Degradable metal stent with medicine storage cavity and manufacturing method thereof
By designing a biodegradable metal stent with a drug-reservoir, the inner and outer stent layers work together to release drugs, solving the problem that drug-eluting stents cannot continuously release drugs, achieving long-term drug treatment effects and good mechanical support, and avoiding stent residue.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-05
- Publication Date
- 2026-03-31
AI Technical Summary
Existing drug-eluting stents cannot continuously release drugs in blood vessels, and their non-degradability leads to long-term persistence, increasing the risk of vascular inflammation and failing to effectively prevent restenosis.
Design a biodegradable metal stent with a drug storage chamber. Both the inner and outer stents are hollow structures. The inner stent degrades more slowly than the outer stent and is fixed by a positioning and locking mechanism. The outer stent degrades and releases the drug first, while the inner stent provides support later, thus delaying the release of the drug in the storage tank.
It achieves long-term drug release, prevents restenosis, avoids stent residue, has good mechanical properties, and matches degradation with angiogenesis.
Smart Images
Figure CN121754350A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of medical device manufacturing technology, and in particular to a biodegradable metal stent with a drug storage cavity and its manufacturing method. Background Technology
[0002] Currently, the application of stent implantation in coronary angiography is still limited by issues such as postoperative restenosis. This is because after stent implantation, damage to the vessel wall, excessive proliferation of fibroblasts in the vascular tissue, or inflammatory reactions can lead to thrombosis. Furthermore, if the stent remains at the lesion site for an extended period, plaque buildup and blockage can cause recurrence, leading to further vascular occlusion, stent compression, and even plaque encapsulation, impairing vascular patency and resulting in renewed vascular stenosis.
[0003] To address the aforementioned issues, drug-eluting stents are currently the primary treatment. A drug-eluting stent is a stent with a drug-coated surface. After implantation into a blood vessel, the drug-coated surface releases drugs to inhibit intimal hyperplasia, prevent early inflammatory reactions after stent placement, and reduce the restenosis rate in patients with coronary heart disease.
[0004] However, existing drug-eluting stents only provide temporary relief of the medication they carry during implantation, offering only early-stage therapeutic benefits. Subsequently, the stent merely supports the vessel wall, hindering the release of medication over extended periods and making it difficult to re-carry the medication. This makes it inconvenient for treating later-stage lesions. Furthermore, despite being made of highly biocompatible metals, existing drug-eluting stents remain permanently in the body after drug release, contributing to vascular inflammation and increasing the risk of recurrent atherosclerosis. Therefore, there is a need to design a stent that can continuously release medication, possesses excellent mechanical properties, and has a biodegradable carrier. Summary of the Invention
[0005] The purpose of this invention is to provide a biodegradable metal stent with a drug-filled cavity and its manufacturing method, so as to solve the technical problem that drug-eluting stents used in vascular surgery are not convenient to release drugs for treatment over a long period of time in the prior art.
[0006] The technical problem to be solved by this invention can be achieved through the following technical solution: A biodegradable metal stent with a drug storage chamber, comprising an inner stent and an outer stent; Both the inner and outer scaffolds have a hollow structure, and both the inner and outer scaffolds have a drug coating on their surface. The non-perforated portions of the inner and outer supports are identical in shape and aligned; the non-perforated portions of the inner support are provided with drug storage tanks, which store drugs. Both the inner and outer scaffolds are biodegradable metal scaffolds, and the degradation rate of the inner scaffold is lower than that of the outer scaffold.
[0007] Preferably, a positioning and locking mechanism is provided between the outer support and the inner support, which is used to lock and fix the outer support and the inner support to each other when they are aligned in the non-hollowed-out parts.
[0008] Preferably, the positioning and locking mechanism includes a locking protrusion and a locking groove. The locking protrusion is located on the outer wall of the inner support near the end. The locking groove is located on the outer support near the end, and the locking protrusion and the locking groove are configured to cooperate with each other.
[0009] Preferably, the positioning and locking mechanism includes two tapered end bodies, which are symmetrically arranged at both ends of the inner support; the diameter of each tapered end body on the side closest to the inner support is larger than the diameter of the outer support; the length of the inner support between the two tapered end bodies is equal to the length of the outer support.
[0010] Preferably, the outer support has elastically deformable protrusions at both ends of its edge.
[0011] Preferably, the outer support is a magnesium alloy support and the inner support is an iron alloy support.
[0012] Preferably, both the outer and inner supports are mesh-like perforated structures.
[0013] Preferably, the drug stored in the storage tank is taurine or rapamycin.
[0014] A method for manufacturing a biodegradable metal stent with a drug storage chamber, comprising the following steps: The first step is to cut the metal bracket using laser cutting technology to ensure that the inner and outer brackets have the same hollow shape and size. The second step is to use laser cutting technology to cut out drug storage tanks in the non-perforated parts of the inner support, and then fill the drug storage tanks with drugs. The third step is to assemble the inner support into the outer support, so that the non-perforated parts of the inner and outer supports are aligned, fitted and locked. The fourth step is to ensure that both the inner and outer scaffold layers are coated with a drug-eluting coating. Preferably, the specific operation of applying the drug coating is as follows: the inner and outer scaffolds locked together are placed as a whole in the drug coating solution, and then removed and placed in a vacuum oven to dry.
[0015] The beneficial effects of this invention are: 1. This invention first relies on the drug coating on the outer layer of the stent to release drugs for early treatment. Since the degradation rate of the outer stent is greater than that of the inner stent, the outer stent can degrade before the inner stent, exposing the drug reservoir on the inner stent, and then releasing drugs for treatment. This facilitates drug treatment over a longer period of time and effectively solves the problem that it is inconvenient to treat plaque enlargement or vascular occlusion in the later stages of blood vessels.
[0016] 2. When assembling the outer and inner stents, the outer and inner stents of this invention are positioned and connected by a positioning and locking mechanism, so that the hollow parts of the outer and inner stents are aligned and fitted. This allows the non-hollow parts of the outer stent to effectively block the drug storage tank on the non-hollow parts of the inner stent, thus delaying the release of the drug in the drug storage tank and achieving phased, long-term drug release therapy.
[0017] 3. The positioning and locking mechanism adopted by the outer and inner supports of the present invention is an integral structure with the support itself, which has stable mechanical locking performance and convenient and effective locking operation, which is conducive to the assembly and manufacturing of the entire support.
[0018] 4. In this invention, the outer and inner stents provide support together in the early stages. After the outer stent degrades and disappears, the inner stent can still provide good mechanical support. Compared with other single stents, it has better mechanical properties during the degradation process, and the entire degradation cycle matches the rate of vascular regeneration.
[0019] 5. Both the outer and inner support layers of this invention are made of biodegradable materials, which facilitate degradation and absorption and avoid the generation of residues. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present invention; Figure 2 This is a schematic diagram of the outer support structure with elastic deformation ports in this invention; Figure 3 This is a schematic diagram of the inner support structure with tapered end bodies in this invention; Figure 4 This is a schematic diagram of the overall structure of another embodiment of the present invention; Figure 5 This is a schematic diagram of the outer support structure with snap-fit grooves in this invention; Figure 6 This is a schematic diagram of the inner support structure with snap-fit protrusions in this invention; Figure 7 This is a schematic diagram of the cross-sectional structure of the outer support and the inner support in this invention, which are connected by a snap-fit groove and a snap-fit protrusion. Figure 8 This is a schematic cross-sectional view of the medicine storage tank in this invention.
[0021] Explanation of reference numerals in the attached figures: 1. Inner support; 2. Outer support; 3. Drug storage tank; 4. Snap-fit protrusion; 5. Snap-fit groove; 6. Conical end body; 7. Elastic deformation port. Detailed Implementation
[0022] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0023] like Figures 1-8 As shown, a biodegradable metal stent with a drug reservoir is used as a drug-eluting stent implanted in a blood vessel. The metal stent includes an inner stent 1 and an outer stent 2. Both the inner stent 1 and the outer stent 2 have a hollow structure, and both are covered with a drug-eluting coating. This allows the inner stent 1 and the outer stent 2 to release drugs through the drug-eluting coating after implantation into the blood vessel, thereby reducing smooth muscle cell proliferation and migration and delaying excessive thickening of the vascular intima. Furthermore, the hollow structure of both the inner stent 1 and the outer stent 2 facilitates the simultaneous release of drugs by both layers. The inner support 1 is fixedly assembled inside the outer support 2. Here, the outer diameter of the inner support 1 and the inner diameter of the outer support 2 can be approximately the same, or the outer diameter of the inner support 1 can be slightly larger than the outer diameter of the outer support 2, causing a slight deformation of the inner support 1 and pressing it into the interior of the outer support 2. The non-perforated parts of the inner support 1 and the outer support 2 have the same shape and are aligned and fitted together; that is, the perforated parts of the inner support 1 and the perforated parts of the outer support 2 are aligned and fitted together, and the non-perforated parts are aligned and fitted together. Medicine storage tanks 3 are distributed on the beam 8 of the non-perforated part of the inner support 1. The number of medicine storage tanks 3 can be set according to actual needs. Medicines can be stored in the medicine storage tanks 3. For details, please refer to [reference needed]. Figure 8 As shown, the cross-section of the beam 8 of the non-hollow part of the inner support 1 can be square or circular, while the inward side of the beam 8 of the non-hollow part of the outer support 2 needs to match the shape of the outward side of the beam 8 of the non-hollow part of the inner support 1 so that they can fit together effectively and ensure that the medicine storage tank 3 can be covered. Since the non-perforated part of the inner stent 1 and the non-perforated part of the outer stent 2 are attached together, the non-perforated part of the outer stent 2 can be used as a cover for the drug storage tank 3 to seal it, so that the drug coating on the surface of the inner stent 1 and the outer stent 2 can be used to release the drug first. Both the inner stent 1 and the outer stent 2 are biodegradable metal stents, and the degradation rate of the inner stent 1 is slower than that of the outer stent 2. After the drug coating is released, the inner stent 1 and the outer stent 2 come into contact with the blood and begin to degrade. The outer stent 2 degrades first, leaving the inner stent 1. At this time, the inner stent 1 can still effectively provide good mechanical support for the inside of the blood vessel. The entire degradation cycle matches the rate of vascular regeneration. At the same time, during the degradation of the outer stent 2, the drug reservoir 3 will gradually be exposed, which facilitates the release of the drug in the drug reservoir 3. Combined with the drug release of the drug coating, a longer drug release time is achieved, which can inhibit the proliferation of smooth muscle in the blood vessel for a long time, thereby preventing restenosis of the blood vessel after stent implantation.
[0024] The manufacturing method of the above-mentioned biodegradable metal stent with a drug storage cavity includes the following specific steps: The first step is to cut the metal bracket using laser cutting technology to make the inner bracket 1 and the outer bracket 2 have the same hollow shape and size; The second step is to cut out the drug storage tank 3 on the beam 8 of the non-hollow part of the inner support 1 using laser cutting technology, and fill the drug storage tank 3 with drugs. The third step is to assemble the inner support 1 into the outer support 2, aligning and fitting the non-perforated parts of the inner support 1 and the outer support 2 together, and then locking them together. The fourth step is to ensure that the surface of both the inner stent 1 and the outer stent 2 is covered with a drug coating. The specific operation of coating with drug is as follows: the inner scaffold 1 and the outer scaffold 2 locked together are placed in a coating solution of antiproliferative drugs such as rapamycin, so that the surface of the scaffold is coated with drug. After being immersed for a period of time, the scaffold is taken out and placed in a vacuum oven to dry, thereby obtaining the finished product.
[0025] It should be noted that the wall thickness of the inner stent 1 is processed in the range of 80-100μm; the wall thickness of the outer stent 2 is processed in the range of 40-60μm; the diameter of both is 2-4mm, and the overall length is 10-80mm, which is suitable for most lesions.
[0026] In the specific design, the wall thickness of the inner stent 1 can be processed to 85μm, and the width of the beam 8 in the non-perforated part is 100μm. Based on the processing dimensions of the inner stent 1, the width of the drug storage tank 3 is processed to 60μm and the depth to 70μm, and then the drug is filled in. The dimensions of the drug storage tank 3 can be processed according to actual needs to ensure that a sufficient amount of drug is filled for treatment. At the same time, the wall thickness of the outer stent 2 is processed to 45μm.
[0027] In some specific implementations, a positioning and locking mechanism is provided between the outer support 2 and the inner support 1. The positioning and locking mechanism is used to fix the outer support 2 and the inner support 1 when their hollow parts are aligned and attached together, so as to facilitate the assembly of the outer support 2 and the inner support 1. At the same time, it can ensure that the non-hollow parts of the outer support 2 can effectively cover and shield the medicine storage tank 3 on the inner support 1.
[0028] In a further specific implementation plan, refer to Figures 4 to 7 As shown, the positioning and locking mechanism includes a locking protrusion 4 and a locking groove 5. The locking protrusion 4 is located on the outer wall of the inner support 1 near the end. The locking groove 5 is located on the outer support 2 near the end, and the locking protrusion 4 and the locking groove 5 are configured to cooperate.
[0029] It should be noted that the snap-fit protrusion 4 and the inner support 1 are integrated, and the snap-fit groove 5 and the outer support 2 are integrated. That is, when the inner support 1 and the outer support 2 are tubular, the corresponding protrusions are first obtained through metal deformation processes, such as stamping, and then the whole structure is laser-cut to create a hollow structure. Therefore, the resulting snap-fit protrusion 4 has a certain elastic deformation characteristic, and it also allows the inner support 1 and the outer support 2 to be relatively independent before assembly, avoiding too many parts.
[0030] When the inner support 1 is assembled into the outer support 2, the snap-fit protrusion 4 and the snap-fit groove 5 are on the same side. During the assembly process, the snap-fit protrusion 4 deforms due to compression. When the snap-fit protrusion 4 coincides with the snap-fit groove 5, the snap-fit protrusion 4 springs back and snaps into the snap-fit groove 5 to achieve locking. At the same time, it can also ensure that the hollow parts of the inner support 1 and the outer support 2 are aligned and locked securely, making the assembly operation convenient.
[0031] In other specific implementation schemes, refer to Figures 1 to 3 As shown, the positioning and locking mechanism includes two tapered end bodies 6, which are symmetrically arranged at both ends of the inner support 1. The diameter of each tapered end body 6 on the side closest to the inner support 1 is larger than the diameter of the outer support 2. The length of the inner support 1 between the two tapered end bodies 6 is equal to the length of the outer support 2. The tapered end bodies 6 and the inner support 1 are an integrated structure with a certain degree of elasticity. The two ends of the inner support 1 are pressed against the outer side of the end of the outer support 2 by the tapered end bodies 6, achieving effective limiting. Since the length of the inner support 1 is equal to the length of the outer support 2, it can be ensured that the inner support 1 and the outer support 2 are axially equal and stable, and no displacement will occur.
[0032] Among them, reference Figure 2As shown, both ends of the outer support 2 have compressible elastic deformation protrusions 7, distributed circumferentially. These elastic deformation protrusions 7 are generated during laser cutting of the support and can be wavy. When one end of the inner support 1 is inserted into one end of the outer support 2, the tapered end 6 of the inserted end is compressed and deformed. When the inserted end of the inner support 1 is about to exit from the other end of the outer support 2, since the lengths of the inner support 1 and the outer support 2 are equal, in order to ensure that the tapered end 6 of the insertion end can have... The inner support 1 is effectively pushed out and springs back to its original position, causing the conical end 6 at the other end of the inner support 1 to press against the elastic deformation protrusion 7 on the corresponding side, compressing the elastic deformation protrusion 7 to a certain extent. This means that the overall length of the outer support 2 is compressed to a certain extent, making it easier for the conical end 6 at the insertion end of the inner support 1 to fully push out and have a certain space to spring back to its original position. Then the inner support 1 is released, so that the elastic deformation protrusion 7 is reset, and the conical ends 6 at both ends can effectively fit against the ends of the outer support 2, maintaining relative stability.
[0033] It should be noted that the conical end body 6 and the inner support 1 are cut into a hollow shape by laser cutting process. This allows the side of the conical end body 6 near the inner support 1 to have hollow holes that can cooperate with the elastic deformation protrusions 7. This makes it easy for the elastic deformation protrusions 7 to fit into the corresponding hollow holes. This can prevent relative rotation between the assembled inner support 1 and the outer support 2, which would cause the aligned non-hollow parts to shift and expose the drug storage tank 3 in advance.
[0034] In some specific implementations, the outer stent 2 is a magnesium alloy stent and the inner stent 1 is an iron alloy stent. The degradation rate of the magnesium alloy stent in the blood is much greater than that of the iron alloy stent, which effectively ensures that the outer stent 2 is degraded before the iron alloy stent.
[0035] Of course, other biodegradable polymer materials can also be selected for the outer scaffold 2 and the inner scaffold 1, ensuring that the degradation rate of the outer scaffold 2 is greater than that of the inner scaffold 1.
[0036] In some specific implementation schemes, both the outer support 2 and the inner support 1 are mesh-like hollow structures.
[0037] In some specific implementations, the drug stored in the drug storage tank 3 is taurine or rapamycin, or it may be a combination of other drugs.
[0038] To facilitate understanding of the embodiments of this solution by those skilled in the art, the working principle of this solution will now be briefly explained in conjunction with specific application scenarios: The prepared stent is implanted into the blood vessel. Since both the inner stent 1 and the outer stent 2 are hollow structures, the drug coating on the surface of both begins to dissolve and release drugs to exert a therapeutic effect, which reduces the proliferation and migration of smooth muscle cells and delays excessive thickening of the vascular intima.
[0039] After the drug coating is released, the inner stent 1 and the outer stent 2 come into contact with the blood and begin to degrade. Since the degradation rate of the inner stent 1 is slower than that of the outer stent 2, the outer stent 2 degrades first, leaving the inner stent 1. At this time, the inner stent 1 can still effectively provide good mechanical support to the inside of the blood vessel. The entire degradation cycle matches the rate of vascular regeneration. At the same time, as the outer stent 2 gradually degrades, the drug reservoir 3 will be exposed, thereby releasing the drug in the drug reservoir 3. Combined with the drug release of the drug coating, a relatively long-term drug release is achieved, which can inhibit the proliferation of smooth muscle in the blood vessel for a long time, thereby preventing restenosis of the blood vessel after stent implantation.
[0040] It should be noted that when the inner stent 1 is assembled into the outer stent 2, the presence of the positioning and locking mechanism ensures that the non-perforated parts of the outer stent 2 can effectively cover and shield the drug reservoir 3 on the inner stent 1. This ensures that the drug coating releases the drug first, and the drug in the drug reservoir 3 is temporarily stored. The drug in the drug reservoir 3 is only released after the outer stent 2 has degraded, ensuring a longer drug release time span, which is beneficial for improving long-term treatment effects.
[0041] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A biodegradable metallic stent with a drug reservoir, characterized in that, It comprises an inner layer stent (1) and an outer layer stent (2); The inner layer stent (1) and the outer layer stent (2) are both hollow structures, and the surface layers of the inner layer stent (1) and the outer layer stent (2) are provided with drug coating; The non-hollow parts of the inner layer stent (1) and the outer layer stent (2) are consistent in shape and are aligned and attached; the non-hollow parts of the inner layer stent (1) are provided with drug storage grooves (3), and the drug storage grooves (3) store drugs; The inner layer stent (1) and the outer layer stent (2) are both degradable metal stents, and the degradation rate of the inner layer stent (1) is less than that of the outer layer stent (2).
2. The biodegradable metallic stent with a drug storage cavity according to claim 1, characterized in that, A positioning and locking mechanism is arranged between the outer layer stent (2) and the inner layer stent (1), and the positioning and locking mechanism is used to lock and fix the outer layer stent (2) and the inner layer stent (1) when the non-hollow parts are aligned.
3. The biodegradable metallic stent with a drug storage cavity according to claim 2, characterized in that, The positioning and locking mechanism comprises a clamping protrusion (4) and a clamping groove (5), the clamping protrusion (4) is protrudingly arranged on the outer wall of the inner layer stent (1) near the end, the clamping groove (5) is arranged on the outer layer stent (2) near the end, and the clamping protrusion (4) and the clamping groove (5) are arranged in cooperation.
4. The biodegradable metallic stent with a drug storage cavity according to claim 2, characterized in that, The positioning and locking mechanism comprises two tapered end bodies (6), which are symmetrically arranged at the two ends of the inner layer stent (1); the diameter of each tapered end body (6) near the inner layer stent (1) is greater than the diameter of the outer layer stent (2); the length of the inner layer stent (1) between the two tapered end bodies (6) is equal to the length of the outer layer stent (2).
5. The biodegradable metallic stent with a drug storage cavity according to claim 4, characterized in that, The edges of the two ends of the outer layer stent (2) are provided with elastic deformation protrusions (7).
6. The biodegradable metallic stent with a drug storage cavity according to claim 1, characterized in that, The outer layer stent (2) is a magnesium alloy stent, and the inner layer stent (1) is an iron alloy stent.
7. The biodegradable metallic stent with a drug storage cavity according to claim 1, wherein, The outer layer stent (2) and the inner layer stent (1) are both net-shaped hollow structures.
8. The biodegradable metallic stent with a drug storage cavity according to claim 1, characterized in that, The drug stored in the drug storage groove (3) is taurine or rapamycin.
9. A method for manufacturing a degradable metallic stent with a drug reservoir for manufacturing a degradable metallic stent with a drug reservoir according to any one of claims 1 to 8, characterized in that, The specific steps are as follows: Firstly, the metal stent is cut by laser cutting process, so that the inner layer stent (1) and the outer layer stent (2) are consistent in shape and size; Secondly, the drug storage groove (3) is cut on the non-hollow part of the inner layer stent (1) by laser cutting process, and the drug storage groove (3) is filled with drugs; Thirdly, the inner layer stent (1) is assembled into the outer layer stent (2), so that the non-hollow parts of the inner layer stent (1) and the outer layer stent (2) are aligned and attached and locked; Fourthly, the surface layers of the inner layer stent (1) and the outer layer stent (2) are covered with drug coating.
10. The method of claim 9, wherein the biodegradable metal stent with a drug storage cavity is manufactured by the steps of: The specific operation of covering the drug coating is that the inner layer stent (1) and the outer layer stent (2) locked together are placed in a drug coating solution, then taken out and placed in a vacuum oven for drying.