Gelatin-based embolism gel microsphere, preparation method and application

Abstract

The invention provides gelatin-based embolism gel microspheres, a preparation method and application. Specifically, the gelatin-based embolism gel microsphere comprises a matrix structure and a hole located in the matrix structure, wherein the matrix structure comprises methacrylated gelatin, methacrylated hyaluronic acid, a zwitterionic monomer and a photo-crosslinking acrylate monomer. By utilizing holes in the microspheres and internal ion groups, high-speed and large-quantity drug loading can be realized. In addition, the microspheres also have good mechanical properties and moderate degradability, and are suitable for treatment of cancer vascular embolism.

Description

Technical Field

[0001] The present application relates to the field of pharmaceutical technologies, and particularly to a gelatin-based embolization gel microsphere, a preparation method and an application thereof. Background Art

[0002] Malignant tumors (cancers) are one of the most common fatal diseases. The treatment of cancer remains a major worldwide problem. Especially for certain specific diseases such as liver cancer, the early symptoms are hidden. Usually, most patients are diagnosed at the middle or late stage. At this time, surgical resection is difficult, and the treatment and prognosis are relatively poor. Trans arterial chemoembolization (TACE) is a minimally invasive technique that selectively injects an embolic agent or a combination of anticancer drugs and microparticles and embolizes the tumor-feeding artery, and belongs to a kind of interventional vascular treatment technique. Its advantages are as follows: on the one hand, embolizing the tumor-feeding artery causes ischemia and anoxia necrosis of the tumor tissue; on the other hand, it increases the local drug concentration and prolongs the contact time between the drug and the tumor tissue, and the curative effect is significantly improved compared with simple perfusion chemotherapy and simple embolization. In addition, the microspheres also have the ability to load drugs. After entering the tumor, they slowly release the chemotherapeutic drugs. By increasing the chemotherapeutic drug concentration in the tumor, the systemic drug concentration is reduced, so as to achieve the purpose of increasing the curative effect and reducing the toxic and side effects. TACE is applicable to palliative treatment and relatively radical treatment of liver cancer, renal cancer, pancreatic cancer, lung cancer, pelvic malignant tumors, etc., and radical treatment of hepatic hemangioma. Summary of the Invention

[0003] In view of this, the purpose of the present application is to provide a gelatin-based embolization gel microsphere, a preparation method and an application thereof.

[0004] Based on the above purpose, an embodiment of the present application provides a gelatin-based embolization gel microsphere, which includes a matrix structure and pores located in the matrix structure; wherein, the matrix structure includes methacrylated gelatin, methacrylated hyaluronic acid, zwitterionic monomer and photo-crosslinkable acrylate monomer.

[0005] In some embodiments, the particle size of the microspheres is 50 - 800 μm; and / or

[0006] the pore diameter of the pores is 1 - 40 μm, and the volume of the pores is 0.4 - 0.9 cm 3 / g; and / or

[0007] the compression deformation that the microspheres can withstand does not exceed 84%, and the compression recovery time does not exceed 6 s.

[0008] In some embodiments, the mass ratio of the methacrylated gelatin to the methacrylated hyaluronic acid is 6:5 - 6:1, and can be optionally 8:5 - 10:3; and / or

[0009] The molar ratio of the zwitterionic monomer to the photocrosslinkable acrylate monomer is 0.6 to 1.4, and may be optionally 0.8 to 1.2; and / or

[0010] The mass sum of the zwitterionic monomer and the photocrosslinkable acrylate monomer, and the mass ratio to the methacrylated gelatin is 1:2 to 2:1.

[0011] In some embodiments, the zwitterionic monomer includes at least one of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide, 3-(dimethyl(4-vinylbenzyl)amino)propanesulfonate, 2-(methacryloyloxy)ethyl-2-(trimethylammonio)ethyl phosphate.

[0012] In some embodiments, the photocrosslinkable acrylate monomer includes at least one of dipropylene glycol diacrylate, neopentyl glycol diacrylate, dipropylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, ethylene glycol dimethacrylate.

[0013] In some embodiments, the matrix structure further includes at least one of a photoinitiator and a radical initiator.

[0014] In some embodiments, the photoinitiator includes at least one of 2-hydroxy-2-methylpropiophenone, photoinitiator 500, and photoinitiator 2959.

[0015] Based on the same inventive concept, the embodiments of the present application further provide a method for preparing gelatin-based embolization gel microspheres, including:

[0016] Providing an aqueous phase prepolymer solution; the aqueous phase prepolymer solution includes a zwitterionic monomer, a photocrosslinkable acrylate monomer, methacrylated gelatin with a mass fraction of 6% to 12%, methacrylated hyaluronic acid with a mass fraction of 2% to 5%, a photoinitiator with a mass fraction of 0.1% to 1%, and a low-boiling point small molecule oil with a volume fraction of 5 to 10%; wherein, the molar ratio of the zwitterionic monomer to the photocrosslinkable acrylate monomer is between 0.6 and 1.4; the sum of the mass fractions of the zwitterionic monomer and the photocrosslinkable acrylate monomer is 6 to 12%;

[0017] Providing an oil phase solution; wherein, the oil phase solution includes an organic oil and a dispersant;

[0018] Exposing the oil phase solution to the initiation wavelength corresponding to the photoinitiator, and dropping the aqueous phase prepolymer solution into the oil phase solution under stirring at a first temperature for a first period of time; performing a polymerization reaction at a second temperature for a second period of time;

[0019] The product obtained from the polymerization reaction is filtered and then dispersed in water, and heated and distilled under reduced pressure until small molecule oils in the product are distilled out, thereby obtaining the gelatin-based embolization gel microspheres.

[0020] In some embodiments, the first temperature is 22-26 °C, and the first duration is 15-30 min; and / or

[0021] the second temperature is 0 °C - 20 °C, and the second duration is 6-12 h;

[0022] The temperature of the heating and distillation is not greater than 50 °C.

[0023] Based on the same inventive concept, the embodiments of the present application also provide the use of the gelatin-based embolization gel microspheres described in any one of the foregoing in the preparation of embolization preparations.

[0024] As can be seen from the above, the gelatin-based embolization gel microspheres, preparation method and application provided by the present application, the gelatin-based embolization gel microspheres include a matrix structure and pores located in the matrix structure; wherein, the matrix structure includes methacrylated gelatin, methacrylated hyaluronic acid, zwitterionic monomers and photo-crosslinkable acrylate monomers. Utilizing the pores and internal ionic groups in the microspheres, high-speed and large-scale drug loading can be achieved. In addition, the microspheres also have good mechanical properties and moderate degradability, and are suitable for cancer vascular embolization treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present application or related technologies, the following will briefly introduce the drawings required for use in the embodiments or related technology descriptions. Obviously, the drawings in the following descriptions are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is an enlarged photograph of the appearance of the dried gelatin-based embolization gel microspheres prepared in Example 1 of the present application;

[0027] Figure 2 It is an enlarged photograph of the appearance of the gelatin-based embolization gel microspheres loaded with doxorubicin prepared in Example 1 of the present application;

[0028] Figure 3 It is the concentration-time curve of doxorubicin absorption of the gelatin-based embolization gel microspheres prepared in Example 1 of the present application soaked in a 100 mg / mL doxorubicin solution;

[0029] Figure 4 It is the release curve of the gelatin-based embolization gel microspheres loaded with doxorubicin prepared in Example 1 of the present application in 25 °C physiological saline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] To make the objectives, technical solutions, and advantages of this application clearer and more understandable, the following further elaborates on this application in detail with reference to specific embodiments and the accompanying drawings.

[0031] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the embodiments of this application should have the ordinary meanings understood by those of ordinary skill in the field to which this application belongs. The "first", "second", and similar terms used in the embodiments of this application do not denote any order, quantity, or importance, but are only used to distinguish different components. "Containing" or "including" can be open, semi-closed, and closed. In other words, the terms also include "substantially consisting of...", or "consisting of...".

[0032] Traditional TACE embolization materials mainly include lipiodol, gelatin sponge, polyvinyl alcohol microspheres, etc. Gelatin, as a biomedical material, has advantages such as biocompatibility, low immunogenicity, biodegradability, and easy operability, and has been used in the embolization field for a long time. Currently, there are mainly two forms of gelatin sponge used clinically, including gelatin sponge microparticles and thin slices. Among them, gelatin sponge microparticles are commonly used particulate embolization agents in clinics. Due to their good morphological stability, mechanical properties, and degradability, good clinical embolization effects have been achieved. Although the effects are good, it has no other functions. If gelatin can be prepared into microspheres and drug loading can be achieved, drugs can be released while embolization is performed, achieving better therapeutic effects. However, in related technologies, the gelatin prepolymer solution mixed with drugs is homogenized through a microporous membrane and then formed into spheres by inverse emulsification. Although such a scheme can achieve drug loading, there are still great problems in clinical applications. One is that the time from co-forming spheres with drugs in the prepolymer solution to use is unpredictable, and the microspheres need to exist for a long time, making it impossible to ensure that the drugs do not deteriorate over a long time. The other is that when multiple substances are mixed, the material itself involves organisms, and it is very difficult to meet the standards for various biological toxicity detections and verification of degradation products. If gelatin microspheres are prepared first and rapid and large-scale drug loading is achieved before use, the problems in related technologies can be solved and the requirements of clinical applications can be met. However, although gelatin itself has hydrogen bond interactions and a small amount of ionic interactions, it is difficult to achieve rapid and large-scale drug loading after forming spheres due to the presence of a skin membrane.

[0033] In view of this, the embodiments of this application provide a gelatin-based embolization gel microsphere, a preparation method, and an application. The gelatin-based embolization gel microsphere includes a matrix structure and pores located in the matrix structure. Among them, the matrix structure includes methacrylated gelatin, methacrylated hyaluronic acid, zwitterionic monomers, and photo-crosslinkable acrylate monomers. By using the pores and internal ionic groups in the microspheres, high-speed and large-scale drug loading can be achieved. In addition, the microspheres also have good mechanical properties and moderate degradability, and are suitable for cancer vascular embolization treatment.

[0034] In a first aspect, an embodiment of the present application provides a gelatin-based embolization gel microsphere, which includes a matrix structure and pores located in the matrix structure; wherein, the matrix structure includes methacrylated gelatin, methacrylated hyaluronic acid, zwitterionic monomers, and photocrosslinkable acrylate monomers.

[0035] Here, the matrix structure includes methacrylated gelatin, methacrylated hyaluronic acid, zwitterionic monomers, and photocrosslinkable acrylate monomers. The gelatin skeleton plays a role in maintaining rigidity. Combining the flexibility of the zwitterionic polymer and hyaluronic acid achieves good mechanical properties and a moderate water-locking degree. Secondly, all monomers in the matrix structure contain abundant functional groups that can act. For example, the amino and carboxyl groups on gelatin, the carboxyl group on hyaluronic acid, the anions and cations in zwitterionic monomers, the ester groups in photocrosslinkable acrylate monomers, etc., can all form bonds with different types of polar drugs, especially having better binding properties for basic drugs. The pores in the matrix structure facilitate the entry and binding of drugs.

[0036] It should be noted that the pores can be obtained by distilling low-boiling-point oil. Here, the low-boiling-point oil refers to an oil with a boiling point between 40 and 98 °C.

[0037] Methacrylated gelatin can be prepared by reacting methacrylic anhydride with the amino groups of gelatin, and the reaction degree ranges from 6 to 12% calculated based on the mass of the grafted group and gelatin; it can also be directly purchased as a commercially available product.

[0038] Methacrylated hyaluronic acid can be obtained by reacting hyaluronic acid molecules with methacrylate esters, or it can be directly purchased as a commercially available product.

[0039] In some embodiments, the zwitterionic monomer includes at least one of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, 3-(dimethyl(4-vinylbenzyl)amino)propanesulfonate, and 2-(methacryloyloxy)ethyl-2-(trimethylammonio)ethyl phosphate.

[0040] In some embodiments, the photocrosslinkable acrylate monomer includes at least one of dipropylene glycol triacrylate, neopentyl glycol diacrylate, dipropylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, and ethylene glycol dimethacrylate. Optionally, the photocrosslinkable acrylate monomer is polyethylene glycol diacrylate.

[0041] In some embodiments, the particle size of the microspheres is 50 to 800 μm, such as 50 to 500 μm, 100 to 600 μm, 260 to 700 μm, 450 to 800 μm, 300 to 800 μm, 200 to 600 μm, 150 to 500 μm, 500 to 800 μm, etc. Such a particle size of the microspheres helps to enter the tumor blood supply artery and achieve embolization.

[0042] In some embodiments, the pore diameter of the pores is 1 to 40 μm, such as 1 to 10 μm, 1 to 30 μm, 2 to 30 μm, 2 to 40 μm, 2 to 20 μm, 2 to 15 μm, 3 to 40 μm, etc.; the volume of the pores is 0.4 to 0.9 cm 3 / g, such as 0.42 to 0.81 cm 3 / g, 0.46 to 0.75 cm 3 / g, 0.53 to 0.85 cm 3 / g, 0.45 to 0.9 cm 3 / g, 0.5 to 0.9 cm 3 / g, etc. Such microspheres have a large number of pores, which helps the drug to enter the microspheres and make sufficient contact with the ionic groups in the matrix structure in the microspheres, achieving the technical effect of high-speed and large-capacity drug loading.

[0043] In some embodiments, the compression deformation that the microspheres can withstand does not exceed 84%, and the compression recovery time does not exceed 6 s. Here, the compression deformation of the microspheres can be 30%, 50%, 62%, 70%, 75%, 84%, etc., which will not be listed one by one. Exemplarily, the compression deformation is 62 to 84%, and the compression recovery time is 2 to 6 s.

[0044] In some embodiments, after the microspheres are loaded with drugs, such as when the loaded doxorubicin concentration reaches 40 to 50 ml / mg, the compression deformation that can be withstood does not exceed 60%, and the compression recovery time does not exceed 12 s. Such as 5 s, 8 s, 11 s, etc. Exemplarily, the compression deformation of the microspheres after loading drugs can be 46 to 60%, and the compression recovery time is 4 to 12 s.

[0045] In some embodiments, the mass ratio of the methacrylated gelatin to the methacrylated hyaluronic acid is 6:5 to 6:1, such as 5:1, 5:4, 8:3, 2:1, 10:3, 4:1, etc. It can be selected as 8:5 to 10:3. It should be noted that if the mass ratio is lower than 6:5, the overall rigidity of the microspheres is insufficient and the molding is unstable; if the mass ratio is higher than 6:1, it is easy to cause insufficient overall flexibility of the microspheres and the comprehensive performance is reduced.

[0046] In some embodiments, calculated by the mass percentage of the swelling water in the dry beads, the equilibrium swelling ratio of the microspheres is 42% to 76%, and the volume increase ratio after swelling is less than 12%, such as 10%, 8%, etc.

[0047] In some embodiments, the molar ratio of the zwitterionic monomer to the photocrosslinkable acrylate monomer is 0.6 to 1.4, such as 0.6, 0.8, 1.0, 1.1, 1.3, 1.4, etc.

[0048] In some embodiments, the mass ratio of the sum of the masses of the zwitterionic monomer and the photocrosslinkable acrylate monomer to the mass of the methacrylated gelatin is 1:2 to 2:1. Such a ratio helps the progress of photoinitiation to form a microsphere structure with a stable structure.

[0049] In some embodiments, the matrix structure further includes at least one of a photoinitiator and a radical initiator. The photoinitiator is beneficial for photoinitiation, and the radical initiator can assist the photoinitiation reaction to facilitate the formation of microspheres with excellent mechanical properties and swelling properties.

[0050] In some embodiments, the photoinitiator includes at least one of 2-hydroxy-2-methylpropiophenone, photoinitiator 500, and photoinitiator 2959. Here, both photoinitiator 500 and photoinitiator 2959 are commercial photoinitiators.

[0051] In some embodiments, the radical initiator includes at least one of potassium persulfate and ammonium persulfate.

[0052] In a second aspect, an embodiment of the present application provides a method for preparing gelatin-based embolization gel microspheres. Specifically, the preparation method includes:

[0053] Providing an aqueous phase prepolymer solution; the aqueous phase prepolymer solution includes a zwitterionic monomer, a photocrosslinkable acrylate monomer, methacrylated gelatin with a mass fraction of 6% to 12%, methacrylated hyaluronic acid with a mass fraction of 2% to 5%, a photoinitiator with a mass fraction of 0.1% to 1%, and a low-boiling-point small molecule oil with a volume fraction of 5 to 10%; wherein, the molar ratio of the zwitterionic monomer to the photocrosslinkable acrylate monomer is between 0.6 and 1.4; the sum of the mass fractions of the zwitterionic monomer and the photocrosslinkable acrylate monomer is 6 to 12%;

[0054] Providing an oil phase solution; wherein, the oil phase solution includes an organic oil and a dispersant;

[0055] Exposing the oil phase solution to the initiation wavelength corresponding to the photoinitiator, dropping the aqueous phase prepolymer solution into the oil phase solution under stirring at a first temperature, and stirring for a first period of time; performing a polymerization reaction at a second temperature for a second period of time;

[0056] The product obtained from the polymerization reaction is filtered and then dispersed in water, and heated and distilled under reduced pressure until the low-boiling small-molecule oils in the product are distilled out, obtaining the gelatin-based embolization gel microspheres.

[0057] In some embodiments, the aqueous phase prepolymer solution further includes a radical initiator with a mass fraction of 0.1-0.3%.

[0058] In some embodiments, the volume ratio of the oil phase solution to the aqueous phase prepolymer solution is (5-10):1, such as 5:1, 6:1, 7:1, 9:1, 10:1. Optionally, the volume ratio of the oil phase solution to the aqueous phase prepolymer solution is (6-8):1.

[0059] In some embodiments, the low-boiling small-molecule oils are oils with a boiling point lower than that of water. Exemplarily, the boiling point of the low-boiling small-molecule oils is 40-98°C. Optionally, the boiling-point small-molecule oils include at least one of petroleum ether, n-hexane, cyclohexane, and n-heptane.

[0060] In some embodiments, the mass percentage of the dispersant is 4-8%. Optionally, the organic oil includes at least one of liquid paraffin, n-hexane, mineral oil, and silicone oil. Optionally, the dispersant includes at least one of Span80, Tween 20, cellulose acetate propionate, and cellulose acetate butyrate.

[0061] In some embodiments, in the aqueous phase prepolymer solution, the molar ratio of the zwitterionic monomer to the photocrosslinkable acrylate monomer is 0.8-1.2; the mass fraction of the methacrylated gelatin is 8-10%; the mass fraction of the methacrylated hyaluronic acid is 3-5%; the volume fraction of the low-boiling small-molecule oils is 6-8%; the sum of the mass fractions of the zwitterionic monomer and the photocrosslinkable acrylate monomer is 8-10.5%.

[0062] In some embodiments, the first temperature is 22-26°C, optionally 25°C; the first duration is 15-30 min.

[0063] In some embodiments, the second temperature is 0°C - 20°C, and the second duration is 6-12 h.

[0064] In some embodiments, the temperature of the heating and distillation is not greater than 50°C. Optionally, the pressure value is controlled within the temperature range where the small-molecule oils reach the boiling point while water does not reach the boiling point.

[0065] In some embodiments, the stirring speed is between 200-500 rmp, such as 240 rmp, 300 rmp, 340 rmp, 460 rmp, 500 rmp, etc.

[0066] To obtain gelatin-based embolization gel microspheres with better quality, the preparation method may further include the following steps: after heating and distillation, washing, purifying, sieving, and drying the product.

[0067] It should be noted that the above-mentioned preparation method can obtain the gelatin-based embolization gel microspheres with a particle size between 50 and 800 μm provided in the first aspect of the embodiment. By adjusting the substances and ratios of the aqueous phase prepolymer solution, the substances and ratios of the oil solution, and preparation conditions such as the stirring rate, the particle size distribution of the gelatin-based embolization gel microspheres can be controlled.

[0068] In a third aspect, the embodiments of the present application also provide the application of any of the above-mentioned gelatin-based embolization gel microspheres in the preparation of embolization preparations. Specifically, the gelatin-based embolization gel microspheres can rapidly load water-soluble and ionic drugs. Exemplarily, referring to Figure 3 , taking the target drug doxorubicin as an example, the drug loading concentration can reach 15 - 55 mg / mL of microspheres in 60 minutes and 60 - 100 mg / mL of microspheres in 12 hours. Here, mg / mL of microspheres refers to the amount of drug in mg loaded per ml of microspheres.

[0069] Furthermore, the gelatin-based embolization gel microspheres have an obvious drug sustained-release behavior after loading drugs. Referring to Figure 4 , taking the release behavior of microspheres loaded with doxorubicin at a concentration of 84 mg / mL as an example, when the drug-loaded microspheres are placed in excess physiological saline, the release amount within 1 day is about 16 - 23% of the total amount of loaded drugs, the release amount within 3 days is about 42 - 56% of the total amount of loaded drugs, and the release amount of the total amount of loaded drugs within 12 days is 92 - 96%.

[0070] In addition, the gelatin-based embolization gel microspheres provided by the embodiments of the present application have good biodegradability. Exemplarily, in physiological saline, the time when the microspheres start to degrade is between 9 and 15 days, and the time for complete degradation is between 18 and 27 days.

[0071] It can be seen that the gelatin-based embolization gel microspheres provided by the embodiments of the present application have the characteristics of being able to rapidly absorb a large amount of drugs and having a sustained release, and the gelatin-based embolization gel microspheres have good biodegradability, which can meet the needs of clinical medication.

[0072] To make the technical solutions of the present application clearer and easier to understand, the following will combine the accompanying drawings and specific embodiments to detail the gelatin-based embolization gel microspheres, preparation method, and application provided by the present application. The experimental methods used in the following embodiments are all conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0073] Example 1

[0074] This embodiment provides a gelatin-based embolization gel microsphere and a preparation method thereof, which are prepared from at least the following substances:

[0075] Aqueous phase prepolymer solution: including zwitterionic monomer, photocrosslinkable acrylate monomer, gelatin methacrylate with a mass fraction of 8.5%, hyaluronic acid methacrylate with a mass fraction of 3.2%, photoinitiator with a mass fraction of 0.4%, radical initiator with a mass fraction of 0.2%, and low-boiling-point small molecule oil with a volume fraction of 7.4%; wherein, the molar ratio of the zwitterionic monomer to the photocrosslinkable acrylate monomer is 1.1; the sum of the mass fractions of the zwitterionic monomer and the photocrosslinkable acrylate monomer is 8.2%.

[0076] Among them, the zwitterionic monomer is 3-(dimethyl(4-vinylbenzyl)amino)propanesulfonate; the photocrosslinkable acrylate monomer can be selected as dipropylene glycol diacrylate. The low-boiling-point small molecule oil is petroleum ether, and its boiling point is between 40 and 80 °C. The radical initiator is potassium persulfate. The photoinitiator is 2-hydroxy-2-methylpropiophenone.

[0077] Oil phase solution, including organic oil and dispersant, and the mass percentage of the dispersant in the organic oil is 6.5%; the organic oil is liquid paraffin; the dispersant is Span80.

[0078] The volume ratio of the oil phase solution to the aqueous phase prepolymer solution is 8:1.

[0079] Expose the oil phase solution to the initiation wavelength of 278 nm corresponding to the photoinitiator, and at room temperature of 25 °C, drop the aqueous phase prepolymer solution into the oil phase solution with stirring at a rate of 300 rmp, and stir for 20 min; carry out a polymerization reaction at 20 °C for 8 h.

[0080] Filter the product obtained from the polymerization reaction and disperse it in water, carry out reduced pressure distillation at 40 °C until the small molecule oil in the product evaporates, and then carry out washing, purification, sieving, and drying to obtain the fast drug-loading gelatin-based embolization gel microspheres.

[0081] Perform performance tests on the gelatin-based embolization gel microspheres prepared by the above method in the following manner:

[0082] Obtain the internal pore diameter of the microspheres by observing under a microscope after freeze-drying, and obtain the pore volume of the microspheres by the mercury displacement method.

[0083] Test the compressible deformation that the microspheres can withstand through the compression mode of a universal mechanical testing machine, and the compression recovery time can be obtained by observation.

[0084] The equilibrium swelling ratio is calculated by the mass ratio of the swelling water absorbed by swelling to the mass of the dry sphere before swelling.

[0085] The concentration difference of the drug solution before and after absorption is measured by the ultraviolet spectral characteristic peak method to obtain the drug concentration loaded on the microspheres; the release concentration is obtained by testing the microspheres placed in physiological saline, and the product of the concentration and the volume of the solution environment is the release amount.

[0086] Whether the gel starts to degrade is judged by observing the morphology of the microspheres placed in physiological saline and the presence of flocculent degradation products in the saline, and the degradation ends when the morphology of the microspheres completely disappears.

[0087] It should be noted that the same test methods are used in the following examples and comparative examples, and will not be elaborated here.

[0088] After testing, the performance of the gelatin-based embolization gel microspheres is as follows:

[0089] As Figure 1 shown, the particle size of the microspheres is between 200 and 400 μm; the internal pore diameter is 2 to 15 μm, and the pore volume is 0.65 cm 3 / g.

[0090] The microspheres can withstand a compression deformation of 74% and the compression recovery time is 4 s.

[0091] The microspheres are put into a large amount of adriamycin hydrochloride aqueous solution with a concentration of 100 mg / mL for drug loading (as Figure 2 shown). Referring to Figure 3 , the concentration of adriamycin loaded is determined by ultraviolet testing by sampling from the adriamycin aqueous solution, and the drug loading concentration of the microspheres is 21.4 mg / mL after 1 hour and 84 mg / mL after 12 hours.

[0092] When the drug loading of the microspheres reaches 45 mg / mL, the microspheres can withstand a compression deformation of 52% and the compression recovery time is 6 s.

[0093] The equilibrium swelling ratio of the microspheres is 64% according to the mass ratio of the swelling water to the dry sphere, and the volume increase rate after swelling is 9.5%.

[0094] As Figure 4 shown, the microspheres loaded with adriamycin at a concentration of 84 mg / mL are placed in excess physiological saline. The release amount within 1 day is about 17.6% of the total amount of the loaded drug, the release amount within 3 days is about 49.2% of the total amount of the loaded drug, and the release amount of the loaded drug after 12 days is 95.3% of the total amount of the drug.

[0095] The microspheres are degradable. In physiological saline, the microspheres start to degrade at 10 days and are completely degraded at 21 days.

[0096] Example 2

[0097] This embodiment provides a fast drug-loading gelatin-based embolization gel microsphere and a preparation method thereof, which are prepared from at least the following substances:

[0098] Aqueous phase prepolymer solution: including zwitterionic monomer, photo-crosslinkable acrylate monomer, gelatin methacrylate with a mass fraction of 10.2%, hyaluronic acid methacrylate with a mass fraction of 2.4%, photoinitiator with a mass fraction of 0.5%, radical initiator with a mass fraction of 0.15%, and low-boiling-point small molecule oil with a volume fraction of 8.2%; wherein, the molar ratio of the zwitterionic monomer to the photo-crosslinkable acrylate monomer is 0.8; the sum of the mass fractions of the zwitterionic monomer and the photo-crosslinkable acrylate monomer is 10.4%;

[0099] Oil phase solution; wherein, the oil phase solution includes organic oil and dispersant, and the mass percentage of the dispersant in the organic oil is 7.5%; the organic oil is silicone oil; the dispersant is Tween 20.

[0100] The volume ratio of the oil phase solution to the aqueous phase solution is 7.5:1.

[0101] The zwitterionic monomer is 3-(dimethyl(4-vinylbenzyl)amino)propanesulfonate.

[0102] The photo-crosslinkable acrylate monomer can be selected as dipropylene glycol diacrylate.

[0103] The low-boiling-point small molecule oil is n-hexane, and its boiling point is between 65 and 70 °C.

[0104] The radical initiator is potassium persulfate.

[0105] The photoinitiator is photoinitiator 2959.

[0106] Expose the oil phase solution to the initiation wavelength of 365 nm corresponding to the photoinitiator, and drop the aqueous phase prepolymer solution into the oil phase solution under stirring at a rate of 200 rmp at room temperature, and stir for 25 min; carry out a polymerization reaction at 15 °C for 10 h. It should be noted that the room temperature in this application refers to 22 - 26 °C, and optionally 25 °C.

[0107] Filter the product obtained from the polymerization reaction and disperse it in water, carry out vacuum distillation at 35 °C until the small molecule oil in the product evaporates, and then carry out multiple washings, purifications, sievings, and dryings to obtain the fast drug-loading gelatin-based embolization gel microsphere.

[0108] After testing, the performance of the gelatin-based embolization gel microsphere prepared in this embodiment is as follows:

[0109] The particle size of the microspheres ranges from 300 to 500 μm; the internal pore diameter ranges from 2 to 20 μm, and the pore volume is 0.72 cm 3 / g.

[0110] The microspheres were put into a large amount of aqueous doxorubicin hydrochloride solution with a concentration of 100 mg / mL for drug loading. Samples were taken from the aqueous solution for UV testing to determine the loaded doxorubicin concentration. It was obtained that the drug loading concentration was 18.6 mg / mL of microspheres after 1 hour and 87.5 mg / mL of microspheres after 12 hours.

[0111] When not loaded, the compressibility of the microspheres was 74%, and the compression recovery time was 4 s; when loaded to 42 mg / mL of microspheres, the compressibility was 56%, and the compression recovery time was 7 s.

[0112] The equilibrium swelling ratio of the microspheres was 68% based on the mass ratio of swollen water to dry spheres, and the volume increase rate after swelling was 10.2%.

[0113] The microspheres with a loaded doxorubicin concentration of 87.5 ml / mg were placed in excess physiological saline. The release amount within 1 day was about 19.2% of the total drug amount of the loaded drug, the release amount within 3 days was about 51.4% of the total drug amount of the loaded drug, and the release of the loaded drug amount within 12 days was 97.4% of the total drug amount.

[0114] The gelatin-based embolization gel microspheres are degradable. In physiological saline PBS, the microspheres started to degrade at 13 days and were completely degraded at 22 days.

[0115] Example 3

[0116] This example provides a fast-drug-loading gelatin-based embolization gel microsphere and its preparation method, which are prepared from at least the following substances:

[0117] Aqueous phase prepolymer solution: including zwitterionic monomer, photo-crosslinkable acrylate monomer, methacrylated gelatin with a mass fraction of 7.4%, methacrylated hyaluronic acid with a mass fraction of 4.6%, photoinitiator with a mass fraction of 0.3%, free radical initiator with a mass fraction of 0.25%, and low-boiling point small molecule oil with a volume fraction of 6.5%; wherein, the molar ratio of the zwitterionic monomer to the photo-crosslinkable acrylate monomer is 1.3; the sum of the mass fractions of the zwitterionic monomer and the photo-crosslinkable acrylate monomer is 9.5%;

[0118] Oil phase solution; wherein, the oil phase solution includes organic oil and dispersant, and the mass ratio of the dispersant is 4.1% of the organic oil; the organic oil is silicone oil; the dispersant is cellulose acetate propionate.

[0119] The volume ratio of the oil phase solution to the aqueous phase solution is 8.5:1.

[0120] The zwitterionic monomer is 2-(methacryloyloxy)ethyl-2-(trimethylammonio)ethyl phosphate.

[0121] The photocrosslinkable acrylate monomer can be selected as polyethylene glycol diacrylate.

[0122] The low-boiling point small molecule oil is cyclohexane, and its boiling point is between 80-85 °C.

[0123] The radical initiator is ammonium persulfate.

[0124] The photoinitiator is photoinitiator 500.

[0125] Expose the oil phase solution to the initiation wavelength of 250 nm corresponding to the photoinitiator, and dropwise add the aqueous phase prepolymer solution to the oil phase solution under stirring at a rate of 500 rmp at room temperature, and stir for 30 min; carry out a polymerization reaction at 5 °C for 10 h;

[0126] Filter the product obtained from the polymerization reaction and disperse it in water. Carry out vacuum distillation at 55 °C until the small molecule oil in the product evaporates, and then carry out multiple washings, purifications, sievings, and dryings to obtain the fast drug-loading gelatin-based embolization gel microspheres.

[0127] Perform performance tests on the above-prepared gelatin-based embolization gel microspheres, and the results are as follows:

[0128] The particle size of the microspheres is between 50 and 150 μm. The internal pore diameter is between 1 and 10 μm, and the pore volume is 0.76 cm 3 / g.

[0129] Put the microspheres into a large amount of aqueous doxorubicin hydrochloride solution with a concentration of 100 mg / mL for drug loading, and take samples from the aqueous solution for UV testing to determine the loaded doxorubicin concentration. The drug loading concentration after 1 hour is 22.5 mg / mL for the microspheres, and the drug loading concentration after 12 hours is 90.2 mg / mL for the microspheres.

[0130] The compressibility that can be tolerated by the unloaded gelatin-based embolization gel microspheres is 71%, and the compression recovery time is 6 s; when the microspheres are loaded to 48 mg / mL, the compressibility that can be tolerated is 56%, and the compression recovery time is 7 s.

[0131] The equilibrium swelling ratio of the gelatin-based embolization gel microspheres is 74% according to the mass ratio of the swollen water to the dry microspheres, and the volume increase rate after swelling is 11.3%.

[0132] The drug-loaded microspheres with an adriamycin concentration of 90.2 ml / mg were placed in an excess of physiological saline. The release amount within 1 day was approximately 20.4% of the total drug amount loaded, the release amount within 3 days was approximately 48.7% of the total drug amount loaded, and the release amount of the loaded drug within 12 days was 96.5% of the total drug amount.

[0133] The gelatin-based embolization gel microspheres are degradable. In physiological saline PBS, the microspheres start to degrade at 12 days and are completely degraded at 21 days.

[0134] Example 4

[0135] This embodiment provides a gelatin-based embolization gel microsphere and its preparation method, which are prepared from at least the following substances:

[0136] Aqueous phase prepolymer solution: It includes zwitterionic monomers, photocrosslinkable acrylate monomers, gelatin methacrylate with a mass fraction of 11.9%, hyaluronic acid methacrylate with a mass fraction of 2.1%, a photoinitiator with a mass fraction of 0.4%, a radical initiator with a mass fraction of 0.1%, and a low-boiling-point small molecule oil with a volume fraction of 9.5%; wherein, the molar ratio of the zwitterionic monomer to the photocrosslinkable acrylate monomer is 0.7; the sum of the mass fractions of the zwitterionic monomer and the photocrosslinkable acrylate monomer is 6.2%;

[0137] Oil phase solution; wherein, the oil phase solution includes organic oil and a dispersant, and the mass percentage of the dispersant is 6.8% of the organic oil; the organic oil is liquid paraffin; the dispersant is cellulose acetate butyrate.

[0138] The volume ratio of the oil phase solution to the aqueous phase prepolymer solution is 9.5:1.

[0139] The zwitterionic monomer is [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide.

[0140] The photocrosslinkable acrylate monomer can be selected as 1,4-butanediol diacrylate.

[0141] The low-boiling-point small molecule oil is n-hexane, and its boiling point is between 65 and 70 °C.

[0142] The radical initiator is ammonium persulfate.

[0143] The photoinitiator is photoinitiator 2959.

[0144] Expose the oil phase solution to the initiation wavelength of 365 nm corresponding to the photoinitiator, and drop the aqueous phase prepolymer solution into the oil phase solution under stirring at a rate of 100 rmp at room temperature, and stir for 25 min; carry out a polymerization reaction at 15 °C for 8 h;

[0145] The product obtained from the polymerization reaction was filtered and then dispersed in water. It was distilled under reduced pressure at 45°C until small molecular oils in the product were distilled out. Then, it was washed, purified, sieved, and dried multiple times to obtain the gelatin-based embolization gel microspheres.

[0146] The properties of the prepared gelatin-based embolization gel microspheres are as follows:

[0147] The particle size of the microspheres is between 600 and 800 μm. The internal pore diameter is between 3 and 30 μm, and the pore volume is 0.68 cm 3 / g.

[0148] The microspheres were put into a large amount of aqueous doxorubicin hydrochloride solution with a concentration of 100 mg / mL for drug loading. Samples were taken from the aqueous solution for ultraviolet testing to determine the loaded doxorubicin concentration. It was obtained that the drug loading concentration of the microspheres was 17.8 mg / mL after 1 hour and 84.1 mg / mL after 12 hours.

[0149] The unloaded gelatin-based embolization gel microspheres could withstand a compression deformation of 66%, and the compression recovery time was 8 s; when the microspheres were loaded to 49 mg / mL, the compression deformation that could be withstood was 59%, and the compression recovery time was 6 s.

[0150] The equilibrium swelling ratio of the gelatin-based embolization gel microspheres was 72% according to the mass ratio of the swollen water to the dry microspheres, and the volume increase rate after swelling was 10.6%.

[0151] The drug-loaded microspheres with a loaded doxorubicin concentration of 90.2 ml / mg were placed in excess physiological saline. The release amount within 1 day was approximately 23.1% of the total drug amount of the loaded drug, the release amount within 3 days was approximately 56.4% of the total drug amount of the loaded drug, and the release amount of the loaded drug after 12 days was 98.3% of the total drug amount.

[0152] The gelatin-based embolization gel microspheres are degradable. In physiological saline PBS, the microspheres started to degrade at 10 days and were completely degraded at 22 days.

[0153] Comparative Example 1

[0154] Compared with Example 1, low-boiling point small molecular oils were not added to the aqueous phase prepolymer solution, and the process of distillation under reduced pressure was omitted in the preparation method.

[0155] The properties of the obtained gelatin-based embolization gel microspheres are as follows:

[0156] The particle size of the microspheres is between 200 and 400 μm, the internal pore diameter is between 2 and 15 μm, and the pore volume is 0.36 cm 3 / g.

[0157] The microspheres were put into a large amount of aqueous doxorubicin hydrochloride solution with a concentration of 100 mg / mL for drug loading. Samples were taken from the aqueous solution for UV testing to determine the loaded doxorubicin concentration. It was found that the drug loading concentration of the microspheres was 7.5 mg / mL after 1 hour and 62.6 mg / mL after 12 hours.

[0158] The compressibility of the gelatin-based embolization gel microspheres without loading was 79%, and the compression recovery time was 2 s; when the microspheres were loaded with 46 mg / mL, the compressibility was 52%, and the compression recovery time was 6 s.

[0159] The equilibrium swelling ratio of the gelatin-based embolization gel microspheres was 61% based on the mass ratio of the swollen water to the dry microspheres, and the volume increase rate after swelling was 8.9%.

[0160] The drug-loaded microspheres with a doxorubicin loading concentration of 62.6 mL / mg were placed in excess physiological saline. The release amount within 1 day was about 11.2% of the total drug amount of the loaded drug, the release amount within 3 days was about 32.4% of the total drug amount of the loaded drug, and the release amount of the loaded drug after 12 days was 72.5% of the total drug amount.

[0161] The gelatin-based embolization gel microspheres were degradable. In physiological saline, the microspheres started to degrade at 14 days and were completely degraded at 32 days.

[0162] Since no low-boiling-point small molecule oils were added for pore formation, the interior of the microspheres was tightly bound, resulting in a decrease in drug loading amount, a reduction in drug release rate, and a delay in the start time of degradation.

[0163] Comparative Example 2

[0164] Compared with Example 1, no zwitterionic monomer was added to the aqueous phase prepolymer solution, but the mass of the zwitterionic monomer was entirely replaced by a photocrosslinkable acrylate monomer.

[0165] The properties of the obtained gelatin-based embolization gel microspheres were as follows:

[0166] The particle size of the microspheres was between 150 and 350 μm, the internal pore size was between 1 and 15 μm, and the pore volume was 0.57 cm 3 / g.

[0167] The microspheres were put into a large amount of aqueous doxorubicin hydrochloride solution with a concentration of 100 mg / mL for drug loading. Samples were taken from the aqueous solution for UV testing to determine the loaded doxorubicin concentration. It was found that the drug loading concentration of the microspheres was 14.6 mg / mL after 1 hour and 46.2 mg / mL after 12 hours.

[0168] The compressibility of the unloaded gelatin-based embolization gel microspheres is 52%, and the compression recovery time is 2 s; when loaded with 46 mg / mL microspheres, the compressibility is 43%, and the compression recovery time is 5 s.

[0169] The equilibrium swelling ratio of the gelatin-based embolization gel microspheres is 46% according to the mass ratio of swelling water to dry microspheres, and the volume increase rate after swelling is 8.9%.

[0170] When the drug-loaded microspheres with a doxorubicin concentration of 46.2 mL / mg are placed in an excess of physiological saline, the release amount within 1 day is about 31.4% of the total drug amount of the loaded drug, the release amount within 3 days is about 72.8% of the total drug amount of the loaded drug, and the release amount of the loaded drug within 12 days is 99.1% of the total drug amount.

[0171] The gelatin-based embolization gel microspheres are degradable. In physiological saline, the microspheres start to degrade at 9 days and are completely degraded at 16 days.

[0172] Since no zwitterionic monomer is added, the internal part of the microspheres and the drug binding sites are reduced, resulting in a decrease in drug loading capacity and a reduction in the drug release rate. The start time of degradation is advanced due to the reduction of interactions.

[0173] Comparative Example 3

[0174] Compared with Example 1, in the aqueous phase prepolymer solution, no photo-crosslinkable acrylate monomer is added, but the mass of the photo-crosslinkable acrylate monomer is entirely replaced by a zwitterionic monomer.

[0175] The properties of the obtained gelatin-based embolization gel microspheres are as follows:

[0176] The particle size of the microspheres is between 200 and 600 μm, the internal pore diameter is between 2 and 20 μm, and the pore volume is 0.54 cm 3 / g.

[0177] When the microspheres are put into an aqueous solution of a large amount of doxorubicin hydrochloride with a concentration of 100 mg / mL for drug loading, and samples are taken from the aqueous solution for UV testing to determine the loaded doxorubicin concentration, it is obtained that the drug loading concentration of the microspheres is 9.3 mg / mL after 1 hour and 49.5 mg / mL after 12 hours.

[0178] The compressibility of the unloaded gelatin-based embolization gel microspheres is 44%, and the compression recovery time is 3 s; when loaded with 44 mg / mL microspheres, the compressibility is 41%, and the compression recovery time is 6 s.

[0179] The equilibrium swelling ratio of the gelatin-based embolization gel microspheres is 67% according to the mass ratio of swelling water to dry microspheres, and the volume increase rate after swelling is 9.1%.

[0180] The drug-loaded microspheres with an adriamycin concentration of 49.5 mL / mg were placed in an excessive amount of physiological saline. The release amount within 1 day was approximately 27.4% of the total drug amount, the release amount within 3 days was approximately 48.5% of the total drug amount, and the release amount of the loaded drug within 12 days was 86.4% of the total drug amount.

[0181] The gelatin-based embolization gel microspheres are degradable. In physiological saline, the microspheres start to degrade at 13 days and are completely degraded at 20 days.

[0182] Due to the lack of photo-crosslinkable acrylate monomers, reactions between methacrylated gelatin and independent reactions of zwitterionic monomers are likely to occur during the internal reaction of the microspheres, resulting in inhomogeneity. At the same time, the particle size inhomogeneity increases. First, it leads to a significant reduction in the mechanical strength of the microspheres. Second, due to the self-polymerization of zwitterionic monomers, self-association between ions is likely to occur, reducing the binding with drugs and thus affecting drug loading. At the same time, due to the inhomogeneity of the internal structure of the microspheres, some drugs are tightly encapsulated, resulting in a fast initial drug release rate and a slow later release rate.

[0183] Comparative Example 4

[0184] Compared with Example 1, gelatin was used to replace methacrylated gelatin, and other components and preparation processes remained unchanged.

[0185] During the preparation process, since gelatin dissolves at high temperature and precipitates in the oil phase at low temperature for rapid prototyping. At the same time, it is difficult to completely precipitate low-boiling point small-molecule oils through the vacuum distillation process, and residues are likely to be generated.

[0186] The properties of the obtained gelatin-based embolization gel microspheres are as follows:

[0187] The particle size of the microspheres is between 150 - 300 μm, the internal pore diameter is between 1 - 15 μm, and the pore volume is 0.48 cm 3 / g;

[0188] The microspheres were put into an aqueous solution of a large amount of adriamycin hydrochloride with a concentration of 100 mg / mL for drug loading. Samples were taken from the aqueous solution for UV testing to determine the loaded adriamycin concentration. The drug loading concentration after 1 hour was 6.2 mg / mL of microspheres, and the drug loading concentration after 12 hours was 35.6 mg / mL of microspheres.

[0189] The unloaded gelatin-based embolization gel microspheres can withstand a compression deformation of 67% and the compression recovery time is 1 s; when the loading reaches 30 mg / mL of microspheres, the compression that can be withstood is 54% and the compression recovery time is 4 s.

[0190] The equilibrium swelling ratio of the gelatin-based embolization gel microspheres is 42% in terms of the mass ratio of swelling water to dry microspheres, and the volume increase ratio after swelling is 3.5%.

[0191] The drug-loaded microspheres with a doxorubicin concentration of 35.6 mg / mL were placed in excess physiological saline. The release amount within 1 day was approximately 17.5% of the total drug amount, the release amount within 3 days was approximately 52.4% of the total drug amount, and the release amount of the loaded drug within 12 days was 89.5% of the total drug amount.

[0192] The gelatin-based embolization gel microspheres are degradable. In physiological saline, the microspheres start to degrade at 11 days and are completely degraded at 22 days.

[0193] Due to the unmodified gelatin, precipitation and aggregation occur during the heating-cooling process, easily resulting in agglomeration inside the microspheres, further leading to non-uniform local structures, and encapsulating small molecule oils. The non-uniformity also causes a large number of drug-binding sites not to be exposed, seriously affecting the drug loading rate and the final drug loading amount. However, due to the rigidity of the molecular chain of gelatin itself, the microspheres still maintain good mechanical strength.

[0194] Comparative Example 5

[0195] Compared with Example 2, the mass fractions of methacrylated hyaluronic acid and methacrylated gelatin were interchanged, that is, the mass fraction of methacrylated hyaluronic acid was 10.2% and the mass fraction of methacrylated gelatin was 2.4%, while other components and preparation processes remained unchanged.

[0196] The obtained microspheres have unstable formability, and are prone to aggregation and a very non-uniform particle size distribution.

[0197] The properties of the obtained gelatin-based embolization gel microspheres are as follows:

[0198] The particle size of the microspheres is between 300 and 700 μm, the internal pore diameter is between 2 and 30 μm, and the pore volume is 0.52 cm 3 / g.

[0199] The microspheres were put into a large amount of doxorubicin hydrochloride aqueous solution with a concentration of 100 mg / mL for drug loading. Samples were taken from the aqueous solution for UV testing to determine the loaded doxorubicin concentration. The drug loading concentration of the microspheres was 8.4 mg / mL after 1 hour and 52.7 mg / mL after 12 hours.

[0200] The unloaded gelatin-based embolization gel microspheres can withstand a compressive deformation of 21% and the compression recovery time is 2 s; when the microspheres are loaded with 48 mg / mL, the compressive deformation that can be withstood is 12.4% and the compression recovery time is 4 s.

[0201] The equilibrium swelling ratio of the gelatin-based embolization gel microspheres is 149% in terms of the mass ratio of swelling water to dry microspheres, and the volume increase ratio after swelling is 34.7%.

[0202] The drug-loaded microspheres with a doxorubicin concentration of 52.7 mg / mL were placed in excess physiological saline. The release amount within 1 day was approximately 23.7% of the total drug amount loaded, the release amount within 3 days was approximately 61.3% of the total drug amount loaded, and the release amount of the loaded drug within 12 days was 94.9% of the total drug amount.

[0203] The gelatin-based embolization gel microspheres are degradable. In physiological saline, the microspheres start to degrade at 12 days and are completely degraded at 25 days.

[0204] Since the addition of rigid gelatin molecular chains is significantly reduced, the formability of the microspheres is unstable and the particle size is uneven; at the same time, the mechanical properties of the microspheres are significantly deteriorated and they cannot withstand large compression. Moreover, due to the stronger water absorption of hyaluronic acid itself, the gel is prone to swelling and deformation, and the particle size is also larger.

[0205] Comparative Example 6

[0206] Compared with Example 2, potassium persulfate, a free radical initiator, is not added during the preparation process, and other components and preparation processes remain unchanged.

[0207] The properties of the obtained gelatin-based embolization gel microspheres are as follows:

[0208] The particle size of the microspheres is between 300 and 500 μm, the internal pore diameter is between 2 and 20 μm, and the pore volume is 0.58 cm 3 / g.

[0209] The microspheres were put into a large amount of doxorubicin hydrochloride aqueous solution with a concentration of 100 mg / mL for drug loading. Samples were taken from the aqueous solution for ultraviolet testing to determine the loaded doxorubicin concentration. The drug loading concentration after 1 hour was 14.7 mg / mL for the microspheres, and the drug loading concentration after 12 hours was 61.2 mg / mL for the microspheres.

[0210] The unloaded gelatin-based embolization gel microspheres can withstand a compression of 74%, and the compression recovery time is 4 s; when the microspheres are loaded to 46 mg / mL, the compression that can be withstood is 42%, and the compression recovery time is 6 s.

[0211] The equilibrium swelling ratio of the gelatin-based embolization gel microspheres is 71% in terms of the mass ratio of swelling water to dry microspheres, and the volume increase ratio after swelling is 9.6%.

[0212] The drug-loaded microspheres with doxorubicin concentration of 61.2 mg / mL were placed in excess physiological saline. The release amount within 1 day was about 18.9% of the total drug amount loaded, the release amount within 3 days was about 55.1% of the total drug amount loaded, and the release amount of the loaded drug at 12 days was 95.2% of the total drug amount.

[0213] The gelatin-based embolization gel microspheres are degradable. In physiological saline, the microspheres start to degrade at 11 days and are completely degraded at 23 days.

[0214] Due to the lack of free radical initiator and only the photoinitiator, there may be some defects during the polymerization process, especially during the polymerization of zwitterionic monomers, resulting in a local reduction in performance.

[0215] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present application (including the claims) is limited to these examples; under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of brevity.

[0216] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omission, modification, equivalent substitution, improvement, etc. made within the spirit and principle of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A gelatin-based embolic gel microsphere, characterized in that: The microspheres include a matrix structure and pores in the matrix structure; wherein the matrix structure includes methacrylated gelatin, methacrylated hyaluronic acid, zwitterionic monomers and photo-crosslinked acrylate monomers.

2. The gelatin-based embolic gel microspheres according to claim 1, characterized in that: The particle size of the microspheres is 50 to 800 μm; and / or The pore diameter is 1-40 μm, and the volume of the pore is 0.4-0.9 cm 3 / g; and / or The microspheres can withstand a compression deformation of no more than 84%, and a compression recovery time of no more than 6 seconds.

3. The gelatin-based embolic gel microspheres according to claim 1, characterized in that: The mass ratio of the methacryloyl gelatin to the methacryloyl hyaluronic acid is 6:5 to 6:1, and can be 8:5 to 10:3; and / or The molar ratio of the zwitterionic monomer to the photo-crosslinkable acrylate monomer is 0.6 to 1.4, and can be 0.8 to 1.2; and / or The mass ratio of the sum of the mass of the zwitterionic monomer and the photo-crosslinked acrylate monomer to the methacrylated gelatin is 1:2 to 2:

1.

4. The gelatin-based embolic gel microspheres according to claim 1, characterized in that: The zwitterionic monomer includes at least one of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonatepropyl)ammonium hydroxide, 3-(dimethyl(4-vinylbenzyl)amino)propanesulfonate, and 2-(methacryloyloxy)ethyl-2-(trimethylamino)ethyl phosphate.

5. The gelatin-based embolic gel microspheres according to claim 1, characterized in that: The photo-crosslinked acrylate monomer includes at least one of tripropylene glycol diacrylate, neopentyl glycol diacrylate, dipropylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, and ethylene glycol dimethacrylate.

6. The gelatin-based embolic gel microspheres according to claim 1, characterized in that: The matrix structure also includes at least one of a photoinitiator and a free radical initiator.

7. The gelatin-based embolic gel microspheres according to claim 6, characterized in that: The photoinitiator includes at least one of 2-hydroxy-2-methylpropiophenone, photoinitiator 500 and photoinitiator 2959.

8. A method for preparing gelatin-based embolic gel microspheres, characterized in that: include: Providing an aqueous prepolymer solution; The aqueous prepolymer solution comprises zwitterionic monomers, photo-crosslinked acrylate monomers, methacrylated gelatin with a mass fraction of 6% to 12%, methacrylated hyaluronic acid with a mass fraction of 2% to 5%, photoinitiator with a mass fraction of 0.1% to 1%, and low-boiling point small molecule oil with a volume fraction of 5% to 10%; wherein the molar ratio of the zwitterionic monomer to the photo-crosslinked acrylate monomer is between 0.6 and 1.4; and the sum of the mass fractions of the zwitterionic monomer and the photo-crosslinked acrylate monomer is 6 to 12%; Providing an oil phase solution; wherein the oil phase solution comprises an organic oil and a dispersant; Exposing the oil phase solution to an initiation wavelength corresponding to the photoinitiator, dropping the aqueous prepolymer solution into the oil phase solution under stirring at a first temperature, stirring for a first time; and polymerizing at a second temperature for a second time; The product obtained by the polymerization reaction is filtered and then dispersed in water, and heated and distilled under reduced pressure until the small molecule oil in the product is evaporated to obtain the gelatin-based embolic gel microspheres.

9. The preparation method according to claim 8, characterized in that: The first temperature is 22-26° C., and the first time period is 15-30 minutes; and / or The second temperature is 0°C to 20°C, and the second time period is 6-12h; The temperature of the heated distillation is not greater than 50°C.

10. Use of the gelatin-based embolic gel microspheres according to any one of claims 1 to 7 in the preparation of embolic preparations.

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