Preparation method and application of endoscopically delivered aggregate powder for preventing digestive tract stenosis after endoscopic submucosal dissection

Abstract

The invention belongs to the technical field of biological materials, and particularly relates to a preparation method and application of agglomerate powder capable of being delivered under an endoscope for preventing digestive tract stenosis after endoscopic submucosal dissection. The preparation method comprises the following steps: dissolving a polysaccharide compound in a solvent, and adding unsaturated carboxylic acid anhydride for graft modification; respectively dissolving the modified polysaccharide and the hydrophilic polymer, and mixing; preparing a suspension containing a polyphenol compound and a therapeutic active substance; and mixing the mixed solution and the suspension until phase separation, collecting a condensed phase, and performing freeze drying and grinding treatment to obtain condensed powder. The aggregate powder has excellent wet tissue adhesion capacity, can be directly delivered to the surface of a wound through an endoscope working channel, forms a protective barrier, slowly releases treatment active substances, inhibits local inflammatory response and tissue fibrosis, effectively prevents digestive tract endoscopic submucosal dissection postoperative stenosis, and is particularly suitable for preventing esophageal ESD postoperative stenosis.

Description

Technical Field

[0001] This invention belongs to the field of biomaterials technology, specifically relating to a method for preparing and applying an endoscopically deliverable aggregate powder for preventing endoscopic stenosis after endoscopic submucosal dissection. Background Technology

[0002] Endoscopic submucosal dissection (ESD), as a mature minimally invasive treatment method, has been widely used in the treatment of early-stage gastrointestinal cancers and precancerous lesions. However, post-ESD gastrointestinal stricture remains one of its major complications, especially when the circumferential resection exceeds 75% or the longitudinal resection length exceeds 3 cm, the incidence of stricture can be as high as 70%-90%. Among these, esophageal stricture is the most common, seriously affecting patients' quality of life. The mechanisms of post-ESD gastrointestinal stricture mainly include: 1) excessive inflammatory response in the exposed muscular layer after mucosal resection, leading to fibroblast proliferation and collagen deposition; 2) incomplete epithelial regeneration, resulting in delayed wound healing; and 3) excessive tissue contraction during wound contraction. These mechanisms collectively promote the fibrotic process, ultimately leading to the formation of gastrointestinal stricture.

[0003] Currently, clinical measures to prevent gastrointestinal stricture after ESD mainly include: 1) glucocorticoid therapy, such as local injection or oral prednisone (30-40 mg daily for 8-12 weeks); 2) endoscopic balloon dilation; and 3) biodegradable stent implantation. However, these methods all have significant limitations. Long-term use of glucocorticoids can cause systemic adverse reactions such as osteoporosis, diabetes, immunosuppression, and gastrointestinal ulcers; local injection increases the risk of esophageal perforation and local overdose. Balloon dilation requires multiple procedures (average 6-8 times), causing significant patient discomfort, and the dilation itself may cause new tissue damage and inflammatory reactions. Stent implantation carries risks such as displacement, impaction, and secondary injury.

[0004] In recent years, biomaterials have shown promising applications in preventing gastrointestinal stenosis after ESD (endoscopic submucosal dissection). Studies have shown that biomaterials such as cell sheets, collagen scaffolds, hydroxypropyl methylcellulose, and hyaluronic acid have certain effects in preventing stenosis. However, these materials still face many challenges in clinical application: 1) it is difficult to achieve long-term stable adhesion in the dynamic environment of the gastrointestinal tract; 2) the limitations of the endoscopic working channel impose strict requirements on the material delivery method; 3) the synergistic mechanism between biomaterials and drugs is still unclear. Summary of the Invention

[0005] This invention aims to address the problems existing in the prior art by providing a method for preparing and applying an endoscopic delivery aggregate powder for preventing gastrointestinal stenosis after endoscopic submucosal dissection. This aggregate powder possesses excellent tissue adhesion properties, controllable degradation characteristics, and sustained drug release function, effectively preventing gastrointestinal stenosis after endoscopic submucosal dissection.

[0006] To achieve the above objectives, the present invention employs the following technical solutions.

[0007] In a first aspect, the present invention provides a method for preparing endoscopically delivered aggregate powder to prevent gastrointestinal stricture after endoscopic submucosal dissection, comprising the following steps: Step 1: Dissolve the polysaccharide compound in a solvent to obtain a polysaccharide solution; Step 2: Add unsaturated carboxylic anhydride to the polysaccharide solution to carry out a grafting reaction, and obtain the grafted modified polysaccharide compound after treatment; Step 3: Dissolve the grafted polysaccharide compound in an aqueous medium to obtain a first aqueous solution with a mass concentration of 1%-5% (w / v); dissolve the hydrophilic polymer in an aqueous medium to obtain a second aqueous solution with a mass concentration of 10%-100% (w / v). Step 4: Mix the first aqueous solution and the second aqueous solution to obtain a mixed solution; Step 5: Prepare an aqueous suspension containing polyphenolic compounds and therapeutic active substances in a mass ratio of 50:1 to 1:10. Step 6: Mix the mixed solution with the aqueous suspension and stir until phase separation occurs. Centrifuge at 6000 rpm for 10-30 minutes, collect the aggregated phase, and obtain aggregated powder after freeze-drying and grinding.

[0008] Further, in step 1, the polysaccharide compound is one or more combinations of chitosan, chitin, hyaluronic acid, alginate, starch, cellulose and its derivatives, and glycosaminoglycans.

[0009] Furthermore, in step 1, the solvent is deionized water, dilute acetic acid solution, dilute hydrochloric acid solution, urea aqueous solution, etc.

[0010] Furthermore, in step 2, the unsaturated carboxylic anhydride is one or more combinations of methacrylic anhydride, acrylic anhydride, maleic anhydride and their derivatives.

[0011] Furthermore, in step 2, the mass ratio of unsaturated carboxylic anhydride to polysaccharide compound is 0.2-5; the reaction time is 0.5-24 hours; and the reaction temperature is room temperature to 60°C.

[0012] Further, in step 3, the hydrophilic polymer is one or more combinations of polyethylene glycol, tetra-armed polyethylene glycol, hexa-armed polyethylene glycol, octa-armed polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, and their copolymers.

[0013] Furthermore, in step 4, the volume ratio of the first aqueous solution to the second aqueous solution is 0.5-10.

[0014] Furthermore, in step 5, the polyphenolic compound is one or more combinations of tannic acid, catechin, gallic acid, caffeic acid, ferulic acid, and chlorogenic acid.

[0015] Furthermore, in step 5, the therapeutically active substance is one or more combinations of glucocorticoids, anti-inflammatory drugs, anti-fibrotic drugs, growth factors, and cytokine regulators.

[0016] Furthermore, in step 6, the volume ratio of the mixed solution to the aqueous suspension is 0.25-8; the freeze-drying time is 24-96 hours.

[0017] In a second aspect, the present invention provides an endoscopic delivery aggregate powder prepared by the above method for preventing gastrointestinal stenosis after endoscopic submucosal dissection.

[0018] Furthermore, the particle size of the aforementioned aggregate powder is 10-500 μm.

[0019] Furthermore, the aforementioned aggregate powder exhibits degradation characteristics under physiological conditions.

[0020] Furthermore, the aforementioned aggregate powder forms an adhesion layer upon contact with tissue, and its tissue adhesion strength is 30-200 kPa.

[0021] A third aspect of the present invention provides the use of the above-described endoscopic delivery of agglomerated powder in the prevention of stricture following endoscopic mucosal dissection of the esophagus.

[0022] A fourth aspect of the present invention provides the use of the above-described endoscopically deliverable aggregate powder in preventing stenosis following endoscopic mucosal dissection of gastric tissue.

[0023] A fifth aspect of the invention provides the use of the above-described endoscopically deliverable aggregate powder in preventing stenosis after colorectal endoscopic mucosal dissection.

[0024] This invention is based on the following technical approach: utilizing the strong adhesion properties of polysaccharide compounds modified with unsaturated carboxylic anhydride grafts, combined with the network structure of hydrophilic polymers and the cross-linking ability of polyphenolic compounds, a novel aggregate material is constructed. This material can: 1) achieve strong adhesion to digestive tract tissues through multiple mechanisms such as physical entanglement, hydrogen bonding, hydrophobic interactions, and covalent cross-linking; 2) form a protective barrier to prevent irritation of the wound by digestive tract contents; and 3) achieve local sustained-release therapy by loading therapeutic active substances, inhibiting inflammatory responses and fibrosis. Finally, this aggregate powder can be directly delivered to the target site through the endoscopic working channel, demonstrating a significant effect in preventing digestive tract stenosis after ESD surgery.

[0025] Specifically, the adhesion mechanism of the present invention is based on the following multiple effects: 1) The carboxyl groups introduced by the grafted unsaturated carboxylic anhydride can form covalent bonds with the amino groups of tissue proteins, significantly enhancing wet adhesion; 2) The phenolic hydroxyl groups in polyphenolic compounds can form a large number of hydrogen bonds and hydrophobic interactions with proteins and glycoproteins in tissues, and undergo oxidative cross-linking under physiological conditions, further enhancing the binding force between the material and the tissue; 3) The hydrophilic polymer forms a tight internal network structure with polysaccharides and polyphenols, improving the mechanical stability and viscoelasticity of the material, enabling it to adapt to the dynamic environment of the digestive tract.

[0026] Compared with the prior art, the present invention has the following significant advantages.

[0027] The endoscopic delivery of the aggregate powder of the present invention has been demonstrated in vivo in animal models to prevent postoperative stricture of the digestive tract after ESD.

[0028] 1. The endoscopically deliverable aggregate powder constructed in this invention is suitable for tissue defects of any shape; it is easy to operate during application, can be directly applied to the in-situ site of the digestive tract defect through the narrow endoscope channel, and can be applied immediately after surgery.

[0029] 2. The endoscopic delivery aggregate powder of the present invention has excellent wet tissue adhesion ability and can adhere stably to the surface of the artificial ulcer in the digestive tract for a long time. Currently, the adhesion strength of commercial fibrin glue to esophageal tissue in the test model is mostly between 15-30 kPa. The powder of the present invention can fully meet the mechanical requirements of covering the entire critical healing cycle of the ulcer after a single endoscopic administration, thereby technically ensuring the avoidance of repeated operations and reducing the economic and psychological burden on patients.

[0030] 3. The endoscopic delivery of aggregate powder of the present invention can provide sustained in-situ drug release for a long time. The cumulative drug release rate of the present invention is within the common effective window of an ideal sustained-release system, which can effectively increase the local drug concentration, enhance the therapeutic effect of the drug, and reduce the systemic side effects caused by the drug.

[0031] 4. The endoscopic delivery of aggregate powder of the present invention has the advantages of good biocompatibility and low cytotoxicity.

[0032] 5. The endoscopic delivery of aggregate powder of the present invention has the effects of anti-oxidation and reducing oxidative stress in damaged tissues. Attached Figure Description

[0033] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0034] Figure 1 The image shows the adhesion strength test results of the endoscopically deliverable aggregate powder prepared in Example 1 of this invention to the esophageal submucosa. The vertical axis represents the adhesion strength value (kPa).

[0035] Figure 2 The results of the cell biocompatibility test for the endoscopically deliverable aggregate powder prepared in Example 1 of this invention are shown (the control group was cultured in complete culture medium, and the treatment group was cultured in complete culture medium containing the material). The left side shows the live / dead cell staining images under a fluorescence microscope (green represents live cells, and red represents dead cells), and the right side shows the CCK-8 experiment analysis results. The horizontal axis represents the culture time (24h, 48h, 72h), and the vertical axis represents the cell viability (%).

[0036] Figure 3 This study evaluates the preventive effect of the endoscopically deliverable aggregate powder prepared in Example 1 of the present invention on a Bama miniature pig esophageal ESD postoperative stenosis model. The figure shows the esophageal lumen diameter observed endoscopically within 28 days after surgery. The control group (surgery group only) showed significant stenosis, while the treatment group (group with aggregate powder applied to the postoperative wound) maintained good esophageal patency.

[0037] Figure 4 The images show immunohistochemical staining of esophageal tissue sections treated with endoscopically deliverable agglomerate powder, prepared in Example 1 of this invention. The images display the expression of fibrosis-related proteins (α-SMA, collagen I, collagen III, and fibronectin). Brown areas represent positive staining, and blue represents cell nuclei. The control group (surgery group only) showed extensive positive staining, while the treatment group (postoperative wound agglomerate powder application group) showed decreased staining, indicating a reduced degree of fibrosis. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] Experimental methods not specified in the examples are generally performed under standard conditions and as described in the manual, or as recommended by the manufacturer; the equipment, materials, reagents, etc. used are commercially available unless otherwise specified.

[0040] In a first aspect, the present invention provides a method for preparing an endoscopically deliverable aggregate powder for preventing stenosis following endoscopic submucosal dissection of the digestive tract, comprising the following steps: Step 1: Dissolve at least one polysaccharide compound in a solvent to obtain a polysaccharide solution; Step 2: Add unsaturated carboxylic anhydride to the polysaccharide solution to carry out a grafting reaction, and obtain the grafted modified polysaccharide compound after treatment; Step 3: Dissolve the grafted polysaccharide compound in an aqueous medium to obtain a first aqueous solution with a mass concentration of 1%-5% (w / v); dissolve the hydrophilic polymer in an aqueous medium to obtain a second aqueous solution with a mass concentration of 10%-100% (w / v). Step 4: Mix the first aqueous solution and the second aqueous solution to obtain a mixed solution; the volume ratio of the first aqueous solution to the second aqueous solution is 0.5-10. Step 5: Prepare an aqueous suspension containing polyphenolic compounds and therapeutic active substances in a mass ratio of 50:1 to 1:10. Step 6: Mix the mixed solution with the aqueous suspension and stir until phase separation occurs. Centrifuge at 6000 rpm for 10-30 minutes, collect the aggregated phase, and freeze-dry and grind it to obtain aggregate powder. The volume ratio of the mixed solution to the aqueous suspension is 0.25-8. The freeze-drying time is 24-96 hours.

[0041] In this invention, the polysaccharide compound is selected from at least one of chitosan, chitin, hyaluronic acid, alginate, starch, cellulose and its derivatives, and glycosaminoglycans.

[0042] In one embodiment of the present invention, the unsaturated carboxylic anhydride is selected from at least one of methacrylic anhydride, acrylic anhydride, maleic anhydride, and their derivatives. The mass ratio of unsaturated carboxylic anhydride to polysaccharide is 0.2-5; the reaction time is 0.5-24 hours; and the reaction temperature is room temperature to 60°C.

[0043] In one embodiment of the present invention, the hydrophilic polymer is selected from at least one of polyethylene glycol, tetra-armed polyethylene glycol, hexa-armed polyethylene glycol, octa-armed polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, and copolymers thereof.

[0044] In one embodiment of the present invention, the polyphenolic compound is selected from at least one of tannic acid, catechin, gallic acid, caffeic acid, ferulic acid, and chlorogenic acid.

[0045] In one embodiment of the present invention, the therapeutically active substance is selected from at least one of glucocorticoids, anti-inflammatory drugs, anti-fibrotic drugs, growth factors, and cytokine regulators.

[0046] As one embodiment of the present invention, the stenosis of the digestive tract after endoscopic submucosal dissection is esophageal stenosis after endoscopic submucosal dissection, gastric stenosis after endoscopic submucosal dissection, or colorectal stenosis after endoscopic submucosal dissection.

[0047] Example 1.

[0048] Chitosan was dissolved in acetic acid solution to obtain a chitosan solution with a mass concentration of 3%. Methacrylic anhydride was slowly added to the chitosan solution at a mass ratio of 3.5:1. The reaction was carried out at 40°C for 3 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic acid-grafted chitosan. Methacrylic acid-grafted chitosan and polyethylene glycol were dissolved separately in deionized water, yielding solutions with mass concentrations of 2% (w / v) and 100% (w / v), respectively. These solutions were then mixed in equal volumes at room temperature with stirring to obtain a mixed solution. Tannic acid was dissolved in deionized water at room temperature under stirring to prepare a tannic acid solution. After adding glucocorticoids and mixing evenly, the solution was mixed with a methacrylic acid-grafted chitosan-polyethylene glycol mixture at a volume ratio of 3:2 and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 20 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 96 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0049] The prepared powder exhibited an adhesion strength of 89.93 ± 6.44 kPa upon contact with the submucosa of the porcine esophagus. Degradation tests in simulated gastric juice solution at 37°C showed that the aggregated powder degraded slowly, decreasing to approximately 42.67% of its initial mass by day 40. In vitro drug release experiments demonstrated sustained drug release over 14 days, with a release rate of 81.37 ± 4.86% measured on day 14. This sustained drug release characteristic of the material minimizes systemic toxicity while maintaining local drug concentration, thereby improving therapeutic efficacy.

[0050] Figure 1 The adhesion properties of the aggregate powder in Example 1 were demonstrated, proving that the drug-loaded aggregate powder delivered endoscopically has strong adhesion to the submucosal tissue of the esophagus.

[0051] Figure 2 The biosafety of the aggregate powder in Example 1 was demonstrated.

[0052] Figure 3 This study demonstrates the preventive effect of the drug-loaded agglomerate powder in Example 1 on post-ESD esophageal stricture. Using Bama miniature pigs as a model of post-ESD esophageal stricture, during follow-up assessment after ESD, the control group (surgery only) developed severe esophageal stricture on day 28. In contrast, the treatment group (post-operative spraying with drug-loaded agglomerate powder) showed reduced stricture severity and improved luminal patency. This demonstrates that endoscopically deliverable drug-loaded agglomerate powder can prevent post-ESD esophageal stricture.

[0053] Figure 4 Immunohistochemical analysis of tissue sections near artificial esophageal ulcers treated with the agglomerate powder in Example 1 is presented. Immunohistochemical analysis was performed on the expression levels of fibrosis-related proteins in the esophageal tissue samples, including α-SMA, fibronectin, collagen I, and collagen III. Compared with the control group, the expression of fibrosis-related proteins in the treatment group was significantly reduced, demonstrating the anti-fibrotic effect of the agglomerate powder and indicating its significant efficacy in preventing esophageal stricture caused by fibrosis after ESD surgery.

[0054] Example 2.

[0055] Chitosan was dissolved in acetic acid solution to obtain a chitosan solution with a mass concentration of 2%. Methacrylic anhydride was slowly added to the chitosan solution at a mass ratio of 5:1. The reaction was carried out at 60°C for 12 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic acid-grafted chitosan. Methacrylic acid-grafted chitosan and polyethylene glycol were dissolved separately in deionized water, yielding solutions with mass concentrations of 4% (w / v) and 50% (w / v), respectively. These solutions were then mixed thoroughly at a volume ratio of 1:2 under stirring at room temperature to obtain a mixed solution. Gallic acid was dissolved in deionized water at room temperature under stirring to prepare a gallic acid solution. After adding glucocorticoids and mixing evenly, the solution was mixed with a methacrylic acid-grafted chitosan-polyethylene glycol mixture at a volume ratio of 3:1 and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 72 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0056] After contact with porcine gastric mucosa, its adhesion performance was measured to be approximately 55.81 ± 7.25 kPa. Stability observation under simulated digestive fluid conditions at 37°C showed that the material system retained approximately 63.92% of its original mass on day 40. In vitro release characteristics studies showed that the system exhibited a continuous release pattern during the observation period. At day 14, the cumulative release rate was 71.21 ± 4.92%.

[0057] Example 3.

[0058] Chitosan was dissolved in acetic acid solution to obtain a chitosan solution with a mass concentration of 3%. Methacrylic anhydride was slowly added to the chitosan solution at a mass ratio of 3.5:1. The reaction was carried out at 40°C for 12 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic acid-grafted chitosan. Methacrylic acid-grafted chitosan and polyvinyl alcohol were dissolved separately in deionized water, yielding solutions with mass concentrations of 4% (w / v) and 10% (w / v), respectively. These solutions were then mixed thoroughly at a volume ratio of 1:2 under stirring at room temperature to obtain a mixed solution. Gallic acid was dissolved in deionized water at room temperature under stirring to prepare a gallic acid solution. After adding growth factors and mixing evenly, the solution was mixed with a methacrylic acid-grafted chitosan-polyvinyl alcohol mixture at a volume ratio of 3:1 and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 72 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0059] The obtained powder exhibited an adhesion force of approximately 51.35 ± 7.85 kPa upon contact with the submucosal tissue of the porcine esophagus. A 40-day degradation assessment under simulated upper gastrointestinal fluid conditions (37°C) showed a residual mass of 59.6%. In vitro sustained-release studies demonstrated stable drug release over 14 days, with a final cumulative release rate of 71.45 ± 5.38%.

[0060] Example 4.

[0061] Hyaluronic acid was dissolved in deionized water to obtain a 1% (w / v) hyaluronic acid solution. Methacrylic anhydride was slowly added to the hyaluronic acid solution at a mass ratio of 3:1, and the reaction was carried out at room temperature in the dark for 12 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic anhydride-grafted hyaluronic acid. The methacrylic anhydride-grafted hyaluronic acid and tetra-arm polyethylene glycol were dissolved separately in deionized water, yielding solutions with mass concentrations of 1% (w / v) and 20% (w / v), respectively. These solutions were then mixed in equal volumes at room temperature under stirring to obtain a mixed solution. Tannic acid was dissolved in deionized water at room temperature under stirring to prepare a tannic acid solution. After adding an anti-fibrotic drug and mixing evenly, the solution was mixed with a 1:1 volume ratio of a methacrylic anhydride-grafted hyaluronic acid and a four-arm polyethylene glycol mixture and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 10 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 48 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0062] The adhesion strength of the prepared material to the submucosa of the porcine colon was 51.60 ± 8.40 kPa. After 40 days in simulated colonic fluid (37°C), approximately 49.8% of the mass remained. In vitro drug release experiments showed that the powder achieved colon-targeted sustained release within 14 days, with a cumulative release of 61.90 ± 7.12%.

[0063] Example 5.

[0064] Hyaluronic acid was dissolved in deionized water to obtain a 1% (w / v) hyaluronic acid solution. Methacrylic anhydride was slowly added to the hyaluronic acid solution at a mass ratio of 3:1, and the reaction was carried out at room temperature in the dark for 6 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic anhydride-grafted hyaluronic acid. Methacrylic anhydride-grafted hyaluronic acid and tetra-arm polyethylene glycol were dissolved separately in deionized water, yielding solutions with mass concentrations of 2% (w / v) and 20% (w / v), respectively. These solutions were then mixed in equal volumes at room temperature under stirring to obtain a mixed solution. Tannic acid was dissolved in deionized water at room temperature under stirring to prepare a tannic acid solution. After adding an anti-fibrotic drug and mixing evenly, the solution was mixed with a 1:2 volume ratio of a methacrylic anhydride-grafted hyaluronic acid and a four-arm polyethylene glycol mixture and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 72 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0065] The prepared material exhibited an adhesion force of 49.85 ± 8.31 kPa upon contact with the submucosa of the porcine colon. After 40 days of degradation in simulated colonic fluid (37°C), the mass retention rate was approximately 49.7%. In vitro drug release studies showed that the powder maintained colon-targeted release characteristics for 14 days, with a final cumulative release rate of 61.90 ± 1.45%, which is beneficial for local drug accumulation at the lesion site.

[0066] Example 6.

[0067] Glycosamine was dissolved in deionized water to obtain a 2% (w / v) solution. Maleic anhydride was slowly added to the glycosamine solution at a mass ratio of 2:1, and the reaction was carried out at 60°C for 6 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain maleic anhydride-grafted glycosamine. Maleic anhydride-grafted glycosamine and polyvinyl alcohol were dissolved separately in deionized water to obtain solutions with mass concentrations of 2% (w / v) and 10% (w / v), respectively. These solutions were then mixed in equal volumes at room temperature under stirring to obtain a mixed solution. Gallic acid was dissolved in deionized water at room temperature under stirring to prepare a gallic acid solution. After adding growth factors and mixing evenly, the solution was mixed with a mixed solution of maleic anhydride grafted glycosaminoglycan and polyvinyl alcohol in an equal volume ratio and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 72 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0068] Upon contact with the submucosa of the porcine colon, the powder exhibited an adhesion strength of approximately 42.85 ± 7.15 kPa. After being cultured in a simulated colon at 37°C for 40 days, its mass retention was approximately 43.7%. In in vitro drug release tests, the system maintained stable colon-targeted release behavior for 14 days, ultimately achieving a cumulative release rate of 61.91 ± 6.41%, demonstrating good potential for local drug delivery.

[0069] Example 7.

[0070] Glycosaminoglycans were dissolved in deionized water to obtain a 3% (w / w) solution. Maleic anhydride was slowly added to the glycosaminoglycan solution at a mass ratio of 2:1, and the reaction was carried out at 40°C for 6 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain maleic anhydride-grafted glycosaminoglycans. Maleic anhydride-grafted glycosaminoglycans and polyvinylpyrrolidone were separately dissolved in deionized water and mixed evenly in equal volumes at room temperature under stirring to obtain a mixed solution. The obtained solutions had mass concentrations of 2% (w / v) and 10% (w / v), respectively. Gallic acid was dissolved in deionized water at room temperature under stirring to prepare gallic acid solutions. After adding glucocorticoids and mixing evenly, the solutions were mixed with a mixture of maleic anhydride grafted glycosaminoglycans and polyvinylpyrrolidone in an equal volume ratio and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as aggregates. The aggregates were washed multiple times with deionized water and then dried. After freeze-drying the aggregates for 96 h, they were ground into powder to obtain endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0071] The material exhibited adhesion to the submucosa of the porcine rectum at a force of 32.35 ± 9.05 kPa. In a culture system simulating a specific biochemical environment of the rectal region, after 40 days at 37°C, approximately 39.1% of the material remained intact. In vitro release data indicated that the powder achieved sustained rectal-specific release within 14 days, with a cumulative release rate of 51.40 ± 7.14%, demonstrating excellent site-specific drug release performance.

[0072] Example 8.

[0073] Hyaluronic acid was dissolved in deionized water to obtain a 1% (w / v) hyaluronic acid solution. Methacrylic anhydride was slowly added to the hyaluronic acid solution at a mass ratio of 3:1, and the reaction was carried out at room temperature in the dark for 6 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic anhydride-grafted hyaluronic acid. Methacrylic anhydride-grafted hyaluronic acid and six-arm polyethylene glycol were dissolved separately in deionized water to obtain solutions with mass concentrations of 5% (w / v) and 10% (w / v), respectively. These solutions were then mixed in equal volumes at room temperature under stirring to obtain a mixed solution. Gallic acid was dissolved in deionized water at room temperature under stirring to prepare a gallic acid solution. After adding an anti-fibrotic drug and mixing evenly, the solution was mixed with a methacrylic anhydride-grafted hyaluronic acid and a six-arm polyethylene glycol mixture in an equal volume ratio and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 96 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0074] After contact with the submucosa of the porcine esophagus, the powder exhibited an adhesion strength of approximately 72.20 ± 7.65 kPa. In a medium simulating the physiological environment of the esophagus, placed at 37°C for 40 days, the material mass retention rate was approximately 51.2%. In vitro release studies showed that the powder exhibited stable drug release over 14 days, with a cumulative release rate of 61.60 ± 5.52%, indicating its suitability for local treatment of esophageal diseases.

[0075] Example 9.

[0076] Hyaluronic acid was dissolved in deionized water to obtain a 1% (w / v) hyaluronic acid solution. Methacrylic anhydride was slowly added to the hyaluronic acid solution at a mass ratio of 2:1, and the reaction was carried out at room temperature in the dark for 6 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic anhydride-grafted hyaluronic acid. Methacrylic anhydride-grafted hyaluronic acid and six-arm polyethylene glycol were dissolved separately in deionized water to obtain solutions with mass concentrations of 2% (w / v) and 10% (w / v), respectively. These solutions were then mixed in equal volumes at room temperature under stirring to obtain a mixed solution. Gallic acid was dissolved in deionized water at room temperature under stirring to prepare a gallic acid solution. After adding an anti-fibrotic drug and mixing evenly, the solution was mixed with a methacrylic anhydride-grafted hyaluronic acid and a six-arm polyethylene glycol mixture in an equal volume ratio and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 96 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0077] The adhesion force between the powder and the submucosa of porcine gastric tissue was measured to be 53.45 ± 7.10 kPa. In a solution simulating the dynamic physiological environment of the stomach, after incubation at 37°C for 40 days, the mass retention rate was approximately 51.9%. In vitro drug release assessment showed that the material maintained sustained drug release characteristics for 14 days, with a cumulative release of 62.85 ± 5.70%, making it suitable for local sustained-release therapy in the stomach.

[0078] Example 10.

[0079] Hyaluronic acid was dissolved in deionized water to obtain a 1% (w / v) hyaluronic acid solution. Methacrylic anhydride was slowly added to the hyaluronic acid solution at a mass ratio of 2:1, and the reaction was carried out at room temperature in the dark for 6 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic anhydride-grafted hyaluronic acid. Methacrylic anhydride-grafted hyaluronic acid and six-arm polyethylene glycol were dissolved separately in deionized water to obtain solutions with mass concentrations of 2% (w / v) and 10% (w / v), respectively. These solutions were then mixed in equal volumes at room temperature under stirring to obtain a mixed solution. Tannic acid was dissolved in deionized water at room temperature under stirring to prepare a tannic acid solution. After adding an anti-fibrotic drug and mixing evenly, the solution was mixed with a methacrylic anhydride-grafted hyaluronic acid and a six-arm polyethylene glycol mixture in an equal volume ratio and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 96 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0080] In tests on the surface of porcine gastric submucosa, the powder exhibited an adhesion force of approximately 61.80 ± 6.95 kPa. In a simulated gastric acid environment at 37°C for 40 days, the material retained approximately 51.8% of its mass. In vitro sustained-release experiments confirmed that the material maintained stable drug release over 14 days, with a cumulative release of 71.27 ± 4.32%.

[0081] Example 11.

[0082] Hyaluronic acid was dissolved in deionized water to obtain a 1% (w / v) hyaluronic acid solution. Methacrylic anhydride was slowly added to the hyaluronic acid solution at a mass ratio of 3:1, and the reaction was carried out at room temperature in the dark for 6 hours. After dialyzing the reaction mixture, the resulting product was freeze-dried to obtain methacrylic anhydride-grafted hyaluronic acid. Methacrylic anhydride-grafted hyaluronic acid and six-arm polyethylene glycol were dissolved separately in deionized water, yielding solutions with mass concentrations of 1% (w / v) and 10% (w / v), respectively. These solutions were then mixed in equal volumes at room temperature under stirring to obtain a mixed solution. Tannic acid was dissolved in deionized water at room temperature under stirring to prepare a tannic acid solution. After adding glucocorticoids and mixing evenly, the solution was mixed with a methacrylic anhydride-grafted hyaluronic acid and a six-arm polyethylene glycol mixture in an equal volume ratio and stirred vigorously with a glass rod until phase separation occurred. After centrifugation at 6000 rpm for 30 min, the supernatant was discarded, and the lower aggregate phase was collected as the aggregate. The aggregate was washed several times with deionized water and then dried. The aggregate was freeze-dried for 96 h and then ground into powder to obtain an endoscopically deliverable aggregate powder for preventing stenosis after endoscopic submucosal dissection of the digestive tract.

[0083] Upon contact with the submucosa of the porcine colon, the powder system exhibited an adhesion strength of approximately 42.50 ± 8.81 kPa. In a culture system simulating changes in the colonic environment, after incubation at 37°C for 40 days, its mass retention was approximately 46.9%. In vitro drug release studies showed that the system achieved a cumulative release of 61.85 ± 7.49% over 14 days.

[0084] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method of preparing a powder of coacervates for endoscopic delivery to prevent stenosis of the digestive tract after endoscopic submucosal dissection, characterized in that, The method comprises the following steps: Step 1, dissolving polysaccharide compound in solvent to obtain polysaccharide solution; Step 2, adding unsaturated carboxylic anhydride to the polysaccharide solution to carry out grafting reaction, and obtaining graft-modified polysaccharide compound after treatment; Step 3, dissolving the graft-modified polysaccharide compound in aqueous medium to obtain first aqueous solution with mass concentration of 1%-5%, and dissolving hydrophilic polymer in aqueous medium to obtain second aqueous solution with mass concentration of 10%-100%; Step 4, mixing the first aqueous solution and the second aqueous solution to obtain mixed solution; Step 5, preparing aqueous suspension containing polyphenol compound and therapeutically active substance with mass ratio of 50:1-1:10; Step 6, mixing the mixed solution and the aqueous suspension and stirring until phase separation occurs, collecting coacervate phase, and obtaining coacervate powder after freeze-drying and grinding treatment.

2. The method of claim 1, wherein the agglomerate powder is prepared by a method comprising: The polysaccharide compound is one or more combinations of chitosan, chitin, hyaluronic acid, alginate, starch, cellulose and its derivatives, and glycosaminoglycan.

3. The method of claim 1, wherein the agglomerate powder is prepared by a method comprising: The unsaturated carboxylic anhydride is one or more combinations of methacrylic anhydride, acrylic anhydride, maleic anhydride and its derivatives.

4. The method of claim 1, wherein the agglomerate powder is prepared by a method comprising: The hydrophilic polymer is one or more combinations of polyethylene glycol, four-arm polyethylene glycol, six-arm polyethylene glycol, eight-arm polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide and its copolymer.

5. The method of claim 1, wherein The polyphenol compound is one or more combinations of tannic acid, catechin, gallic acid, caffeic acid, ferulic acid and chlorogenic acid.

6. The method of claim 1, wherein The therapeutically active substance is one or more combinations of glucocorticoid, anti-inflammatory drug, anti-fibrotic drug, growth factor and cytokine modulator.

7. An endoscopically delivered coagulum powder for preventing stenosis of the digestive tract after endoscopic submucosal dissection, characterized by, The coacervate powder is prepared according to the method of any one of claims 1-6.

8. A pharmaceutical composition comprising the coacervate powder of claim 7.

9. Use of the coacervate powder of claim 7 in the preparation of a medicament for preventing submucosal tissue resection-induced stenosis of digestive tract.

10. Use according to claim 9, characterized in that, The submucosal tissue resection-induced stenosis of digestive tract is at least one of esophageal stenosis after endoscopic submucosal dissection, gastric tissue stenosis after endoscopic submucosal dissection, or colorectal stenosis after endoscopic submucosal dissection.

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