an imidazole ring, which can generate hydrogen bonding with cationic drugs, thereby improving the drug loading performance and sustained release capacity of the embolic microspheres for cationic drugs. That is, the embolic microspheres achieve a dual anchoring effect on the cationic drug load through the ionic group and the imidazole group, enhancing the stability of the drug, delaying the sustained release effect of the drug, and at the same time having a high drug loading capacity. In addition, the introduction of the imidazole group improves the suspension performance of the embolic microspheres.

[0043] Alternatively, the aqueous solution is prepared by the following method: First, an imidazole monomer with a double bond, a cross-linking agent with a double bond, and an initiator are dissolved in a 30% to 70% ethanol aqueous solution to prepare a first aqueous phase solution, and then a water-soluble monomer with an anionic group is dissolved in a 10% to 30% sodium hydroxide aqueous solution to prepare a second aqueous phase solution. The first aqueous phase solution and the second aqueous phase solution are then mixed to prepare an aqueous phase solution.

[0044] As an example, the concentration of the ethanol aqueous solution may be 30%, 40%, 50%, 60% or 70%.

[0045] As an example, the concentration of the sodium hydroxide aqueous solution may be 10%, 15%, 20%, 25% or 30%.

[0046] As an example, the reaction temperature of the raw materials including the aqueous solution, the oil solution and the catalyst can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C.

[0047] As an example, the reaction time of the raw materials including the aqueous solution, the oil solution and the catalyst can be 2 h, 4 h, 6 h, 8 h, 12 h, 14 h, 18 h, 22 h or 24 h.

[0048] As an example, the mass of a 30% to 70% ethanol aqueous solution is 6 to 10 times the mass of the cross-linking agent with double bonds.

[0049] As an example, the molar ratio of sodium hydroxide to the anionic group in the water-soluble monomer with an anionic group in a 10% to 30% sodium hydroxide aqueous solution is 0.5 to 1:1.

[0050] As an example, the initiator includes at least one of dibenzoyl peroxide, azobisisobutyronitrile, azobisisoheptylonitrile, azodialkylimidazolinium salt, potassium persulfate, and ammonium persulfate.

[0051] As an example, the dispersant includes at least one of cellulose acetate butyrate, OPs, Spans, Tweens, AEOs, PEGs, and PVAs (eg, PVA-1788, PVA-1799).

[0052] Optionally, the mass of the dispersant is 1 wt% to 5 wt% of the mass of the oil phase solvent.

[0053] As an example, the oil phase solvent includes at least one of butyl acetate, liquid paraffin, dimethyl silicone oil, soybean oil, cycloalkane, and paraffin (eg, n-decane).

[0054] As an example, the catalyst includes N,N,N',N'-tetramethylethylenediamine and / or triethylamine.

[0055] Optionally, the catalyst accounts for 10% to 20% of the mass of the reaction material, wherein the mass of the reaction material includes the total mass of the added monomers and the cross-linking agent.

[0056] As an example, the alkali solution includes a 0.5 wt% to 1 wt% NaHCO 3 aqueous solution.

[0057] Optionally, the molar ratio of the imidazole monomer with a double bond, the water-soluble monomer with an anionic group, the cross-linking agent with a double bond, and the initiator is 1:0.25-2.5:0.02-0.5:0.01-0.03.

[0058] In a third aspect, an embodiment of the present application provides a drug-loaded embolic microsphere, which includes the above-mentioned embolic microsphere, wherein the embolic microsphere is loaded with a cationizable drug via an anionic group and an imidazole group; Optionally, the cationizable drug includes at least one of doxorubicin, aclarubicin, epirubicin, idarubicin, valrubicin, irinotecan, topotecan, vinorelbine, vindesine, gemcitabine, capecitabine, sorafenib, regorafenib, donafenib, cabozantinib, cranvatinib, sunitinib, osimertinib, and apatinib.

[0059] In this application, the hydrophilic anionic group is negatively charged, which not only gives the drug-loaded embolic microspheres good hydrophilicity and elasticity, but also allows them to adsorb cationic drugs through electrostatic interaction. The imidazole ring in the imidazole monomer can generate hydrogen bonds with the cationic drug, thereby improving the drug loading performance and sustained release capacity of the drug-loaded embolic microspheres for cationic drugs. That is, the drug-loaded embolic microspheres achieve a dual anchoring effect on the cationic drug load through the ionic group and the imidazole group, enhancing the stability of the drug, delaying the sustained release effect of the drug, and at the same time achieving a higher drug loading capacity. In addition, the introduction of the imidazole group improves the suspension performance of the drug-loaded embolic microspheres.

[0060] The drug-loaded embolic microspheres include at least one of structural formula 1 and structural formula 2: Wherein, structural formula 1 is as follows: ; Structural formula 2 is as follows: ; Wherein, R is selected from a negatively charged anionic group, and the drug is a cationic drug.

[0061] The following is a further detailed description of the embolic microspheres and their preparation method, and the drug-loaded embolic microspheres of the present application in conjunction with the examples.

[0062] Example 1 The present invention provides an embolic microsphere and a preparation method thereof, which comprises the following steps: Weigh 8.9 g (94 mmol) of vinylimidazole, 2.92 g (18.8 mmol) of MBA, and 254 mg (0.94 mmol) of KPS, and mix them evenly with 16 mL of 50% ethanol aqueous solution under magnetic stirring, which is recorded as aqueous phase 1. Then weigh 19.5 g (94 mmol) of AMPS and mix it evenly with 13 mL of 20% NaOH solution, which is recorded as aqueous phase 2. After evenly mixing aqueous phase 1 and aqueous phase 2, set aside. Add 150 mL of butyl acetate to the flask, add 7.5 g of cellulose acetate butyrate and dissolve it completely, then add the previously mixed aqueous phase solution to the flask, add 1.6 mL of TMEDA after even dispersion, and heat the reaction for a while. The resulting product is washed with butyl acetate and deionized water, then boiled in alkaline water, and finally sieved to obtain embolic microspheres, such as Figure 1 shown.

[0063] The synthetic route diagram of Example 1 is as follows: Figure 2 shown.

[0064] Example 2 The present embodiment provides an embolic microsphere and a preparation method thereof, wherein the amount of vinylimidazole is changed from 8.9 g (94 mmol) to 3.56 g (37.6 mmol) based on Example 1, while other conditions remain unchanged.

[0065] Example 3 The present embodiment provides an embolic microsphere and a preparation method thereof, wherein the amount of vinylimidazole is changed from 8.9 g (94 mmol) to 14.24 g (150.4 mmol) based on Example 1, while other conditions remain unchanged.

[0066] Example 4 The present embodiment provides an embolic microsphere and a preparation method thereof. Based on Example 1, the amount of AMPS is changed from 19.5 g (94 mmol) to 7.8 g (37.6 mmol), and the amount of 20% NaOH solution is changed from 13 mL to 5.2 mL, while other conditions remain unchanged.

[0067] Example 5 The present embodiment provides an embolic microsphere and a preparation method thereof. Based on Example 1, the amount of AMPS is changed from 19.5 g (94 mmol) to 31.13 g (150.4 mmol), and the amount of 20% NaOH solution is changed from 13 mL to 20.8 mL, while other conditions remain unchanged.

[0068] Example 6 The present invention provides an embolic microsphere and a preparation method thereof, which comprises the following steps: Weigh 8.9 g (94 mmol) of vinyl imidazole, 11.28 g (18.8 mmol) of polyethylene glycol diacrylate (C2H4O) n C6H6O3, n = 10) and 254 mg (0.94 mmol) of KPS were mixed uniformly with 16 mL of 50% aqueous ethanol under magnetic stirring, designated as aqueous phase 1. Then, 19.5 g (94 mmol) of AMPS was weighed and mixed uniformly with 13 mL of 20% NaOH solution, designated as aqueous phase 2. Aqueous phases 1 and 2 were mixed uniformly and set aside. 150 mL of butyl acetate was added to a flask, along with 7.5 g of cellulose acetate butyrate, which was completely dissolved. The previously mixed aqueous phase solution was then added to the flask. After uniform dispersion, 1.6 mL of TMEDA was added and the reaction was heated for a period of time. The resulting product was washed with butyl acetate and deionized water, then boiled in alkaline water, and finally sieved to obtain embolic microspheres.

[0069] The synthetic route diagram of Example 6 is as follows: Figure 3 shown.

[0070] Example 7 The present invention provides an embolic microsphere and a preparation method thereof, which comprises the following steps: 8.9 g (94 mmol) of vinylimidazole, 2.92 g (18.8 mmol) of MBA, and 254 mg (0.94 mmol) of KPS were weighed and mixed thoroughly with 16 mL of 50% aqueous ethanol under magnetic stirring, designated as aqueous phase 1. Next, 6.8 g (94 mmol) of acrylic acid was weighed and mixed thoroughly with 13 mL of 20% NaOH solution, designated as aqueous phase 2. Aqueous phases 1 and 2 were mixed thoroughly and set aside. 150 mL of butyl acetate was added to a flask, along with 7.5 g of cellulose acetate butyrate, which was completely dissolved. The previously mixed aqueous phase solution was then added to the flask, and after uniform dispersion, 1.6 mL of TMEDA was added. The reaction was heated for a period of time. The resulting product was washed with butyl acetate and deionized water, then boiled in alkaline water, and sieved to obtain embolic microspheres.

[0071] The synthetic route of Example 7 is shown in FIG. Figure 4 shown.

[0072] Comparative Example 1 Comparative Example 1 provides a kind of microspheres, which are commercially available CalliSphere microspheres.

[0073] Comparative Example 2 The comparative example of the present application provides an embolic microsphere and a preparation method thereof, which comprises the following steps: Weigh 2.92 g (18.8 mmol) of MBA and 254 mg (0.94 mmol) of KPS and mix them evenly with 16 mL of 50% aqueous ethanol under magnetic stirring. This is referred to as aqueous phase 1. Then, weigh 6.8 g (94 mmol) of acrylic acid and mix them evenly with 13 mL of 20% NaOH solution. This is referred to as aqueous phase 2. Aqueous phases 1 and 2 are mixed evenly and set aside. Add 150 mL of butyl acetate to a flask, then add 7.5 g of cellulose acetate butyrate and dissolve it completely. Then, add the previously mixed aqueous phase solution to the flask. After uniform dispersion, add 1.6 mL of TMEDA and heat the reaction for a period of time. The resulting product is washed with butyl acetate and deionized water, then boiled in alkaline water, and finally sieved to obtain embolic microspheres.

[0074] The synthetic route diagram of Comparative Example 2 is as follows: Figure 5 shown.

[0075] Test Example 1 Drug loading test The embolic microspheres prepared in Examples 1 to 7 and Comparative Examples 1 to 2 were divided into two groups, each containing 1 mL, and numbered. Filter paper was used to remove surface moisture from the microspheres. The embolic microspheres were transferred into a vial, and 10 mL of irinotecan hydrochloride solution (20 mg / mL) and 6 mL of gemcitabine hydrochloride solution (20 mg / mL) were added, respectively. The mixture was mixed and shaken, and the solution concentrations were tested at 5 min, 15 min, and 30 min, respectively. The drug loading rate of the embolic microspheres was calculated. The results are shown in Tables 1 and 2 below.

[0076] Table 1 Drug loading efficiency of irinotecan for embolic microspheres prepared in Examples 1-7 and Comparative Examples 1-2

[0077] Table 2 Drug loading rate of gemcitabine in embolic microspheres prepared in Examples 1 to 7 and Comparative Examples 1 to 2

[0078] From the comparison between Examples 1 to 6 and Comparative Example 1, it can be seen that the drug loading rates of the embolic microspheres prepared in Examples 1 to 6 for irinotecan and gemcitabine are higher than those in Comparative Example 1, which indicates that the introduction of the imidazole ring can enhance the drug loading performance of the embolic microspheres containing sulfonate groups for gemcitabine and irinotecan.

[0079] From the comparison between Example 7 and Comparative Example 2, it can be seen that the drug loading rate of the embolic microspheres prepared in Example 7 for irinotecan and gemcitabine is higher than that in Comparative Example 2, which indicates that the introduction of the imidazole ring can enhance the drug loading performance of the embolic microspheres containing carboxylate groups for gemcitabine and irinotecan.

[0080] From the comparison between Example 1 and Example 7, it can be seen that the drug loading rate of the embolic microspheres prepared in Example 1 for irinotecan and gemcitabine is higher than that in Example 7. This difference in drug loading is mainly due to the fact that the electronegativity of the sulfonate group is greater than that of the carboxylate group.

[0081] From the comparison between Example 1 and Examples 4-5, it can be seen that the addition of vinylimidazole and AMPS can both improve the drug loading capacity of the embolic microspheres for irinotecan and gemcitabine, but the improvement of AMPS is more significant. This is because when the embolic microspheres are loaded with drugs, the ion exchange mechanism of the sulfonate group for cationic drugs is dominant, so AMPS has a greater effect on the drug loading capacity of the embolic microspheres, while the imidazole ring has a smaller effect on it.

[0082] A comparison of Examples 1 and 6 shows that when long-chain crosslinkers are used, the distance between embolic microsphere groups increases, the crosslinked microsphere structure becomes looser, and the drug loading rate of the embolic microspheres increases slightly, but the drug loading capacity does not change significantly. This is because the loose structure allows drug molecules to diffuse more quickly, thereby increasing the drug loading rate. However, since the material ratio remains unchanged, the drug loading capacity does not change significantly.

[0083] Test Example 2 Drug Release Test The embolic microspheres loaded with drugs (irinotecan and gemcitabine) from Examples 1 to 7 and Comparative Examples 1 to 2 were added to a dialysis bag. The dialysis bag was then placed in a beaker, and physiological saline (20 mL) was added to the beaker and sealed. Samples were taken every 5 min, 30 min, and 60 min, and the drug concentration in the dialysis bag solution was measured. The drug release rate of the embolic microspheres was obtained by dividing the result by the drug loading data of the microspheres. The results are shown in Tables 3 and 4 below.

[0084] Table 3 Release rate of irinotecan from embolic microspheres prepared in Examples 1 to 7 and Comparative Examples 1 to 2

[0085] Table 4 Release rate of gemcitabine from embolic microspheres prepared in Examples 1 to 7 and Comparative Examples 1 to 2

[0086] From the comparison between Examples 1 to 6 and Comparative Example 1, it can be seen that the embolic microspheres prepared in Examples 1 to 6 have better drug sustained-release properties for irinotecan and gemcitabine, while the embolic microspheres prepared in Comparative Example 1 have only sulfonate groups and have a burst release phenomenon during drug release.

[0087] From the comparison between Example 7 and Comparative Example 2, it can be seen that the embolic microspheres prepared in Example 7 have a higher sustained-release ability for irinotecan and gemcitabine than those in Comparative Example 2, which indicates that the introduction of imidazole rings can enhance the sustained-release ability of embolic microspheres containing carboxylate groups for gemcitabine and irinotecan.

[0088] From the comparison between Example 1 and Example 7, it can be seen that the embolic microspheres prepared in Example 1 have higher drug sustained-release performance for irinotecan and gemcitabine than those in Example 7. This difference in drug sustained-release performance is due to the fact that the electronegativity of the sulfonate group is greater than that of the carboxylate group, and the sulfonate group has a stronger binding force to the cationic drug molecules; and secondly, the sulfonate group is more spatially matched with the imidazole group, resulting in a strong drug sustained-release ability of the embolic microspheres prepared in Example 1.

[0089] From the comparison between Example 1 and Examples 4-5, it can be seen that the increase of vinyl imidazole and AMPS can improve the drug sustained release effect of irinotecan and gemcitabine from the embolic microspheres, but the drug sustained release effect is improved more significantly. This is because when the embolic microspheres release the drug, the "anchoring effect" of the imidazole ring on the cationic drug molecules can enhance the stability between the group and the cationic drug molecules, resulting in the sustained release ability of the embolic microspheres becoming stronger with the increase of imidazole rings.

[0090] From the comparison between Example 1 and Example 6, it can be seen that when a long-chain cross-linking agent is selected, the distance between the embolic microsphere groups becomes longer, the structure of the embolic microspheres formed by cross-linking becomes loose, and the drug release rate of the embolic microspheres is accelerated. This is because the loose structure can enable the drug molecules to diffuse more quickly, thereby accelerating the drug release rate.

[0091] Test Example 3 Suspension Performance Test 1 mL of embolic microspheres from Examples 1-7 and Comparative Examples 1-2, stored in normal saline, was placed in a 10 mL vial. 10 mL of iodixanol 320 was added and gently shaken. The time required for 70% of the total volume to settle was measured. This time was the duration for which 1 mL of microspheres remained suspended in 10 mL of iodixanol 320 (the duration for which no precipitation occurred). The results are shown in Table 5.

[0092] Table 5 Suspension time of embolic microspheres prepared in Examples 1 to 7 and Comparative Examples 1 to 2

[0093] From the comparison between Examples 1 to 7 and Comparative Examples 1 to 2, it can be seen that after the imidazole groups are introduced into the embolic microspheres of Examples 1 to 7, the suspension performance of the embolic microspheres prepared is improved. This is because the imidazole groups can form hydrogen bonds with water molecules in the solution, thereby enhancing the affinity of the embolic microspheres to the contrast agent solution, thereby improving the suspension performance.

[0094] From the comparison between Example 1 and Example 7, it can be seen that when a long cross-linking agent is used, the density of the embolic microspheres is reduced, which also leads to an enhanced suspension of the microspheres.

[0095] The foregoing description is merely a specific embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An embolic microsphere, characterized in that: The embolic microspheres include a network structure formed by cross-linking an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, and a cross-linking agent with a double bond. The embolic microspheres include an anionic group and an imidazole group.

2. The embolic microsphere according to claim 1, characterized in that The anionic group includes at least one of a carboxylate group and a sulfonate group.

3. The embolic microsphere according to claim 1, characterized in that The water-soluble monomer with an anionic group includes at least one of a first water-soluble monomer and a second water-soluble monomer, wherein the first water-soluble monomer includes a carboxylic acid compound or a carboxylate compound having both a carboxylate radical and a double bond, and the second water-soluble monomer includes a sulfonic acid compound or a sulfonate compound having both a sulfonate radical and a double bond; Optionally, the first water-soluble monomer includes at least one of acrylic acid, methacrylic acid, acrylic anhydride, maleic acid, maleic anhydride, itaconic acid, β-(acryloyloxy)propionic acid, 2,4-hexadienoic acid, and 2,4-pentadienoic acid; Optionally, the second water-soluble monomer includes 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and / or sodium p-styrenesulfonate.

4. The embolic microsphere according to claim 1, characterized in that The imidazole monomer with a double bond includes a compound with a double bond and an imidazole group, wherein the imidazole group has at least one N atom that can participate in an active reaction; Optionally, the imidazole monomer with a double bond includes vinyl imidazole and / or N-acryloyl-L-histidine.

5. The embolic microsphere according to claim 1, characterized in that: The cross-linking agent with double bonds includes at least one of a short-chain cross-linking agent and a long-chain cross-linking agent formed by acrylamide and its derivatives, acrylate and its derivatives; Optionally, the long chain cross-linking agent comprises high molecular weight polyethylene glycol diacrylate ((C2H4O) n C6H6O3, n≥5), at least one of glycerol 1,3-diglycerol glycol diacrylate and its derivatives; The short chain crosslinking agents include N,N'-methylenebisacrylamide, N,N'-ethyleneacrylamide, low molecular weight polyethylene glycol diacrylate ((C2H4O) n C6H6O3, n = 1 to 4) and at least one of its derivatives; and / or, The molar ratio of the imidazole monomer with a double bond, the water-soluble monomer with an anionic group, and the cross-linking agent with a double bond is 1: (0.25-2.5): (0.02-0.5).

6. A method for preparing embolic microspheres according to claim 1, characterized in that: The preparation method of the embolic microspheres comprises: reacting raw materials including an aqueous solution, an oily solution and a catalyst at a temperature of 50° C. to 80° C. for 2 h to 24 h; The aqueous solution comprises an imidazole monomer with a double bond, a water-soluble monomer with an anionic group, a cross-linking agent with a double bond, and an initiator; and the oil solution comprises an oil solvent and a dispersant.

7. The method for preparing embolic microspheres according to claim 6, characterized in that: The initiator comprises at least one of dibenzoyl peroxide, azobisisobutyronitrile, azobisisoheptonitrile, azodialkylimidazolinium salt, potassium persulfate and ammonium persulfate; and / or, The dispersant includes at least one of cellulose acetate butyrate, OP, Span, Tween, AEO, PEG and PVA; and / or, The oil phase solvent comprises at least one of butyl acetate, liquid paraffin, dimethyl silicone oil, soybean oil, cycloalkanes and paraffins; and / or, The catalyst comprises N,N,N',N'-tetramethylethylenediamine and / or triethylamine; and / or, The molar ratio of the imidazole monomer with a double bond, the water-soluble monomer with an anionic group, the cross-linking agent with a double bond, and the initiator is 1:0.25-2.5:0.02-0.5:0.01-0.

03.

8. The method for preparing embolic microspheres according to claim 6, characterized in that: The aqueous phase solution is prepared by the following method: First, the imidazole monomer with a double bond, the cross-linking agent with a double bond, and the initiator are dissolved in a 30% to 70% ethanol aqueous solution to prepare a first aqueous phase solution, and then the water-soluble monomer with an anionic group is dissolved in a 10% to 30% sodium hydroxide aqueous solution to prepare a second aqueous phase solution, and then the first aqueous phase solution and the second aqueous phase solution are mixed to prepare the aqueous phase solution; Optionally, the mass of the 30% to 70% ethanol aqueous solution is 6 to 10 times the mass of the cross-linking agent with double bonds; Optionally, the molar ratio of sodium hydroxide in the 10% to 30% sodium hydroxide aqueous solution to the anionic group in the water-soluble monomer with an anionic group is 0.5 to 1:

1.

9. A drug-loaded embolic microsphere, characterized in that: The embolic microspheres according to any one of claims 1 to 5 are loaded with cationizable drugs via the anionic groups and imidazole groups; Optionally, the cationizable drug includes at least one of doxorubicin, aclarubicin, epirubicin, idarubicin, valrubicin, irinotecan, topotecan, vinorelbine, vindesine, gemcitabine, capecitabine, sorafenib, regorafenib, donafenib, cabozantinib, cavatinib, sunitinib, osimertinib, and apatinib.

10. The drug-loaded embolic microspheres according to claim 9, characterized in that: The drug-loaded embolic microspheres include at least one of structural formula 1 and structural formula 2: Wherein, the structural formula 1 is as follows: ； The structural formula 2 is as follows: ； Wherein, R is selected from a negatively charged anionic group, and the drug is a cationic drug.

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