Preparation method of starch hydrogel microspheres

Abstract

The invention provides a preparation method of starch hydrogel microspheres, and belongs to the technical field of embolism microsphere manufacturing. The preparation method of the starch hydrogel microspheres comprises the following steps: adding a first cross-linking agent into a starch solution, and mixing to obtain a water-phase solution; adding the oil phase solution into the water phase solution, and mixing to obtain a mixed liquid; adding a second cross-linking agent into the mixed liquid, mixing and reacting to obtain the starch hydrogel microspheres, and the starch hydrogel microspheres prepared by the method have the advantages of long in-vivo degradation time and adjustable degradation time, and can be suitable for more disease types.

Description

Technical Field

[0001] The present application relates to the technical field of embolic microsphere manufacturing, and in particular to a method for preparing starch hydrogel microspheres. Background Art

[0002] Embolic materials are materials commonly used in the medical field to block blood or liquid in blood vessels or other organs. They coagulate into a solid-like substance in the blood or liquid they come into contact with, which blocks the flow of liquid. Embolic materials generally have good biocompatibility, bioabsorbability, and other biological and physical properties to adapt to their specific medical application environments. Vascular embolization is widely used. It can be used to treat vascular lesions, such as ruptured blood vessels, arteriovenous malformations, aneurysms, and arteriovenous fistulas, as well as hyperemic tumors, tumor-like lesions, and organ hyperfunction. In short, no matter what kind of lesion, as long as the clinical treatment purpose can be achieved by vascular embolization without causing damage to important tissues and organ functions, and the patient can withstand the post-embolization reaction, vascular embolization can be considered for treatment.

[0003] At present, the most widely used embolic materials in China are PVA microspheres and gelatin sponge particles. Among them, the permanent implantation of PVA microspheres due to their non-degradability may cause persistent inflammation and other side effects, which greatly affects the patient's willingness to choose embolization. Gelatin sponge particles (Ailikang) are made from pig skin gelatin. They are insoluble in water, but degradable in the body. They are medium-term embolic materials and completely degrade in 14 to 90 days. Although gelatin sponge particles provide patients with an optional degradable embolic agent, as an animal-derived raw material and containing formaldehyde cross-linking agents with toxic side effects, it is difficult to become a universal choice.

[0004] Based on this, since existing embolic materials all have their own defects, technicians have thought of using starch from natural plant sources to prepare embolic materials. However, the starch embolic microspheres prepared by existing processes have the problem of too short in vivo degradation cycle (usually no more than 24 hours), resulting in fewer applicable diseases. Summary of the invention

[0005] The purpose of the present application is to provide a method for preparing starch hydrogel microspheres. The starch hydrogel microspheres prepared by the method have the advantages of a long in vivo degradation time and an adjustable degradation time, and can be applied to more types of diseases.

[0006] The embodiment of the present application is implemented as follows:

[0007] The present invention provides a method for preparing starch hydrogel microspheres, comprising the following steps:

[0008] A first cross-linking agent is added to the starch solution and mixed to obtain an aqueous solution; an oil phase solution is added to the aqueous solution and mixed to obtain a mixed liquid; a second cross-linking agent is added to the mixed liquid and mixed to react to obtain starch hydrogel microspheres.

[0009] In the above technical scheme, in the process of preparing starch hydrogel microspheres, the crosslinking agent is added in two steps. Specifically, the first crosslinking agent is added in the process of forming an aqueous phase solution, and the second crosslinking agent is added to the system after the aqueous phase and the oil phase are mixed. The crosslinking agent adopts this specific adding method, which can make the prepared starch hydrogel microspheres have a longer in vivo degradation time. At the same time, the in vivo degradation time of the prepared starch hydrogel microspheres can be adjusted by adjusting the mass ratio of the first crosslinking agent and the second crosslinking agent, thereby matching more types of diseases.

[0010] In some optional embodiments, the ratio of the mass of the first cross-linking agent to the mass of the second cross-linking agent is 1:(0.4-1.5).

[0011] In the above technical solution, the ratio of the mass of the first cross-linking agent to the mass of the second cross-linking agent is limited to a specific range, so that the adjustable range of the in vivo degradation time of the prepared starch hydrogel microspheres is larger, so that it can be applied to more types of diseases.

[0012] In some optional embodiments, the mass of the first cross-linking agent is greater than the mass of the second cross-linking agent.

[0013] In the above technical solution, the mass of the first cross-linking agent is set to be greater than the mass of the second cross-linking agent, so that the in vivo degradation time of the prepared starch hydrogel microspheres can be greater than 7 days, thereby being particularly suitable for diseases requiring long-term embolization.

[0014] In some optional embodiments, the mass of the first cross-linking agent is less than the mass of the second cross-linking agent.

[0015] In the above technical solution, the mass of the first cross-linking agent is set to be less than the mass of the second cross-linking agent, so that the in vivo degradation time of the prepared starch hydrogel microspheres can be less than 7 days (for example, 2 to 5 days), thereby being particularly suitable for diseases requiring short-acting embolization.

[0016] In some optional embodiments, the first cross-linking agent and / or the second cross-linking agent comprises a phosphate-based cross-linking agent.

[0017] Optionally, the phosphoric acid cross-linking agent is a mixture of sodium trimetaphosphate and sodium tripolyphosphate.

[0018] In the above technical solution, the first cross-linking agent and / or the second cross-linking agent adopts a phosphate cross-linking agent. Since this type of cross-linking agent has low toxicity, it can be better adapted to natural plant starch, so that the prepared starch hydrogel microspheres have better biocompatibility.

[0019] Furthermore, the phosphoric acid cross-linking agent uses a mixture of sodium trimetaphosphate and sodium tripolyphosphate, which has the advantage of better cross-linking effect.

[0020] In some optional embodiments, in the mixture, the mass ratio of sodium trimetaphosphate to sodium tripolyphosphate is 10:(0.8-1.2).

[0021] In the above technical solution, the mass ratio of the two cross-linking agents in the mixture is limited to a specific range, which can bring out a better cross-linking effect.

[0022] In some optional embodiments, in the aqueous solution, the mass ratio of starch to the first cross-linking agent is 10:(1-2).

[0023] In the above technical scheme, the mass ratio of starch and the first cross-linking agent in the aqueous phase solution is limited to a specific range so that the two have a more appropriate mass ratio in the aqueous phase, thereby making the prepared starch hydrogel microspheres have the advantages of good sphericity and not easy to agglomerate.

[0024] In some optional embodiments, in the starch solution, the mass concentration of starch is 8-12 g / mL.

[0025] In the above technical solution, the mass concentration of starch in the starch solution is limited to a specific range, and the appropriate concentration can be better mixed and dispersed with the cross-linking agent, so that the prepared starch hydrogel microspheres have the advantages of good sphericity and are not easy to agglomerate.

[0026] In some optional embodiments, the step of preparing the oil phase solution includes: adding an emulsifier to a mixed solvent of cyclohexane and n-decane and mixing the mixture to obtain an oil phase solution.

[0027] In the above technical solution, in the process of preparing the oil phase solution, a mixed system of cyclohexane and n-decane is used as a solvent, which can better dissolve and disperse the emulsifier, thereby exerting a better emulsification effect after the subsequent mixing of the oil phase and the water phase.

[0028] In some optional embodiments, in the mixed solvent, the volume ratio of cyclohexane to n-decane is 1:(0.8-1.2).

[0029] In the above technical scheme, the volume ratio of cyclohexane and n-decane in the mixed solvent is limited to a specific range so that the two have a more suitable volume ratio in the miscible system, thereby being able to better dissolve and disperse the emulsifier, thereby exerting a better emulsification effect after the subsequent mixing of the oil phase and the water phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. 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 related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A process flow chart of a method for preparing starch hydrogel microspheres provided in an embodiment of the present application;

[0032] Figure 2 This is an optical microscope image of the starch hydrogel microspheres provided in Example 1 of the present application;

[0033] Figure 3 An optical microscope image of starch hydrogel microspheres provided in Example 2 of the present application;

[0034] Figure 4 An optical microscope image of the starch hydrogel microspheres provided in Comparative Example 1 of the present application;

[0035] Figure 5 An optical microscope image of starch hydrogel microspheres provided in Comparative Example 2 of the present application;

[0036] Figure 6 An optical microscope image of starch hydrogel microspheres provided in Comparative Example 3 of the present application;

[0037] Figure 7 The in vivo degradation test results provided for Control Group 1 of this application;

[0038] Figure 8 The in vivo degradation test results provided for Control Group 2 of this application;

[0039] Fig. 9 The in vivo degradation test results provided in Example 1 of the present application;

[0040] Fig.10 The in vivo degradation test results provided in Example 2 of the present application;

[0041] Fig.11 The in vivo degradation test results provided for Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0043] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to the three situations of “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0044] In addition, in the description of the present application, unless otherwise specified, the meaning of "multiple" in "one or more" refers to two or more; the range of "value a ~ value b" includes the two end values ​​"a" and "b", and the "unit" in "value a ~ value b + unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0045] The following is a detailed description of a method for preparing starch hydrogel microspheres according to an embodiment of the present application.

[0046] The present invention provides a method for preparing starch hydrogel microspheres, comprising the following steps:

[0047] A first cross-linking agent is added to the starch solution and mixed to obtain an aqueous solution; an oil phase solution is added to the aqueous solution and mixed to obtain a mixed liquid; a second cross-linking agent is added to the mixed liquid and mixed to react to obtain starch hydrogel microspheres.

[0048] In the present application, in the process of preparing starch hydrogel microspheres, the crosslinking agent is added in two steps. Specifically, the first crosslinking agent is added in the process of forming an aqueous phase solution, and the second crosslinking agent is added to the system after the aqueous phase and the oil phase are mixed. The crosslinking agent adopts this specific gradient feeding method, which can make the prepared starch hydrogel microspheres have a longer in vivo degradation time. At the same time, the in vivo degradation time of the prepared starch hydrogel microspheres can be adjusted by adjusting the mass ratio of the first crosslinking agent and the second crosslinking agent, thereby matching more types of diseases.

[0049] It should be noted that "the cross-linking agent adopts this specific gradient addition method, which can make the prepared starch hydrogel microspheres have a longer in vivo degradation time", wherein the longer degradation time is compared with the existing starch hydrogel microspheres with an in vivo degradation time of less than 24 hours.

[0050] It should be noted that the preparation process of the starch solution can be carried out according to conventional methods in the art, for example, starch and sodium hydroxide are added to distilled water and stirred under heating conditions until the solution becomes a transparent paste.

[0051] It should be noted that the manner of adding the first cross-linking agent and / or the second cross-linking agent is not limited, for example, it can be in solid form or in liquid form. In the embodiments of the present application, they are added in liquid form, for example, in a 0.2-0.25 g / mL aqueous solution.

[0052] It is understandable that after the mixing reaction step, the steps of standing, filtering, washing and sieving are further included in sequence, and each step can be performed according to conventional operations in the art.

[0053] It should be noted that the mass ratio of the first cross-linking agent to the second cross-linking agent is not limited and can be adaptively adjusted according to actual needs.

[0054] As an example, the ratio of the mass of the first cross-linking agent to the mass of the second cross-linking agent is 1:(0.4-1.5), for example, but not limited to, the mass ratio is any one of 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4 and 1:1.5 or a range between any two of them.

[0055] In this embodiment, the ratio of the mass of the first cross-linking agent to the mass of the second cross-linking agent is limited to a specific range, so that the adjustable range of the in vivo degradation time of the prepared starch hydrogel microspheres is larger, so that it can be applied to more types of diseases.

[0056] As an example, the mass of the first cross-linking agent is greater than the mass of the second cross-linking agent.

[0057] In this embodiment, the mass of the first cross-linking agent is set to be greater than the mass of the second cross-linking agent, so that the in vivo degradation time of the prepared starch hydrogel microspheres can be greater than 7 days, thereby being particularly suitable for diseases requiring long-term embolization.

[0058] As an example, the mass of the first cross-linking agent is less than the mass of the second cross-linking agent.

[0059] In this embodiment, the mass of the first cross-linking agent is set to be less than the mass of the second cross-linking agent, so that the in vivo degradation time of the prepared starch hydrogel microspheres can be less than 7 days (e.g., 2 to 5 days), thereby being particularly suitable for diseases requiring short-acting embolization.

[0060] It should be noted that the types of the first cross-linking agent and / or the second cross-linking agent are not limited and can be adaptively adjusted according to actual needs.

[0061] As an example, the first cross-linking agent and / or the second cross-linking agent includes a phosphoric acid-based cross-linking agent.

[0062] As an example, the phosphoric acid cross-linking agent is a mixture of sodium trimetaphosphate and sodium tripolyphosphate.

[0063] In this embodiment, the first cross-linking agent and / or the second cross-linking agent is a phosphate cross-linking agent. Since this type of cross-linking agent has low toxicity, it can be well adapted to natural plant starch, so that the prepared starch hydrogel microspheres have good biocompatibility.

[0064] In this embodiment, the phosphoric acid cross-linking agent is a mixture of sodium trimetaphosphate and sodium tripolyphosphate, which has the advantage of better cross-linking effect.

[0065] As an example, in the mixture, the mass ratio of sodium trimetaphosphate to sodium tripolyphosphate is 10:(0.8-1.2), for example but not limited to the mass ratio of any one of 10:0.8, 10:0.9, 10:1, 10:1.1 and 10:1.2 or a range between any two of them.

[0066] In this embodiment, the mass ratio of the two cross-linking agents in the mixture is limited to a specific range, so that a more excellent cross-linking effect can be exerted.

[0067] As an example, in the aqueous solution, the mass ratio of starch to the first cross-linking agent is 10:(1-2), for example, but not limited to, the mass ratio is any one of 10:1, 10:1.1, 10:1.2, 10:1.3, 10:1.4, 10:1.5, 10:1.6, 10:1.7, 10:1.8, 10:1.9 and 10:2 or a range between any two of them.

[0068] In this embodiment, the mass ratio of starch and the first cross-linking agent in the aqueous phase solution is limited to a specific range so that the two have a more appropriate mass ratio in the aqueous phase, thereby making the prepared starch hydrogel microspheres have the advantages of good sphericity and not easy to agglomerate.

[0069] As an example, in the starch solution, the mass concentration of starch is 8 to 12 g / mL, for example but not limited to a mass concentration of any one of 8 g / mL, 9 g / mL, 10 g / mL, 11 g / mL and 12 g / mL or a range between any two of them.

[0070] In this embodiment, the mass concentration of starch in the starch solution is limited to a specific range, and the appropriate concentration can be better mixed and dispersed with the cross-linking agent, so that the prepared starch hydrogel microspheres have the advantages of good sphericity and are not easy to agglomerate.

[0071] As an example, the preparation step of the oil phase solution includes: adding an emulsifier into a mixed solvent of cyclohexane and n-decane and mixing them to obtain an oil phase solution.

[0072] In this embodiment, in the process of preparing the oil phase solution, a mixed system of cyclohexane and n-decane is used as a solvent, which can better dissolve and disperse the emulsifier, thereby exerting a better emulsification effect after the subsequent mixing of the oil phase and the water phase.

[0073] As an example, in the mixed solvent, the volume ratio of cyclohexane and n-decane is 1:(0.8~1.2), for example but not limited to, the volume ratio of the two is any one of 1:0.8, 1:0.9, 1:1, 1:1.1 and 1:2 or a range between any two of them.

[0074] In this embodiment, the volume ratio of cyclohexane and n-decane in the mixed solvent is limited to a specific range so that the two have a more suitable volume ratio in the miscible system, thereby being able to better dissolve and disperse the emulsifier, thereby exerting a better emulsification effect after the subsequent mixing of the oil phase and the water phase.

[0075] It should be noted that the type of emulsifier is not limited and can be selected according to the conventional method in the art, for example, it can be emulsifier OP-4.

[0076] It should be noted that the processes or steps not specifically described or limited in the starch hydrogel microspheres can be arranged according to conventional selection in the art.

[0077] As an example, the process flow chart of the preparation method of starch hydrogel microspheres is shown in Figure 1 .

[0078] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0079] Example 1

[0080] The present invention provides a method for preparing starch hydrogel microspheres, comprising the following steps:

[0081] Add 10g starch and 1g sodium hydroxide to 100mL distilled water and heat and stir until transparent paste, let stand and cool for use. Take 25mL starch solution, add 7mL aqueous solution containing 1.4g STMP and 0.14g STPP to it under stirring, stir until fully dissolved, and obtain an aqueous phase solution. Add 0.5g emulsifier (OP-4) to 100mL mixed solvent (the volume ratio of cyclohexane and n-decane is 1:1) and stir to obtain an oil phase solution. Add the oil phase solution to the aqueous phase solution and stir to obtain a mixed liquid. Add 3mL of aqueous solution containing 0.6g STMP and 0.06g STPP to the mixed liquid, stir and react at room temperature (25℃) for 24h, and after the reaction is completed, let stand, filter, wash (wash 3 times with ethyl acetate to remove oil phase impurities) and sieve in sequence to obtain starch hydrogel microspheres.

[0082] Example 2

[0083] The present invention provides a method for preparing starch hydrogel microspheres, comprising the following steps:

[0084] Add 10g starch and 1g sodium hydroxide to 100mL distilled water and heat and stir until transparent paste, let stand and cool for use. Take 25mL starch solution, add 7mL aqueous solution containing 1.4g STMP and 0.14g STPP to it under stirring, stir until fully dissolved, and obtain an aqueous phase solution. Add 0.5g emulsifier (OP-4) to 100mL mixed solvent (the volume ratio of cyclohexane and n-decane is 1:1) and stir to obtain an oil phase solution. Add the oil phase solution to the aqueous phase solution and stir to obtain a mixed liquid. Add 10mL of aqueous solution containing 2g STMP and 0.2g STPP to the mixed liquid, stir and react at room temperature (25℃) for 24h, and after the reaction is completed, let stand, filter, wash (wash 3 times with ethyl acetate to remove oil phase impurities) and sieve in sequence to obtain starch hydrogel microspheres.

[0085] Example 3

[0086] The present invention provides a method for preparing starch hydrogel microspheres, comprising the following steps:

[0087] Add 10g starch and 1g sodium hydroxide to 100mL distilled water and heat and stir until transparent paste, let stand and cool for use. Take 25mL starch solution, add 7mL aqueous solution containing 1.4g STMP and 0.14g STPP to it under stirring, stir until fully dissolved, and obtain an aqueous phase solution. Add 0.5g emulsifier (OP-4) to 100mL mixed solvent (the volume ratio of cyclohexane and n-decane is 1:1) and stir to obtain an oil phase solution. Add the oil phase solution to the aqueous phase solution and stir to obtain a mixed liquid. Add 5mL of aqueous solution containing 1g STMP and 0.1g STPP to the mixed liquid, stir and react at room temperature (25℃) for 24h, and after the reaction is completed, let stand, filter, wash (wash 3 times with ethyl acetate to remove oil phase impurities) and sieve in sequence to obtain starch hydrogel microspheres.

[0088] Comparative Example 1

[0089] The comparative example of the present application provides a method for preparing starch hydrogel microspheres, comprising the following steps:

[0090] Add 10g starch and 1g sodium hydroxide to 100mL distilled water and heat and stir until transparent paste, let stand and cool for use. Take 25mL starch solution, add 7mL aqueous solution containing 1.4g STMP and 0.14g STPP to it under stirring, stir until fully dissolved, and obtain an aqueous phase solution. Add 0.5g emulsifier (OP-4) to 100mL mixed solvent (the volume ratio of cyclohexane and n-decane is 1:1) and stir to obtain an oil phase solution. Add the oil phase solution to the aqueous phase solution and stir the reaction at room temperature (25℃) for 24h. After the reaction is completed, let stand, filter, wash (wash 3 times with ethyl acetate to remove oil phase impurities) and sieve in sequence to obtain starch hydrogel microspheres.

[0091] Comparative Example 2

[0092] The comparative example of the present application provides a method for preparing starch hydrogel microspheres, comprising the following steps:

[0093] Add 10g starch and 1g sodium hydroxide to 100mL distilled water and heat and stir until transparent paste, let stand and cool for use. Add 0.5g emulsifier (OP-4) to 100mL mixed solvent (volume ratio of cyclohexane and n-decane is 1:1) and stir to obtain oil phase solution. Take 25mL starch solution, add oil phase solution to it under stirring and stir to obtain mixed liquid. Then add 7mL aqueous solution containing 1.4g STMP and 0.14g STPP to the mixed liquid, stir and react at room temperature (25℃) for 24h, and after the reaction is completed, let stand, filter, wash (wash 3 times with ethyl acetate to remove oil phase impurities) and sieve in turn to obtain starch hydrogel microspheres.

[0094] Comparative Example 3

[0095] The comparative example of the present application provides a method for preparing starch hydrogel microspheres, comprising the following steps:

[0096] Add 10g starch and 1g sodium hydroxide to 100mL distilled water and heat and stir until transparent paste, let stand and cool for use. Add 0.5g emulsifier (OP-4) to 100mL mixed solvent (volume ratio of cyclohexane and n-decane is 1:1) and stir to obtain oil phase solution. Take 25mL starch solution, add oil phase solution to it under stirring and stir to obtain mixed liquid. Then add 17mL aqueous solution containing 3.4g STMP and 0.34g STPP to the mixed liquid, stir and react at room temperature (25℃) for 24h, and after the reaction is completed, let stand, filter, wash (wash 3 times with ethyl acetate to remove oil phase impurities) and sieve in turn to obtain starch hydrogel microspheres.

[0097] Test example

[0098] 1. Microstructure test of hydrogel microspheres

[0099] Test method:

[0100] The starch hydrogel microspheres prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were numbered respectively, and then the microstructure of each sample was tested respectively.

[0101] The specific test steps are as follows:

[0102] Take 100 mL of 300-600 μm microspheres from each group after screening and add 100 mL of normal saline respectively. After the microspheres are allowed to settle and stratify, remove the upper clear liquid and pour in 100 mL of normal saline again. Repeat the operation three or more times to obtain replaced microspheres with normal saline as the storage medium. Take pictures under an optical microscope to observe the microstructure of the microspheres.

[0103] See also Figure 2 to Figure 6,in, Figure 2 Corresponding to Example 1 (scale is 400 μm), Figure 3 Corresponding to Example 2 (scale is 400 μm), Figure 4 Corresponding to the comparative example 1 (scale bar is 400 μm), Figure 5 Corresponding to Example 2 (scale bar is 400 μm), Figure 6 Corresponding to Comparative Example 3 (scale bar: 300 μm).

[0104] Depend on Figure 2 to Figure 6 The test results show that the starch hydrogel microspheres prepared by the preparation method provided in the examples of the present application have the advantages of good sphericity and good dispersibility. It should be noted that if the cross-linking agent is added only after the water phase and the oil phase are mixed, the prepared microspheres will be severely agglomerated, making it difficult to apply them later, and the agglomeration of the microspheres will be more serious as the amount of the cross-linking agent increases.

[0105] 2. Solid content test of hydrogel microspheres

[0106] Test method:

[0107] The starch hydrogel microspheres prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were numbered respectively, and then the solid content of each sample was tested respectively.

[0108] The specific test steps are as follows:

[0109] The moisture content of each group of 300-600 micron microspheres before replacement was tested by a moisture meter, and the average value was taken after three times to obtain the corresponding solid content. The corresponding test results are statistically shown in Table 1.

[0110] 3. In vitro degradation time test of hydrogel microspheres

[0111] Test method:

[0112] The starch hydrogel microspheres prepared in Examples 1 to 3 and Comparative Example 1 were numbered respectively, and then the in vitro degradation time of each sample was tested respectively.

[0113] The specific test steps are as follows:

[0114] Take 2 mL of the replaced microspheres of 300-600 microns in each group, add them to 18 mL of physiological saline solution containing α-amylase, and configure the enzyme concentration to 500 U / L. Incubate on a shaker at 37°C, visually observe the reaction bottle at regular intervals, and when the microspheres are no longer visible, take 0.5 mL of the mixed liquid and dilute it to 1 mL for microscopic photography. The time when no microspheres are found under the microscopic photography is the complete degradation time of the microspheres, and the corresponding test results are statistically reported in Table 1.

[0115] 4. In vivo degradation time test of hydrogel microspheres

[0116] Test method:

[0117] The starch hydrogel microspheres prepared in Examples 1 to 3 and Comparative Example 1 were numbered respectively. At the same time, commercially available PVA microspheres (Coreichi (Shenzhen) Medical Technology Development Co., Ltd.-non-degradable) and gelatin sponge particles (Ailikang Pharmaceutical Technology Co., Ltd., complete degradation time 14 to 90 days) were used as control groups 1 and 2. Then, the in vivo degradation time of each sample was tested and the test results were statistically reported in Table 1.

[0118] The specific test steps are as follows:

[0119] Five healthy experimental rabbits were prepared, and the blood vessels and veins at the rabbit ears were photographed under a light source (i.e., the blood vessels and veins at the rabbit ears were photographed before the operation); then, a 22G retention needle was inserted into the central artery at a distance of 4 to 5 cm from the base of the rabbit ears, from the proximal end to the distal end, in accordance with the direction of blood flow, the needle was withdrawn, and the suspended sample was slowly injected (pulse injection, speed 1 mL / min) until obvious injection resistance appeared, and the light source was irradiated from the back of the ear to see that the central artery of the rabbit ear turned white and there was no blood circulation; after the injection, the injection site was pressed to stop bleeding, and the retention needle was pulled out at the same time, and the needle insertion site during the operation was marked, and then, the blood vessels and veins at the rabbit ears were photographed under a light source at 0 h, 2 h, 1 day, 2 days, and 7 days after surgery, respectively, to count the degradation status of the sample in the animal body.

[0120] It should be noted that if the blood vessels of the rabbit are completely normal, it means that the sample has been completely degraded; if the blood vessels of the rabbit are still damaged, it means that the sample has not been completely degraded, and the more severe the damage, the better the embolization effect of the sample (that is, the more difficult it is to degrade).

[0121] See also Figure 7 to Figure 11 ,in, Figure 7 Corresponding to control group 1, Figure 8 Corresponding to control group 2, Fig. 9 Corresponding to Example 1, Fig.10 Corresponding to Example 2, Fig.11 Corresponding ratio 1.

[0122] Depend on Figure 7 to Figure 11From the test results, it can be seen that in the control group 1 and the control group 2, the blood vessels and veins of the rabbits were still severely damaged 7 days after surgery, indicating that the blood vessels were still in a state of severe obstruction (that is, the samples were not decomposed); in Example 1, the blood vessels and veins of the rabbits returned to normal between 2 days and 7 days after surgery, indicating that the in vivo degradation time of the sample in Example 1 was 2 to 7 days; in Example 2, the damage to the blood vessels and veins of the rabbits 7 days after surgery was alleviated compared with 1 day after surgery but did not return to normal, indicating that the in vivo degradation time of the sample in Example 2 was greater than 7 days; in Comparative Example 1, the blood vessels and veins of the rabbits returned to normal 1 day after surgery, indicating that the in vivo degradation time of the sample in Comparative Example 1 was within 24 hours.

[0123] Table 1

[0124] sample Solid content (%) In vitro degradation time Degradation time in vivo Example 1 7.42 6h 2～24h Example 2 10.21 5 days 2-7 days Example 3 8.73 3 days 1 to 5 days Comparative Example 1 2.45 >30 days >7 days Comparative Example 2 8.41 — — Comparative Example 3 12.42 — — Control group 1 — — >7 days Control group 2 — — >7 days

[0125] It should be noted that “—” in Table 1 means that no test was performed.

[0126] Combined with Table 1 and Figure 2 to Figure 11 From the test results, it can be seen that the starch hydrogel microspheres prepared by the preparation method provided in the embodiments of the present application have the advantages of good sphericity and good dispersibility, and have a long degradation time in the body and the specific degradation time is adjustable, and can be applied to more types of diseases.

[0127] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A method for preparing starch hydrogel microspheres, characterized in that: The following steps are involved: adding a first cross-linking agent to the starch solution and mixing to obtain an aqueous phase solution; adding the oil phase solution to the aqueous phase solution and mixing to obtain a mixed liquid; A second cross-linking agent is added to the mixed liquid and mixed to react to obtain starch hydrogel microspheres.

2. The method for preparing starch hydrogel microspheres according to claim 1, characterized in that: The ratio of the mass of the first cross-linking agent to the mass of the second cross-linking agent is 1:(0.4-1.5).

3. The method for preparing starch hydrogel microspheres according to claim 2, characterized in that: The mass of the first cross-linking agent is greater than the mass of the second cross-linking agent.

4. The method for preparing starch hydrogel microspheres according to claim 2, characterized in that: The mass of the first cross-linking agent is smaller than the mass of the second cross-linking agent.

5. The method for preparing starch hydrogel microspheres according to any one of claims 1 to 4, characterized in that: The first cross-linking agent and / or the second cross-linking agent include a phosphoric acid cross-linking agent; Optionally, the phosphoric acid cross-linking agent is a mixture of sodium trimetaphosphate and sodium tripolyphosphate.

6. The method for preparing starch hydrogel microspheres according to claim 5, characterized in that: In the mixture, the mass ratio of the sodium trimetaphosphate to the sodium tripolyphosphate is 10:(0.8-1.2).

7. The method for preparing starch hydrogel microspheres according to any one of claims 1 to 4, characterized in that: In the aqueous phase solution, the mass ratio of starch to the first cross-linking agent is 10:(1-2).

8. The method for preparing starch hydrogel microspheres according to any one of claims 1 to 4, characterized in that: In the starch solution, the mass concentration of starch is 8-12 g / mL.

9. The method for preparing starch hydrogel microspheres according to any one of claims 1 to 4, characterized in that: The preparation step of the oil phase solution comprises: adding an emulsifier into a mixed solvent of cyclohexane and n-decane and mixing the mixture to obtain the oil phase solution.

10. The method for preparing starch hydrogel microspheres according to claim 9, characterized in that: In the mixed solvent, the volume ratio of the cyclohexane to the n-decane is 1:(0.8-1.2).

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