Premixes, kits and uses for the preparation of embolizing agents

Abstract

The application provides a premix agent for preparing embolic agents, a kit and application thereof. The premix agent adopts a mass ratio of poloxamer and sodium alginate of 9:1-20:1, can form a solution with good injection in use, and maintains good gel performance, and has good preparation and use convenience.

Description

Technical Field

[0001] This application belongs to the field of pharmaceutical technology, specifically relating to a premix, kit, and application for preparing embolic agents. Background Technology

[0002] Endovascular embolization is a minimally invasive procedure that selectively delivers embolic material to the lesion site via an interventional catheter, forming an embolus in situ to block the lesion. This procedure provides a safer and more effective treatment for various vascular diseases and highly vascular tumors, and the appropriate embolic material is the most important factor in achieving effective embolization.

[0003] Traditional embolization materials mainly fall into two categories: solid embolization agents, such as polyvinyl alcohol microspheres and gelatin embolization particles, which can be suspended in the injection solution and injected through a catheter. However, they have poor filling properties for complex shapes and locations and pose a risk of catheter blockage. Liquid embolization agents, such as n-BCA (butyl cyanoacrylate) and Onyx (ethylene-vinyl alcohol copolymer dissolved in dimethyl sulfoxide), have better delivery and conformability. However, n-BCA is an adhesive material and is also prone to catheter blockage. Onyx material itself does not degrade, the solvent has poor biocompatibility, and it is easy to cause inflammation or other side effects. In addition, the curing time is short and difficult to control, making the surgical procedure more difficult.

[0004] Hydrogels, as a type of hydrophilic polymer material widely used in cell culture, drug delivery and sustained release, and dressings, possess excellent biocompatibility and drug-loading properties. In recent years, research has also begun to utilize hydrogels as hemostatic materials, achieving rapid hemostasis. However, the application of hydrogels as embolic agents places higher demands on the safety, stability, curing properties, and degradation performance of the hydrogel materials. Existing hydrogel materials or formulations often fail to meet the embolic requirements of clinical use.

[0005] Therefore, in view of the shortcomings of existing technologies, it is of particular importance in this field to develop a liquid embolizing agent material with excellent injectability, stable embolization effect, controllable degradation and good biocompatibility, and suitable for embolization treatment of diseases. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application provides a premix for preparing embolic agents, comprising: poloxamer and sodium alginate, wherein the mass ratio of poloxamer to sodium alginate is 9:1-20:1.

[0007] In some embodiments, the mass ratio of poloxamer to sodium alginate is 10:1 to 18:1.

[0008] In some embodiments, the premix does not include a gelling accelerator. Preferably, the gelling accelerator is selected from one or more of hydroxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, chitosan or its derivatives, carboxymethyl cellulose, polyethylene glycol, polyvinylpyrrolidone, p-toluenesulfonic acid, and zinc oxide.

[0009] In some embodiments, the molecular weight of the poloxamer is 6000-20000 g / mol.

[0010] In some embodiments, the number of oxyethylene units in the poloxamer is 50-200, and the number of oxypropylene units is 15-80.

[0011] In some embodiments, the molecular weight of the sodium alginate is 50,000-200,000 g / mol.

[0012] In some embodiments, the premix is ​​a solution, wherein the poloxamer and sodium alginate together account for 2wt%-25wt% of the total mass of the solution.

[0013] In some embodiments, the premix consists of poloxamer, sodium alginate, and the balance water.

[0014] In some embodiments, the premix is ​​a powder.

[0015] In some embodiments, the premix is ​​a lyophilizing agent.

[0016] In some embodiments, the water content of the premix is ​​≤5wt%.

[0017] In some embodiments, the water content of the premix is ​​≤3wt%, preferably ≤2wt%.

[0018] In some embodiments, poloxamer and sodium alginate together account for 93wt%-99.9wt% of the total mass of the premix. This application also provides a method for preparing the premix, comprising the following steps: providing poloxamer and sodium alginate in a mass ratio of 9:1-20:1, dispersing them in a solvent, dissolving them, and preparing a solution.

[0019] In some embodiments, the poloxamer and sodium alginate together account for 2wt%-25wt% of the total mass of the solution.

[0020] In some embodiments, the solvent is deionized water.

[0021] In some embodiments, the method further includes drying the solution to obtain a powder.

[0022] In some embodiments, the method further includes lyophilizing the solution to obtain a lyophilizing agent; preferably, the total mass fraction of poloxamer and sodium alginate in the solution is 2wt%-6wt%.

[0023] In some embodiments, the solution is further subjected to a membrane filtration sterilization step before being freeze-dried.

[0024] This application provides a kit for preparing a vascular embolization agent, comprising a bottle A containing a premix as described above, and a bottle B containing a crosslinking agent, said crosslinking agent comprising a divalent or trivalent metal salt.

[0025] In some embodiments, the divalent metal salt is selected from at least one of calcium chloride, calcium nitrate, strontium chloride, calcium gluconate, calcium bicarbonate, calcium sulfate, calcium hydroxide, and calcium carbonate, and the trivalent metal salt is selected from at least one of aluminum chloride and ferric nitrate.

[0026] In some embodiments, the crosslinking agent is an aqueous solution of a divalent or trivalent metal salt with a mass fraction of 2%-8%.

[0027] In some embodiments, a C-bottle containing a redissolving agent is also included.

[0028] In some embodiments, the resolvent is water for injection, or optionally includes a developer.

[0029] In some embodiments, the resolvent is used to formulate the premix into a premixed solution, wherein the total mass fraction of the poloxamer and sodium alginate in the premixed solution is 6wt%-25wt%.

[0030] This application also provides a method for preparing an embolic agent, comprising: providing a premixed solution, wherein the total mass fraction of poloxamer and sodium alginate in the premixed solution is 6wt%-25wt%;

[0031] A crosslinking agent is provided, wherein the crosslinking agent is an aqueous solution of a divalent or trivalent metal salt with a mass fraction of 2% to 8%; The premixed liquid and the crosslinking agent are mixed at a predetermined volume ratio to obtain the embolic agent.

[0032] In some embodiments, the premix is ​​a lyophilizing agent, and the premix is ​​provided by the following steps: mixing the premix with a reconstituter and dissolving it.

[0033] In some embodiments, the resolvent is water for injection, or optionally includes a developer.

[0034] In some embodiments, the volume ratio of the premixed liquid to the crosslinking agent is 1:2 to 1:10.

[0035] In some embodiments, the premixed liquid and the crosslinking agent are mixed at a predetermined rate via a coaxial dual-lumen microcatheter.

[0036] In some embodiments, the injection rate ratio of the premix to the crosslinking agent is 1:2 to 1:10.

[0037] In some embodiments, the injection rate of the premixed solution is 0.2-1.5 mL / min, and the injection rate of the crosslinking agent is 0.4-10 mL / min.

[0038] In some embodiments, the distal end of the outer tube of the coaxial dual-lumen microcatheter is 1-10 mm longer than the distal end of the inner tube, the premixed liquid is injected through the inner tube, and the crosslinking agent is injected through the gap between the outer and inner tubes.

[0039] This application provides the use of the premixed agents or kits described above in the preparation of embolic agents.

[0040] In some embodiments, the embolic agent is used for tumor embolization therapy. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of an in vitro simulated hepatic artery circulation blood flow device used in an in vitro simulated embolization experiment according to an embodiment of this application; Figure 2 CT imaging of rabbit renal tumor artery 1-4 weeks after embolization, according to an embodiment of this application; Figure 3 This is a gross anatomical photograph of the rabbit renal tumor artery after embolization, according to an embodiment of this application. Detailed Implementation

[0042] The present invention will be further described below with reference to different embodiments, but the present invention is not limited to the scope of the embodiments described herein.

[0043] Hydrogels have been reported as embolic agents, but gelling agents need to be added to maintain the gel's curing properties. Sodium alginate and calcium salts solidify upon contact, leading to increased viscosity and difficulty in injection. Currently, there are no hydrogel formulations that are easy to prepare and apply clinically, and storage and transportation costs are increased.

[0044] premix This application first provides a premix for use in preparing an embolic agent by mixing with a crosslinking agent. This premix can be formulated into a solution of suitable viscosity, exhibits excellent injectability, and after mixing with the crosslinking agent, demonstrates excellent curing properties, forming a hydrogel embolic agent with excellent degradation performance, thus meeting the performance requirements for in-situ embolization in vivo. This premix is ​​designed to maintain good flowability and injectability during use, and even after mixing with the crosslinking agent, it better achieves in-situ embolization; therefore, it is understood that this premix does not contain a crosslinking agent.

[0045] The premix provided in this application includes poloxamer and sodium alginate, with a mass ratio of poloxamer to sodium alginate of 9:1-20:1. Within this ratio range, the prepared premix maintains suitable viscosity and temperature responsiveness, exhibits good flowability when injected using a microcatheter, and its curing rate meets the requirements for in-situ curing in clinical applications. If this ratio is changed, for example, by increasing the amount of poloxamer, the gelation speed may be faster, but the degradation cycle may be shorter, making it more difficult to achieve the desired therapeutic effect. If the amount of sodium alginate is increased, the viscosity increases, making injection more difficult and failing to maintain good temperature-sensitive properties.

[0046] In some implementations, the mass ratio of poloxamer to sodium alginate is any ratio within the range of 9:1 to 20:1; for example, it is 10:1 to 18:1, 11:1 to 16:1; specifically, the mass ratio of poloxamer to sodium alginate can be 9:1, 10:1, 11:1, 11.5:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1 or any ratio between two of these values.

[0047] When poloxamer and sodium alginate are within the above-mentioned mass ratio range, excellent gelling and injection properties can be achieved. Therefore, in some embodiments, the premix does not include gelation accelerators, such as hydroxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, chitosan or its derivatives, carboxymethyl cellulose, polyethylene glycol, polyvinylpyrrolidone, p-toluenesulfonic acid, and zinc oxide. The embodiments of this application, without adding these gelation accelerators, can still rapidly solidify after premixing and injection to produce an embolic gel that meets the mechanical and degradation properties required for embolization therapy. The solution provided by the embodiments of this application can balance injection performance, curing performance, and degradation performance, and simplifies the composition, resulting in better medical safety.

[0048] Poloxamer is a nonionic polymer compound, a block copolymer formed from polyethylene oxide (PEO) and polypropylene oxide (PPO) segments, with a structural unit represented as PEO-PPO-PEO. Poloxamer exhibits temperature responsiveness. In some embodiments, the molecular weight of poloxamer is 6000-20000 g / mol, for example 8000-10000 g / mol, or 10000-14000 g / mol. In some embodiments, poloxamer is selected from any one or a combination of poloxamer 407, poloxamer 188, and so on.

[0049] Sodium alginate is a natural high molecular weight polymer comprising mannuronic acid and guluronic acid structural units. The molecular weight of sodium alginate ranges from 50,000 to 200,000 g / mol, for example, 50,000 g / mol, 100,000 g / mol, 150,000 g / mol, or 200,000 g / mol.

[0050] In some embodiments, this application provides a premix, which is a solution comprising poloxamer and sodium alginate as described above.

[0051] It is understood that, in this embodiment, the premix also includes a solvent. In some embodiments, the solvent is water, preferably injectable water or deionized water. In some embodiments, the solvent does not contain metal ions, especially metal ions that promote the curing of sodium alginate and poloxamer, to ensure that the premix is ​​uncured when injected into the subject, maintaining excellent injectability.

[0052] In some embodiments, the total mass of poloxamer and sodium alginate accounts for 2wt%-25wt% of the total mass of the solution, for example, 5wt%-25wt%, 5.5wt%-25wt%, 6wt%-25wt%, 6wt%-20wt%, 6wt%-18wt%, 5.5wt%-18wt%, 10wt%-20wt%, or 15wt%-20wt%. Specifically, the total mass of poloxamer and sodium alginate accounts for 2wt%, 3wt%, 3.3wt%, 5wt%, 5.5wt%, 6wt%, 10wt%, 12wt%, 13wt%, 15wt%, 16wt%, 16.8wt%, 17wt%, 18wt%, 18.5wt%, 19wt%, 20wt%, or 25wt%, or any value between these values.

[0053] In some embodiments, the premix comprises poloxamer and sodium alginate in the mass ratio described above, and a solvent, wherein the total mass of poloxamer and sodium alginate in the premix is ​​2wt%-25wt%, preferably 6wt%-25wt%, and more preferably 10wt%-20wt%.

[0054] In some embodiments, the premix comprises poloxamer and sodium alginate in the mass ratio described above, and water, wherein the total mass of poloxamer and sodium alginate in the premix comprises 2 wt%-25 wt% of water.

[0055] In some embodiments, the premix comprises, by total mass of the premix, 1.9wt%-20wt% poloxamer, 0.1wt%-2wt% sodium alginate, and 75wt%-98wt% solvent.

[0056] In some embodiments, the premix comprises, by total mass, 1.9 wt%-19 wt% poloxamer, 0.1 wt%-1.5 wt% sodium alginate, and 80 wt%-97 wt% solvent.

[0057] In some embodiments, the premix comprises, by total mass, 10wt%-19wt% poloxamer, 0.5wt%-2wt% sodium alginate, and 80wt%-89wt% solvent.

[0058] In some embodiments, the premix comprises, by total mass, 13wt%-19wt% poloxamer, 0.5wt%-2wt% sodium alginate, and 80wt%-86wt% solvent.

[0059] In some embodiments, this application provides a premix, which is a powder comprising poloxamer and sodium alginate in the mass ratio described above.

[0060] In some embodiments, the premix is ​​a lyophilizing agent. Preferably, the lyophilizing agent has a water content of ≤5wt%, for example ≤4wt%, ≤3wt%, ≤2wt%, or, for example, a water content in the range of 0.01wt%-2wt%.

[0061] When the water content of the lyophilizer is controlled at ≤5wt%, especially ≤2wt%, better reconstitution effect and shelf life can be obtained.

[0062] In some embodiments, poloxamer and sodium alginate together account for 93wt%-99.9wt% of the total mass of the premix, for example 95wt%, 96wt%, 97wt%, 98wt%, or 99wt%.

[0063] Formulating liquid embolic agents into powders, especially lyophilized powders, can significantly reduce storage and transportation costs. However, ensuring that the embolic agent components, after being formulated into powder, can be easily and rapidly reconstituted to meet clinical requirements for formulation efficiency and injection performance, while maintaining excellent curing, embolic, and degradation properties after reconstitution, is a key issue that needs to be addressed. The inventors of this application unexpectedly discovered that lyophilizing a 2wt%-6wt% aqueous solution of poloxamer and sodium alginate in the aforementioned mass ratio yields excellent reconstitution results. Higher concentrations result in higher solution viscosity, making membrane filtration sterilization impossible before lyophilization, and reducing the reconstitution rate after lyophilization; lower concentrations significantly increase lyophilization costs without further improvement in reconstitution performance. This application also provides a method for preparing the aforementioned premix, comprising providing poloxamer and sodium alginate in a mass ratio of 9:1-20:1, dispersing them in a solvent, dissolving them, and preparing a solution. The solvent is preferably deionized water.

[0064] In some embodiments, poloxamer and sodium alginate together account for 2wt%-25wt% of the total mass of the solution.

[0065] In some embodiments, poloxamer and sodium alginate together account for 6 wt%-25 wt% of the total mass of the solution. The premix is ​​in solution form and can be used directly to prepare liquid embolic agents.

[0066] In other embodiments, the preparation method further includes the step of drying the prepared solution to obtain a powder, preferably freeze-drying. As some specific examples, poloxamer and sodium alginate together account for 2wt%-6wt% of the total mass of the solution, which is then freeze-dried to obtain a freeze-dried premix.

[0067] In some embodiments of this application, a premix for preparing an embolic agent is also provided, wherein the premix comprises poloxamer and sodium alginate, wherein the mass ratio of poloxamer to sodium alginate is 9:1-20:1, and the premix is ​​in powder form.

[0068] In some embodiments of this application, a premix for preparing an embolic agent is also provided, wherein the premix comprises poloxamer and sodium alginate, the mass ratio of poloxamer to sodium alginate being 9:1-20:1, and the premix is ​​a lyophilizing agent. The lyophilizing agent has a water content ≤5wt%, for example ≤4wt%, ≤3wt%, ≤2wt%, or, for example, a water content in the range of 0.01wt%-2wt%.

[0069] When the water content of the lyophilizer is controlled at ≤5wt%, especially ≤2wt%, better reconstitution effect and shelf life can be obtained.

[0070] In some embodiments, the powder or lyophilized agent has the definition described above.

[0071] In some embodiments, this application provides a method for preparing a lyophilized agent for liquid embolization, comprising providing poloxamer and sodium alginate in a mass ratio of 9:1-20:1, dispersing them in a solvent, dissolving them, preparing a solution, and then lyophilizing the solution. The solvent is preferably deionized water. In some embodiments, poloxamer and sodium alginate together account for 2wt%-6wt% of the total mass of the solution. In some embodiments, the water content of the obtained lyophilized agent is ≤5wt%, preferably ≤2wt%.

[0072] In some embodiments, before freeze-drying the solution, a step of sterilizing the solution by membrane filtration is included. A solution with a total mass fraction of 2wt%-6wt% poloxamer and sodium alginate is prepared, with a viscosity favorable for membrane filtration sterilization. In some embodiments, a membrane with a pore size of 0.1-0.45 μm is used for filtration sterilization, for example, a filter membrane with a pore size of 0.22 μm.

[0073] Reagent test kit This application also provides a kit for conveniently preparing embolic agents that can be solidified in situ in vivo. It is understood that this kit can also be used to prepare other suitable hydrogels.

[0074] This kit includes at least two separate bottles, A and B. Bottle A contains the premix as described above, which can be a solution, powder, or lyophilized form. Bottle B contains a cross-linking agent, which includes a substance that promotes the gelation of sodium alginate, such as a divalent or trivalent metal salt. The divalent metal salt can be selected from, but is not limited to, at least one of calcium chloride, calcium nitrate, strontium chloride, calcium gluconate, calcium bicarbonate, calcium sulfate, calcium hydroxide, and calcium carbonate. The trivalent metal salt can be selected from, but is not limited to, at least one of aluminum chloride and ferric nitrate.

[0075] In some embodiments, the crosslinking agent is an aqueous solution of a divalent or trivalent metal salt at a concentration of 2wt%-8wt%, for example, 3wt%-6wt%.

[0076] In some embodiments, the premix in vial A is a powder or lyophilized agent, and the kit further includes vial C containing a reconstitution solvent. This reconstitution solvent is used to dissolve the dried premix in vial A to prepare a premix solution. In some embodiments, the reconstitution solvent is water for injection, or optionally includes a developer selected from iodixanol, iodofol, or iohexol; for example, the reconstitution solvent is a 30wt%-45wt% aqueous solution of the developer, such as 30wt%-45wt% iohexol. In some embodiments, the total mass fraction of poloxamer and sodium alginate in the prepared premix solution is 6wt%-25wt%, for example, 10wt%-25wt%, 13wt%-20wt%, or 15wt%-20wt%.

[0077] In some embodiments, the kit may also include a medical device, such as a microcatheter and syringe, for injecting the premix and crosslinking agent into the target lesion.

[0078] In some embodiments, the kit may also include instructions for using the kit.

[0079] In some embodiments, the phase transition temperature of the premix is ​​20-37°C, preferably 22-35°C. In some embodiments, the gelation time of the premix at 37°C is 10-120 s, preferably 10-60 s.

[0080] In this embodiment, the lyophilizing agent is lyophilized using the following method: Cool to -5℃ to -10℃ and maintain for 1 h to 5 h; Then rapidly cool to -30℃ to -50℃ and maintain for 5 h to 15 h, then evacuate to 10 Pa to 40 Pa and maintain this vacuum level in subsequent steps; Slowly raise the temperature to -20℃ to 10℃ and maintain it for 30h-100h; Raise the temperature to 20°C to 35°C and maintain it for 5-20 hours.

[0081] Embolizing agents This application provides an embolizing agent that can rapidly solidify in the human body, has good gelation and degradation properties, and can be used for in vivo vascular embolization, such as tumor embolization therapy and in vivo hemostasis.

[0082] The preparation can be done using the premix provided in the embodiments of this application, or it can be conveniently prepared using the kit provided in the embodiments of this application.

[0083] In some embodiments, the embolic agent of this application is prepared by the following method: A premixed solution is provided, wherein the total mass fraction of poloxamer and sodium alginate is 6wt%-25wt%. Provide a crosslinking agent, which is an aqueous solution of a divalent or trivalent metal salt with a mass fraction of 2% to 8%; The premixed liquid is mixed with a crosslinking agent at a predetermined volume ratio to obtain an embolic agent.

[0084] In some embodiments, the embolic agent is in a gel state.

[0085] In some embodiments, the premix is ​​a solution comprising an aqueous solution of 6 wt%-25 wt% poloxamer and sodium alginate, and thus this solution is directly used as the premix and mixed with the crosslinking agent in a predetermined ratio. In other embodiments, the premix is ​​a lyophilizing agent, which is first mixed with a reconstituter to prepare a premix, and then mixed with the crosslinking agent in a predetermined volume ratio.

[0086] In some embodiments, the volume ratio of the premix to the crosslinking agent is 1:2 to 1:10, for example, any ratio within the range of 1:2, 1:3, 1:5, 1:6, 1:8, 1:10 or 1:2 to 1:10.

[0087] The premixed liquid and crosslinking agent are mixed at a predetermined rate via a coaxial dual-lumen microcatheter, which can adapt to in-situ curing in vivo and achieve excellent curing effect.

[0088] In some specific embodiments, when mixing with a coaxial dual-lumen microcatheter, the injection rate ratio of the premix to the crosslinking agent is 1:2 to 1:10. In some embodiments, the injection rate of the premix is ​​0.2-1.5 mL / min, and the injection rate of the crosslinking agent is 0.4-10 mL / min. In some embodiments, the distal end of the outer tube of the coaxial dual-lumen microcatheter is 1-10 mm longer than the distal end of the inner tube; the premix is ​​injected through the inner tube, and the crosslinking agent is injected through the gap between the outer and inner tubes.

[0089] This application also provides the application of the above-mentioned premix or kit in the preparation of embolic agents. The embolic agents are used for tumor embolization therapy.

[0090] Embolization therapy Furthermore, this application provides a method for tumor embolization therapy, comprising: providing a premixed solution, wherein the total mass fraction of poloxamer and sodium alginate in the premixed solution is 6wt%-25wt%, and the mass ratio of poloxamer to sodium alginate is 9:1-20:1; A crosslinking agent is provided, wherein the crosslinking agent is an aqueous solution of a divalent or trivalent metal salt with a mass fraction of 2% to 8%; The premixed solution and the crosslinking agent are injected into the subject at a predetermined volume ratio of 1:2 to 1:10.

[0091] In some embodiments, the premix and crosslinking agent are injected into arteries near the tumor via a coaxial dual-lumen microcatheter to block blood supply to the tumor and inhibit tumor growth. The specific concentration of the premix provided in this application has excellent injectability and can be conveniently injected using existing coaxial dual-lumen microcatheters. Furthermore, after mixing with the crosslinking agent, it exhibits good temperature sensitivity and curing properties, allowing it to solidify at a predetermined location at an ideal curing rate, thus achieving embolization therapy. In this application, there is no particular limitation on the type of dual-lumen microcatheter; those skilled in the art can select a suitable type based on the type of disease being treated.

[0092] In some exemplary embodiments, the injection rate ratio of the premix to the crosslinking agent is 1:2 to 1:10, for example, 1:2 to 1:5. For example, the injection rate of the premix is ​​0.2-1.5 mL / min, for example, 1-1.5 mL / min; the injection rate of the crosslinking agent is 0.4-10 mL / min, for example, 2-5 mL / min. In some embodiments, the distal end of the outer tube of the coaxial dual-lumen microcatheter is 1-10 mm longer than the distal end of the inner tube. The premix is ​​injected through the inner tube, and the crosslinking agent is injected through the gap between the outer and inner tubes. This promotes rapid contact between the premix and the crosslinking agent when the premix is ​​injected to the predetermined position, enabling better mixing and achieving a better curing effect. In some embodiments, the inner diameter of the inner tube of the coaxial dual-lumen microcatheter is 0.6-1.0 mm, and the inner diameter of the outer tube is 0.8-2 mm.

[0093] For example, the embolizing agent of this application can be used for embolization treatment of highly vascularized solid tumors, such as liver cancer.

[0094] The present invention is further illustrated below by way of specific embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods not specifically described in the following embodiments are performed according to conventional methods and conditions, or as selected in accordance with the product instructions.

[0095] The reagent list is shown in Table 1 below.

[0096] Table 1

[0097] Test method: Phase transition temperature: The viscosity change of the test solution in the range of 20-40℃ was measured using a rotational rheometer at a frequency of 1 Hz and a heating rate of 1 ℃ / min. The starting point of significant viscosity increase was recorded as the phase transition temperature.

[0098] Gelation time: Inject the test sample into a reagent bottle in a 37°C constant temperature water bath. Start timing after injection and continuously rotate the reagent bottle until the liquid in the bottle stops flowing. Record this time as the gelation time.

[0099] Viscosity at room temperature: Inject the test solution onto the surface of the rotational rheometer, set the temperature to 20℃ and the frequency to 1 Hz, and record the viscosity of the test sample under these conditions.

[0100] Degradation time: The premixed solution of the test sample and the crosslinking agent solution (5wt% calcium chloride solution) were simultaneously injected and mixed through a double-lumen microcatheter and injected into a reagent bottle containing PBS solution in a 37℃ constant temperature water bath. The volume ratio of the premixed solution injected to the volume of PBS solution in the bottle was 1:10. The mass of the premixed solution was used as the initial mass. During the process, the mass change of the remaining embolic agent in the bottle was continuously observed and measured until the mass loss of the embolic agent approached 100%. This time was recorded as the complete degradation time under this ratio.

[0101] Reconstitution time: Freeze-dry the test solution, reconstitute the freeze-dried powder to the predetermined concentration using water for injection as a solvent, observe the dissolution, and record the time required for complete dissolution to form a homogeneous solution.

[0102] The freeze-drying procedure used in this application embodiment is as follows: cooling to -5°C and holding for 2 hours, then rapidly cooling to -40°C and holding for 8 hours, then evacuating to 20 Pa and maintaining this vacuum level in subsequent steps, then slowly heating to -20°C and holding for 50 hours, then heating to 30°C and holding for 10 hours.

[0103] Example 1: Preparation of a solution-type premix In this embodiment, a solution-type premix was prepared using the components listed in Table 2, and the gelation properties, injection properties, and degradation properties of different premixes were evaluated.

[0104] Table 2

[0105] 1 The solution was mixed with a 5% calcium chloride solution at a volume ratio of 1:1, solidified, and then the degradation time was measured.

[0106] As can be seen from Table 2, the solution-type premixed liquid for vascular embolization provided in this application embodiment has a phase transition temperature below body temperature. Therefore, after injection into the human body, it can solidify in situ under the action of body temperature. Its viscosity at room temperature can meet the requirements of catheter injection, and the degradation time after implantation is longer than one month, so as to achieve a long-term ischemic necrosis treatment effect for tumors.

[0107] When the mass ratio of poloxamer to sodium alginate is within the range of 9:1-20:1, it exhibits good thermosensitive properties and gelling performance. Especially when the total solute concentration of the solution is 10-25 wt%, its phase transition temperature can be maintained within the range of 22-37℃. Therefore, it can form gels at a suitable rate at body temperature, and the viscosity at room temperature remains below 2.5 Pa·s, exhibiting good injectability. The gelation time is within the acceptable range for interventional therapy. The gel formed by directly mixing it with 5% calcium chloride and then solidifying it also has good embolization and degradation properties, making it suitable for use as a liquid formulation. According to groups C1-C3, when the mass ratio of poloxamer to sodium alginate is less than 9:1, the proportion of poloxamer is too low, resulting in poor thermosensitive response of the solution and difficulty in gelling at body temperature. When the mass ratio of poloxamer to sodium alginate is greater than 20:1, although it exhibits good thermosensitive properties, the gel strength is insufficient, and the degradation time is short, easily leading to recanalization before the completion of treatment, affecting the effectiveness of embolization therapy. Specifically, the comparisons between Y1 and Y12, Y14, and between Y3 and Y13 show that while adding a gelation accelerator to the solution shortens the gelation time to some extent, the degradation time is not significantly improved, and the viscosity of the solution at room temperature increases significantly, all exceeding 2.5 Pa·s, increasing the difficulty of injection. This is presumably because the gelation accelerator promotes cross-linking, thus acting as a thickener. Furthermore, the data for Y8 indicate that while adding p-toluenesulfonic acid can catalyze the grafting reaction between poloxamer and sodium alginate, the molecular structure of poloxamer changes due to the grafting reaction, reducing its thermosensitive properties and making rapid gelation difficult at body temperature. Therefore, a gelation accelerator is not essential in this application.

[0108] Example 2 Preparation of lyophilized premix In this embodiment, solutions were prepared according to the formulations listed in Table 3 and then lyophilized to obtain lyophilized premixes. When used, the lyophilized premixes can be reconstituted with a rehydrating solvent to different solute concentrations. In this embodiment, deionized water was used to reconstitute the lyophilized premixes to different concentrations to further investigate the basic performance of the premixes after being prepared as lyophilized agents. The results are shown in Table 4.

[0109] Table 3

[0110] Table 4

[0111] The inventors discovered in experiments that when poloxamer and sodium alginate are kept in a specific mass ratio and prepared as an aqueous solution with a total concentration of 2wt%-6wt%, the viscosity is significantly reduced, meeting the viscosity requirements of sterilization filtration processes. Furthermore, after lyophilization, the lyophilized premix can be reconstituted according to the required concentration before use. The reconstitution time is short, generally within 10-40 minutes, and it still maintains good gelation and degradation properties, possessing the performance of an embolic agent. Therefore, the premix provided in this application can be used to prepare lyophilized premixes to achieve membrane filtration sterilization, thereby significantly extending the shelf life, reducing storage requirements and transportation costs, and maintaining excellent ease of use.

[0112] Based on the results in Tables 3 and 4, it is further demonstrated that preparing a lyophilized agent by maintaining a specific mass ratio of poloxamer and sodium alginate to an aqueous solution with a total concentration of 2wt%-6wt% results in good injectability, gelation properties, and degradation performance after reconstitution, fully meeting the performance requirements of an embolic agent. If the total concentration of the solution is high, such as in Y29 where the solution-type premix from Example 1 is directly lyophilized, the viscosity before lyophilization is high, making membrane filtration sterilization impossible, and the reconstitution time after lyophilization is long, resulting in a high water content in the lyophilized product and a prolonged gelation time. Furthermore, the inventors found that lyophilized powders with a water content below 5%, especially below 2%, exhibit better reconstitution effects.

[0113] Example 3 Preparation of a two-component embolic agent In this embodiment, a two-component embolic agent was prepared by taking the premixed agent according to Table 5 and preparing a premixed liquid of a predetermined concentration. The premixed liquid was then mixed with crosslinking agents of different concentrations, and the gelation and embolization properties of the two-component embolic agent were evaluated. The results are shown in Table 6. The phase transition temperature and gelation time in Table 6 were measured after the addition of the crosslinking agent.

[0114] The preparation method of the premix includes: A1, A2, A3, and C1-1 are solution-type premixes, and the raw materials of a predetermined mass are directly prepared into a premix of a predetermined concentration; A4-A9 and C1-2 are freeze-dried premixes prepared according to Table 3 of Example 2, which are then reconstituted according to the solute concentration in Table 5 to obtain a premix of sodium alginate and poloxamer with a predetermined total concentration.

[0115] Table 5

[0116] Table 6

[0117] The data in Table 6 show that the premix provided in the embodiments of this application, after being prepared at a predetermined concentration and mixed with the crosslinking agent, all have a phase transition temperature below 36°C. They can rapidly gel at body temperature and quickly solidify after injection into the lesion to achieve embolization, preventing leakage into the bloodstream due to delayed solidification. Furthermore, the degradation time is greater than 60 days, resulting in a good embolization effect and reducing the likelihood of recanalization. In contrast, in Comparative Examples C1-1 and C1-2, the mass ratio of poloxamer to sodium alginate is greater than 20:1. Although the phase transition temperature is below 37°C, the gelation time is significantly prolonged, the solidification speed is slow, and the degradation time is short.

[0118] Example 4: Embolization Performance Evaluation Test Using a Dual-Lumen Microcatheter Preparation of premixed solution: Take 12g P407 and 1g sodium alginate, dissolve them in 500mL of water, freeze dry, and then reconstitute until the total solubility of poloxamer and sodium alginate is 15wt%.

[0119] Crosslinking agent: 3 wt% CaCl2 aqueous solution.

[0120] Dual-lumen microcatheter configuration (premixed solution injected through the inner tube, cross-linking agent injected through the gap between the outer and inner tubes): Model 1: Inner tube inner diameter 0.9 mm, outer tube inner diameter 1.6 mm, the far end of the outer tube is flush with the far end of the inner tube; Model 2: Inner tube inner diameter 0.9 mm, outer tube inner diameter 1.6 mm, outer tube distal end is 3 mm longer than inner tube distal end; Model 3: Inner tube inner diameter 0.9 mm, outer tube inner diameter 1.6 mm, the distal end of the outer tube is 1 mm shorter than the distal end of the inner tube; Model 4: Inner tube inner diameter 0.6mm, outer tube inner diameter 0.9mm, the far end of the outer tube is flush with the far end of the inner tube; Model 5: Inner tube inner diameter 0.6 mm, outer tube inner diameter 0.9 mm, outer tube distal end is 8 mm longer than inner tube distal end; Model 6: Inner tube inner diameter 0.6mm, outer tube inner diameter 0.9mm, the far end of the outer tube is 3mm shorter than the far end of the inner tube; The following experimental procedures were followed to conduct in vitro simulated embolism experiments and in vivo embolism experiments in large animals—white pigs—for each group of embolism experiments.

[0121] In vitro simulated embolization effect: such as Figure 1The diagram shows an in vitro simulated hepatic artery circulation device, made of transparent silicone tubing. A controlled-flow PBS solution serves as the simulated blood, flowing into the device from the common hepatic artery 1. The solution temperature is controlled at approximately 37°C. Embolizable hepatic artery branch areas (right limb 2 and left limb 3) are marked with yellow curves. During embolization testing, a liquid embolic agent is injected into the embolization site via a dual-lumen microcatheter combination. The agent coagulates at the target location, blocking blood flow in that area. Timing begins after embolization. During this time, a staining agent can be injected through the catheter to observe whether patency is restored and the staining agent flows through. If patency restoration is observed, the time is recorded as the embolization failure time for that sample, allowing for comparison of the in vitro embolization effects of different samples.

[0122] Evaluation of embolization effect in animals: Large white pigs were selected as the subjects of the experiment. Suitable branches of the hepatic or renal arteries were selected for embolization. Liquid embolizing agents containing contrast agents were injected into the target embolization site through a double-lumen microcatheter to form an embolus and block blood flow. After embolization, contrast agents were injected into the area at 0 / 1 / 3 / 7 / 14 / 28 / 56 / 72 days after the operation, and the embolization patency was observed under DSA (digital subtraction angiography). If patency was not restored, angiography was continued at subsequent times. If patency was restored, the time was recorded as the embolization patency time, and no further angiography was required. The embolization effects of different liquid embolizing agent samples in animals were compared in this way. The results are shown in Table 7.

[0123] Table 7

[0124] Based on the above results, it can be seen that the vascular embolization agent provided in this application embodiment can achieve in vivo embolization through injection via a dual-lumen microcatheter, achieving in-situ solidification at the distal end of the catheter. Furthermore, the embolization method provided in this application embodiment, using an injection rate ratio of 1:2 to 1:10 for the premixed solution and the cross-linking agent, with an injection rate of 0.2-1.5 mL / min for the premixed solution and 0.4-10 mL / min for the cross-linking agent, achieves excellent injection solidification effects, maintains a superior solidification rate, and avoids the inability to form stable cross-links due to blood flow during mixing, thus preventing stable embolization and facilitating recanalization. It also avoids excessively fast injection speeds, which can lead to excessive injection pressure and a rapid solidification rate, resulting in insufficient embolization volume and difficulty in maintaining long-term embolization. Furthermore, using a dual-lumen microcatheter with an outer tube longer than the inner tube allows the premixed solution and cross-linking agent to mix thoroughly within the catheter without being affected by blood flow, thus achieving sufficient cross-linking solidification and ensuring long-term embolization effects.

[0125] Example 5: Animal Tumor Model Comparative Embolization Effect Test Preparation of premixed solution: Take 12g P407 and 1g sodium alginate, dissolve them in 500mL of water, freeze dry, and then reconstitute until the total solubility of poloxamer and sodium alginate is 15wt%.

[0126] Crosslinking agent: Select a 3wt% CaCl2 aqueous solution. For dual-lumen microcatheter type 1, set the mixing ratio to 1:0.1. For type 2, set the mixing ratio to 1:5.

[0127] Animal model: A rabbit kidney tumor model (VX2) was selected. The premixed solution and cross-linking agent solution were mixed and solidified in the rabbit renal artery through a coaxial double-lumen microcatheter, and the embolization effect and tumor changes were observed.

[0128] Experimental results Figure 2 and Figure 3 As shown, Figure 2 CT imaging of rabbit renal tumor arteries 1-4 weeks after embolization showed that, for type 1, the tumor tissue slowly increased in size after 1 week of embolization, but there was no obvious high-density shadow in the renal cell carcinoma tissue. By 4 weeks, the tumor tissue increased rapidly and was difficult to distinguish from the surrounding tissue. For type 2, after 1 week of embolization, the tumor showed a crescent-shaped high-density shadow, and the tumor tissue did not increase significantly, indicating that the embolization agent successfully embolized the renal tumor tissue. As time went on, the crescent shape gradually decreased but still existed, and the tumor tissue did not increase significantly. This shows that the embolization agent of type 2 can remain in the rabbit renal tumor tissue for 4 weeks, demonstrating its medium- and long-term efficacy. Figure 3 Gross anatomical results of two groups of rabbit renal tumor arteries after embolization were presented. It was found that the renal tumors in group 1 were larger and had metastasized to multiple distant sites, while the tumors in group 2 had fewer distant metastases and were smaller. These results confirm that the embolic agent of group 2 can effectively achieve embolization and inhibition of solid tumors.

[0129] According to the premix, kit, and application of the embolic agent provided in this application, the premix uses a mass ratio of poloxamer to sodium alginate of 9:1-20:1, which can form an injectable solution with good gel properties during use and is convenient to use.

[0130] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A premix for preparing embolic agents, characterized in that, include: The premix consists of poloxamer and sodium alginate, wherein the mass ratio of poloxamer to sodium alginate is 9:1 to 20:1, and the premix is ​​a solution, wherein the poloxamer and sodium alginate together account for 6 wt% to 25 wt% of the total mass of the solution.

2. The premix according to claim 1, characterized in that, The premix does not include a gelling accelerator, which is selected from one or more of hydroxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, chitosan or its derivatives, carboxymethyl cellulose, polyethylene glycol, polyvinylpyrrolidone, p-toluenesulfonic acid, and zinc oxide.

3. The premix according to claim 1, characterized in that, The molecular weight of the poloxamer is 6000-20000 g / mol. Preferably, the number of oxyethylene units in the poloxamer is 50-200 and the number of oxypropylene units is 15-80.

4. The premix according to claim 1, wherein the solution comprises a solvent, the solvent being water and / or a contrast agent.

5. A kit for preparing a vascular embolization agent, characterized in that, Includes bottle A: containing the premix of any one of claims 1-4, and bottle B: containing a crosslinking agent, said crosslinking agent comprising a divalent or trivalent metal salt.

6. The reagent kit according to claim 5, characterized in that, The divalent metal salt is selected from at least one of calcium chloride, calcium nitrate, strontium chloride, calcium gluconate, calcium bicarbonate, calcium sulfate, calcium hydroxide, and calcium carbonate; the trivalent metal salt is selected from at least one of aluminum chloride and ferric nitrate; preferably, the crosslinking agent is an aqueous solution of divalent or trivalent metal salt with a mass fraction of 2%-8%.

7. A method for preparing an embolic agent, characterized in that, include: A premix is ​​provided, wherein the total mass fraction of poloxamer and sodium alginate in the premix is ​​6wt%-25wt%, and the mass ratio of poloxamer to sodium alginate is 9:1-20:

1. A crosslinking agent is provided, wherein the crosslinking agent is an aqueous solution of a divalent or trivalent metal salt with a mass fraction of 2% to 8%; The premixed liquid and the crosslinking agent are mixed at a predetermined volume ratio to obtain the embolic agent.

8. The preparation method according to claim 7, characterized in that, The volume ratio of the premixed liquid to the crosslinking agent is 1:2 to 1:

10.

9. The use of the premix as described in any one of claims 1-4 or the kit as described in any one of claims 5-6 in the preparation of embolic agents.

10. The application according to claim 9, characterized in that, The embolic agent is a liquid embolic agent used for tumor embolization therapy.

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