A foam sclerosing agent for treating low flow vascular malformations and a method for its preparation

Abstract

The application relates to the technical field of medicines, and particularly discloses a foam sclerosing agent for treating low-flow vascular malformations and a preparation method thereof. The foam sclerosing agent comprises a drug conjugate, a stabilizer, a water-solubility enhancer, a foaming gas and a solvent for injection. The drug conjugate is formed by covalently connecting polylauric alcohol and bleomycin through a citric anhydride bridge, thereby solving the problems of uneven drug distribution and poor synergy in physical mixing. The preparation method comprises the following steps: firstly, synthesizing the conjugate through esterification and amidation reaction, and then mixing the conjugate with excipients and foaming through the Tessari method. The conjugate formed by bridging two drugs through the citric anhydride can be synergistically released in the microenvironment of a lesion, thereby significantly improving the curative effect, reducing the single-drug dose and the toxic and side effects, and the foam preparation has high stability and clear development, and is suitable for precise interventional treatment under the guidance of color Doppler ultrasound.

Description

Technical Field

[0001] This invention belongs to the field of medical technology and relates to a foam sclerosing agent for treating low-flow-rate vascular malformations and its preparation method. Background Technology

[0002] Low-flow-rate vascular malformations (HLVs) are congenital vascular developmental abnormalities, primarily including venous malformations (VMs) and lymphatic malformations (LMs). These conditions do not resolve spontaneously and often worsen with age, leading to pain, bleeding, functional impairment, and cosmetic defects; in severe cases, they can even be life-threatening. Current treatment methods include surgical resection, laser therapy, and interventional sclerotherapy. Surgical treatment is the most effective, but due to its invasiveness and high recurrence rate, it is gradually being replaced by sclerotherapy.

[0003] Commonly used sclerosing agents in clinical practice, such as anhydrous ethanol, polidocanol, and bleomycin, each have their limitations. Polidocanol is a cleaning agent-type sclerosing agent that causes malformed blood vessels to close by destroying vascular endothelial cells, promoting thrombosis and fibrosis. Bleomycin is an antitumor antibiotic that promotes vascular wall fibrosis by causing DNA strand breaks and inhibiting cell division. Although both have certain therapeutic effects, there are still the following problems when used alone: ​​(1) the efficacy is limited, especially for diffuse, microcystic, or blood sinusoidal lesions; (2) the required drug dose is large, which can easily cause local or systemic adverse reactions, such as pain, swelling, skin necrosis, and pulmonary fibrosis; (3) the recurrence rate is high, and multiple treatments are often required. In order to overcome the shortcomings of monotherapy, attempts have been made to combine polidocanol and bleomycin in the existing technology. However, such combinations are mostly limited to physical mixing. Since the molecular structures, physicochemical properties, and mechanisms of action of the two drugs are very different, simple physical mixing may face compatibility stability challenges and it is difficult to ensure that the two drugs are evenly distributed in the lesion and achieve a true synergistic effect.

[0004] Therefore, there is an urgent need to develop a novel foam curing agent that can not only ensure the stability and compatibility of polidocanol and bleomycin in foam formulations, but also enable the two to produce a deep synergistic effect at the molecular and cellular levels through specific component design and preparation processes. This would significantly improve the efficacy while greatly reducing the dosage and corresponding toxic side effects of each single drug, ultimately providing a safer, more efficient, and standardized minimally invasive treatment solution for low-flow-rate vascular malformations. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a foam sclerosing agent for treating low-flow-rate vascular malformations and its preparation method. The core of this scheme lies in using citric anhydride molecules as key bridging agents. The active carboxyl groups of citric anhydride undergo esterification and amidation reactions with the hydroxyl groups of polidocanol and the amino groups of bleomycin, respectively, to form stable chemical conjugates. These conjugates are then grafted with hydroxypropyl-β-cyclodextrin using the remaining third carboxyl group on the citric anhydride to improve water solubility and biocompatibility. Finally, poloxamer 407 is introduced as a stabilizer during the foam preparation stage to jointly construct a highly stable foam system, thereby preparing a foam sclerosing agent with a deep synergistic effect. This design aims to achieve synchronous and synergistic release of polidocanol and bleomycin in the lesion microenvironment, thereby significantly improving treatment efficiency while greatly reducing the dosage of each single drug and related toxic side effects. Ultimately, this provides a minimally invasive treatment solution for low-flow-rate vascular malformations that is more effective, safer, and more reliable.

[0006] To achieve the above and other objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising a drug conjugate, a stabilizer, a water-soluble enhancer, a foaming gas, and an injectable solvent; the drug conjugate comprises the following raw materials in parts by weight: 10-20 parts of polidocanol, 11-22 parts of citric anhydride, and 10-20 parts of bleomycin, and its preparation method is as follows: (1) Under sterile, light-protected, and inert gas protection conditions, the prescribed amount of citric anhydride is dissolved in an appropriate amount of anhydrous dimethyl sulfoxide, a catalyst and the prescribed amount of polidocanol are added first, and the reaction is carried out at 30-40°C for 2-4 hours, so that one carboxyl group of citric anhydride undergoes an esterification reaction with the hydroxyl group of polidocanol to generate a polidocanol-citric anhydride intermediate; (2) Subsequently, the prescribed amount of bleomycin and a condensing agent are added to the above reaction system, the pH is adjusted to 7.0-8.0, and the reaction is continued at room temperature for 4-6 hours, so that the other carboxyl group of citric anhydride undergoes an amidation reaction with the amino group of bleomycin, and finally the drug conjugate is obtained.

[0008] Furthermore, the stabilizer is poloxamer 407; the water-soluble enhancer is hydroxypropyl-β-cyclodextrin; and the foaming gas is carbon dioxide or air, preferably air.

[0009] Furthermore, in the method for preparing the drug conjugate, the weight ratio of polidocanol, citric anhydride and bleomycin is 1:1.1:1.

[0010] Furthermore, the catalyst in the preparation method (1) of the drug conjugate is 4-dimethylaminopyridine, and the condensing agent in the preparation method (2) is 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride.

[0011] Furthermore, the solvent for injection is physiological saline or glucose injection solution, used to dissolve and dilute the drug.

[0012] This invention also provides a method for preparing a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising the following steps:

[0013] S1. Preparation of drug solution: Under aseptic conditions, take the drug conjugate prepared above, add the prescribed amount of poloxamer 407 and hydroxypropyl-β-cyclodextrin, dissolve and bring to volume with an injectable solvent, vortex and mix evenly to obtain a mixed drug solution;

[0014] S2. Foam preparation: Using the Tessari method, take one syringe to draw all the mixed liquid obtained in step S1, and take another syringe to draw a preset volume of foaming gas. Connect the two syringes through a three-way valve and inject back and forth rapidly 15-20 times at a frequency of 3-5 times per second until a uniform, fine, and stable white foam is formed, which is the foam hardener.

[0015] Furthermore, in step S2, the volume ratio of the mixed drug solution to the foaming gas is 1:2-6, preferably 1:4.

[0016] Preferably, in step S2, after 10 rapid injections, the channel of the three-way valve is narrowed and injection continues, which helps to produce higher quality foam.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) This invention abandons simple physical blending and innovatively uses citric anhydride as a "molecular linking bridge". Under the action of catalyst and condensing agent, one of its carboxyl groups undergoes esterification with the hydroxyl group of polidocanol, and the other carboxyl group undergoes amidation with the amino group of bleomycin, thereby covalently synthesizing a "polidocanol-citric anhydride-bleomycin" drug conjugate with a well-defined structure. This chemical reaction transforms two functionally independent drugs into a single new chemical entity, which fundamentally solves the problem of uneven drug distribution and asynchronous behavior in vivo when physically mixed, and lays a solid molecular foundation for achieving precise and synergistic drug delivery.

[0019] (2) The present invention uses citric anhydride to synthesize a drug conjugate with polidocanol and bleomycin, and then uses it to make a foam curing agent by gas foaming. When the foam curing agent is delivered to a low-flow-rate vascular malformation lesion, in the relatively hypoxic and acidic microenvironment commonly found in the lesion, the ester bond and amide bond in the drug conjugate can undergo specific hydrolysis, which can simultaneously release the active forms of polidocanol and bleomycin. Podocanol can rapidly destroy the vascular endothelial cell membrane, greatly increasing the efficiency of bleomycin entering the cell. The two work together to achieve a dual attack on the malformed blood vessel wall of "membrane attack" and "DNA damage", producing a synergistic killing effect far exceeding that of physical mixing.

[0020] (3) This invention uses poloxamer 407 as a stabilizer and adds hydroxypropyl-β-cyclodextrin as a water solubility enhancer. Poloxamer 407 can significantly reduce interfacial tension and synergistically stabilize the gas-liquid interface with the amphiphilic nature of the drug conjugate itself. Hydroxypropyl-β-cyclodextrin further improves the solubility and formulation uniformity of the conjugate through inclusion. Combined with the optimized Tessari preparation process, stable foam with fine and uniform bubbles and a significantly prolonged half-life can be prepared. When this foam is injected under the guidance of color Doppler ultrasound, it can be visualized more clearly and fill the abnormal cavity more persistently, ensuring accurate drug dosage and uniform distribution, and greatly improving the predictability and reproducibility of the treatment effect each time.

[0021] (4) Based on the synergistic effect brought about by the above chemical coupling, the total drug load required to achieve excellent therapeutic effect is significantly reduced, thereby directly reducing the risk of systemic toxicity caused by high doses of each single drug. At the same time, the prodrug design mitigates the immediate stimulation of the injection site by the free drug. Therefore, the present invention can effectively reduce the incidence of complications such as local swelling, pain, and necrosis that are common in existing physical therapy combinations, providing patients with a minimally invasive treatment option that is more effective and safer. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0023] Figure 1 This describes the Tessari method used in the preparation of the foam hardener of this invention.

[0024] Figure 2 This is a schematic diagram of ultrasound-guided lesion puncture during a clinical trial.

[0025] Figure 3 Images of patient 1 before undergoing ultrasound-guided foam sclerotherapy.

[0026] Figure 4Images of patient 1 after undergoing ultrasound-guided foam sclerotherapy.

[0027] Figure 5 Comparison of examination results before and after ultrasound-guided foam sclerotherapy for patient 2;

[0028] Figure 6 Images of patient 3 before ultrasound-guided foam sclerotherapy;

[0029] Figure 7 Images of patient 3 after undergoing ultrasound-guided foam sclerotherapy.

[0030] Figure 8 Images of patient 4 before ultrasound-guided foam sclerotherapy.

[0031] Figure 9 This is an image of patient 4 after undergoing ultrasound-guided foam sclerotherapy. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0034] The materials used in the following implementation are as follows: stabilizer is poloxamer 407, water-soluble reinforcing agent is hydroxypropyl-β-cyclodextrin, catalyst is 4-dimethylaminopyridine, condensing agent is 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and all other materials are new materials purchased from the market unless otherwise specified. Furthermore, the Tessari process for preparing the foam curing agent is as follows: Figure 1 As shown.

[0035] Example 1: This example provides a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising a drug conjugate, a stabilizer, a water-soluble enhancer, air, and physiological saline; the drug conjugate comprises the following raw materials in parts by weight: 10 parts polidocanol, 11 parts citric anhydride, and 10 parts bleomycin, and its preparation method is as follows: (1) Under sterile, light-protected, and nitrogen-protected conditions, citric anhydride is first dissolved in 30 parts by weight of anhydrous dimethyl sulfoxide, and 0.5 parts by weight of catalyst and polidocanol are added, and the solution is heated to 30 ppm. (1) React in a constant temperature water bath at ℃ for 2 hours to generate polidocanol-citric anhydride intermediate; (2) Then, bleomycin and 12 parts by weight of condensing agent were added to the above reaction system, the pH was adjusted to 7.0 with 1 mol / L sodium hydroxide solution, and the reaction was continued at room temperature for 4 hours. After the reaction was completed, the reaction solution was transferred into a dialysis bag with a molecular weight cutoff of 1000 Da, and purified water was dialyzed for 24 hours to remove small molecule byproducts and solvents. Then the dialysate was freeze-dried to obtain the drug conjugate.

[0036] This embodiment also provides a method for preparing a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising the following steps:

[0037] S1. Preparation of drug solution: Under aseptic conditions, take 1.0 g of the drug conjugate prepared above, add 1.0 g of stabilizer and 0.5 g of water-soluble enhancer, dissolve in physiological saline for injection and bring the volume to 10 mL, place on a vortex shaker and shake at 2500 rpm for 3 minutes to obtain a clear mixed drug solution.

[0038] S2. Foam preparation: Using the Tessari method, 10 mL of mixed drug solution is drawn with one syringe, and 20 mL of clean air filtered through a 0.22 μm microporous membrane is drawn with another syringe. The two syringes are connected through a three-way valve and injected rapidly back and forth at a frequency of 3 times per second. After 10 injections, the channel of the three-way valve is reduced to 1 / 2 of the original channel area, and injections are continued for 5 more times until a uniform, fine, and stable white foam is formed, which is the foam hardener.

[0039] Example 2: This example provides a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising a drug conjugate, a stabilizer, a water-soluble enhancer, air, and physiological saline; the drug conjugate comprises the following raw materials in parts by weight: 15 parts polidocanol, 16.5 parts citric anhydride, and 15 parts bleomycin, and its preparation method is as follows: (1) Under sterile, light-protected, and nitrogen-protected conditions, citric anhydride is first dissolved in 40 parts by weight of anhydrous dimethyl sulfoxide, and 0.8 parts by weight of catalyst and polidocanol are added, and then... (2) After reacting in a constant temperature water bath at 5℃ for 3 hours, a polidocanol-citric anhydride intermediate was generated; (3) Bleomycin and 18 parts by weight of condensing agent were added to the above reaction system, the pH was adjusted to 7.5 with 1 mol / L sodium hydroxide solution, and the reaction was continued at room temperature for 5 hours. After the reaction was completed, the reaction solution was transferred into a dialysis bag with a molecular weight cutoff of 1000 Da, and purified water was dialyzed for 24 hours to remove small molecule byproducts and solvents. Then the dialysate was freeze-dried to obtain the drug conjugate.

[0040] This embodiment also provides a method for preparing a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising the following steps:

[0041] S1. Preparation of drug solution: Under aseptic conditions, take 1.5g of the drug conjugate prepared above, add 1.5g of stabilizer and 1.0g of water-soluble enhancer, dissolve in physiological saline for injection and bring the volume to 15mL, place on a vortex shaker and shake at 2500rpm for 3 minutes to obtain a clear mixed drug solution.

[0042] S2. Foam preparation: Using the Tessari method, 15 mL of mixed drug solution was drawn with one syringe, and 60 mL of clean air filtered through a 0.22 μm microporous membrane was drawn with another syringe. The two syringes were connected through a three-way valve, and the mixture was rapidly injected back and forth 18 times at a frequency of 4 times per second. After 10 injections, the channel of the three-way valve was reduced to 1 / 2 of its original area, and the injection was continued for 8 more times until a uniform, fine, and stable white foam was formed, which is the foam hardener.

[0043] Example 3: This example provides a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising a drug conjugate, a stabilizer, a water-soluble enhancer, air, and physiological saline; the drug conjugate comprises the following raw materials in parts by weight: 20 parts polidocanol, 22 parts citric anhydride, and 20 parts bleomycin, and its preparation method is as follows: (1) Under sterile, light-protected, and nitrogen-protected conditions, citric anhydride is first dissolved in 50 parts by weight of anhydrous dimethyl sulfoxide, and 1.0 part by weight of catalyst and polidocanol are added, and the mixture is heated to 40°C. (1) The reaction was carried out in a constant temperature water bath at ℃ for 4 hours to generate polidocanol-citric anhydride intermediate; (2) Bleomycin and 24 parts by weight of condensing agent were added to the above reaction system, the pH was adjusted to 8.0 with 1 mol / L sodium hydroxide solution, and the reaction was continued at room temperature for 6 hours. After the reaction was completed, the reaction solution was transferred into a dialysis bag with a molecular weight cutoff of 1000 Da, and purified water was dialyzed for 24 hours to remove small molecule byproducts and solvents. Then the dialysate was freeze-dried to obtain the drug conjugate.

[0044] This embodiment also provides a method for preparing a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising the following steps:

[0045] S1. Preparation of drug solution: Under aseptic conditions, take 2.0 g of the drug conjugate prepared above, add 2.0 g of stabilizer and 1.5 g of water-soluble enhancer, dissolve in physiological saline for injection and bring the volume to 20 mL, place on a vortex shaker and shake at 2500 rpm for 3 minutes to obtain a clear mixed drug solution.

[0046] S2. Foam preparation: Using the Tessari method, 20 mL of mixed drug solution is drawn with one syringe, and 120 mL of clean air filtered through a 0.22 μm microporous membrane is drawn with another syringe. The two syringes are connected through a three-way valve, and the mixture is rapidly injected back and forth 20 times at a frequency of 5 times per second. After 10 injections, the channel of the three-way valve is reduced to 1 / 2 of its original area, and injections are continued for another 10 times until a uniform, fine, and stable white foam is formed, which is the foam hardener.

[0047] Example 4: This example provides a foam sclerosing agent for treating low-flow-rate vascular malformations. The difference between this example and Example 2 is that the foaming gas used is carbon dioxide. That is, the foam sclerosing agent includes a drug conjugate, a stabilizer, a water-soluble enhancer, carbon dioxide, and physiological saline. The drug conjugate includes the following raw materials in parts by weight: 15 parts polidocanol, 16.5 parts citric anhydride, and 15 parts bleomycin. The preparation method is as follows: (1) Under sterile, light-protected, and nitrogen-protected conditions, first dissolve citric anhydride in 40 parts by weight of anhydrous dimethyl sulfoxide, and then add... 0.8 parts by weight of catalyst and polidocanol were reacted in a constant temperature water bath at 35°C for 3 hours to generate polidocanol-citric anhydride intermediate; (2) Bleomycin and 18 parts by weight of condensing agent were added to the above reaction system, the pH was adjusted to 7.5 with 1 mol / L sodium hydroxide solution, and the reaction was continued at room temperature for 5 hours. After the reaction was completed, the reaction solution was transferred into a dialysis bag with a molecular weight cutoff of 1000 Da, and purified water was dialyzed for 24 hours to remove small molecule byproducts and solvents. Then the dialysate was freeze-dried to obtain the drug conjugate.

[0048] This embodiment also provides a method for preparing a foam sclerosing agent for treating low-flow-rate vascular malformations, comprising the following steps:

[0049] S1. Preparation of drug solution: Under aseptic conditions, take 1.5g of the drug conjugate prepared above, add 1.5g of stabilizer and 1.0g of water-soluble enhancer, dissolve in physiological saline for injection and bring the volume to 15mL, place on a vortex shaker and shake at 2500rpm for 3 minutes to obtain a clear mixed drug solution.

[0050] S2. Foam preparation: Using the Tessari method, 15 mL of the mixed drug solution was drawn with one syringe, and 60 mL of clean carbon dioxide filtered through a 0.22 μm microporous membrane was drawn with another syringe. The two syringes were connected through a three-way valve, and the solution was injected back and forth rapidly at a frequency of 4 times per second for 18 times. After 10 injections, the channel of the three-way valve was reduced to 1 / 2 of its original channel area, and the injection was continued for 8 more times until a uniform, fine, and stable white foam was formed, which is the foam hardener.

[0051] Example 5: This example provides a foam curing agent for treating low-flow-rate vascular malformations and its preparation method. The only difference from Example 2 is the volume ratio of the mixed drug solution to air in step S2 of the foam curing agent preparation method. In this example, the volume ratio of the mixed drug solution to air is 1:3. The specific steps are as follows:

[0052] S1. Preparation of drug solution: Under aseptic conditions, take 1.5g of the drug conjugate prepared above, add 1.5g of stabilizer and 1.0g of water-soluble enhancer, dissolve in physiological saline for injection and bring the volume to 15mL, place on a vortex shaker and shake at 2500rpm for 3 minutes to obtain a clear mixed drug solution.

[0053] S2. Foam preparation: Using the Tessari method, 15 mL of mixed drug solution was drawn with one syringe, and 45 mL of clean air filtered through a 0.22 μm microporous membrane was drawn with another syringe. The two syringes were connected through a three-way valve, and the mixture was rapidly injected back and forth 18 times at a frequency of 4 times per second. After 10 injections, the channel of the three-way valve was reduced to 1 / 2 of its original area, and the injection was continued for 8 more times until a uniform, fine, and stable white foam was formed, which is the foam hardener.

[0054] The remaining raw materials and preparation methods are the same as in Example 2.

[0055] Example 6: This example provides a foam curing agent for treating low-flow-rate vascular malformations and its preparation method. The only difference from Example 2 is the volume ratio of the mixed drug solution to air in step S2 of the foam curing agent preparation method. In this example, the volume ratio of the mixed drug solution to air is 1:5. The specific steps are as follows:

[0056] S1. Preparation of drug solution: Under aseptic conditions, take 1.5g of the drug conjugate prepared above, add 1.5g of stabilizer and 1.0g of water-soluble enhancer, dissolve in physiological saline for injection and bring the volume to 15mL, place on a vortex shaker and shake at 2500rpm for 3 minutes to obtain a clear mixed drug solution.

[0057] S2. Foam preparation: Using the Tessari method, 15 mL of mixed drug solution was drawn with one syringe, and 75 mL of clean air filtered through a 0.22 μm microporous membrane was drawn with another syringe. The two syringes were connected through a three-way valve, and the mixture was rapidly injected back and forth 18 times at a frequency of 4 times per second. After 10 injections, the channel of the three-way valve was reduced to 1 / 2 of its original area, and the injection was continued for 8 more times until a uniform, fine, and stable white foam was formed, which is the foam hardener.

[0058] Comparative Example 1: This comparative example provides a foam curing agent composed of a physical mixture of polidocanol and bleomycin. The raw materials are polidocanol, bleomycin hydrochloride for injection, poloxamer 407, hydroxypropyl-β-cyclodextrin, and physiological saline for injection. The preparation method is as follows:

[0059] S1: Preparation of drug solution: Under aseptic conditions, in a clean vial, first add 1.5 mL of polidocanol injection, then add 15 mg of bleomycin hydrochloride for injection, 1.5 g of poloxamer 407 and 1.0 g of hydroxypropyl-β-cyclodextrin, and finally add an appropriate amount of physiological saline for injection to bring the total volume to 15 mL. Place the vial on a vortex mixer and shake and mix at 2500 rpm for 5 minutes until all solids are completely dissolved to obtain a clear physical mixture of drugs.

[0060] S2: Foam preparation: Using the Tessari method, 15 mL of mixed drug solution is drawn with one syringe, and 60 mL of clean air filtered through a 0.22 μm microporous membrane is drawn with another syringe. The two syringes are connected through a three-way valve and injected back and forth rapidly at a frequency of 3 times per second. After 18 injections, the channel of the three-way valve is reduced to 1 / 2 of the original channel area, and injection is continued for 8 more times until uniform foam is formed, thus obtaining the physical mixed foam hardener.

[0061] Comparative Example 2: This comparative example provides a foam curing agent without stabilizers and water-soluble enhancers and its preparation method. The drug conjugate was prepared according to the method of Example 2, but when preparing the drug solution, the drug conjugate was only diluted to 15 mL with physiological saline, and poloxamer 407 and hydroxypropyl-β-cyclodextrin were not added. The subsequent foam preparation method was exactly the same as in Example 1.

[0062] Comparative Example 3: This comparative example only provides a conventional foam curing agent containing only polidocanol.

[0063] Comparative Example 4: This comparative example provides an injectable solution containing only bleomycin, without foaming treatment.

[0064] Experimental methods:

[0065] Foam performance testing: Key performance characteristics of the foam hardener samples prepared in Examples 1-6 and Comparative Examples 1-2 were characterized using a foam stability analyzer. Freshly prepared foam was rapidly injected into a standard quartz sample cell, and monitoring began immediately. Each sample was prepared in parallel and independently tested five times by the same operator strictly following the methods described in the examples. The foam half-life, foam water separation time, and foam fusion time were recorded, and the average values ​​were taken. The results are shown in Table 1.

[0066] Table 1. Results of foam performance tests

[0067]

[0068] In vitro drug release study: A Franz diffusion cell was used with a regenerated cellulose membrane as a barrier, and a phosphate buffer solution at pH 7.4 was used as the receiving solution. Samples were taken at predetermined time points at 37°C, and the cumulative release rate of bleomycin was determined by HPLC. The results are shown in Table 2.

[0069] Table 2. Cumulative release rate of bleomycin (%)

[0070]

[0071] In vitro cytotoxicity and synergistic anti-angiogenic effect experiment: Human umbilical vein endothelial cells were used as a model to simulate abnormal vascular endothelial cells. The cells were divided into six groups: blank control group, Example 2 group, Example 4 group, Comparative Example 1 group, Comparative Example 3 group, and Comparative Example 4 group. The cell proliferation inhibition rate after 24 hours of drug treatment was determined by the CCK-8 assay; the inhibition rate of endothelial cell tube formation in each group was determined by the Transwell chamber assay. The experimental results are shown in Table 3.

[0072] Animal experiment: A rabbit auricular vein sclerosis model was constructed and the rabbits were randomly divided into 6 groups: sham surgery group (injected with an equal volume of saline foam), Example 2 group, Example 4 group, Comparative Example 1 group, Comparative Example 3 group, and Comparative Example 4 group, with 10 rabbits in each group. Treatment was performed by injecting foam sclerosing agents under ultrasound guidance, with an injection volume to lesion volume ratio of 1:1. Changes in lesion volume and adverse reactions (redness, swelling, necrosis, etc.) were observed and recorded on days 7, 14, and 28 after treatment. On day 28, tissue samples were collected for pathological HE staining to observe the degree of vascular occlusion, inflammation, and fibrosis, and a pathological score (0-4 points) was assigned: 0 points (no change), 1 point (mild occlusion, <25%), 2 points (moderate occlusion, 25%-50%), 3 points (significant occlusion, 50%-75%), and 4 points (complete occlusion with fibrosis, >75%). The experimental results are shown in Table 4.

[0073] Table 3. In vitro cytotoxicity and synergistic anti-angiogenic effect experiments

[0074]

[0075] Table 4 Results of animal experiments

[0076]

[0077] As shown in Table 1, the foam half-life of Examples 1-3 is significantly longer than that of the comparative examples. This demonstrates that the present invention, by preparing "drug conjugates," alters the surface chemical properties of the drug, improving its compatibility with stabilizers and water-soluble solubilizers, thereby producing more stable and higher-quality foam, which is beneficial for the long-term retention of the drug within the lesion. Table 2 shows that the chemical conjugate of Example 2 exhibits obvious sustained-release characteristics, while Comparative Examples 1 (physical mixing) and 4 (bleomycin solution) show burst-release effects in the early stages. This indicates that chemical conjugation can prevent rapid drug release, which is beneficial for reducing systemic toxicity and prolonging the local action time. Table 3 shows that the examples of the present invention have the strongest inhibitory ability on cell proliferation, significantly exceeding that of the two single drugs and the physical mixing group. In the tube formation inhibition experiment, the inhibition rate of the examples is much higher than that of the physical mixing group. This indicates that the present invention, by covalently conjugating the drug, may have altered the way the drug enters the cell or synergistically interfered with cell signaling pathways, producing a significant synergistic effect that cannot be achieved by simple physical mixing. Table 4 shows the results analysis: After 28 days of treatment, the lesion volume reduction rate of the foam group containing the drug conjugate of the present invention reached 85.6%, significantly higher than that of other groups. Pathological sections showed that the vascular endothelial cells in the Example 2 group were completely destroyed, and the lumen was filled with dense fibrous tissue, resulting in the best occlusion effect. The efficacy of Example 4 was slightly less, possibly related to its slightly poorer foam stability as shown in Table 1, leading to a slightly shorter effective drug residence time. Meanwhile, no serious adverse reactions such as skin ulceration or tissue necrosis occurred in any of the example groups, confirming the safety of the formulation of the present invention.

[0078] Clinical trials:

[0079] Medical Records: Based on the above examples and comparative examples, the foam sclerosing agent prepared in Example 2 was used to treat patients diagnosed with low-flow vascular malformations. The selected cases of confirmed low-flow vascular malformations included patients aged 2 months to 39 years, with lesions located in the head, face, neck, trunk, and limbs. None of the cases underwent open surgery. Lesion sizes ranged from 0.8cm × 1cm × 0.8cm to 23cm × 6cm × 4.9cm. Diagnosis was based on a detailed medical history, clinical signs, color Doppler ultrasound, and MRI examinations. Only a portion of the cases are presented here.

[0080] Treatment methods: The anesthesia method is selected based on the location of the lesion, the patient's age, cooperation level, and tolerance: inhalation anesthesia, regional block anesthesia, general anesthesia, or direct treatment. Inhalation anesthesia is routinely used for children; direct injection is chosen for adults with small lesions; and regional block anesthesia or general anesthesia is chosen for large or diffuse lesions. The necessary foam sclerosing agent is prepared simultaneously with the start of anesthesia and used immediately. After anesthesia preparation, the surgical field is routinely disinfected with iodine solution, and sterile drapes are laid. During the procedure, ultrasound localization of the lesion is performed. Under ultrasound guidance, 2-20 scalp needles are inserted subcutaneously along the tangential direction through normal tissue at the edge of the lesion. Figure 2 As shown, after tracing a distance subcutaneously, the needle is inserted into the center of the lesion. Successful puncture results in blood return. For venous malformations, a tourniquet is applied to the distal limb before surgery. Blood is aspirated until the vein collapses, then the medication is injected evenly. For large cystic lymphatic malformations, a thicker syringe needle is used for direct puncture, the cyst contents are aspirated, and then the medication is injected evenly. For small cystic lymphatic malformations, the medication is injected evenly directly. Real-time dynamic ultrasound shows foam gradually filling the entire malformed lumen. After standing for 2-5 minutes, no blood return is observed, indicating significant resistance to the foam sclerosing agent injection. The medication dosage for the extremities, around the eyes, nose, lips, and ears slightly exceeds half the lesion volume, while the dosage for the head, face, neck, and trunk exceeds two-thirds of the lesion volume. After needle removal, pressure is applied to the puncture site for 5-10 minutes, with a slightly longer pressure time for the head and face until there is no bleeding. Post-operatively, observe changes in lesion volume, surface color, and local skin temperature. Treat any discomfort promptly. One month after injection, patients should have an outpatient follow-up ultrasound and physical examination. If necessary, an MRI should be performed once every two treatment cycles.

[0081] Efficacy evaluation criteria: Three criteria are primarily established: markedly effective, effective, and ineffective. Markedly effective: After treatment, the patient's clinical manifestations are not obvious, pain is reduced, low-flow-rate vascular malformations are significantly improved, mobility is enhanced, and quality of life is high. Effective: After a period of treatment, the impact of low-flow-rate vascular malformations gradually decreases, and after clinical examination, various indicators gradually approach normalization. Ineffective: Despite appropriate treatment, the patient's clinical manifestations of low-flow-rate vascular malformations remain prominent, and there is no significant difference from before treatment; continued treatment or a change in treatment plan is required.

[0082] Case 1: Patient Ye XX: Male, 2 years and 4 months old, admitted to the hospital due to "gradually increasing cyanotic mass on the right lower extremity and buttock for 2 months". Present Illness: The patient's family reported that two months prior, they accidentally discovered a soft, non-tender, and non-ulcerated cyanotic mass on the child's right lower extremity and buttock. They initially mistook it for a birthmark and did not seek any treatment. Subsequently, the lesion gradually enlarged, became noticeably raised, and gradually spread to the scrotum. Six days prior, the scrotal skin became cyanotic, blanching upon pressure, and the scrotal emptying test was positive. Skin temperature was normal, with no ulceration or bleeding. The patient then presented to our hospital. After physical examination, the outpatient physician performed a superficial organ ultrasound, which revealed multiple abnormal echoes in the subcutaneous tissue of the right perineum and thigh, suggesting a possible vascular malformation. Hospitalization was recommended. Clinical Diagnosis: Vascular malformation. The patient subsequently underwent foam sclerotherapy embolization under ultrasound guidance. Comparison before and after treatment was performed. Figure 3 and Figure 4 As shown, the vascular malformation of the patient improved significantly after clinical examination.

[0083] Case 2: Patient Zhao XX, female, 5 years old, was admitted to the hospital due to "a bluish-purple mass on the tip of her nose for 4 months". Present Illness: Four months prior to admission, the patient's family noticed clusters of purplish-red patches on the skin of her nose tip. The patches had irregular edges, were not raised above the skin surface, and did not blanch upon pressure. There was no ulceration or bleeding on the surface of the skin. Symptomatic and supportive treatment, including topical application of traditional Chinese medicine, was given, but the symptoms did not improve. During the course of the illness, the area of ​​the erythema gradually increased with the child's growth and development, and the color deepened to bluish-purple. She then came to our hospital for examination. After physical examination, the outpatient physician recommended hospitalization. Clinical Diagnosis: Vascular malformation (nasal tip). Treatment was then performed under ultrasound guidance using foam sclerotherapy. Figure 5 As shown, the lesion has significantly shrunk.

[0084] Case 3: Patient Yang XX, male, 2 months old, was admitted to the hospital due to "a gradually increasing soft mass on the right cheek for 1 month". Present Illness: The family noticed a soft mass on the right cheek shortly after birth. The surface skin was not ulcerated or bleeding, and there was no tenderness. The mass changed shape with the patient's position. The patient was initially seen in the pediatric department and referred to our department. Due to the infant's premature birth and low birth weight, our outpatient physician, after examination, determined that the infant was not currently suitable for treatment and advised the family to observe the infant for half a month to one month before returning for further consultation. During the course of the illness, the mass rapidly increased in size, leading to admission. A plain MRI revealed a soft tissue mass in the right parotid gland area, with indistinct borders extending into the right parapharyngeal space, highly suggestive of a vascular malformation, predominantly lymphatic. After examination and review of the MRI, the outpatient physician recommended hospitalization. The clinical diagnosis was confirmed as lymphangioma (right cheek). Treatment with foam sclerotherapy under ultrasound guidance was then performed. Figure 6 and Figure 7 As shown, the lesion has significantly shrunk.

[0085] Case 4: Patient Shi XX, male, 4 years and 5 months old, was admitted to the hospital due to "a bluish-purple swelling on the right palm for more than 8 months". Present Illness: Eight months prior to admission, a dark red swelling appeared on the right palm without any obvious cause. Initially, it was small, with indistinct borders, slightly protruding from the skin surface, non-tender, and did not blanch on pressure. There was no ulceration or bleeding on the surface of the skin, and it was not taken seriously or treated. Later, the lesion rapidly enlarged, prompting him to seek medical attention at our hospital. Physical examination by our outpatient physician revealed significant asymmetry between the patient's hands, with significant swelling of the right palm, no palpable fluctuation, a bluish-purple swelling and vascular shadows, positive tenderness, no ulceration or bleeding, and significant swelling of the fingers. A plain MRI scan revealed a subcutaneous soft tissue mass on the radial side of the right palm, most likely a vascular malformation. Hospitalization was recommended to confirm the clinical diagnosis: vascular malformation (right hand). The patient then underwent foam sclerotherapy under ultrasound guidance. Comparison before and after treatment was performed. Figure 8 and Figure 9 As shown, the lesions in the patient have shrunk significantly after clinical examination.

[0086] Treatment Results: Follow-up ultrasound examinations were performed 3-12 months after treatment, and MRI scans were performed if necessary. These examinations were largely consistent with preoperative examinations to facilitate postoperative comparison and analysis, and to assess the effectiveness of the treatment. Using the same ultrasound diagnostic instrument and the same color Doppler ultrasound physician as the preoperative examination, and combined with clinical manifestations, the efficacy was evaluated. The results showed that 91.6% of patients achieved significant efficacy, 5.6% achieved efficacy, and only 2% experienced no ineffectiveness. Furthermore, no recurrence of the condition was observed during the 3-12 month follow-up after treatment.

[0087] The above clinical observation results show that the foam sclerosing agent prepared in this invention, when used under ultrasound guidance, has the characteristics of significant efficacy, good safety, and mild complications in the treatment of low-flow-rate vascular malformations.

[0088] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0089] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A foam sclerosing agent for treating low-flow-rate vascular malformations, characterized in that, The product includes a drug conjugate, a stabilizer, a water-soluble enhancer, a foaming gas, and an injection solvent. The drug conjugate comprises the following raw materials in parts by weight: 10-20 parts of polidocanol, 11-22 parts of citric anhydride, and 10-20 parts of bleomycin. The preparation method is as follows: (1) Dissolve citric anhydride in anhydrous dimethyl sulfoxide, add the catalyst 4-dimethylaminopyridine to react with polidocanol, and obtain a polidocanol-citric anhydride intermediate; (2) Subsequently, add bleomycin and the condensing agent 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride to the above reaction system, adjust the pH to 7.0-8.0, continue the reaction, and finally obtain the drug conjugate.

2. The foam sclerosing agent for treating low-flow-rate vascular malformations according to claim 1, characterized in that, The stabilizer is poloxamer 407; the water-soluble enhancer is hydroxypropyl-β-cyclodextrin; and the foaming gas is air or carbon dioxide.

3. A foam sclerosing agent for treating low-flow-rate vascular malformations according to claim 1, characterized in that, In the preparation method of the drug conjugate, the weight ratio of polidocanol, citric anhydride and bleomycin is 1:1.1:

1.

4. A foam sclerosing agent for treating low-flow-rate vascular malformations according to claim 1, characterized in that, The solvent for injection is physiological saline or glucose injection solution.

5. A method for preparing a foam sclerosing agent for treating low-flow-rate vascular malformations according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Preparation of drug solution: Take the drug conjugate, stabilizer and water-soluble enhancer, dissolve and dilute with an injectable solvent, vortex and mix evenly to obtain a mixed drug solution; S2. Foam preparation: Using the Tessari method, the mixed drug solution and foaming gas are injected rapidly back and forth at a volume ratio of 1:2-6 through a three-way valve at a frequency of 3-5 times per second. After 10 rapid injections, the channel of the three-way valve is reduced, and injection is continued until white foam is formed, which is the foam hardener.

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