Reagent combination and method for removing vascular tissue on stent

Abstract

The invention relates to a reagent combination and a method for removing vascular tissues on a stent, and belongs to the technical field of biology. Aiming at the defects of an existing method for removing the vascular tissue on the stent, a brand-new scheme for removing the vascular tissue on the stent is designed, the scheme comprises a specific reagent combination and a treatment process, the stent and the degradable part of the stent are not damaged while the vascular tissue is efficiently removed, in addition, the method can be implemented in specific treatment equipment, and the treatment cost is reduced. Standardization and automation are achieved, and research, development and design of the degradable stent are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of biotechnology and relates to a reagent combination and method for removing vascular tissue on a stent. Background Technology

[0002] Vascular stents are tiny, expandable mesh tubes that are implanted into narrowed or blocked blood vessels through minimally invasive surgery. They mechanically expand the vessel walls to restore blood flow and ensure blood supply to vital organs such as the heart, brain, and lower limbs. They mainly include bare-metal stents, drug-eluting stents, and biodegradable stents. Biodegradable stents are made from materials that can gradually degrade in vivo (such as polylactic acid). During stent development, it is necessary to study the degradation behavior of the biodegradable polymer in vivo. Studies of degradation behavior typically require observing the surface morphology of the degradable material after degradation or measuring changes in mass before and after degradation. However, after implantation, the stent surface undergoes endothelialization and adheres to vascular tissue. Therefore, it is necessary to fully separate the stent surface from the vascular tissue without affecting or damaging the biodegradable material of the stent.

[0003] Currently, methods for removing vascular tissue from stents mainly include mechanical and enzymatic methods. Mechanical methods involve mechanical dissection to remove vascular tissue from the implant surface, using tools such as tweezers, scissors, and scalpels. However, this method may result in incomplete removal or damage to biodegradable materials. Enzymatic methods utilize enzymes such as trypsin and collagenase to dissolve vascular tissue. Compared to mechanical methods, this is gentler, effectively removing vascular tissue with less damage to biodegradable materials. For example, CN103157099A discloses a mixed enzyme digestion solution for rapid digestion of the vascular adventitia and its preparation method. The mixed enzyme digestion solution includes a digestion solution and a stop solution. The digestion solution contains the following components: trypsin, type 2 collagenase, glycerol, potassium chloride, potassium dihydrogen phosphate, sodium chloride, and disodium hydrogen phosphate. However, this type of method also has limitations, such as long enzymatic digestion time, high cost, and difficulty in completely removing certain stubborn adhered tissues.

[0004] In summary, there is an urgent need to develop technical solutions that can efficiently remove vascular tissue from stents without damaging biodegradable materials. Summary of the Invention

[0005] To address the shortcomings of existing technologies and practical needs, this invention provides a reagent combination and method for removing vascular tissue from stents, aiming to remove vascular tissue from the stent surface while avoiding damage to the biodegradable materials within the stent.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a reagent combination for removing vascular tissue on a stent, the reagent combination comprising a first decomposing solution, a second decomposing solution and a third decomposing solution;

[0008] The first decomposition solution contains: collagenase 1.8~2.2 mg / mL (e.g., 1.9, 2.0, or 2.1 mg / mL), calcium ions 0.1~0.4 mmol / mL (e.g., 0.1, 0.15, 0.2, 0.25, 0.3, or 0.35 mmol / mL), elastase 0.8~1.2 mg / mL (e.g., 0.9, 1, or 1.1 mg / mL), magnesium ions 0.1~0.3 mmol / mL (e.g., 0.12, 0.125, 0.15, 0.2, 0.25, 0.275, 0.28, or 0.29 mmol / mL), and ammonium ions 0.04~0.08 mmol / mL (e.g., 0.04, 0.05, 0.06, or 0.07 mmol / mL).

[0009] The second decomposition solution contains: collagenase 1.8~2.5 mg / mL (e.g., 1.9, 2, 2.1, 2.2, 2.3 or 2.4 mg / mL, etc.), calcium ions 0.1~0.5 mmol / mL (e.g., 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4 or 0.45 mmol / mL, etc.), elastase 2.2~2.8 mg / mL (e.g., 2.3, 2.4, 2.5, 2.6 or 2.7 mg / mL, etc.), magnesium ions 0.1~0.5 mmol / mL (e.g., 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4 or 0.45 mmol / mL, etc.), and ammonium ions 0.04~0.08 mmol / mL (e.g., 0.05, 0.06 or 0.07 mmol / mL, etc.).

[0010] The third decomposition solution contains: collagenase 0.8-1.2 mg / mL (e.g., 0.85, 0.9, 0.95, 1, or 1.1 mg / mL), calcium ions 0.1-0.2 mmol / mL (e.g., 0.15, 0.16, 0.18, or 0.19 mmol / mL), elastase 1-3 mg / mL (e.g., 1.2, 1.25, 1.5, 2, 2.5, 2.75, 2.8, or 2.9 mg / mL), magnesium ions 0.1-0.4 mmol / mL (e.g., 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.38, or 0.39 mmol / mL), and ammonium ions 0.04-0.08 mmol / mL (e.g., 0.05, 0.06, or 0.07 mmol / mL).

[0011] This invention addresses the removal process of vascular tissue on stents by deeply analyzing the structure of vascular tissue and designing novel reagent combinations. It also designs a first decomposition solution, a second decomposition solution, and a third decomposition solution with specific compositions and contents, which work synergistically to achieve efficient removal of vascular tissue without damaging the stent or its biodegradable components.

[0012] Preferably, the concentration ratio of collagenase to elastase in the first decomposition solution is (1.8~2.5):1, for example, it can be 1.9:1, 1.95:1, 2:1, 2.2:1 or 2.4:1, etc.

[0013] Preferably, the concentration ratio of collagenase to elastase in the second decomposition solution is 1:(1~1.3), for example, it can be 1:1.1, 1:1.2, 1:1.25 or 1:1.28, etc.

[0014] Preferably, the concentration ratio of collagenase to elastase in the third decomposition solution is 1:(1.8~2.5), for example, it can be 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3 or 1:2.4, etc.

[0015] In this invention, the concentration ratio of collagenase and elastase in the first and third decomposition solutions is designed to further improve the removal effect.

[0016] Preferably, the collagenase includes collagenase type I and / or collagenase type II.

[0017] Preferably, the solvents for the first, second, and third decomposition solutions are each independently PBS buffer.

[0018] Preferably, the stent comprises a vascular stent, and the vascular stent comprises a biodegradable vascular stent.

[0019] In a second aspect, the present invention provides the application of the reagent combination for removing vascular tissue on a stent as described in the first aspect in the removal of vascular tissue on a stent.

[0020] Thirdly, the present invention provides a method for removing vascular tissue from a stent, the method comprising: treating the stent with the reagent combination for removing vascular tissue from a stent as described in the first aspect, wherein the treatment of the stent specifically comprises placing the stent sequentially in a first decomposition solution, a second decomposition solution and a third decomposition solution for a first treatment, a second treatment and a third treatment.

[0021] Preferably, the first processing time is 1-5 hours, the second processing time is 20-30 hours, and the third processing time is 5-25 hours.

[0022] Preferably, the temperatures of the first, second, and third treatments are each independently 30-40°C, for example, 31, 32, 33, 35, 36, 37, 38, or 39°C.

[0023] This invention is based on a designed reagent combination for removing vascular tissue from stents, and further designs the processing technology, organically setting the processing sequence and time to achieve faster decomposition.

[0024] Preferably, the processing support is carried out in a reaction device, which includes a reaction vessel, a support mounting device, a temperature control device, and a peristaltic pump circulation device.

[0025] Preferably, the reactor includes a reactor chamber and a reactor cover disposed on top of the reactor chamber.

[0026] Preferably, the support mounting device is disposed inside the reaction vessel chamber, one end of the support mounting device is connected to the reaction vessel cover, and the other end of the support mounting device is used to place a vascular tissue support, and the vascular tissue support does not contact the inner wall of the reaction vessel chamber.

[0027] Preferably, the reaction vessel chamber is provided with an inlet and an outlet, both of which are equipped with filter screens. The water inlet height is the same as the height at which the vascular tissue scaffold is placed on the support mounting device. The inlet and outlet are respectively used for connecting pipelines to the outlet and inlet of the peristaltic pump circulation device.

[0028] Preferably, the temperature control device is provided on one side of the reaction vessel chamber, and the temperature control device is used to control the temperature of the liquid in the reaction vessel chamber.

[0029] Preferably, the bracket mounting device is a traction bracket mounting device or a round rod bracket mounting device; or, the interior of the reactor chamber is divided into a reaction chamber and a heating chamber, the reaction chamber is located on one side of the heating chamber, the bracket mounting device and the water outlet are provided in the reaction chamber, the temperature control device is provided on the top of the heating chamber, and the water inlet is provided on the side of the heating chamber away from the reaction chamber.

[0030] Preferably, the reaction chamber and the heating chamber are separated by a partition plate; the partition plate is provided with an inclined liquid channel, the inlet of the inclined liquid channel is located near the inner top of the heating chamber, and the height of the outlet of the inclined liquid channel is greater than the height of the vascular tissue support placed by the support mounting device; or, the partition plate is evenly provided with small holes, which are used for the liquid in the heating chamber to flow into the reaction chamber.

[0031] Preferably, the filter screen is an ultrafiltration membrane module; the molecular weight cutoff of the ultrafiltration membrane module is 20~50 kDa.

[0032] Preferably, the processing is carried out in a circulation system, which includes an automated control device and at least one set of decomposition and circulation devices.

[0033] Preferably, the automated control device is used to control the decomposition operation of the decomposition cycle device.

[0034] Preferably, each set of the decomposition and circulation devices includes three vascular tissue decomposition and circulation devices connected in series, which are respectively referred to as the first vascular tissue decomposition and circulation device, the second vascular tissue decomposition and circulation device, and the third vascular tissue decomposition and circulation device; the outlet pipe of the first vascular tissue decomposition and circulation device is connected to the inlet pipe of the second vascular tissue decomposition and circulation device, and the outlet pipe of the second vascular tissue decomposition and circulation device is connected to the inlet pipe of the third vascular tissue decomposition and circulation device; the inlet pipe of the first vascular tissue decomposition and circulation device is the main inlet pipe, and the outlet pipe of the third vascular tissue decomposition and circulation device is the main outlet pipe; the filter screen is provided at the inlet and outlet of the first vascular tissue decomposition and circulation device, the second vascular tissue decomposition and circulation device, and the third vascular tissue decomposition and circulation device; the first vascular tissue decomposition and circulation device, the second vascular tissue decomposition and circulation device, and the third vascular tissue decomposition and circulation device all adopt the above-mentioned reaction equipment.

[0035] In this invention, a device for removing vascular tissue from a stent is further designed to achieve a standardized and automated processing procedure, significantly improving processing efficiency.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects:

[0037] This invention addresses the process of removing vascular tissue from stents. It deeply analyzes the structure of vascular tissue and proposes a solution for removing vascular tissue from stents, including specific reagent combinations and processing techniques. This solution can efficiently remove vascular tissue without damaging the stent and its biodegradable components. Furthermore, it can be implemented in specific processing equipment, achieving standardization and automation, significantly improving processing efficiency, and contributing to the research and design of biodegradable stents. Attached Figure Description

[0038] Figure 1 A diagram of a vascular stent with vascular tissue;

[0039] Figure 2 This is a schematic diagram of the equipment structure;

[0040] Figure 3 This is a schematic diagram of the reactor structure;

[0041] Figure 4 This is a schematic diagram of a reactor with an external heating chamber.

[0042] Figure 5 This is a schematic diagram of a series reaction apparatus.

[0043] Figure 6 Image of the surface morphology of the vascular stent after processing;

[0044] Among them, 1-Reaction vessel; 2-Peristaltic pump circulation device; 3-Support mounting device; 4-Temperature control device; 5-Reaction vessel chamber; 6-Reaction vessel cover; 7-Connecting buckle; 8-Central rod; 9-Wire mesh frame; 10-Connector; 11-Opening and closing part; 12-Traction line; 13-Outlet; 14-Inlet; 15-Filter screen; 18-Reaction chamber; 19-Heating chamber; 20-Inclined liquid channel; 21-Baffle plate; 22-Automation equipment; 23-Transfer device; 24-First vascular tissue decomposition and circulation device; 25-Second vascular tissue decomposition and circulation device; 26-Third vascular tissue decomposition and circulation device; 27-Buckling buckle; 28-Main inlet; 29-Main outlet. Detailed Implementation

[0045] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0046] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0047] In a specific embodiment of the present invention, the method for obtaining the stent after implantation into a blood vessel is as follows:

[0048] The scaffold containing vascular tissue is separated from the body, and excess tissue not in contact with the scaffold is removed using tools such as scissors, resulting in a scaffold with vascular tissue attached. Figure 1 As shown; then the scaffold with vascular tissue was immersed in freshly prepared formalin and fixed for 24 h. After fixation, the vascular tissue was rinsed with deionized water (rinsed 6 times), then dried and weighed, and recorded as the mass at time 0.

[0049] In a specific embodiment of the present invention, the removal process is examined by weighing with an electronic balance or observing the surface morphology with a microscope.

[0050] In specific embodiments of the present invention, the removal process can be carried out in conventional containers (such as test tubes, beakers, etc.), or it can be carried out using specific equipment. A schematic diagram of the equipment used for the removal process is shown below. Figure 2 As shown, it includes a peristaltic pump, pump tubing, and a reaction vessel. The reaction vessel consists of a reaction vessel chamber, a support mounting device, a temperature control device, etc. The reaction vessel chamber comprises a compartment, a reaction vessel cover, an inlet, an outlet, and a filter screen. The specific structure is as follows... Figure 3 As shown, the inlet filter screen prevents impurities in the pump pipe from contaminating the vascular tissue, while the outlet filter screen prevents blood tissue decomposition products from flowing into the pump pipe. The reactor lid has connecting clips for connecting the support mounting device, preventing movement of the support mounting device due to water flow. Furthermore, the flushing action enhances the removal of vascular tissue, achieving faster removal with the aid of flushing. The support mounting device is positioned flush with the inlet. The area of ​​the holes in the support mounting device should be set at 1-5 cm². 2 It consists of a frame and a center rod. The frame is a cuboid with one side that can be opened and closed (all six faces are ≥1cm). 2 (Apertures), the central rod can be detached from and snapped into place from the mesh frame. The vascular tissue, including the stent, is inserted through the central rod. Fluid flows through the mesh frame, allowing removal of the vascular tissue from the central rod. For faster tissue removal, the diameter of the central rod must be smaller than the inner diameter of the vascular tissue, allowing the vascular tissue to move in a circular motion around the central rod.

[0051] Furthermore, to avoid the heater's influence on the tissue during the heating process, the reactor chamber is divided into a reaction chamber and a heating chamber, such as... Figure 4 A heater and temperature monitor are placed in the heating chamber to heat the solution to a temperature of 37℃±2℃. A solution outflow channel is provided on the side of the heating chamber adjacent to the reaction chamber, preferably as follows: Figure 4 The oblique holes, or spaced-apart through holes, are designed to ensure the solution in the heating chamber enters the reaction chamber evenly. This allows for more uniform heating of the solution. The solution, reaching the required temperature, flows into the reaction chamber through the small holes, flushing and decomposing the vascular tissue.

[0052] Furthermore, to avoid manually replacing the first decomposition solution (hereinafter referred to as Solution A), the second decomposition solution (hereinafter referred to as Solution D), and the third decomposition solution (hereinafter referred to as Solution C), automated equipment can be used to connect the three reaction vessels in series, such as... Figure 5 The reactor consists of three reactors: Solution A, Solution B, and Solution C. The inlet of Solution A is connected to the outlet of a peristaltic pump, and the reactors are connected by pump pipes. The outlet of Solution C is connected to the inlet of the peristaltic pump. An automated device with a programmed timer is installed between the three reactors. At designated times, the reactor lids, support mounting devices, and vascular tissue are transferred between the reactors via latches and conveyor belts. Filters containing 50 kDa ultrafiltration membranes with a molecular weight cutoff (MWCO) of 50 kDa are installed at the inlet and outlet of the reactors. Since 50 kDa ultrafiltration membranes can retain elastase and collagenase, the filters prevent mixing of the solutions from the three reactors connected in series.

[0053] Example 1

[0054] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0055] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 1. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0056] Table 1

[0057]

[0058] Methods for removing vascular tissue from a stent include:

[0059] (1) Obtaining the stent after implantation into the blood vessel;

[0060] (2) Prepare solutions A, B and C.

[0061] (3) Use a 37℃ constant temperature water bath. Take 3 centrifuge tubes and add solution A, solution B and solution C into the 3 centrifuge tubes in sequence.

[0062] (4) Take a scaffold with vascular tissue, put it into solution A, keep the vascular tissue completely submerged in the solution, seal it with sealing film, and place it in a 37°C constant temperature water bath for 1 h. Take out the centrifuge tube every 5 min, use a pipette to blow the solution in the centrifuge tube to keep it in full contact, and replace it with fresh solution A every 1 h.

[0063] (5) Remove the support from solution A and place it into solution B. Seal the opening with sealing film and place solution B in a 37°C constant temperature water bath for 30 h. Remove the centrifuge tube every 5 min and use a pipette to purge the solution from the centrifuge tube to maintain full contact. Replace with fresh solution B every 2 h.

[0064] (6) Remove the stent from solution B and place it in solution C, keeping the vascular tissue completely submerged in the solution. After sealing with sealing film, place it in a 37°C constant temperature water bath for 5 h. Remove the centrifuge tube every 5 min and use a pipette to purge the solution from the centrifuge tube to maintain full contact. Replace with fresh solution C every 1 h.

[0065] (7) Remove the stent, rinse with deionized water, and observe the surface morphology of the stent under a microscope, such as... Figure 6 As shown, the vascular tissue on the stent surface was completely decomposed, and the stent was not destroyed.

[0066] Example 2

[0067] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0068] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 2. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0069] Table 2

[0070]

[0071] The method for removing vascular tissue from the stent was the same as in Example 1. After 36 hours of treatment, it was observed that the vascular tissue on the stent surface was completely decomposed, and the stent was not destroyed.

[0072] Example 3

[0073] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0074] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 3. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0075] Table 3

[0076]

[0077] The method for removing vascular tissue from the stent was the same as in Example 1, except that in step (6), the stent was reacted in solution C for 7 hours. After a total of 38 hours of treatment, it was observed that the vascular tissue on the stent surface was completely decomposed, and the stent was not destroyed.

[0078] Example 4

[0079] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0080] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 4. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0081] Table 4

[0082]

[0083] Methods for removing vascular tissue from a stent include:

[0084] (1) Obtaining the stent after implantation into the blood vessel;

[0085] (2) Prepare solutions A, B and C.

[0086] (3) Set up the equipment (structural diagram as shown) Figure 2 As shown, add solution A to the reactor, start the equipment, set the flow rate to 1 mL / min, set the temperature to 37℃, stabilize for 5 min, insert the stent with vascular tissue along the central rod of the stent installation device, put it into the mesh frame, react for 0.5 h, remove the stent installation device, and rinse the equipment with PBS solution;

[0087] (4) Add solution B to the reactor, set the flow rate to 5 mL / min, set the temperature to 37℃, stabilize for 5 min, insert the stent with vascular tissue along the central rod of the stent installation device, put it into the mesh frame, react for 20 h, remove the stent installation device, and rinse the equipment with PBS solution.

[0088] (5) Add solution C to the reactor, set the flow rate to 3 mL / min, set the temperature to 37℃, stabilize for 5 min, insert the stent with vascular tissue along the central rod of the stent mounting device, place it in the mesh frame, react for 3 h, remove the stent mounting device, remove the stent, rinse with deionized water, and observe that the vascular tissue on the stent surface is completely decomposed. The total treatment time is 23.5 h, and the removal efficiency is improved by combining the flushing effect of the fluid on the stent.

[0089] Example 5

[0090] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0091] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 5. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0092] Table 5

[0093]

[0094] Methods for removing vascular tissue from a stent include:

[0095] (1) Obtaining the stent after implantation into the blood vessel;

[0096] (2) Prepare solutions A, B and C.

[0097] (3) Set up the equipment (structural diagram as shown) Figure 5 As shown in the figure, three reaction vessels are connected in series. Solution A, solution B and solution C are added to the reaction vessels in sequence, and the equipment is turned on. The flow rate is set to 5 mL / min, the temperature is 37℃, and the reaction is stabilized for 5 min.

[0098] (4) Place the stent with vascular tissue into the stent installation device, place it into the reaction vessel of solution A, and hang it in the buckle.

[0099] (5) The stent was removed after reaction and rinsed with deionized water. The complete decomposition of vascular tissue on the stent surface was observed. The use of a series reaction vessel significantly reduced the number of manual operation steps. Combined with the flushing effect of the fluid on the stent, the total treatment time was 18 hours, which improved the removal efficiency.

[0100] Example 6

[0101] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0102] Compared with Example 4, the only difference was that collagenase I in each solution was replaced with collagenase II in equal amounts, and the vascular tissue on the surface of the stent was completely decomposed.

[0103] Example 7

[0104] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0105] Compared with Example 4, the only difference is that collagenase I in each solution was replaced with an equal amount of mixed collagenase (the mass ratio of collagenase I and collagenase II does not need to be specially limited and can be designed according to actual needs, as long as the total amount of collagenase remains unchanged, for example, it can be 1:1). It was observed that the vascular tissue on the surface of the stent was completely decomposed.

[0106] Example 8

[0107] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0108] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 6. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0109] Table 6

[0110]

[0111] The method for removing vascular tissue from the stent is the same as in Example 1, and the complete decomposition of vascular tissue on the stent surface is observed.

[0112] Example 9

[0113] This embodiment provides a reagent combination and method for removing vascular tissue from a stent.

[0114] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 7. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0115] Table 7

[0116]

[0117] The method for removing vascular tissue from the stent is the same as in Example 1, and the complete decomposition of vascular tissue on the stent surface is observed.

[0118] Example 10

[0119] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0120] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 8. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0121] Table 8

[0122]

[0123] The method for removing vascular tissue from the stent is the same as in Example 1, and it was observed that the vascular tissue on the stent surface was not completely decomposed.

[0124] Example 11

[0125] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0126] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 9. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0127] Table 9

[0128]

[0129] The method for removing vascular tissue from the stent is the same as in Example 1, and it was observed that the vascular tissue on the stent surface was not completely decomposed.

[0130] As can be seen from the results of Examples 1, 8, 9, 10, and 11, the specific concentration ratio of collagenase and elastase in solution A designed in this invention can further improve the removal effect.

[0131] Example 12

[0132] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0133] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 10. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0134] Table 10

[0135]

[0136] The method for removing vascular tissue from the stent is the same as in Example 1, and the complete decomposition of vascular tissue on the stent surface is observed.

[0137] Example 13

[0138] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0139] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 11. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0140] Table 11

[0141]

[0142] The method for removing vascular tissue from the stent is the same as in Example 1, and the complete decomposition of vascular tissue on the stent surface is observed.

[0143] Example 14

[0144] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0145] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 12. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0146] Table 12

[0147]

[0148] The method for removing vascular tissue from the stent is the same as in Example 1, and it was observed that the vascular tissue on the stent surface was not completely decomposed.

[0149] Example 15

[0150] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0151] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 13. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0152] Table 13

[0153]

[0154] The method for removing vascular tissue from the stent is the same as in Example 1, and it was observed that the vascular tissue on the stent surface was not completely decomposed.

[0155] As can be seen from the results of Examples 1, 12, 13, 14, and 15, the specific concentration ratio of collagenase and elastase in solution B designed in this invention can further improve the removal effect.

[0156] Example 16

[0157] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0158] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 14. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0159] Table 14

[0160]

[0161] The method for removing vascular tissue from the stent is the same as in Example 1, and the complete decomposition of vascular tissue on the stent surface is observed.

[0162] Example 17

[0163] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0164] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 15. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0165] Table 15

[0166]

[0167] The method for removing vascular tissue from the stent is the same as in Example 1, and the complete decomposition of vascular tissue on the stent surface is observed.

[0168] Example 18

[0169] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0170] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 16. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0171] Table 16

[0172]

[0173] The method for removing vascular tissue from the stent is the same as in Example 1, and it was observed that the vascular tissue on the stent surface was not completely decomposed.

[0174] Example 19

[0175] This embodiment provides a reagent combination and method for removing vascular tissue on a stent, as described in Example 8.

[0176] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 17. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0177] Table 17

[0178]

[0179] The method for removing vascular tissue from the stent is the same as in Example 1, and it was observed that the vascular tissue on the stent surface was not completely decomposed.

[0180] As can be seen from the results of Examples 1, 16, 17, 18, and 19, the specific concentration ratio of collagenase and elastase in solution C designed in this invention can further improve the removal effect.

[0181] Comparative Example 1

[0182] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0183] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 18. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0184] Table 18

[0185]

[0186] The method for removing vascular tissue from the stent is the same as in Example 1, except that the reaction time in solution A is 5 hours, the reaction time in solution B is 35 hours, and the reaction time in solution C is 25 hours. It was observed that the vascular tissue on the stent surface was not completely decomposed, and some vascular tissue remained on the stent surface (approximately 20%). Even if the reaction time of solution C is further extended, vascular tissue residue was still observed when the morphology of the stent surface was observed under a microscope.

[0187] Comparative Example 2

[0188] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0189] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 19. The solvent for all solutions is an aqueous PBS solution with pH=7.4.

[0190] Table 19

[0191]

[0192] The method for removing vascular tissue from the stent is the same as in Example 1, except that the reaction time in solution A is 5 hours, the reaction time in solution B is 35 hours, and the reaction time in solution C is 25 hours. It was observed that the vascular tissue on the stent surface was not completely decomposed, and some vascular tissue remained on the stent surface.

[0193] As can be seen from Examples 1-3 and Comparative Examples 1 and 2, the decomposition solution designed by the present invention with a specific enzyme concentration range can achieve effective decomposition. However, when the enzyme concentration range is too low or too high, it may lead to insufficient enzymatic hydrolysis efficiency or steric hindrance, neither of which can achieve effective decomposition.

[0194] Comparative Example 3

[0195] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0196] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 20. The solvent is PBS aqueous solution with pH=7.4. Based on Example 1, the total amount of enzyme is kept constant and the reaction has no stepwise concentration.

[0197] Table 20

[0198]

[0199] The method for removing vascular tissue from the stent is the same as in Example 1, except that: in reaction step (5), the stent is not removed and the reaction continues in solution A for 30 h; in step (6), the stent is not removed and the reaction continues in solution A for 5 h; it is observed that the vascular tissue on the stent surface is not completely decomposed and some vascular tissue remains on the stent surface.

[0200] Comparative Example 4

[0201] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0202] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 21. The solvent is PBS aqueous solution with pH=7.4. Based on Example 1, the total amount of enzyme is kept constant and the reaction has no stepwise concentration.

[0203] Table 21

[0204]

[0205] The method for removing vascular tissue from the stent is the same as in Example 1, except that: in step (6), the stent is not removed and the reaction continues in solution B for 5 h; the decomposition effect of vascular tissue on the stent surface is better than that in Comparative Example 4, but it is still not completely decomposed, and some vascular tissue remains on the stent surface.

[0206] Comparative Example 5

[0207] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0208] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 22. The solvent is PBS aqueous solution with pH=7.4. Based on Example 1, the total amount of enzyme is kept constant and the reaction has no stepwise concentration.

[0209] Table 22

[0210]

[0211] The method for removing vascular tissue from the stent is the same as in Example 1, except that there is no reaction step (4), and the reaction in step (5) lasts for 31 hours; it is observed that the vascular tissue on the stent surface is not completely decomposed, and some vascular tissue remains on the stent surface.

[0212] As can be seen from the results of Comparative Examples 3-5, it is difficult to effectively remove vascular tissue without using the specific first, second, and third decomposition solutions designed in this invention.

[0213] Comparative Example 6

[0214] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0215] The reagent combination includes solution A, solution B and solution C, and the composition is shown in Table 23. The solvent is PBS aqueous solution with pH=7.4. Based on Example 1, the total amount of enzyme is kept constant, and a single enzyme reaction is carried out.

[0216] Table 23

[0217]

[0218] The method for removing vascular tissue from the stent is the same as in Example 1. Observation of the stent surface shows that the collagen of the vascular tissue outer membrane cannot be decomposed, the solution cannot be dispersed inside the vascular tissue, and the vascular tissue cannot be decomposed.

[0219] Comparative Example 7

[0220] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0221] The reagent combination includes solution A, solution B and solution C, the composition of which is shown in Table 24. The solvent is PBS aqueous solution with pH=7.4. Based on Example 1, the total amount of enzyme is kept constant, and a single enzyme reaction is carried out.

[0222] Table 24

[0223]

[0224] The method for removing vascular tissue from the stent is the same as in Example 1. Observing the stent surface, the elastin in the outer membrane of the vascular tissue cannot be decomposed. After the solution decomposes part of the collagen, it cannot decompose the elastin further. As a result, the solution is blocked by the elastin and cannot be further decomposed. The collagen fiber network is decomposed, resulting in the vascular tissue becoming tight.

[0225] The results of Comparative Examples 6 and 7 show that without the synergistic treatment of collagenase and elastase designed in this invention, it is difficult to effectively remove vascular tissue.

[0226] Comparative Example 8

[0227] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0228] The reagent combination includes solution A, solution B and solution C, and the composition is shown in Table 25. The solvent is PBS aqueous solution with pH=7.4. Based on Example 2, the amount of ions is changed.

[0229] Table 25

[0230]

[0231] The method for removing vascular tissue from the stent is the same as in Example 2. It was observed that some vascular tissue remained on the stent surface (approximately 10% remained).

[0232] Comparative Example 9

[0233] This comparative example provides a reagent combination and method for removing vascular tissue from a stent.

[0234] The reagent combination includes solution A, solution B and solution C, and the composition is shown in Table 26. The solvent is PBS aqueous solution with pH=7.4. Based on Example 2, the amount of ions is changed.

[0235] Table 26

[0236]

[0237] The method for removing vascular tissue from the stent is the same as in Example 2. The decomposition efficiency of each solution is relatively fast in the early stage, but after 2-3 hours, the decomposition gradually slows down, and some vascular tissue remains on the stent surface.

[0238] The results of Comparative Examples 8 and 9 show that without the ion system designed in this invention for synergistic processing, it is difficult to effectively remove vascular tissue.

[0239] In summary, this invention addresses the shortcomings of current methods for removing vascular tissue from stents by designing a novel solution that includes specific reagent combinations and processing techniques. This solution can efficiently remove vascular tissue without damaging the stent or its biodegradable components. Furthermore, it can be implemented in specific processing equipment, achieving standardization and automation, thus contributing to the research and design of biodegradable stents.

[0240] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A reagent combination for removing vascular tissue from a stent, characterized in that, The reagent combination includes a first decomposition solution, a second decomposition solution, and a third decomposition solution; The first decomposition solution contains: collagenase 1.8~2.2 mg / mL, calcium ions 0.1~0.4 mmol / mL, elastase 0.8~1.2 mg / mL, magnesium ions 0.1~0.3 mmol / mL, and ammonium ions 0.04~0.08 mmol / mL; The second decomposition solution contains: collagenase 1.8~2.5 mg / mL, calcium ions 0.1~0.5 mmol / mL, elastase 2.2~2.8 mg / mL, magnesium ions 0.1~0.5 mmol / mL, and ammonium ions 0.04~0.08 mmol / mL; The third decomposition solution contains: collagenase 0.8~1.2 mg / mL, calcium ions 0.1~0.2 mmol / mL, elastase 1.8~2.2 mg / mL, magnesium ions 0.1~0.4 mmol / mL, and ammonium ions 0.04~0.08 mmol / mL.

2. The reagent combination for removing vascular tissue on a stent according to claim 1, characterized in that, The concentration ratio of collagenase to elastase in the first decomposition solution is (1.8~2.5):1; The concentration ratio of collagenase to elastase in the second decomposition solution is 1:(1~1.3).

3. The reagent combination for removing vascular tissue on a stent according to claim 1, characterized in that, The concentration ratio of collagenase to elastase in the third decomposition solution is 1:(1.8~2.5).

4. The reagent combination for removing vascular tissue on a stent according to claim 1, characterized in that, The collagenases include collagenase type I and / or collagenase type II.

5. The reagent combination for removing vascular tissue on a stent according to claim 1, characterized in that, The solvents for the first, second, and third decomposition solutions are each independently PBS buffer. The stent includes a vascular stent, and the vascular stent includes a biodegradable vascular stent.

6. The use of the reagent combination for removing vascular tissue on a stent according to any one of claims 1-5 in the removal of vascular tissue on a stent.

7. A method for removing vascular tissue from a stent, characterized in that, The method includes treating the stent using the reagent combination for removing vascular tissue on the stent as described in any one of claims 1-5, wherein the stent treatment specifically includes placing the stent in the first decomposition solution, the second decomposition solution and the third decomposition solution in sequence for first treatment, second treatment and third treatment.

8. The method for removing vascular tissue from a stent according to claim 7, characterized in that, The first processing time is 1~5 h, the second processing time is 20~30 h, and the third processing time is 5~25 h.

9. The method for removing vascular tissue from a stent according to claim 7, characterized in that, The processing support is carried out in a reaction device, which includes a reaction vessel, a support mounting device, a temperature control device, and a peristaltic pump circulation device.

10. The method for removing vascular tissue from a stent according to claim 9, characterized in that, The bracket installation device is a traction bracket installation device or a round rod bracket installation device.

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