Interventional therapy drug carriers and interventional therapy systems

Abstract

This invention relates to the field of medical device technology, and discloses an interventional therapy drug carrier and an interventional therapy system. The interventional therapy drug carrier includes a catheter, a stent, and a balloon. The stent is adapted to self-expand radially, is fitted onto the catheter, with its distal end fixedly connected to the catheter and its proximal end movably connected to the catheter. A pull cord is connected to a movable ring extending outside the body; pulling the cord retracts the stent, thus achieving retrieval and avoiding the problem of long-term implantation. The balloon surrounds and is attached to the outside of the stent; the balloon is adapted to expand with the stent, and the outer wall of the balloon is coated with medication. In this invention, the inner side of the balloon is a self-expanding stent, allowing blood flow, solving the problem of blood flow obstruction caused by traditional balloons. The stent acts as a balloon support, providing radial support after expansion, thereby increasing the balloon's adherence to the wall, while the release of medication can treat and prevent intravascular restenosis.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to interventional therapy drug carriers and interventional therapy systems. Background Technology

[0002] With the continuous development of my country's economy and the rising level of national consumption, various unhealthy lifestyle habits such as poor diet and staying up late have led to a year-on-year increase in the number of patients with cardiovascular and cerebrovascular diseases, and the rate of patients seeking medical treatment and undergoing surgery is also increasing year by year. Percutaneous peripheral intervention (PPI) has become the preferred treatment for symptomatic peripheral arterial occlusive disease (PAD). Compared with surgical bypass grafting, this minimally invasive treatment provides equivalent pain relief and limb salvage while minimizing patient morbidity, complications, and costs.

[0003] The common method involves delivering medication into the blood vessel via a stent or balloon. To ensure surgical safety, retrievable stents cannot remain in the body for too long; therefore, conventional stents that are permanently implanted are typically used in the vessel wall where medication delivery is required. While conventional stent interventions are less invasive, the poor adhesion between the drug-eluting coating and the vessel wall has been a major concern. Insufficient adhesion can lead to the drug being washed away by blood flow, reducing its absorption rate. Balloon dilation completely blocks blood flow, resulting in a very short release time for the drug coating. Even this short release time cannot guarantee sufficient absorption by the vessel wall, and the drug may be carried away by the blood flow. Prolonged dilation time, on the other hand, may cause damage to the body. Therefore, the application of balloons in certain locations is inevitably limited. Summary of the Invention

[0004] In view of this, the present invention provides an interventional therapy drug carrier and an interventional therapy system to solve the problems of balloon dilation easily blocking blood flow and poor adhesion of the drug coating.

[0005] In a first aspect, the present invention provides an interventional therapeutic drug carrier, comprising a catheter, a stent, and a balloon. The stent is adapted to self-expand radially, is sleeved on the catheter, has its distal end fixedly connected to the catheter, and its proximal end movably connected to the catheter; the balloon surrounds and is attached to the outside of the stent; the balloon is adapted to expand with the expansion of the stent, and the outer wall of the balloon is coated with a drug.

[0006] Beneficial Effects: The interventional drug delivery carrier provided by this invention features a self-expanding stent, which is fitted over a catheter, with a balloon covering the outside of the stent. When the stent is inserted into the blood vessel via the catheter, the sheath is retracted, allowing the stent to self-expand. After expansion, a gap exists between the stent and the catheter, allowing blood flow to pass through, thus solving the problem of blood flow obstruction caused by traditional balloons. Furthermore, the stent acts as a support for the balloon, providing radial support after expansion, thereby increasing the balloon's apposition to the vessel wall and overcoming the deficiency of poor apposition when using simply covered drug-eluting stents. Simultaneously, drug release can treat and prevent intravascular restenosis. Because the stent inside the balloon allows blood flow without obstructing it, the balloon can expand for an extended period within the blood vessel, ensuring sufficient drug absorption and improving therapeutic efficacy, thus solving the problems of short drug release time and poor therapeutic effect associated with traditional balloons.

[0007] In one alternative embodiment, the catheter is provided with a fixed ring that is fixedly connected to the catheter and a movable ring that is slidably fitted outside the catheter. The distal end of the support is connected to the fixed ring, and the proximal end of the support is connected to the movable ring.

[0008] Beneficial effects: This setup ensures the relative positions of the stent and catheter, guaranteeing that the balloon will not move during delivery.

[0009] In one alternative embodiment, the catheter has a through-hole, and the proximal end of the stent is connected to a pull cord adapted to extend outside the body, the pull cord being connected to a movable ring; the proximal end of the pull cord passes through the through-hole on the catheter and extends from the interior of the catheter to the outside of the body; pulling the pull cord is adapted to retract the stent.

[0010] Beneficial effects: The proximal end of the stent is connected to a pull cord via a movable ring. During catheter delivery, the pull cord remains at least partially outside the body. After the medication is released, pulling the pull cord causes the stent to retract and return to the outside of the body along with the catheter. This solves the problems of traditional stents being non-retrievable, requiring long-term implantation, and potentially leading to inflammation, thrombosis, and vascular damage.

[0011] In one optional embodiment, unlike conventional membrane-covered stents with single-layer membrane structures, the stent outer balloon includes an inner soft capsule attached to the outer surface of the stent and an outer soft capsule sleeved outside the inner soft capsule. The proximal ends of both the inner and outer soft capsules are connected to the proximal end of the stent, and the distal ends of both the inner and outer soft capsules are connected to the distal end of the stent, forming a closed cavity between the inner and outer soft capsules. The compliance of the outer soft capsule is significantly greater than that of the inner soft capsule, and the outer soft capsule is adapted to expand radially under pressure.

[0012] Beneficial effects: By injecting fluid into the closed cavity, the external soft capsule is expanded by the fluid pressure, thereby improving the apposition of the external soft capsule to the blood vessel. This allows the drugs attached to the surface of the external soft capsule to fully contact the blood vessel and be absorbed by the blood vessel, thus improving the therapeutic effect. This solves the problems of poor apposition of stents or drug coatings to the blood vessel and poor drug treatment effect.

[0013] In one alternative embodiment, the interventional therapy drug carrier further includes at least one injection conduit; the injection conduit is arranged side by side on the outside of the catheter, the proximal end of the injection conduit is connected to the proximal end of the catheter, and the distal end of the injection conduit communicates with the lumen of the balloon.

[0014] Beneficial effects: This design allows for easy injection of filling medium into the sealed cavity of the balloon via the injection tubing.

[0015] In one alternative embodiment, the outer surface of the outer soft capsule in a contracted state is compressed to form several grooves, the drug is loaded in the grooves, and the grooves are adapted to return to a flat surface as the outer soft capsule expands.

[0016] Beneficial effects: Drug delivery via grooves reduces drug loss during stent transport. Upon reaching the designated location, the outer balloon is subjected to the radial force of stent expansion and the pressure of the filling medium. The surface of the outer balloon recovers, the grooves disappear, and the drug crystals in the grooves are squeezed onto the vessel wall, or even puncture the vessel wall to enter the blood vessel, achieving a full therapeutic effect.

[0017] In one alternative embodiment, in the contracted state, the length of the external soft balloon along the catheter axis is at least twice the length of the stent along the catheter axis.

[0018] Beneficial effects: In the contracted state, since the length of the outer soft capsule along the catheter axis is greater than the length of the stent along the catheter axis, the outer soft capsule contracts and wrinkles, and the surface can form the grooves mentioned above through compression, which are used to load drugs and reduce drug loss during delivery.

[0019] In one alternative embodiment, the outer surface of the drug is coated with a sustained-release layer, which includes one or more of the following polymers: polylactic acid, polylactic acid-glycolic acid copolymer, polydioxanone, urea, butylated hydroxyphenol, or acetylglucosyl tributyl ester.

[0020] Beneficial effects: By setting a sustained-release layer on the surface of the drug, the present invention allows for selection of the drug release time according to the actual condition. The aforementioned copolymer enables sustained drug release.

[0021] In one alternative embodiment, the stent is made of Fe-Ni-Cr, Ni-Co-Cr, Fe-Ni-Co, and NiTi alloys or BeCu alloys; or, the balloon is made of an elastic material, including polyurethane, synthetic rubber, or natural latex; or, the injection conduit is made of titanium alloy, steel, or rubber.

[0022] Beneficial effects: The stent is made of a highly elastic material, enabling self-expansion. The balloon is made of a highly resilient material, allowing for expansion and improving balloon adhesion. The injection tubing is made of a high-strength, highly elastic material, allowing it to bend outwards as the stent expands while withstanding the pressure exerted during balloon inflation.

[0023] In one alternative embodiment, the drug includes paclitaxel, sirolimus, tacrolimus, or everolimus; the drug accounts for 1 wt% to 20 wt% of the polymer.

[0024] Beneficial effects: The above-mentioned drugs can be used for PPIs. By controlling the proportion of the drug in the polymer within the range of 1wt% to 20wt%, good therapeutic effects can be ensured.

[0025] Secondly, the present invention also provides an interventional therapy system, including any of the interventional therapy drug carriers described in the above technical solutions.

[0026] Beneficial effects: Since the interventional therapy system includes an interventional therapy drug carrier, it has the same effects as the interventional therapy drug carrier, which will not be elaborated here. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a stent in an interventional drug delivery system before expansion.

[0029] Figure 2 for Figure 1 Enlarged view of a portion of the surface of the soft tissue capsule in China and abroad;

[0030] Figure 3 for Figure 1 The diagram shows the structure of the stent in the interventional drug delivery system after expansion.

[0031] Figure 4 for Figure 3 The diagram shows the blood flow pathway after the stent expands in the interventional drug delivery system.

[0032] Figure 5 for Figure 3 The image shows a cross-sectional view of the stent in the interventional drug delivery system along the axial direction.

[0033] Figure 6 for Figure 3 The diagram shows a radial cross-sectional view of the stent in the interventional drug delivery system.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Catheter; 2. Stent; 3. Balloon; 31. Inner soft balloon; 32. Outer soft balloon; 321. Groove; 4. Fixation ring; 5. Movable ring; 6. Pull cord; 7. Injection tubing; 8. Connecting wire; 9. Fixation buckle; 10. Drug; 20. Vessel wall. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that, in the embodiments of this invention, "proximal end" and "distal end" refer to the operator's perspective; the end closer to the operator is the proximal end, and the end farther from the operator is the distal end. For example... Figure 1 As shown in the center direction F, the direction along F is from near to far.

[0038] The following is a detailed explanation of the English abbreviations used in the embodiments of the present invention.

[0039] PPI refers to percutaneous peripheral interventional therapy, a treatment method that uses interventional devices to eliminate stenosis or thrombosis in the coronary arteries and peripheral arteries through a minimally invasive, non-surgical approach.

[0040] PAD refers to peripheral artery disease, also known as arterial occlusive disease. It is a disease caused by systemic atherosclerosis that slows blood flow to the limbs. It is most often used to refer to limb ischemia secondary to atherosclerotic occlusion.

[0041] PTX refers to paclitaxel, with the molecular formula Cx. 47 H 51 NO 14 It is a highly effective, low-toxicity, broad-spectrum natural anticancer drug10, which has been widely used in the treatment of breast cancer, ovarian cancer, some head and neck cancers, and lung cancer.

[0042] RAPA refers to rapamycin, also known as sirolimus, with the molecular formula C10. 51 H 79 NO 13 It is a novel and highly effective immunosuppressant used clinically to treat organ transplant rejection and autoimmune diseases.

[0043] TAC, or tacrolimus, also known as FK506, is an immunosuppressive macrolide drug with a high degree of immunosuppression. It is a derivative of sirolimus.

[0044] SDZRAD refers to everolimus, also known as 40-O-(2-hydroxyethyl)-rapamycin, which is a derivative of rapamycin and also has a certain therapeutic effect on cancer.

[0045] Currently, common interventional consumables for percutaneous peripherally inserted procedures include balloons and stents. Balloons mainly have the following drawbacks:

[0046] After balloon dilation, blood flow to the blood vessel may be completely blocked. Therefore, the drug coating has only a very short release time. The short release time cannot guarantee that the drug will be fully absorbed by the blood vessel wall and may be carried away by the blood flow. If the dilation time is prolonged, it may cause damage to the body. Therefore, the application of balloons in some special locations is inevitably limited to a certain extent.

[0047] Stents are less invasive in interventional procedures, but they also have the following drawbacks:

[0048] 1. Due to time constraints during surgery, retrievable stents cannot remain in the body for too long.

[0049] 2. To ensure drug release time, conventional stents that are permanently implanted in the body are generally required. However, the poor adhesion between the drug-eluting coating and the blood vessel wall has been a major concern. Poor adhesion can easily cause the drug on the coating to be washed away by the blood flow, thereby reducing the proportion absorbed by the blood vessels.

[0050] In response, some improved solutions have been provided in related technologies, but these can only be used for local dilation treatment, and there is a high possibility of restenosis after the treatment.

[0051] Therefore, the interventional therapy drug carrier and interventional therapy system provided by the present invention aim to gradually solve the above-mentioned technical problems.

[0052] The following is combined Figures 1 to 6 The following describes embodiments of the present invention.

[0053] According to an embodiment of the present invention, in one aspect, an interventional therapeutic drug carrier is provided, comprising a catheter 1, a stent 2, and a balloon 3. The stent 2 is sleeved on the catheter 1, and the catheter 1 is enclosed in a sheath. When the stent 2 is inserted into a blood vessel using the catheter 1, the sheath can be retracted to allow the stent 2 to self-expand radially. The distal end of the stent 2 is fixedly connected to the catheter 1, and the proximal end of the stent 2 is movably connected to the catheter 1. The balloon 3 surrounds and is attached to the outside of the stent 2. The balloon 3 can be inflated by injecting a filling medium into the sealed cavity of the balloon through an injection tube. The outer wall of the balloon 3 is coated with a drug 10.

[0054] The interventional drug delivery system provided in this embodiment features a self-expanding stent 2, which is fitted over the catheter 1, with a balloon 3 covering the outside of the stent 2. When the balloon 3 is inserted into the blood vessel using the catheter 1, the sheath is retracted, and the stent 2 self-expands. Figure 4 As shown, Figure 4 In the diagram, direction A indicates the direction of blood flow within the blood flow channel. Stent 2 expands close to the vessel wall 20. After expansion, a gap exists between stent 2 and catheter 1, allowing blood flow to pass through, thus solving the problem of blood flow obstruction caused by traditional balloon 3. Furthermore, stent 2 acts as a support for balloon 3, providing radial support after expansion, thereby increasing the apposition of balloon 3 to the vessel wall. Simultaneously, the release of drug 10 can treat and prevent intravascular restenosis. Because the stent 2 inside balloon 3 allows blood flow without obstructing it, balloon 3 can remain in the blood vessel for a longer period, allowing for sufficient absorption of drug 10, improving treatment efficacy, and solving the problems of short drug release time and poor treatment effect associated with traditional balloon 3.

[0055] In one embodiment, the catheter 1 is provided with a fixed ring 4 fixedly connected to the catheter 1 and a movable ring 5 slidably sleeved outside the catheter 1. The distal end of the support 2 is connected to the fixed ring 4, and the proximal end of the support 2 is connected to the movable ring 5.

[0056] By setting a fixed ring 4 and a movable ring 5 on the conduit 1, the distal end of the stent 2 is connected to the fixed ring 4, which can ensure the relative position of the stent 2 and the conduit 1 and ensure that the stent 2 will not move during delivery.

[0057] In one embodiment, both the fixed ring 4 and the movable ring 5 are made of metal.

[0058] In one implementation, the two ends of the bracket 2 are connected to a connecting line 8 and a fixed ring 4 and a movable ring 5, respectively. Specifically, the connecting line 8 includes a metal wire.

[0059] In one embodiment, the catheter 1 is provided with a through hole, and the proximal end of the stent 2 is connected to a pull cord 6 adapted to extend outside the body. The distal end of the pull cord 6 is connected to a movable ring 5. The proximal end of the pull cord 6 passes through the through hole on the catheter 1 and extends from the inside of the catheter 1 to the outside of the body. Pulling the pull cord 6 is adapted to retract the stent 2.

[0060] Specifically, the movable ring 5 is connected to a pull cord 6 that is suitable for extending outside the body. Pulling the pull cord 6 can cause the proximal connecting line 8 to retract through the movable ring 5. The distal fixed ring 4 is immovable and provides a reaction force, which is suitable for retracting the stent 2.

[0061] By connecting a pull cord 6 to the proximal end of the stent 2, the pull cord 6 remains at least partially outside the body during the delivery of the catheter 1. Thus, after the drug 10 is released, pulling the pull cord 6 will cause the stent 2 to contract and retract outside the body along with the catheter. This solves the problem that conventional stents need to be implanted in the body for a long time to release drugs, which may lead to inflammation, thrombosis and vascular damage.

[0062] In a further embodiment, a pull-wire cavity is provided on the inner wall of the conduit 1, and a pull rope is pulled in the pull-wire cavity. A through hole is opened near the moving ring, and the pull rope passes through the through hole and connects to the moving ring.

[0063] In one embodiment, the balloon 3 includes an inner soft balloon 31 attached to the outer surface of the stent 2 and an outer soft balloon 32 sleeved on the outside of the inner soft balloon 31. The proximal ends of the inner soft balloon 31 and the outer soft balloon 32 are connected to the proximal end of the stent 2, and the distal ends of the inner soft balloon 31 and the outer soft balloon 32 are connected to the distal end of the stent 2. A closed cavity is formed between the inner soft balloon 31 and the outer soft balloon 32. The compliance of the outer soft balloon 32 is significantly greater than that of the inner soft balloon 31, and the outer soft balloon 32 is adapted to expand radially under pressure.

[0064] Because balloon 3 has a double-layered structure consisting of an inner soft balloon 31 and an outer soft balloon 32, a closed cavity is formed between the inner soft balloon 31 and the outer soft balloon 32. By injecting fluid into this closed cavity, the fluid pressure inflates the outer soft balloon 32, thereby improving its adhesion to the blood vessel wall. This allows the medication 10 adhering to the surface of the outer soft balloon 32 to fully contact and be absorbed by the blood vessel, improving the therapeutic effect. The outer soft balloon 32 expands outward and can change its shape according to the pressure changes of the filling medium, thus adapting to different blood vessel sizes and angles.

[0065] Because the compliance of the outer soft capsule 32 is significantly greater than that of the inner soft capsule 31, when fluid is injected into the closed cavity between the outer soft capsule 32 and the inner soft capsule 31, the outer soft capsule 32 is more likely to expand and deform, while the inner soft capsule 31 is less likely to deform and remains attached to the outer surface of the stent 2. This ensures that the outer soft capsule 32 of the balloon 3 expands and adheres to the wall normally, thus improving the treatment effect.

[0066] In one embodiment, the interventional therapy drug carrier further includes at least one injection conduit 7; the injection conduit 7 is arranged side by side on the outside of the catheter 1, the proximal end of the injection conduit 7 is connected to the proximal end of the catheter 1, and the distal end of the injection conduit 7 is connected to the lumen of the balloon 3.

[0067] Since the interventional therapy drug carrier also includes an injection channel, the proximal end of which is close to the proximal end of the catheter 1. The proximal end of the injection channel is also the operating end. The injection channel is used to inject filling fluid into the closed cavity of the balloon 3, so that the outer soft balloon 32 is inflated and thus fully conforms to the blood vessel wall.

[0068] Specifically, the number of injection channels 7 can be increased according to the balloon inflation to prevent the middle of the balloon from shifting to a certain position or concave inward during inflation, ensuring uniform inflation of the middle of the balloon and thus improving balloon adhesion to the wall. When two injection channels 7 are provided, the two injection channels 7 can be symmetrically arranged about the axis of the catheter 1.

[0069] Specifically, the injection tubing 7 and the catheter 1 can be seamless or have a gap. When there is a gap, the injection tubing 7 is fixedly connected to the catheter 1 by a fixing buckle 9.

[0070] In one embodiment, to facilitate the injection of the filling medium, the proximal end of the injection conduit 7 is provided with a bend away from the proximal end of the conduit 1.

[0071] In one embodiment, the outer surface of the outer soft capsule 32 in a contracted state is compressed to form a plurality of grooves 321, the drug 10 is loaded in the grooves 321, and the grooves 321 are adapted to return to the plane as the outer soft capsule 32 expands.

[0072] Because the outer surface of the outer soft capsule 32 is compressed to form several grooves 321, and the grooves 321 contain drug crystals 10, such as rapamycin (RAPA), paclitaxel (PTX), tacrolimus (TAC), everolimus (SDZRAD), etc., it can be used to treat and prevent intravascular restenosis. Drug loading through the grooves 321 reduces drug loss during stent delivery. After reaching the designated position, the outer soft capsule 32 is subjected to the radial force of the stent 2 expansion and the pressure of the filling medium. The surface of the outer soft capsule 32 returns to its original position, the grooves 321 disappear, and the drug crystals 10 in the grooves 321 are squeezed onto the vessel wall, or even puncture the vessel wall and enter the vessel, achieving a full therapeutic effect.

[0073] In one embodiment, in the contracted state, the length of the outer soft balloon 32 along the axial direction of the catheter 1 is at least twice the length of the stent 2 along the axial direction of the catheter 1.

[0074] In the contracted state, since the length of the outer soft capsule 32 along the axial direction of the catheter 1 is greater than the length of the stent 2 along the axial direction of the catheter 1, the outer soft capsule 32 contracts and wrinkles, and the surface can form the groove 321 mentioned above by compression, which is used to load the drug 10 and reduce the loss of the drug 10 during delivery.

[0075] Since the length of the outer soft capsule 32 along the axial direction of the catheter 1 is at least twice the length of the stent 2 along the axial direction of the catheter 1, it can be ensured that there are a sufficient number of grooves 321 on the surface of the outer soft capsule 32 to increase the drug loading capacity.

[0076] In one embodiment, the outer surface of the drug 10 is coated with a sustained-release layer, which includes one or more of the following polymers: polylactic acid, polylactic acid-glycolic acid copolymer, polydioxanone, urea, butylated hydroxyphenol, or acetylglucosyl tributyl ester.

[0077] By providing a sustained-release layer on the surface of the drug 10, the present invention allows for selection of the drug 10 release time according to the actual condition. The aforementioned copolymer enables sustained release of the drug 10.

[0078] In one embodiment, the material of the support 2 includes Fe-Ni-Cr, Ni-Co-Cr, Fe-Ni-Co, NiTi alloy, or BeCu alloy.

[0079] The stent 2 is made of a highly elastic material and is capable of self-expansion. The materials of the stent 2 include, but are not limited to, the materials mentioned above.

[0080] In one embodiment, the balloon 3 is made of an elastic material, including polyurethane, synthetic rubber, or natural latex.

[0081] The balloon 3 is made of a material with good resilience, which enables it to inflate and improves its adhesion to the wall. The materials of the balloon 3 include, but are not limited to, the materials mentioned above.

[0082] In one embodiment, the injection conduit 7 is made of titanium alloy, steel, or rubber.

[0083] The injection conduit 7 is made of a high-strength, highly elastic material, allowing it to bend outwards as the stent 2 expands, while also withstanding the pressure exerted when the filling medium is injected into the balloon 3. The materials used for the injection conduit 7 include, but are not limited to, the materials described above.

[0084] In one embodiment, the drug 10 includes paclitaxel, sirolimus, tacrolimus, or everolimus; the drug 10 accounts for 1.wt% to 20.wt% of the polymer.

[0085] The aforementioned drug 10 can be used for PPIs. By controlling the proportion of drug 10 in the polymer within the range of 1 wt% to 20 wt%, good therapeutic effects can be ensured.

[0086] A drug coating is provided on the outer surface of the outer soft capsule 32. The drug coating is a polymer, including polylactic acid (including racemic polylactic acid (PLLA), dextran polylactic acid (PDLA) and racemic polylactic acid (PDLLA), polylactic acid-glycolic acid copolymer (PLGA), poly(p-dioxanone) (PPDO), urea, butylated hydroxyphenol or acetylsic acid-tributyl ester). The drug coating is a copolymer composed of one or more of the above substances.

[0087] Specifically, the preparation process of the drug coating on the outer surface of the balloon 3 in this invention can be carried out by means of ultrasonic precision spraying machine spraying, solution film forming and pressing, immersion and extraction, etc., preferably by using ultrasonic precision spraying machine spraying.

[0088] In summary, the interventional therapy drug carrier provided by this invention has the following advantages:

[0089] 1. Through the structural design of attaching the balloon 3 to the stent 2, blood flow is allowed to pass through when the stent 2 expands;

[0090] 2. The balloon 3 is supported by the stent 2. The expansion of the stent 2 and the pressure of the filling medium can provide radial support for the balloon 3, thereby enhancing the adhesion between the outer soft balloon 32 and the blood vessel wall, increasing the proportion of drug 10 absorbed by the blood vessel wall, and solving the problem that the balloon 3 lacks internal support and the surface of the balloon 3 collapses inward during the expansion process, resulting in poor contact between the drug coating and the blood vessel wall, which leads to the drug 10 being carried away by the blood flow.

[0091] 3. The distal end of stent 2 is fixedly connected to catheter 1 via a fixing ring 4, and the proximal end is connected to an external pull cord 6 via a movable moving ring 5. Pulling the pull cord 6 can retract stent 2, eliminating the need for stent 2 to remain in the body and thus avoiding potential inflammation, thrombosis, and vascular damage that may result from stent 2 remaining in the body.

[0092] 4. The outer soft capsule 32 is designed with grooves 321 on its surface to load the drug 10, which can greatly reduce the loss of drug 10 during delivery. At the same time, the stent 2 allows blood flow to pass through after expansion, so the drug 10 can be released for a long time without causing harm to the human body.

[0093] According to an embodiment of the present invention, another aspect provides an interventional therapy system comprising the interventional therapy drug carrier of any of the above embodiments.

[0094] Since interventional therapy systems include interventional drug carriers and have the same effects as interventional drug carriers, they will not be elaborated upon here.

[0095] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A drug carrier for interventional therapy, characterized in that, include: The conduit (1) is provided with a fixed ring (4) fixedly connected to the conduit (1) and a movable ring (5) slidably sleeved outside the conduit (1), and the conduit (1) is provided with a through hole; A radially self-expanding stent (2) is fitted onto the conduit (1), the distal end of the stent (2) is connected to the fixed ring (4) via a connecting line (8), and the proximal end of the stent (2) is connected to the movable ring (5). The proximal end of the stent (2) is connected to a pull cord (6) adapted to extend outside the body, the distal end of the pull cord (6) is connected to the movable ring (5), the proximal end of the pull cord (6) passes through a through hole on the catheter (1) and extends from the inside of the catheter (1) to the outside body; pulling the pull cord (6) is adapted to retract the stent (2). A balloon (3) surrounds and is attached to the outside of the stent (2); The balloon (3) includes an inner soft balloon (31) attached to the outer surface of the stent (2) and an outer soft balloon (32) sleeved on the outside of the inner soft balloon (31). The proximal ends of the inner soft balloon (31) and the outer soft balloon (32) are connected to the proximal end of the stent (2), and the distal ends of the inner soft balloon (31) and the outer soft balloon (32) are connected to the distal end of the stent (2). A closed cavity is formed between the inner soft balloon (31) and the outer soft balloon (32). The external soft capsule (32) is adapted to expand radially by injecting liquid into the sealed cavity and relying on the liquid pressure, based on the expansion of the stent (2) as it expands with its own expansion; The outer surface of the outer soft capsule (32) in the contracted state is squeezed to form a plurality of grooves (321), the drug (10) is loaded in the grooves (321), and the grooves (321) are adapted to return to the plane as the outer soft capsule (32) expands; The balloon (3) is adapted to expand with the expansion of the stent (2), and the outer wall of the balloon (3) is attached with a drug (10); after the stent (2) expands, there is a gap between it and the catheter (1) that allows blood flow.

2. The interventional therapy drug carrier according to claim 1, characterized in that, The compliance of the outer soft capsule (32) is significantly greater than that of the inner soft capsule (31), and the outer soft capsule (32) is adapted to expand radially under pressure.

3. The interventional therapy drug carrier according to claim 2, characterized in that, The interventional drug carrier also includes at least one injection conduit (7), which is arranged side by side on the outside of the catheter (1). The proximal end of the injection conduit (7) is connected to the proximal end of the catheter (1), and the distal end of the injection conduit (7) is connected to the sealed cavity.

4. The interventional therapy drug carrier according to claim 3, characterized in that, In the contracted state, the length of the external soft capsule (32) along the axial direction of the catheter (1) is at least twice the length of the stent (2) along the axial direction of the catheter (1).

5. The interventional therapy drug carrier according to claim 1, characterized in that, The outer surface of the drug (10) is covered with a sustained-release layer, which includes one or more of the following polymers: polylactic acid, polylactic acid-glycolic acid copolymer, polydioxanone, urea, butylated hydroxyphenol, or acetylglucosyl tributyl ester.

6. The interventional therapy drug carrier according to claim 4, characterized in that, The materials of the support (2) include Fe-Ni-Cr system, Ni-Co-Cr system, Fe-Ni-Co system and NiTi alloy or BeCu alloy; Alternatively, the balloon (3) may be made of an elastic material, including polyurethane, synthetic rubber or natural latex; Alternatively, the material of the injection conduit (7) may include titanium alloy, steel, or rubber; Alternatively, the drug (10) may include paclitaxel, sirolimus, tacrolimus or everolimus; the drug (10) may be present in the polymer in an amount of 1 wt% to 20 wt%.

7. An interventional therapy system, characterized in that, The interventional therapeutic drug carrier includes any one of claims 1 to 6.

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