Preparation method of secondary cross-linked embolization microspheres and embolization microspheres

Abstract

The embodiment of the present application provides a preparation method of secondary cross-linked embolization microspheres and the embolization microspheres, relating to the field of medical interventional therapy materials. The preparation method of the secondary cross-linked embolization microspheres mainly involves formulating an aqueous phase with a modified water-soluble polymer, a water-soluble monomer with ionic functional groups and polymerizable double bonds, and an initiator. The modified water-soluble polymer is obtained by grafting a water-soluble cross-linking agent with double bonds onto the water-soluble polymer. The aqueous phase is dropped into the oil phase to form an inverse suspension polymerization system, and then a first cross-linking reaction is carried out to obtain preliminarily cross-linked embolization microspheres. The preliminarily cross-linked embolization microspheres are subjected to a second cross-linking reaction with a metal ion inorganic salt to obtain secondary cross-linked embolization microspheres. The embolization microspheres of the embodiment of the present application have relatively high compression elasticity, a large drug loading capacity, and a fast drug loading speed.

Description

Technical Field

[0001] This application relates to the field of medical intervention treatment materials. Specifically, it relates to a preparation method of secondary cross-linked embolization microspheres and the embolization microspheres. Background Art

[0002] Currently, the commercially available embolization microspheres mainly use polyvinyl alcohol as the skeleton material of the microspheres. By grafting monomers with double bonds onto the molecular chain of polyvinyl alcohol, and then cross-linking and polymerizing this monomer with a monomer with ionic functional groups, charged embolization microspheres are formed, thus realizing the drug-loading function. The microspheres prepared by this single cross-linking have certain mechanical properties (strength and compression elasticity) and drug-loading properties. When more monomers are grafted onto polyvinyl alcohol, the cross-linked microspheres will contain more ionic functional groups, and their drug-loading ability will be stronger. However, at the same time, the cross-linking degree of the microspheres will be higher, the compression elasticity will be worse, and the swelling performance and drug-loading speed of the microspheres will also be worse. This mutual restriction limits the optimization of the drug-loading performance and compression elasticity of the embolization microspheres. For example, Chinese Patent CN201410232150 discloses a preparation method of single cross-linked polyvinyl alcohol embolization microspheres. The compression elasticity of the microspheres prepared by this method can reach more than 50%, but the time required for its loading of doxorubicin to reach equilibrium is 20 minutes, which means that doctors need to wait at least 20 minutes before clinical use; moreover, the drug-loading amount is only about 50%, which will lead to poor treatment effects.

[0003] Another preparation method of embolization microspheres uses water-soluble biocompatible polymer materials such as polyvinyl alcohol as the skeleton material of the microspheres. Polyvinyl alcohol and a water-soluble polymer monomer with ionic functional groups are mixed and dissolved in the water phase, and through the inverse suspension polymerization method, a composite mode of cross-linking and polymerization of polyvinyl alcohol and the water-soluble polymer monomer is realized respectively. Although this cross-linking method obtains a gradient cross-linked structure and the compression elasticity and drug-loading amount of the microspheres are significantly improved, the drug-loading rate is still relatively slow, which will lead to a relatively long waiting time during the clinical use by doctors and affect the quality of the operation. For example, Chinese Patent CN201910504935 discloses a preparation method of gradient cross-linked polyvinyl alcohol embolization microspheres. The compression elasticity of the microspheres prepared by this method can reach more than 70%, and the drug-loading amount can reach 98%, but it takes 30 minutes to reach this drug-loading amount, which also means that doctors need to wait at least 30 minutes before clinical use. Summary of the Invention

[0004] The purpose of the embodiments of this application is to provide a preparation method of secondary cross-linked embolization microspheres and the embolization microspheres, which have relatively high compression elasticity, a large drug-loading amount, and a fast drug-loading speed.

[0005] In the first aspect, the embodiments of this application provide a preparation method of secondary cross-linked embolization microspheres, which includes the following steps:

[0006] A modified water-soluble polymer, a water-soluble monomer with ionic functional groups and polymerizable double bonds, and an initiator are formulated into an aqueous phase. The modified water-soluble polymer is obtained by grafting a water-soluble crosslinker with double bonds onto a water-soluble polymer. The aqueous phase is dropped into an oil phase to form an inverse suspension polymerization system, and then a first crosslinking reaction is carried out to obtain preliminarily crosslinked embolization microspheres.

[0007] The preliminarily crosslinked embolization microspheres are subjected to a second crosslinking reaction with a metal ion inorganic salt to obtain secondarily crosslinked embolization microspheres.

[0008] In the above technical solution, a water-soluble polymer is used as the skeleton material, and a modified water-soluble polymer is obtained by grafting a water-soluble crosslinker. Then, it is formulated with a water-soluble monomer and an initiator to obtain an aqueous phase, and preliminarily crosslinked embolization microspheres are obtained by inverse suspension polymerization. Then, it reacts with a metal ion inorganic salt to further crosslink the embolization microspheres.

[0009] In this application, the water-soluble polymer is first functionalized and then crosslinked. The obtained embolization microspheres have a fast drug loading rate. Moreover, during the second crosslinking, the metal ions in the metal ion inorganic salt are used to complex with the ionic functional groups introduced through the water-soluble monomer in the preliminarily crosslinked embolization microspheres to form a complex, thereby realizing the second crosslinking, and the obtained embolization microspheres have a relatively high compression elasticity. This second crosslinking achieved through complexation avoids the use of highly toxic crosslinkers compared to the conventional second crosslinking method through covalent bonding, and has a fast crosslinking rate. The obtained embolization microspheres have good stability and can be sterilized multiple times for a long time.

[0010] In a possible implementation, the metal ion inorganic salt is selected from at least one of the group consisting of calcium chloride, calcium sulfate, calcium nitrate, ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, zinc chloride, and zinc sulfate;

[0011] and / or, the addition amount of the metal ion inorganic salt is 0.1% - 5% of the preliminarily crosslinked embolization microspheres;

[0012] In the above technical solution, the metal ion inorganic salt can release metal ions as an ionic crosslinker, so as to quickly carry out a complexation reaction with the ionic functional groups in the embolization microspheres.

[0013] In a possible implementation, the temperature of the second crosslinking reaction is 15°C - 45°C, the stirring rate is 200 rpm - 800 rpm, and the time is ≥5 min.

[0014] In a possible implementation, after the preliminarily crosslinked embolization microspheres are loaded with drugs, the second crosslinking reaction is carried out; or the secondarily crosslinked embolization microspheres are loaded with drugs.

[0015] In the above technical solution, the framework structure of the preliminarily cross-linked embolization microspheres has been functionalized, which can shorten their drug loading time. Therefore, the preliminarily cross-linked embolization microspheres can first load drugs and then perform the second cross-linking, or first perform the second cross-linking and then load drugs, without affecting the drug loading rate, and the drug loading rate is fast.

[0016] In a possible implementation, the water-soluble polymer is selected from at least one of the group consisting of polyvinyl alcohol, sodium alginate, sodium hyaluronate, sodium carboxymethyl cellulose, and water-soluble chitosan;

[0017] And / or, the water-soluble cross-linking agent is selected from at least one of the group consisting of N-(2,2-dimethoxy)-2-methylacrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, N-(2,2-dimethoxy)-2-acrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-methylacrylamide, N-(2,2-dimethoxy)-2-methylacrylate, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylate, N-(2,2-dimethoxy)-2-acrylate, and N-(1-hydroxy-2,2-dimethoxyethyl)-2-methylacrylate.

[0018] And / or, the mass percentage of the water-soluble cross-linking agent in the water-soluble polymer is 0.3% - 1%.

[0019] In a possible implementation, the preparation method of the modified water-soluble polymer includes the following steps: mixing and heating the water-soluble polymer and water to dissolve to obtain a homogeneous solution; then adding the water-soluble cross-linking agent and an acid catalyst, and reacting to obtain an aqueous solution containing the modified water-soluble polymer.

[0020] In a possible implementation, the mass percentage of the water-soluble polymer in water is 12% - 22%; the dissolution temperature of the water-soluble polymer is 90°C - 100°C;

[0021] And / or, the acid catalyst is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid, and p-toluenesulfonic acid; the mass percentage of the acid catalyst in water is 6% - 12%;

[0022] And / or, the reaction temperature is 20°C - 30°C.

[0023] In a possible implementation, an aqueous phase is prepared by mixing the aqueous solution containing the modified water-soluble polymer, the water-soluble monomer, and the initiator. The mass percentage of the water-soluble monomer in water is 30% - 80%; the initiator is at least one of ammonium persulfate, sodium persulfate, and potassium persulfate, and the mass percentage of the initiator in water is 0.3% - 0.8%.

[0024] In a possible implementation, the ionic functional group carried by the water-soluble monomer is at least one of a sulfonic acid group and a carboxyl group; optionally, the water-soluble monomer is selected from at least one of the group consisting of sodium 2-acrylamido-2-methylpropanesulfonate, sodium allylsulfonate, sodium methallylsulfonate, and sodium methacrylate;

[0025] And / or, the temperature of the first cross-linking reaction is 50°C to 80°C; the stirring rate is 200 rpm to 800 rpm; the time is 10 h to 20 h.

[0026] In the above technical solution, metal ions easily undergo complexation with sulfonate groups and carboxyl groups to form complexes, thereby achieving secondary cross-linking.

[0027] In a second aspect, an embodiment of the present application provides an embolic microsphere, which is prepared by using the preparation method of the secondary cross-linked embolic microsphere provided in the first aspect.

[0028] In the above technical solution, the embolic microsphere prepared by using the preparation method of the embodiment of the present application has high compressive elasticity, a large drug loading amount, and a fast drug loading speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 is the drug release curve of the preliminarily cross-linked embolic microsphere of Example 8;

[0031] Figure 2 is the drug release curve of the secondary cross-linked embolic microsphere of Example 8. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0033] The preparation method of the secondary cross-linked embolic microsphere and the embolic microsphere of the embodiment of the present application will be specifically described below.

[0034] An embodiment of the present application provides a preparation method of a secondary cross-linked embolic microsphere, which includes the following steps:

[0035] S1. Modify the water-soluble polymer: Graft a water-soluble crosslinking agent (the first crosslinking agent) with a polymerizable double bond onto the water-soluble polymer to obtain a modified water-soluble polymer.

[0036] As an implementation method, the preparation method of the modified water-soluble polymer includes the following steps: Mix and heat the water-soluble polymer and water to dissolve to obtain a homogeneous solution; then add the water-soluble crosslinking agent and an acid catalyst, and continuously stir and react at a certain temperature to obtain an aqueous solution containing the modified water-soluble polymer.

[0037] In step S1, the water-soluble polymer can be at least one selected from the group consisting of polyvinyl alcohol, sodium alginate, sodium hyaluronate, sodium carboxymethyl cellulose, and water-soluble chitosan.

[0038] The water-soluble crosslinking agent can be at least one selected from the group consisting of N-(2,2-dimethoxy)-2-methylacrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, N-(2,2-dimethoxy)-2-acrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-methylacrylamide, N-(2,2-dimethoxy)-2-methylacrylate, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylate, N-(2,2-dimethoxy)-2-acrylate, and N-(1-hydroxy-2,2-dimethoxyethyl)-2-methylacrylate.

[0039] The mass percentage of the water-soluble crosslinking agent in the water-soluble polymer is usually 0.3% - 1%.

[0040] The mass percentage of the water-soluble polymer in water is usually 12% - 22%; the dissolution temperature of the water-soluble polymer (mainly referring to polyvinyl alcohol) is 90°C - 100°C.

[0041] The acid catalyst can be at least one selected from hydrochloric acid, sulfuric acid, nitric acid, and p-toluenesulfonic acid, such as hydrochloric acid; the mass percentage of the acid catalyst in water is 6% - 12%.

[0042] The reaction temperature is 20°C - 30°C, and the stirring rate is 200 rpm - 800 rpm.

[0043] S2. Prepare the aqueous phase in the inverse suspension polymerization system: Prepare an aqueous phase by mixing the modified water-soluble polymer, a water-soluble monomer with ionic functional groups and a polymerizable double bond, and an initiator. As an implementation method: Stir the aqueous solution containing the modified water-soluble polymer obtained in step S1, the water-soluble monomer, and the initiator evenly into a homogeneous solution to obtain the aqueous phase.

[0044] In addition, prepare the oil phase in the inverse suspension polymerization system: Add the oil-soluble dispersant to the oil-phase solvent, stir and dissolve to form a homogeneous solution to obtain the oil phase.

[0045] In step S2, the water-soluble monomer has an ionic functional group which is at least one of a sulfonic acid group and a carboxyl group, and contains a polymerizable double bond; optionally, the water-soluble monomer is selected from at least one of the group consisting of sodium 2-acrylamido-2-methylpropanesulfonate, sodium allylsulfonate, sodium methallylsulfonate, and sodium methacrylate.

[0046] The mass percentage of the water-soluble monomer in water is 30% - 80%; the initiator is at least one of ammonium persulfate, sodium persulfate, and potassium persulfate, and the mass percentage of the initiator in water is 0.3% - 0.8%.

[0047] The oil-soluble dispersant is cellulose acetate butyrate.

[0048] The oily solvent is butyl acetate, ethyl acetate, methyl acetate, and propyl acetate, preferably butyl acetate.

[0049] The mass percentage of the oil-soluble dispersant in the oil phase is 2% - 5%;

[0050] The dissolution temperature of the oil-soluble dispersant is 30°C - 50°C.

[0051] S3. Preliminary cross-linking: Under stirring conditions, drop the water phase into the oil phase to form a water-in-oil inverse suspension polymerization system; after the dropping is completed, heat up the reaction system to the reaction temperature, drop a certain amount of catalyst into the reaction system, and start the first cross-linking reaction (inverse suspension polymerization reaction); after the reaction is completed, stop stirring and heating, let the reaction system stand for stratification, separate the oil phase, collect the microspheres and wash them repeatedly to obtain the preliminarily cross-linked embolization microspheres.

[0052] In step S3, the temperature of the first cross-linking reaction is 50°C - 80°C; the stirring rate is 200 rpm - 800 rpm; the time is 10 h - 20 h.

[0053] S4. Secondary cross-linking: Perform a secondary cross-linking reaction on the preliminarily cross-linked embolization microspheres with a metal ion inorganic salt (the second cross-linking agent) to obtain the secondarily cross-linked embolization microspheres. As an implementation method, first dissolve the metal ion inorganic salt in water, then add the preliminarily cross-linked embolization microspheres obtained in step S3 and mix them evenly, stir at a certain temperature for the secondary cross-linking reaction, and then sieve and rinse to obtain the secondarily cross-linked embolization microspheres.

[0054] In step S4, the metal ion inorganic salt (inorganic salt containing metal ions) can be a calcium salt, an iron salt, a zinc salt, etc., and specifically can be at least one selected from the group consisting of calcium chloride, calcium sulfate, calcium nitrate, ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, zinc chloride, and zinc sulfate.

[0055] The addition amount of the metal ion inorganic salt is 0.1% - 5% of the preliminarily cross-linked embolization microspheres.

[0056] The temperature of the second cross-linking reaction is 15°C - 45°C, the stirring rate is 200 rpm - 800 rpm, and the time is ≥5 min.

[0057] In the embodiment of the present application, in order to obtain drug-loaded embolization microspheres, the preliminarily cross-linked embolization microspheres obtained in step S3 can be loaded with drugs and then subjected to the second cross-linking reaction in step S4; or the secondarily cross-linked embolization microspheres obtained in step S4 can be loaded with drugs. The drug loading method is usually to mix the embolization microspheres with a drug solution until the drug is completely adsorbed. As an implementation method, in the embodiment of the present application, after step S3, the preliminarily cross-linked embolization microspheres are mixed with an adriamycin solution. After the adriamycin is completely adsorbed, a metal ion cross-linking agent is added for the second cross-linking reaction to obtain drug-loaded secondarily cross-linked embolization microspheres.

[0058] The embodiment of the present application also provides an embolization microsphere, which is prepared by using the above method for preparing secondarily cross-linked embolization microspheres. This embolization microsphere has a more complex and stable cross-linked structure compared to a single cross-linking method and a covalently bonded second cross-linking method.

[0059] The features and properties of the present application will be further described in detail below in conjunction with embodiments.

[0060] Example 1

[0061] This example provides a polyvinyl alcohol embolization microsphere, and its preparation process is as follows:

[0062] Step 1: Prepare a modified polyvinyl alcohol aqueous solution

[0063] 100 g of polyvinyl alcohol is added to 500 mL of water, and the temperature is raised to 95°C and stirred to dissolve to form a homogeneous solution; then 2.00 g of N-(2,2-dimethoxy)-2-methylacrylamide is added, and after stirring evenly, 30 mL of hydrochloric acid is added, and the reaction is continuously stirred at 25°C for 12 h to obtain a modified polyvinyl alcohol aqueous solution.

[0064] Step 2: Prepare the oil phase of the reverse suspension polymerization system

[0065] 20 g of cellulose acetate butyrate is added to 500 mL of butyl acetate, and the temperature is stirred at 35°C to dissolve to form a homogeneous solution to obtain the oil phase.

[0066] Step 3: Prepare the aqueous phase of the inverse suspension polymerization system

[0067] Dissolve 5 g of sodium 2-acrylamido-2-methylpropanesulfonate, 0.3 g of potassium persulfate, and 100 g of an aqueous solution of modified polyvinyl alcohol, and stir evenly until a homogeneous solution is obtained to obtain the aqueous phase.

[0068] Step 4: Inverse suspension polymerization

[0069] Under stirring conditions, slowly drop the aqueous phase solution into the oil phase to form an oil-in-water inverse suspension polymerization system. After the dropping is completed, heat the reaction system to 65 °C, and continue to drop 3 mL of tetramethylethylenediamine into the reaction system. The inverse suspension polymerization reaction starts. After the reaction ends, stop stirring and heating, let the reaction system stand for stratification, separate the oil phase, collect the microspheres and wash them repeatedly to obtain the preliminarily cross-linked embolization microspheres.

[0070] Step 5: Secondary cross-linking

[0071] First, dissolve 0.01 g of calcium chloride in 10 mL of water, then add 10 g of the preliminarily cross-linked embolization microspheres and mix evenly. Stir at 25 °C for 5 min, and then sieve and wash to obtain the secondarily cross-linked embolization microspheres.

[0072] Example 2

[0073] This example provides a polyvinyl alcohol embolization microsphere, and the difference in its preparation method from that of Example 1 is that: in Step 5, the addition amount of calcium chloride is 0.03 g.

[0074] Example 3

[0075] This example provides a polyvinyl alcohol embolization microsphere, and the difference in its preparation method from that of Example 1 is that: in Step 5, the addition amount of calcium chloride is 0.05 g.

[0076] Example 4

[0077] This example provides a polyvinyl alcohol embolization microsphere, and the difference in its preparation method from that of Example 1 is that: in Step 5, the addition amount of calcium chloride is 0.1 g.

[0078] Example 5

[0079] This example provides a polyvinyl alcohol embolization microsphere, and the difference in its preparation method from that of Example 1 is that: in Step 5, the addition amount of calcium chloride is 0.3 g.

[0080] Example 6

[0081] This example provides a polyvinyl alcohol embolization microsphere, and the difference in its preparation method from that of Example 1 is that: in Step 5, the addition amount of calcium chloride is 0.5 g.

[0082] Example 7

[0083] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 1 is that: in step 5, the addition amount of calcium chloride is 0.6 g.

[0084] Example 8

[0085] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 1 is that: in step 5, the stirring time is 5 min.

[0086] Example 9

[0087] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 1 is that: in step 5, the stirring time for secondary crosslinking is 15 min.

[0088] Example 10

[0089] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 1 is that: in step 5, the stirring time for secondary crosslinking is 30 min.

[0090] Example 11

[0091] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 1 is that: in step 5, the stirring temperature for secondary crosslinking is 15 °C.

[0092] Example 12

[0093] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 1 is that: in step 5, the stirring temperature for secondary crosslinking is 35 °C.

[0094] Example 13

[0095] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 1 is that: in step 5, the stirring temperature for secondary crosslinking is 45 °C.

[0096] Example 14

[0097] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 8 is that: in step 1, the water-soluble polymer is sodium alginate.

[0098] Example 15

[0099] This example provides a polyvinyl alcohol embolization microsphere. The difference in its preparation method from that of Example 8 is that: in step 5, the metal ion inorganic salt is ferrous chloride.

[0100] Example 16

[0101] This example provides a polyvinyl alcohol embolization microsphere, and the difference between its preparation method and that of Example 8 is that: in Step 3, the water-soluble monomer is sodium methacrylate.

[0102] I. Test the mechanical properties (strength, compression elasticity) of the polyvinyl alcohol embolization microspheres of the above different examples. The test method is as follows: Take different polyvinyl alcohol embolization microspheres (particle size range 100 - 300 μm), spread them flat on a glass slide, place them under the probe of a texture analyzer (TA-XT plusC), and select the Hold Compression mode for testing. The results are shown in Tables 1.1 - 1.4.

[0103] Table 1.1 Influence of the addition amount of metal ion inorganic salts on the mechanical properties of microspheres

[0104]

[0105]

[0106] Note: The addition amount [1] = mass of metal ion inorganic salt / mass of embolization microsphere; It can be seen from Examples 1 - 6 that as the dosage of metal ion inorganic salt increases, the strength and compression elasticity of the secondarily cross-linked embolization microspheres prepared increase. Example 7 shows that when the dosage of metal ion inorganic salt continues to increase, since the cross-linking system is already saturated, the strength of the secondarily cross-linked embolization microspheres does not increase further.

[0107] Table 1.2 Influence of the stirring time of secondary cross-linking on the mechanical properties of microspheres

[0108]

[0109] Table 1.3 Influence of the stirring temperature of secondary cross-linking on the mechanical properties of microspheres

[0110]

[0111] Table 1.5 Influence of other components on the mechanical properties of microspheres

[0112]

[0113] It can be seen from Tables 1.1 - 1.3 that the compression elasticity of the secondarily cross-linked embolization microspheres in the examples of this application can reach more than 60%.

[0114] In addition, through statistics, the cross-linking rate of all the secondarily cross-linked in the examples of this application is fast, and it can be achieved in only 5 minutes.

[0115] Table 1.4 Influence of sterilization on the mechanical properties of microspheres

[0116]

[0117]

[0118] Note: The sterilization method is autoclaving, the sterilization temperature is 121 °C, and the sterilization time each time is 30 min.

[0119] As can be seen from Table 1.4: The embolization microspheres with secondary crosslinking in the examples of the present application have undergone three sterilization treatments, and the strength has not changed significantly; while the preliminarily crosslinked embolization microspheres have undergone one sterilization treatment, and their strength has decreased significantly.

[0120] Second, test the drug loading and drug release performance of the embolization microspheres. The test method is as follows: 1) Mix 10 g of embolization microspheres with 10 mL of adriamycin solution at 700 mg / mL. After the adriamycin is adsorbed completely, use high-performance liquid chromatography to test the residual amount of adriamycin in the supernatant, and then calculate the drug loading of the embolization microspheres through conversion.

[0121] 2) Put the drug-loaded embolization microspheres into a dialysis bag, then put the dialysis bag into a centrifuge tube, add 20 mL of normal saline to the centrifuge tube, seal the centrifuge tube and place it on a constant temperature oscillator at 37.0 °C and oscillate at a speed of 100 revolutions per minute; sample at regular intervals, and take 0.1 ml of the solution at different time points for dilution respectively, and then use high-performance liquid chromatography to test the concentration of the adriamycin solution, and calculate the cumulative release amount of the drug-loaded embolization microspheres.

[0122] Draw the drug release curve of the preliminarily crosslinked embolization microspheres of Example 8 as Figure 1 shown, and the drug release curve of the secondarily crosslinked embolization microspheres of Example 8 as Figure 2 shown, and the statistical results are shown in Table 1.5.

[0123] Table 1.5 Drug loading and drug release performance of embolization microspheres

[0124]

[0125] As can be seen from Table 1.5, for the embolization microspheres treated by secondary crosslinking in the examples of the present application, the drug release time is significantly prolonged after drug loading, and there is an obvious effect of slow drug release.

[0126] In addition, first mix 10 g of the preliminarily cross-linked embolization microspheres of Example 1 with 10 mL of a 700 mg / mL doxorubicin solution. After the doxorubicin is adsorbed, add 0.1 g of calcium chloride and stir and react at 25 °C for 5 min to obtain the drug-loaded secondarily cross-linked embolization microspheres. By comparing and analyzing the drug-loading and drug-release properties of the embolization microspheres obtained before and after the secondary cross-linking in Example 1, it can be seen that the preliminarily cross-linked embolization microspheres can first load the drug and then add the second cross-linking agent, and the drug-loading amount can still reach more than 99%, and it only takes 15 min to reach this drug-loading amount; moreover, it has a good sustained-release effect without affecting the drug-loading rate, and the sustained-release time can reach 15 days.

[0127] In summary, the embolization microspheres prepared by the method for preparing secondarily cross-linked embolization microspheres according to the embodiments of the present application have relatively high compressive elasticity, a large drug-loading amount, and a fast drug-loading speed.

[0128] The above are only the embodiments of the present application and are not intended to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing secondary cross-linked embolization microspheres, characterized in that, it comprises the following steps: Preparing an aqueous phase by mixing a modified water-soluble polymer, a water-soluble monomer with an ionic functional group and a polymerizable double bond, and an initiator, wherein the modified water-soluble polymer is obtained by grafting a water-soluble cross-linking agent with a double bond onto the water-soluble polymer, and among them, the water-soluble polymer is selected from at least one of the group consisting of polyvinyl alcohol, sodium alginate, sodium hyaluronate, sodium carboxymethyl cellulose, and water-soluble chitosan, and the water-soluble cross-linking agent is selected from at least one of the group consisting of N-(2,2-dimethoxy)-2-methylacrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylamide, N-(2,2-dimethoxy)-2-acrylamide, N-(1-hydroxy-2,2-dimethoxyethyl)-2-methylacrylamide, N-(2,2-dimethoxy)-2-methylacrylate, N-(1-hydroxy-2,2-dimethoxyethyl)-2-acrylate, N-(2,2-dimethoxy)-2-acrylate, and N-(1-hydroxy-2,2-dimethoxyethyl)-2-methylacrylate; the ionic functional group carried by the water-soluble monomer is a sulfonic acid group, and the water-soluble monomer is selected from at least one of the group consisting of sodium 2-acrylamido-2-methylpropanesulfonate, sodium allylsulfonate, and sodium methallylsulfonate; Dropping the aqueous phase into an oil phase to form a reverse suspension polymerization system, and then performing a first cross-linking reaction to obtain preliminarily cross-linked embolization microspheres; Performing a second cross-linking reaction on the preliminarily cross-linked embolization microspheres with a metal ion inorganic salt, and the metal ion inorganic salt undergoes complex cross-linking with the sulfonic acid groups in the preliminarily cross-linked embolization microspheres to obtain secondary cross-linked embolization microspheres.

2. The method for preparing secondary cross-linked embolization microspheres according to claim 1, characterized in that, the metal ion inorganic salt is selected from at least one of the group consisting of calcium chloride, calcium sulfate, calcium nitrate, ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, zinc chloride, and zinc sulfate; and / or, the addition amount of the metal ion inorganic salt is 0.1% - 5% of the preliminarily cross-linked embolization microspheres.

3. The method for preparing secondary cross-linked embolization microspheres according to claim 1, characterized in that, the temperature of the second cross-linking reaction is 15°C - 45°C, the stirring rate is 200 rpm - 800 rpm, and the time is ≥5 min.

4. The method for preparing secondary cross-linked embolization microspheres according to claim 1, characterized in that, After loading the preliminarily cross-linked embolization microspheres with drugs, then performing the second cross-linking reaction; or loading the secondary cross-linked embolization microspheres with drugs.

5. The method for preparing secondary cross-linked embolization microspheres according to claim 1, characterized in that, the mass percentage of the water-soluble cross-linking agent in the water-soluble polymer is 0.3% - 1%.

6. The method for preparing secondary cross-linked embolization microspheres according to claim 1, characterized in that, The preparation method of the modified water-soluble polymer includes the following steps: mixing and heating the water-soluble polymer and water to dissolve to obtain a homogeneous solution; then adding the water-soluble cross-linking agent and an acid catalyst, and reacting to obtain an aqueous solution containing the modified water-soluble polymer.

7. The preparation method of the secondary cross-linked embolization microspheres according to claim 6, characterized in that the mass percentage of the water-soluble polymer in the water is 12% to 22%; the dissolution temperature of the water-soluble polymer is 90°C to 100°C; and / or, the acid catalyst is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid and p-toluenesulfonic acid; the mass percentage of the acid catalyst in the water is 6% to 12%; and / or, the reaction temperature is 20°C to 30°C.

8. The preparation method of the secondary cross-linked embolization microspheres according to claim 6, characterized in that preparing an aqueous phase from the aqueous solution containing the modified water-soluble polymer, the water-soluble monomer and the initiator, wherein the mass percentage of the water-soluble monomer in the water is 30% to 80%; the initiator is at least one of ammonium persulfate, sodium persulfate and potassium persulfate, and the mass percentage of the initiator in the water is 0.3% to 0.8%.

9. The preparation method of the secondary cross-linked embolization microspheres according to claim 1, characterized in that the temperature of the first cross-linking reaction is 50°C to 80°C; the stirring rate is 200 rpm to 800 rpm; the time is 10 h to 20 h.

10. An embolization microsphere, characterized in that it is prepared by using the preparation method of the secondary cross-linked embolization microspheres according to any one of claims 1 to 9.

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