A drug releasing device and method for preventing esophageal stricture after esd

Abstract

This invention relates to the field of medical device technology and discloses a drug delivery device and method for preventing esophageal stricture after ESD surgery. The device includes a connecting wire, which is a flexible wire with a length of 40mm-80mm, one end fixed to the top of a drug-filled pouch, and the other end free for extending through the esophagus to the outside of the body. A drug-filled pouch, located at the lower end of the connecting wire, has a double-layer structure, including an inner drug-storage cavity and an outer microporous membrane, and is filled with drug. The connecting wire and the drug-filled pouch are connected in series. This application solves the problems of interference between support and drug release in existing devices, easy tissue damage caused by the support structure, easy displacement of the drug delivery unit, and difficulty in removal.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a drug delivery device and method for preventing esophageal stricture after ESD surgery. Background Technology

[0002] Following endoscopic submucosal dissection (ESD), esophageal stenosis often occurs due to esophageal wall tissue defects and subsequent healing processes. In severe cases, this can lead to dysphagia and eating disorders, requiring repeated endoscopic dilation. To prevent stenosis, current techniques employ various drug delivery devices to deliver hormonal drugs to the surgical site. Common methods include hormonal injection, oral hormonal administration, and esophageal stent placement.

[0003] Hormone injections are typically administered via needle into the surgical site. However, because the esophagus is a dynamic cavity with continuous peristalsis and flushing of contents, the injected medication is diluted, flushed away, or metabolized within hours, making it impossible to maintain an effective drug concentration at the surgical site for more than several days. To maintain efficacy, repeated injections are required, increasing the number of procedures and the amount of instruments used, and each injection carries the risk of puncture injury.

[0004] Oral hormones are usually administered orally or endoscopically into the esophagus, but capsules or sustained-release formulations are easily displaced downwards into the stomach due to esophageal peristalsis, making it impossible to maintain their effect on the surgical site.

[0005] Esophageal stents deliver medication to the stent's surface, aiming to provide both mechanical support and drug release. However, since the stent's support structure and drug release layer are integrated, the stent deforms under peristaltic pressure within the esophagus, causing cracking of the drug coating or alteration of the release area. This results in an unstable drug release rate, prone to initial bursts or insufficient release later. Furthermore, continuous stent pressure can lead to local tissue ischemia, ulceration, and granulation tissue proliferation, potentially inducing restenosis or perforation. It also affects esophageal patency, causing significant foreign body sensation in patients. During removal, the stent may ingrow into other tissues, posing risks of bleeding and perforation.

[0006] Therefore, there is an urgent need for a drug delivery device and method that can effectively solve the above problems and prevent esophageal stricture after ESD. Summary of the Invention

[0007] The present invention aims to provide a drug delivery device and method for preventing esophageal stricture after ESD surgery, and to solve the problems of mutual interference between support and drug release, easy tissue damage caused by the support structure, easy displacement of drug delivery, insufficient drug action period, and difficulty in removal in existing devices.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a drug delivery device for preventing esophageal stricture after ESD surgery, comprising: The connecting wire is a flexible wire with a length of 40mm-80mm. One end is fixed to the top of the medicine pouch, and the other end is a free end, which is used to extend through the esophagus to the outside of the body. The drug pouch, located at the lower end of the connecting line, has a double-layer structure, including an inner drug storage cavity and an outer microporous membrane, and the drug pouch is filled with drugs. The connecting line and the medicine pouch are connected in series.

[0009] This solution also provides a method for using a drug delivery device for preventing esophageal stricture after ESD surgery. The method, applied to the aforementioned drug delivery device for preventing esophageal stricture after ESD surgery, includes the following steps: S1, push the drug delivery device's sac into the target location after esophageal ESD via the mouth, with the pushing depth determined by the location of the sac in the lesion segment; S2, at the same time, the connecting line is led out through the anterior wall of the esophagus to the fixing point for fixation; S3. Before eating, loosen the fixing point and pull the connecting line to remove the medicine bag from the esophagus; after eating, transport the medicine bag back to its original position through the esophagus and fix the connecting line again.

[0010] The principles and advantages of this scheme are: In existing technologies, all esophageal implantable devices follow the basic model of "in vivo anchoring + continuous placement"—the device is fixed to the esophageal wall through a high radial force stent, barbs, or expandable body, and the device remains in place throughout the treatment, preventing patients from adjusting it according to their physiological needs. This design model has inherent and irreconcilable contradictions: the in vivo anchoring structure inevitably causes continuous pressure or puncture damage to the fragile esophageal mucosa after surgery; long-term indwelling of the device severely interferes with the patient's normal eating, affecting their quality of life; and adjustments or replacements during treatment require repeated endoscopic procedures, increasing the medical burden.

[0011] This solution overcomes the aforementioned technical biases and proposes a novel design concept of "external anchoring + intermittent placement," which completely transfers the device's anchoring point from inside the esophagus to outside the body (teeth or behind the ear). This allows patients to remove the device independently before eating and re-insert it after eating, achieving structural decoupling of the anchoring and drug release functions and balancing treatment continuity with quality of life.

[0012] The device consists of a medicated pouch and a single connecting wire. One end of the connecting wire is fixed to the end of the medicated pouch, and the other end extends outside the body, secured by a buckle or tape. The downward force generated by esophageal peristalsis is directly borne by the external fixation point; the connecting wire merely acts as a force transmission medium, without relying on any internal structure to provide anchoring force. Essentially, this design removes the anchoring system from the esophageal lumen, eliminating the need for any internal support structures. The device only has slight contact with the esophageal wall on the surface of the medicated pouch, without any radial compression or puncture fixation, completely eliminating the risk of postoperative damage to the fragile mucosa caused by the anchoring structure.

[0013] The drug release function is achieved by independently suspended double-layered drug-carrying pouches. In existing technologies, the drug coating or drug-loaded layer is integrated with the support structure. The deformation of the support under esophageal peristalsis can change the drug release interface, leading to burst release or interrupted release. This solution connects the drug-carrying pouches in series using flexible connecting lines, allowing the pouches to remain free within the esophageal lumen and not bear any mechanical stress. The drug release rate is determined solely by the microporous membrane and hydrogel coating of the pouches themselves. The inner drug storage chamber is loaded with biodegradable polymer microspheres to provide long-lasting drug storage, while the outer microporous membrane controls the pore size to 50-80 nm. It forms a diffusion barrier, loads the first dose of drug on the surface hydrogel coating and buffers the initial release. The three work together to achieve a stable drug release curve close to zero order, and the release cycle covers the entire critical period of wound healing.

[0014] The conflict between anchoring and retrieval functions is resolved through the design of the connecting wire. In existing technologies, anti-displacement structures (such as barbs or high radial force) and non-invasive retrieval are often mutually exclusive. This solution uses a connecting wire that is directly led out along the anterior wall of the esophagus for external fixation. The connecting wire itself provides axial anti-displacement capability through friction, eliminating the need for high radial force or invasive barbs. During retrieval, traction on the connecting wire causes the medicated pouch to slide out directly, achieving non-invasive retrieval and avoiding secondary traction damage to healed tissue.

[0015] This solution is the first to completely transfer the anchoring point from inside the esophagus to outside the body, eliminating the need for any invasive fixation structures within the esophagus and fundamentally resolving the inherent contradiction between anchoring and injury. Functionally, it is the first to completely separate the drug release and anchoring functions, allowing each functional module to be optimized independently without mutual constraint. In terms of usage, it is the first to propose an "intermittent insertion" mode, allowing patients to remove the device independently before eating, achieving a balance between treatment continuity and normal diet. Regarding operation, it is the first to delegate some operational authority to patients, giving them self-management capabilities and reducing reliance on medical resources. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a drug delivery device for preventing esophageal stricture after ESD surgery according to the present invention; Figure 2 This is a schematic diagram of the first morphological structure of the drug delivery device for preventing esophageal stricture after ESD surgery according to the present invention. Figure 3 This is a schematic diagram of the second form of the drug delivery device for preventing esophageal stricture after ESD surgery according to the present invention. Figure 4 This is a schematic flowchart illustrating the method of using a drug delivery device for preventing esophageal stricture after ESD surgery according to the present invention.

[0017] In the attached diagram: 1. Esophagus; 2. Connecting line; 3. Drug pouch; 4. Drug storage cavity; 5. Biodegradable polymer microspheres; 6. Microporous membrane; 7. Hydrogel coating. Detailed Implementation

[0018] The following detailed description illustrates the specific implementation method: This embodiment presents a drug delivery device and method for preventing esophageal stricture after ESD surgery. By employing a structure where a drug-filled pouch 3 is connected in series with a single connecting wire 2, and the connecting wire 2 is led out externally for fixation, no anchoring structure is required within the esophagus 1. This allows the patient to remove the device voluntarily before eating and reinsert it afterward. It provides reliable anchoring and facilitates non-invasive removal. The drug-filled pouch 3 uses an inner drug storage cavity 4 combined with an outer microporous membrane 6 and a hydrogel coating 7 to achieve stable, sustained release for 7-14 days, with the release rate unaffected by the external environment. This solves the problems of existing devices where internal anchoring structures easily cause esophageal wall damage, long-term placement interferes with normal eating, the drug delivery unit is prone to displacement, the drug's duration of action is insufficient, and removal is difficult.

[0019] Option 1 A drug delivery device for preventing esophageal stricture after ESD surgery is provided, as shown in the attached... Figure 1 As shown, it includes: Connecting wire 2 is a flexible wire with a length of 40mm-80mm, sufficient to cover the distance from the esophagus 1 to the external fixation point. One end is fixed to the top of the drug pouch 3, and the other end is a free end used to extend through the esophagus 1 to the outside of the body for insertion, removal, and anchoring. In this embodiment, connecting wire 2 can be flexibly connected to the drug pouch 3 via end heat pressing or ultrasonic welding to transmit traction force, but not support force.

[0020] In this embodiment, the connecting wire 2 extends upward from the top of the pouch 3, naturally adhering to the esophageal wall to avoid knotting itself and dangling across the lumen. It is led out from the oral cavity and fixed to the cheek to simplify insertion and removal operations, requiring no additional instruments and allowing for easy adjustment of its position. Furthermore, because the connecting wire 2 is extremely thin, the space it occupies within the esophageal lumen is negligible, ensuring the safety and tolerability of the placement.

[0021] In this embodiment, the connecting wire 2 is made of medical thermoplastic polyurethane or silicone material with a Shore hardness of 30-40A, with a diameter of 1.0mm-1.2mm, and the surface is covered with a hydrophilic lubricating coating to reduce friction, facilitate repeated insertion and removal, and make the connecting wire 2 soft and smooth, effectively avoiding scratches and damage.

[0022] In existing technologies, invasive anchoring structures such as high radial force supports, barbs, and expandable bodies are commonly used to prevent device displacement. While providing anchoring force, these structures inevitably cause continuous pressure or puncture damage to the esophageal mucosa. This solution completely transfers the anchoring point outside the body (to the teeth or behind the ear), using the traction of the connecting wire to achieve anchoring. There are no anchoring structures inside the esophagus, thus completely eliminating the risk of anchoring-related tissue damage.

[0023] Medicine pouch 3, as attached Figure 2 As shown, the overall structure is a spindle-shaped or teardrop-shaped double-layer structure. In this embodiment, as shown in the attached diagram... Figure 3 As shown, the drug pouch 3 can also be configured as a capsule or pill, and its structure is not limited. The drug release function and the anchoring function are completely separated structurally, so they do not interfere with each other and can be optimized independently. The drug pouch 3 is only responsible for sustained drug release; it is soft and small in size to reduce point pressure on the esophageal wall, and its overall size is controlled within φ8-10mm × 20-25mm. In this embodiment, the drug pouch 3 includes an inner drug storage cavity 4 and an outer microporous membrane 6, and the drug pouch 3 is loaded with drug.

[0024] In this embodiment, the medicated pouch 3 does not aim for full coverage. Instead, it is directly suspended inside the esophagus 1 by a flexible connecting line 2, without directly compressing the mucosa. Instead, the medicated pouch rolls or swings naturally within the lesion segment as the esophagus 1 moves, achieving dynamic local immersion. The medicated pouch 3 itself is made of 70A-85A TPU (softer area) and has a hydrogel coating 7 on its surface to further buffer the contact force.

[0025] Specifically, the inner drug storage cavity 4 of the drug capsule 3 is made of 85A TPU to form a sealed cavity with a wall thickness of 0.3-0.5mm. It contains biodegradable polymer microspheres 5, which are loaded with drug at a ratio of 30-50% to achieve a matrix-type sustained release. In this embodiment, the particle size of the biodegradable polymer microspheres 5 is 10 mm. -50 .

[0026] The outer microporous membrane 6 of the drug capsule 3 is formed by laser drilling on 70A TPU to create a "reservoir-microporous membrane" controlled release system. In this embodiment, the wall thickness of the outer microporous membrane 6 is 0.2-0.3 mm, and the pore size can be set to 50 mm. -80 The pore density is adjusted according to the target drug release rate, such as 20-40 pores / .

[0027] A hydrogel coating 7 is also provided on the outer surface of the drug pouch 3. In this embodiment, the hydrogel coating 7 is a hydrophilic polyurethane or chitosan, with a thickness of 200-300 μm. The hydrogel can hold 10-20% of the initial drug dose to prevent burst release. After absorbing water, the hydrogel on the drug capsule surface forms a thin, viscous interface. Once dissolved, the drug slowly diffuses through the hydrogel layer to the surrounding mucosa, independent of tight adhesion. This ensures stable drug release kinetics, unaffected by deformation of the supporting structure, and achieves near-zero-order release through a bilayer microporous membrane 6 and hydrogel. The drug capsule 3 employs a bilayer microporous membrane and hydrogel controlled-release structure. The release rate is determined by the internal diffusion barrier and is independent of the external mechanical environment. Even with intermittent removal, its cumulative release curve maintains zero-order kinetic characteristics.

[0028] In this embodiment, a folded freeze-dried hydrogel sheet is provided in the lower middle section of the drug pouch 3. Specifically, the freeze-dried hydrogel sheet can be a chitosan / gelatin composite, carrying the same hormone. After placement, the hydrogel sheet absorbs water and swells within 2-4 hours, unfolding like a "skirt" or "petal" and adhering to the esophageal wall, increasing the effective contact area by 2-3 times. The hydrogel skirt is thin (thickness < 1 mm), ensuring an overall lumen patency > 70%. In this embodiment, the hydrogel itself has a porous structure, does not block the lumen (a central channel is still left after unfolding), and can additionally load the drug, enhancing the local concentration. Without increasing the volume of the substance, the drug-mucosal contact interface is significantly improved, while maintaining the patency of the esophagus 1.

[0029] By combining the connecting line 2 with the medicine pouch 3, the needs for support, low damage, and foreign body sensation can be met simultaneously.

[0030] In this embodiment, the connecting wire 2 and the drug pouch 3 are connected in series. The surfaces of both the connecting wire 2 and the drug pouch 3 are coated with a superhydrophilic lubricating coating such as a polyvinylpyrrolidone lubricating coating to reduce tissue adhesion and further reduce damage.

[0031] In existing technologies, to prevent the device from shifting within the esophagus, all solutions focus on finding anchoring force inside the esophagus, either through high radial force supports, barbs, or expandable bodies. Those skilled in the art have long been constrained by the technical bias that "anchoring must be completed inside the body." This solution takes the opposite approach, transferring the anchoring point outside the body and using the physical traction of connecting wires to achieve positional fixation, eliminating any anchoring structure within the esophagus.

[0032] Drug delivery devices typically integrate support, anchoring, and drug release into one unit, with each function mutually constraining each other and difficult to optimize independently. In this embodiment, the drug delivery device is completely separated from the esophageal wall and anchored externally, with intermittent removal and insertion adapting to feeding needs. Instead of relying on internal support structures or barbs, the anchoring point is moved externally (to the teeth / behind the ear). The traction of the connecting line 2 prevents the drug pouch 3 from shifting downwards, while a degree of relaxation buffers the axial forces generated by swallowing and neck movements, providing reliable anchoring and enabling non-invasive removal. The drug pouch 3 continuously releases drug within the esophagus 1, and its release kinetics remain stable even with intermittent removal (the hydrogel layer rapidly resumes drug release after reinsertion). The drug pouch 3 employs an inner drug storage cavity 4 combined with an outer microporous membrane 6 and a hydrogel coating 7 to achieve stable, level-zero sustained release for 7-14 days.

[0033] In this embodiment, the support and drug release functions are independently optimized to avoid interference and tissue damage. The dual-layer controlled release of the microporous membrane 6 and hydrogel ensures stable drug release. Anchoring does not require additional structures to prevent displacement, and superelastic linearized retrieval enables non-invasive recovery. This achieves a unified approach of long-term stable local drug delivery, low-damage effective support, reliable anchoring, and safe non-invasive retrieval within the dynamic physiological environment of the esophagus 1, solving the problems of mutual interference between support and drug release, high risk of tissue damage, easy displacement, and difficult retrieval in existing devices.

[0034] Option 2 In this embodiment, a method for using a drug delivery device for preventing esophageal stricture after ESD surgery is also provided, which is applied to the aforementioned drug delivery device for preventing esophageal stricture after ESD surgery, as shown in the attached figure. Figure 4 As shown, it includes the following steps: S1, push the drug delivery device's sac 3 orally to the target location after esophageal ESD, with the pushing depth determined by the location of the sac 3 in the lesion segment.

[0035] In this embodiment, the medicated pouch 3 is pushed orally to the target location after the esophageal ESD procedure (guided by endoscopy or directly pushed, assisted by the patient's swallowing action), with the pushing depth determined by the location of the medicated pouch 3 in the lesion segment.

[0036] S2, and at the same time, lead the connecting line 2 through the anterior wall of the esophagus to the fixing point for fixation.

[0037] The free end of connecting wire 2 is led out of the body and fixed in one of the following two ways: Dental fixation: The end of the connecting line 2 is looped around the molar, or the line is attached to the cheek with medical tape, leaving 5-10cm of slack in the line to cushion swallowing. Ear-fixed type: The end of the connecting wire 2 is wrapped around the auricle and fixed behind the ear with a flexible ear hook or tape, while also allowing for some slack.

[0038] After insertion, the position of the drug pouch 3 can be confirmed by endoscopy or X-ray to ensure it is located in the lesion segment.

[0039] S3, before eating, loosen the fixing point and pull the connecting line 2 to remove the medicine bag 3 from the esophagus 1; after eating, transport the medicine bag 3 back to its original position through the esophagus 1 and fix the connecting line 2 again.

[0040] In this embodiment, when it is necessary to temporarily remove the medicine pouch for eating, the fixing point can be loosened, the connecting line 2 can be gently pulled, and the medicine pouch 3 can be slowly pulled out from the esophagus 1. After it is completely removed, it can be placed in a clean container.

[0041] After removal, the medicine pouch 3 can be placed in sterile saline gauze for short-term preservation (within a few hours).

[0042] After eating, push the medicine pouch 3 back into the original position of the esophagus 1 through the mouth and re-secure the connecting line 2.

[0043] When the procedure is completed, or when the sac 3 is damaged or the medication is significantly reduced, the sac 3 can be removed by directly pulling the connecting line 2 without endoscopic assistance, allowing the sac 3 to be removed completely without any invasive procedures.

[0044] In this embodiment, all internal support structures are eliminated, and there is no radial force between the device and the esophageal wall, with only slight mucosal contact, thus eliminating the risks of pressure-induced ischemia, ulceration, restenosis, and perforation. The device is small in size (φ8–10mm × 20–25mm) and has no rigid support ring, so the patient's perception of the device is extremely low. The external fixation suture is made of 1.0–1.2mm ultra-fine and soft suture, and the foreign body sensation in the oral cavity is negligible, greatly reducing the feeling of a foreign body.

[0045] External fixation does not rely on any internal anchoring structures (such as barbs or high radial force), avoiding damage to anchoring-related tissues; the fixation point can be chosen independently (teeth / behind the ear), and patients can adjust it according to their comfort. Furthermore, the device can be removed before eating and reinserted afterward, ensuring treatment continuity without interfering with normal eating and solving the problem of long-term device placement hindering eating.

[0046] The drug capsule 3 uses a double-layer microporous membrane 6 and a hydrogel controlled-release structure. The drug release rate is determined by the internal diffusion barrier and is independent of the external mechanical environment. Even if it is removed intermittently, its cumulative drug release curve still maintains zero-order kinetic characteristics.

[0047] In this embodiment, removal and re-insertion can be completed without endoscopic assistance (endoscopic positioning is required for the first insertion), and the device can be directly pulled out after the procedure without the need for a second endoscopic operation, which significantly reduces the occupation of medical resources and the burden on patients.

[0048] Throughout the entire process of insertion, placement, and removal, the device achieves low-damage interaction with esophageal tissue, long-term stability of drug release, reliable maintenance of device position, and safe and convenient removal operation.

[0049] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A drug delivery device for preventing esophageal stricture after ESD surgery, characterized in that, include: The connecting wire is a flexible wire with a length of 40mm-80mm. One end is fixed to the top of the medicine pouch, and the other end is a free end, which is used to extend through the esophagus to the outside of the body. The drug pouch, located at the lower end of the connecting line, has a double-layer structure, including an inner drug storage cavity and an outer microporous membrane, and the drug pouch is filled with drugs. The connecting line and the medicine pouch are connected in series.

2. The drug delivery device for preventing esophageal stricture after ESD surgery according to claim 1, characterized in that: The outer microporous membrane of the drug capsule has a pore size of 50. -80 Pore ​​density is 20-40 pores / The outer surface of the drug pouch is also provided with a hydrogel coating.

3. A drug delivery device for preventing esophageal stricture after ESD surgery according to claim 1, characterized in that: The connecting wire is made of medical-grade thermoplastic polyurethane or silicone material with a Shore hardness of 30-40A, with a diameter of 1.0mm-1.2mm, and its surface is covered with a hydrophilic lubricating coating.

4. A drug delivery device for preventing esophageal stricture after ESD surgery according to claim 1, characterized in that: The inner drug storage cavity of the drug capsule contains biodegradable polymer microspheres loaded with drug. The particle size of the biodegradable polymer microspheres is 10 mm. -50 .

5. A drug delivery device for preventing esophageal stricture after ESD surgery according to claim 1, characterized in that: A folded freeze-dried hydrogel sheet is provided in the lower middle section of the sac. The freeze-dried hydrogel sheet unfolds and adheres to the esophageal wall after absorbing water.

6. A drug delivery device for preventing esophageal stricture after ESD surgery according to claim 3, characterized in that: The surface of the medicine pouch and the surface of the connecting wire are both covered with a polyvinylpyrrolidone lubricating coating.

7. A drug delivery device for preventing esophageal stricture after ESD surgery according to claim 1, characterized in that: The outer microporous membrane of the drug capsule has a wall thickness of 0.2-0.3 mm.

8. A drug delivery device for preventing esophageal stricture after ESD surgery according to claim 2, characterized in that: The hydrogel coating is a hydrophilic polyurethane or chitosan, with a thickness of 200-300 mm. .

9. A method of using a drug delivery device for preventing esophageal stricture after ESD surgery, characterized in that, A drug delivery device for preventing esophageal stricture after ESD surgery, as described in any one of claims 1-8, comprises the following steps: S1, push the drug delivery device's sac into the target location after esophageal ESD via the mouth, with the pushing depth determined by the location of the sac in the lesion segment; S2, at the same time, the connecting line is led out through the anterior wall of the esophagus to the fixing point for fixation; S3. Before eating, loosen the fixing point and pull the connecting line to remove the medicine bag from the esophagus; after eating, transport the medicine bag back to its original position through the esophagus and fix the connecting line again.

10. A drug delivery device for preventing esophageal stricture after ESD surgery according to claim 9, characterized in that: The distal end of the connecting wire is fixed to the teeth or ear.

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