Degradable intracranial drug eluting stent

Abstract

The application provides a degradable intracranial drug eluting stent, and belongs to the technical field of medical devices. The stent comprises a magnesium-based stent base, a drug coating and a protective coating. The drug coating is coated on the outer surface of the magnesium-based stent base and is used for treating vascular stenosis. The protective coating is coated on the outer surface of the drug coating to protect the drug coating. The magnesium-based stent base is implanted in an intracranial blood vessel at an early stage. The protective coating and the drug coating are degraded in sequence. The drug coating releases an anti-proliferative drug to inhibit the proliferation of vascular smooth muscle cells. The magnesium-based stent base is implanted in an intracranial blood vessel at a later stage. After the drug coating is completely degraded, the magnesium-based stent base starts to degrade and continuously releases magnesium ions to protect and repair nerves. The application mainly solves the technical problems of the existing cerebral vascular stent, such as many long-term complications and single function.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a biodegradable intracranial drug-eluting stent. Background Technology

[0002] Ischemic stroke, a cerebrovascular disease, has a persistently high incidence, disability rate, and mortality rate. Currently, interventional surgery is the primary clinical treatment method. This involves implanting cerebral vascular stents to mechanically support and open narrowed blood vessels, restoring cerebral blood flow. Interventional surgery remains the mainstream treatment option. However, existing cerebral vascular stents still have many shortcomings, making it difficult to meet the needs of ischemic stroke patients throughout the entire course of treatment and rehabilitation. Specific problems include: First, traditional mainstream bare-metal stents or drug-eluting stents mostly use non-degradable metals as the framework. After the stent is implanted, it will remain permanently in the blood vessel. As a foreign body, it will continuously irritate the vascular tissue, which can easily induce local chronic inflammation and delay the process of vascular endothelialization. This greatly increases the probability of restenosis and long-term thrombosis in the later stage of stent implantation, bringing long-term health risks to patients.

[0003] Second, existing stents can only achieve mechanical dilation of blood vessels and restoration of blood flow, intervening only in the problem of vascular stenosis, and cannot address the pathological processes following cerebral ischemia-reperfusion injury. Conventional stents have no effect on problems such as neuronal apoptosis, inflammatory cascade reactions, and damage to neural circuits caused by ischemia, making it difficult to assist in the repair of damaged nerve tissue and improve the long-term neurological prognosis of patients.

[0004] Third, although some studies in recent years have attempted to combine neuroprotective factors or cell therapy with scaffolds (such as the magnesium ion-eluting PLCL scaffold developed by the Peking University / Capital Medical University team and the PSMM microporous microgel scaffold developed by Tongji University), most of these studies are still in the preclinical stage. Their functional designs are relatively one-sided, focusing primarily on neuroprotection or post-treatment tissue repair. They fail to integrate the pathological characteristics of different stages of ischemic stroke with the design of acute-phase vascular opening and restenosis inhibition with subacute and chronic-phase neuroprotection and repair, resulting in poor treatment continuity.

[0005] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0006] The purpose of this invention is to provide a biodegradable intracranial drug-eluting stent to solve the technical problems of existing cerebral vascular stents having many long-term complications and limited functions.

[0007] To achieve the above objectives, the biodegradable intracranial drug-eluting scaffold of the present invention provides the following technical solution: A biodegradable intracranial drug-eluting stent, comprising: Magnesium-based metal scaffold matrix; A drug coating, wherein the drug coating covers the outer surface of the magnesium-based metal stent matrix, for the treatment of vascular stenosis; A protective coating is applied to the outer surface of the drug coating to protect it. In the early stage of implantation of the magnesium-based metal scaffold matrix into intracranial blood vessels, the protective coating and the drug coating degrade sequentially, and the drug coating releases anti-proliferative drugs to inhibit the proliferation of vascular smooth muscle cells. In the middle and late stages of implantation of the magnesium-based metal scaffold matrix into intracranial blood vessels, after the drug coating degrades, the magnesium-based metal scaffold matrix begins to degrade and continuously releases magnesium ions to protect and repair nerves.

[0008] As a further optimized technical solution, an elastic adhesive layer is arranged on the side of the magnesium-based metal stent matrix facing or away from the blood vessel wall. The adhesive layer is arranged between the drug coating and the magnesium-based metal stent matrix to bond and fix the resulting fragments when the magnesium-based metal stent matrix degrades and fragments locally, so as to prevent the fragments from causing thrombosis.

[0009] As a further optimized technical solution, the degradation cycle of the magnesium-based metal scaffold matrix is ​​3 to 12 months; the degradation cycle of the adhesive layer is longer than that of the magnesium-based metal scaffold matrix, so as to ensure that the adhesive layer always maintains its structural integrity before the magnesium-based metal scaffold matrix is ​​completely degraded, thereby continuously bonding and fixing the fragments generated during the degradation process of the magnesium-based metal scaffold matrix.

[0010] As a further optimized technical solution, the magnesium-based metal support substrate is a mesh-like structure made of high-purity magnesium or magnesium alloy. The mesh-like structure is composed of multiple annular wave-shaped support units connected sequentially by connecting rods.

[0011] As a further optimized technical solution, the width of the adhesive layer is greater than the width of the mesh rod and the connecting rod of the mesh tube structure.

[0012] As a further optimized technical solution, the thickness of the adhesive layer is 1–20 μm.

[0013] As a further optimized technical solution, the degradation cycle of the adhesive layer is 6 to 24 months, and the degradation cycle of the adhesive layer is at least 1 to 6 months longer than that of the magnesium-based metal scaffold matrix.

[0014] As a further optimized technical solution, the drug coating is composed of a mixture of a biodegradable polymer and an antiproliferative drug, wherein the antiproliferative drug is selected from at least one of rapamycin, everolimus, zotamolimus, and paclitaxel.

[0015] As a further optimized technical solution, the drug coating completes drug release within 1 to 3 months after implantation of the magnesium-based metal scaffold matrix.

[0016] As a further optimized technical solution, the protective coating is composed of a biodegradable hydrophilic polymer, which is selected from at least one of polyvinyl alcohol, chitosan, hyaluronic acid, or gelatin.

[0017] Beneficial effects: First, this invention, by applying a drug coating to the surface of a magnesium-based metal stent matrix, releases anti-proliferative drugs in the early stages of stent implantation, inhibiting vascular smooth muscle proliferation and preventing in-stent restenosis. In the mid-to-late stages of stent implantation, the magnesium-based metal matrix degrades and releases magnesium ions, continuously exerting neuroprotective and neurorepairing effects. This combines acute-phase vascular opening and anti-stenosis with subacute and chronic-phase neurorepair, forming a complete treatment chain that is more suitable for the rehabilitation needs throughout the entire cycle of ischemic stroke.

[0018] Secondly, the inventor uses a biodegradable magnesium-based metal stent matrix. After the stent completes its functions of vascular support and drug release, it can be gradually degraded and absorbed by the human body in the later stages. It will not remain in the blood vessel as a permanent foreign body, effectively eliminating problems such as chronic inflammation, long-term thrombosis, and late restenosis caused by traditional non-degradable stents.

[0019] Furthermore, magnesium ions are a natural degradation product of the scaffold matrix, eliminating the need for additional loading of functional factors and simplifying the device structure. Magnesium ions are continuously and controllably released locally in ischemic brain tissue, targeting the lesion area to exert neuroprotective and repair effects. Compared with systemic infusion of magnesium, it can effectively avoid systemic adverse reactions such as cardiovascular inhibition, resulting in higher biosafety.

[0020] Finally, by applying a protective coating to the outside of the drug-eluting layer, the outer protective coating prevents the drug-eluting layer from being worn or scratched during stent delivery, catheter advancement, and intravascular deployment. This effectively protects the inner drug-eluting layer, preventing damage and premature drug detachment, and ensuring drug load and the intended release effect. Simultaneously, the protective coating slows down the initial drug release rate, avoiding a sudden surge of drug release at implantation, resulting in a smoother and more controllable drug release process, and reducing adverse reactions caused by excessively high local drug concentrations.

[0021] Furthermore, the adhesive layer, sandwiched between the substrate and the drug coating, primarily serves to ensure the integrity of the magnesium-based stent substrate before complete degradation, preventing stent substrate fragments from detaching and inducing thrombosis during degradation, thus resolving safety hazards during the degradation process of the magnesium-based stent substrate. Simultaneously, as a carrier for the drug coating, the adhesive layer increases the adhesion area of ​​the drug coating, enhances the coating's bonding strength, effectively prevents the drug coating from detaching during stent delivery and vascular deformation, and ensures stable drug release. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, 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 undue limitation of the invention. Wherein: Figure 1 This is a schematic diagram of the magnesium-based metal scaffold matrix structure of one embodiment of the biodegradable intracranial drug-eluting scaffold of the present invention; Figure 2 This is a cross-sectional schematic diagram of a mesh rod of a magnesium-based metal stent matrix according to an embodiment of the biodegradable intracranial drug-eluting stent of the present invention.

[0023] In the figure: 1. Magnesium-based metal scaffold substrate; 1-1. Waveform support unit; 1-2. Connecting rod; 2. Drug coating; 3. Protective coating; 4. Adhesive layer. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0025] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. Furthermore, the term "proximal end" uniformly refers to the end closer to the operator, while "distal end" refers to the end farther from the operator.

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0027] The shapes and sizes of the components in the accompanying drawings do not reflect the actual proportions of the product; they are only intended to illustrate the content of the invention.

[0028] This invention addresses the technical problems of existing cerebral vascular stents, such as numerous long-term complications and limited functionality, by providing a biodegradable intracranial drug-eluting stent. The stent comprises, from the inside out, a magnesium-based metal stent matrix 1, a drug coating 2, and a protective coating 3. After implantation, the layers sequentially begin to function: in the early stages of implantation, the outer protective coating 3 gradually dissolves, and the drug coating 2 releases anti-proliferative drugs, effectively inhibiting vascular smooth muscle cell proliferation and preventing restenosis; in the mid-to-late stages of implantation, the drug coating 2 completely degrades, and the magnesium-based metal stent matrix 1 begins to degrade and continuously releases magnesium ions. These magnesium ions help protect neurons, inhibit inflammatory responses, and promote nerve repair. Furthermore, the stent also includes an adhesive layer 4. The adhesive layer 4 is located between the magnesium-based metal stent matrix 1 and the drug coating 2, and can be positioned on the side of the matrix facing or away from the vessel wall. The adhesive layer 4 added in this invention has a longer degradation cycle than the magnesium-based metal stent matrix 1. This ensures the integrity of the magnesium-based metal stent matrix 1 even when it degrades and fragments, preventing thrombosis caused by fragments. Simultaneously, it improves the stability of the drug coating adhesion and reduces drug detachment. The entire stent is made of fully biodegradable material, avoiding complications such as chronic inflammation and long-term restenosis associated with traditional permanent stents. It achieves sequential and synergistic treatment of acute-phase anti-restenosis and subacute and chronic-phase neuroprotection. Drug and magnesium ions are released locally and targeted, resulting in fewer systemic side effects and a safe and reliable structure.

[0029] Example 1

[0030] like Figure 1-2 As shown, the biodegradable intracranial drug-eluting scaffold includes a magnesium-based metal scaffold matrix 1, a drug coating 2, and a protective coating 3.

[0031] The magnesium-based metal scaffold substrate 1 is made of high-purity magnesium or magnesium alloy, wherein the magnesium alloy is selected from Mg-Zn alloys, Mg-Nd alloys, Mg-Zn-Nd alloys, or Mg-Zn-Zr alloys. The magnesium-based metal scaffold substrate 1 has an overall mesh-like structure, which has good radial support and flexibility, and is suitable for the delivery and release of cerebral blood vessels. Specifically, the mesh-like structure is composed of multiple annular wave-shaped support units 1-1 connected sequentially by connecting rods 1-2.

[0032] The drug coating 2 is applied to the outer surface of each mesh rod and connecting rod 1-2 of the tubular structure for the treatment of vascular stenosis. Specifically, the drug coating 2 is composed of a mixture of a biodegradable polymer and an antiproliferative drug, the antiproliferative drug being selected from at least one of rapamycin, everolimus, zotamolimus, and paclitaxel.

[0033] A protective coating 3 covers the outer surface of the drug-eluting coating 2 and is composed of a biodegradable hydrophilic polymer selected from at least one of polyvinyl alcohol (PVA), chitosan, hyaluronic acid, or gelatin. Specifically, during stent delivery, catheter advancement, and intravascular release, the protective coating 3 prevents the drug-eluting coating 2 from being worn or scratched, effectively protecting the inner drug-eluting coating 2, preventing damage to the drug-eluting coating 2 and premature drug detachment, and ensuring drug load and the predetermined release effect. Simultaneously, it gradually degrades after stent implantation, achieving controlled and sustained drug release.

[0034] In the early stages of implantation of the magnesium-based metal scaffold matrix 1 into intracranial blood vessels, the protective coating 3 and the drug coating 2 degrade sequentially. The drug coating 2 releases anti-proliferative drugs to inhibit the proliferation of vascular smooth muscle cells. In the middle and late stages of implantation, after the drug coating 2 has completely degraded, the magnesium-based metal scaffold matrix 1 begins to degrade and continuously releases magnesium ions (Mg²⁺). + It exerts neuroprotective effects in ischemic brain tissue by inhibiting neuronal apoptosis, reducing inflammatory response, and improving reperfusion injury.

[0035] Furthermore, since magnesium-based metal materials undergo gradual degradation in the human body fluid environment, magnesium-based metal stent matrix 1 is prone to local disintegration and fragmentation during long-term service. Once the scattered metal fragments are released into the blood circulation, they will greatly increase the risk of thrombosis and vascular blockage, reducing the safety of stent use.

[0036] To address the aforementioned technical problems, an elastic adhesive layer 4 is provided between the magnesium-based metal stent substrate 1 and the drug coating 2. This adhesive layer 4 can be positioned on the side of the magnesium-based metal stent substrate 1 facing the blood vessel wall or on the side facing away from the blood vessel wall, depending on actual usage requirements. In this embodiment, as... Figure 2 The adhesive layer 4 shown is applied to the side of the magnesium-based metal stent matrix 1 facing the blood vessel wall.

[0037] The adhesive layer 4 of this invention has a longer degradation cycle than the magnesium-based metal stent matrix 1. It can maintain a stable structure and adhesion throughout the entire degradation cycle of the matrix, and can constrain and fix various fragments generated by matrix fragmentation, preventing fragments from entering blood vessels. In addition, the adhesive layer 4 fills the space between the magnesium-based metal stent matrix 1 and the drug coating 2, further optimizing the bonding stability of the multilayer structure.

[0038] Specifically, the adhesive layer 4 is made of a medical-grade biodegradable elastic polymer material, which can be selected from at least one of polycaprolactone, biodegradable polyurethane, polylactic acid-glycolic acid copolymer, polylactic acid, and polydioxanone. These materials possess good elasticity, adhesive strength, and a controllable degradation rate, with a longer degradation cycle than the magnesium-based metal stent matrix 1. They maintain structural integrity throughout the entire degradation process of the stent matrix, effectively bonding stent fragments and preventing thrombosis, while also enhancing the adhesion stability of the drug coating. Furthermore, the degradation products have good biocompatibility and will not irritate blood vessels or surrounding tissues.

[0039] In this embodiment, the drug coating 2 completes drug release within 1 to 3 months after implantation of the magnesium-based metal scaffold 1 (e.g., 1 month, 2 months, 3 months, or any point between any two adjacent data points). The degradation period of the magnesium-based metal scaffold 1 is 3 to 12 months (e.g., 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 12 months, or any point between any two adjacent data points); the degradation period of the adhesive layer 4 is longer than that of the biodegradable magnesium-based metal scaffold 1, to ensure that the adhesive layer 4 maintains its structural integrity until the biodegradable magnesium-based metal scaffold 1 is completely degraded, thereby continuously bonding and fixing the fragments generated during the degradation process of the magnesium-based metal scaffold 1.

[0040] Furthermore, the width of the adhesive layer 4 is greater than the width of the mesh rods and connecting rods of the tubular structure. This structural design significantly increases the contact area between the adhesive layer 4 and the magnesium-based metal stent matrix 1, enhancing the bonding effect. Even if the stent matrix degrades and fragments in vivo, the adhesive layer can stably restrain and fix the fragments, further avoiding the risk of fragments causing thrombosis. On the other hand, the wider adhesive layer 4 can serve as a carrier substrate for the drug coating, effectively expanding the adhesion area of ​​the drug coating, increasing the overall drug loading capacity, and making the drug coating 4 cover more evenly, avoiding local coating loss or detachment, and ensuring stable drug release according to the preset pattern.

[0041] Furthermore, the thickness of the adhesive layer 4 is 1–20 μm (e.g., 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or any point between any two adjacent data).

[0042] Furthermore, the degradation period of the adhesive layer 4 is 6 to 24 months (e.g., 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 12 months, 13 months, 14 months, 15 months, 16 months, 17 months, 18 months, 19 months, 20 months, 21 months, 22 months, 23 months, 24 months or any point between any two adjacent data), and the degradation period of the adhesive layer is at least 1 to 6 months longer than the degradation period of the magnesium-based metal scaffold matrix 1 (e.g., 1 month, 2 months, 3 months, 4 months, 5 months, 6 months or any point between any two adjacent data).

[0043] Example 2

[0044] The biodegradable intracranial drug-eluting stent provided in this embodiment consists of, from the inside out: a magnesium-based metal stent substrate 1, an adhesive layer 4, a drug coating 2, and a protective coating 3. In this embodiment, the adhesive layer 4 is arranged on the side of the magnesium-based metal stent substrate 1 facing away from the blood vessel wall.

[0045] The magnesium-based metal support substrate 1 is prepared using tubular components made from Mg-3wt%Zn magnesium-zinc alloy. These are processed into a mesh-like support using laser cutting technology. The overall length of the support is 10–30 mm, the diameter is 2.0–4.5 mm, and the wall thickness of the mesh rods is 0.1–0.2 mm. The processed support is then subjected to cleaning, acid etching, and passivation treatments before use.

[0046] Preparation of adhesive layer 4: Polyurethane is selected as the adhesive layer material. A cylindrical base adapted to the inner side of the magnesium-based metal support substrate 1 is made. Then, a mesh structure of the same shape as the magnesium-based metal support substrate 1 is processed in the same way as the magnesium-based metal support substrate 1 and then attached to the inner side of the magnesium-based metal support substrate 1.

[0047] Preparation of drug coating 2: Rapamycin and polylactic acid-glycolic acid copolymer (PLGA) were mixed at a mass ratio of 1:5 and dissolved in dichloromethane to prepare a spraying solution; the solution was uniformly coated on the outside of the adhesive layer and the magnesium-based metal scaffold substrate 1 using a precision spraying device, with a coating thickness of 5-15 μm, and then the solvent was removed by vacuum drying.

[0048] Preparation of protective coating 3: Chitosan was selected as the raw material for the protective coating. Chitosan was dissolved in acetic acid solution, and a protective coating with a thickness of 2–5 μm was formed on the outer side of the drug coating using an dip-coating method. This coating can protect the drug coating from abrasion during stent delivery and simultaneously delay the initial burst release of the drug.

[0049] After the stent is implanted: Implantation 0-1 month: Protective coating 3 gradually dissolves; 1-3 months after implantation: Protective coating 3 completely degrades, and drug coating 2 begins to release drugs, inhibiting restenosis; 3-6 months after implantation: The drug coating is completely degraded, and the magnesium-based metal scaffold matrix 1 begins to degrade gradually, continuously releasing magnesium ions. Magnesium ions inhibit neuronal apoptosis and reduce local inflammation by antagonizing calcium ion overload, regulating microglia polarization, promoting the expression of brain-derived neurotrophic factor, and reducing local inflammation. Throughout the degradation process, the adhesive layer 4 maintains structural integrity, firmly adhering to the degradation fragments of the matrix and preventing thrombosis.

[0050] 6–24 months after implantation: The bonding layer 4 gradually and slowly degrades and is eventually completely absorbed by the body tissue. By this time, all functional layers of the stent and the matrix have completed degradation, leaving no foreign body residue inside the blood vessel. Throughout the entire cycle, the stent sequentially completes the entire process of opening the blood vessel, inhibiting restenosis, and protecting and repairing nerves. This not only solves the long-term complication problem of traditional permanent stents, but also ensures the safety and therapeutic effect of use throughout the implantation process thanks to its multi-layered structural design.

[0051] Example 3

[0052] This embodiment is basically the same in structure as Embodiment 2, the difference being the adjustment of materials and parameters: The magnesium-based metal scaffold matrix is ​​made of Mg-Nd-Zr magnesium alloy, with a degradation period of 9 months; the bonding layer is made of polylactic acid, with a thickness of 5 μm and a degradation period of 15 months, which is 6 months longer than the degradation period of the matrix; the drug coating is made of everolimus as an antiproliferative drug, combined with polylactic acid (PLA). The protective coating 3 is prepared using polyvinyl alcohol.

[0053] The stent in this embodiment also has the functions of timed drug release and timed magnesium release. The adhesive layer stably fixes the degraded fragments, and the drug coating release cycle is still 1 to 3 months, which is suitable for clinical use needs.

[0054] Example 4

[0055] This embodiment is structurally similar to Embodiment 1, with the difference being the arrangement of the scaffold matrix on its outer side: In this embodiment, the biodegradable intracranial drug-eluting scaffold is a base structure scaffold without an adhesive layer. The structure, from the inside out, consists of a magnesium-based metal scaffold matrix, a drug coating, and a protective coating. The scaffold matrix is ​​made of high-purity magnesium, with a degradation cycle of 3 months; the drug coating is prepared using a composite of paclitaxel and PLGA, and the protective coating is prepared using hyaluronic acid. This scaffold can achieve early anti-restenosis and mid-to-late-stage magnesium ion neuroprotection, making it suitable for clinical scenarios requiring rapid scaffold degradation.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are within the protection scope of the present invention.

[0057] It is understood that the above description is merely exemplary and the embodiments of this application do not limit the scope of the application.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are within the protection scope of the present invention.

Claims

1. A biodegradable intracranial drug-eluting stent, characterized in that, include: Magnesium-based metal scaffold matrix (1); Drug coating (2), the drug coating (2) is applied to the outer surface of the magnesium-based metal stent matrix (1) for the treatment of vascular stenosis; A protective coating (3) is applied to the outer surface of the drug coating (2) to protect the drug coating (2). In the early stage of implantation of the magnesium-based metal scaffold matrix (1) into intracranial blood vessels, the protective coating (3) and the drug coating (2) degrade sequentially, and the drug coating (2) releases anti-proliferative drugs to inhibit the proliferation of vascular smooth muscle cells; in the middle and late stages of implantation of the magnesium-based metal scaffold matrix (1) into intracranial blood vessels, after the drug coating (2) degrades, the magnesium-based metal scaffold matrix (1) begins to degrade and continuously releases magnesium ions to protect and repair nerves.

2. The biodegradable intracranial drug-eluting scaffold according to claim 1, characterized in that, The magnesium-based metal stent matrix (1) has an elastic adhesive layer (4) arranged on the side facing or away from the blood vessel wall. The adhesive layer (4) is arranged between the drug coating (2) and the magnesium-based metal stent matrix (1) to bond and fix the generated fragments when the magnesium-based metal stent matrix (1) degrades and fragments locally, so as to prevent the fragments from causing thrombosis.

3. The biodegradable intracranial drug-eluting scaffold according to claim 2, characterized in that, The degradation cycle of the magnesium-based metal scaffold matrix (1) is 3 to 12 months; the degradation cycle of the adhesive layer (4) is longer than that of the magnesium-based metal scaffold matrix (1) to ensure that the adhesive layer (4) maintains its structural integrity before the magnesium-based metal scaffold matrix (1) is completely degraded, thereby continuously bonding and fixing the fragments generated during the degradation process of the magnesium-based metal scaffold matrix (1).

4. The biodegradable intracranial drug-eluting scaffold according to claim 2, characterized in that, The magnesium-based metal support substrate (1) is a mesh structure made of high-purity magnesium or magnesium alloy. The mesh structure is composed of multiple annular wave support units (1-1) connected in sequence by connecting rods (1-2).

5. The biodegradable intracranial drug-eluting scaffold according to claim 4, characterized in that, The width of the adhesive layer (4) is greater than the width of the mesh rod and the connecting rod of the mesh tube structure.

6. The biodegradable intracranial drug-eluting scaffold according to claim 2, characterized in that, The thickness of the adhesive layer (4) is 1 to 20 μm.

7. The biodegradable intracranial drug-eluting scaffold according to claim 6, characterized in that, The degradation cycle of the adhesive layer (4) is 6 to 24 months, and the degradation cycle of the adhesive layer is at least 1 to 6 months longer than that of the magnesium-based metal scaffold matrix (1).

8. The biodegradable intracranial drug-eluting scaffold according to any one of claims 1-7, characterized in that, The drug coating (2) is composed of a mixture of a biodegradable polymer and an antiproliferative drug, wherein the antiproliferative drug is selected from at least one of rapamycin, everolimus, zotamolimus, and paclitaxel.

9. The biodegradable intracranial drug-eluting scaffold according to any one of claims 1-7, characterized in that, The drug coating (2) completes drug release within 1 to 3 months after implantation of the magnesium-based metal scaffold matrix (1).

10. The biodegradable intracranial drug-eluting scaffold according to claim 1, characterized in that, The protective coating (3) is composed of a biodegradable hydrophilic polymer selected from at least one of polyvinyl alcohol, chitosan, hyaluronic acid or gelatin.

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