JP2021137460A - catheter - Google Patents

Abstract

To provide a catheter capable of reliably releasing a medicament at a target portion while protecting a medicament layer during inserting a baloon, and a method to manufacture the catheter.SOLUTION: A catheter 10 comprises a long-sized shaft 11 and a balloon 12 placed on the tip side of the shaft 11 and expandable radially. The balloon 12 has on its surface a base layer 30 containing a temperature responsive polymer having the lowest critical solution temperature lower than a body temperature. The base layer 30 has a hydrophobic medicament layer 31 containing a medicament, on its surface opposite from a surface facing the balloon 12.SELECTED DRAWING: Figure 3

Description

The present invention relates to a catheter inserted into a living lumen, and more particularly to a catheter having a balloon that can be expanded in the living lumen and a method for manufacturing the same.

A catheter having a balloon at the tip is widely used for improving a lesion (stenosis) generated in a living lumen. The catheter includes a long shaft portion and a balloon provided on the distal end side of the shaft portion and expandable in the radial direction. The catheter can spread the lesion by expanding the contracted balloon after reaching the destination in the body via a narrow living lumen.

On the other hand, when the lesion is forcibly expanded by a balloon, smooth muscle cells may proliferate excessively and develop new stenosis (restenosis) in the lesion. Therefore, a drug-eluting balloon in which the outer surface of the balloon is coated with a drug for suppressing stenosis is used. The drug-eluting balloon can be expanded to instantly release the drug coated on the outer surface to the lesion and transfer the drug to the living tissue, thereby suppressing restenosis. As the agent provided on the outer surface of the balloon, those having various uses other than the prevention of restenosis can be used.

The drug-eluting balloon is required not to peel off the drug layer when it is delivered to the target site. In addition, the drug-eluting balloon is required to ensure that the drug is transferred to the living tissue at the target site. For example, Patent Document 1 discloses a catheter having a drug-eluting balloon in which a drug is embedded in a gel that undergoes a phase transition at a temperature equivalent to body temperature.

Japanese Unexamined Patent Publication No. 2003-126241

The catheter of Patent Document 1 embeds a drug in a gel that undergoes a phase transition at a temperature equivalent to body temperature, so that the surface of the gel is lubricated and has good passageability until the balloon reaches the target site, and the balloon When the target site is reached, the lubricity of the gel is reduced and slippage during balloon expansion can be prevented. However, the catheter of Patent Document 1 cannot be said to have sufficient protection of the drug layer at the time of balloon insertion. Further, in the catheter of Patent Document 1, since the drug is contained in the gel, it cannot be said that the transferability of the drug to the living tissue at the time of balloon expansion is sufficient.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a catheter capable of reliably releasing a drug at a target site while protecting the drug layer at the time of inserting a balloon, and a method for manufacturing the same. ..

The catheter according to the present invention that achieves the above object has a long shaft portion and a long shaft portion.
It has a balloon that is arranged on the tip side of the shaft portion and can be expanded in the radial direction.
The balloon has a base layer on the surface containing a temperature-responsive polymer whose lower limit critical solution temperature is lower than body temperature.
The base layer has a hydrophobic drug layer containing the drug on the surface opposite to the surface facing the balloon.

The method for manufacturing a catheter according to the present invention that achieves the above object is a method for manufacturing a catheter having a balloon at the tip of a long shaft portion.
A step of forming a base layer containing a temperature-responsive polymer whose lower limit critical solution temperature is lower than body temperature on the surface of the balloon, and
A step of forming a hydrophobic drug layer containing a drug on the surface of the base layer opposite to the surface facing the balloon,
Have.

In the catheter constructed as described above, the base layer becomes hydrophobic due to body temperature until the balloon reaches the target site in the living body, and the catheter is in a state of being bound to the hydrophobic drug layer, so that the drug layer falls off. Etc. can be prevented. Further, in the catheter of the present invention, at the target site, the temperature of the balloon becomes lower than the lower limit critical solution temperature due to the expanding fluid that expands the balloon, so that the base layer becomes hydrophilic and the drug layer is detached. As a result, the catheter of the present invention can reliably release the drug at the target site while protecting the drug layer when the balloon is inserted.

Further, the base layer may have poly (N-isopropylacrylamide) as the temperature-responsive polymer. Since the lower limit critical solution temperature of poly (N-isopropylacrylamide) is 32 ° C., it is possible to ensure that the base layer exhibits hydrophobicity in vivo.

Further, the lower limit critical solution temperature of the temperature-responsive polymer contained in the base layer may be 0 ° C. to 35 ° C. Thereby, the base layer can surely perform a function in the living body.

Further, the balloon may have an outflow portion that penetrates inside and outside. As a result, the outflow portion can supply a fluid to the base layer from the inside of the balloon to improve the hydrophilization efficiency of the base layer.

The method for manufacturing a catheter configured as described above can manufacture a catheter capable of reliably releasing a drug at a target site while protecting the drug layer when the balloon is inserted.

Further, after the base layer is formed, the base layer may be dried before the drug layer is formed. Thereby, in the production method of the present invention, the drug layer can be formed in a state where the base layer is hydrophobic.

Further, once the drug layer is formed, the drug layer may be dried. Thereby, the production method of the present invention can maintain the hydrophobic state of the base layer after the formation of the drug layer, and can maintain the bonded state of the two by the hydrophobic interaction.

It is a front view which showed the whole structure of a catheter. It is an enlarged cross-sectional view around the balloon in a contracted state. It is an enlarged cross-sectional view around the balloon which expanded from the contracted state and released the drug. It is an enlarged cross-sectional view of the vicinity of the balloon which contracted from the expanded state and adsorbed the remaining drug. It is sectional drawing which showed the folding process of a balloon. It is an enlarged front view of the vicinity of a balloon which concerns on a modification. It is an enlarged front view of the vicinity of the balloon in the expanded state of FIG. It is a photograph of the appearance of the drug layer under the condition 1 of the example. It is a photograph of the appearance of the drug layer under the condition 2 of the example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The dimensional ratios in the drawings may be exaggerated and differ from the actual ratios for convenience of explanation. Further, in the present specification, the side of the catheter 10 to be inserted into the biological lumen is referred to as "tip" or "tip side", and the hand side to be operated is referred to as "base end" or "base end side".

First, the configuration of the catheter 10 will be described. As shown in FIG. 1, the catheter 10 has a long, hollow tubular shaft portion 11, a balloon 12 provided at the tip end portion of the shaft portion 11, and a hub 13 fixed to the base end portion of the shaft portion 11. Have.

In the catheter 10, a long shaft portion 11 is inserted into a living organ, and a balloon 12 provided on the distal end side thereof is expanded at the lesion portion, whereby the lesion portion can be expanded for treatment. The shaft portion 11 is provided with an opening 11a into which the guide wire 14 is introduced near the tip end side. That is, the catheter 10 is a so-called rapid exchange type.

Next, the structure of the tip portion of the shaft portion 11 and the balloon 12 will be described. As shown in FIG. 2, the shaft portion 11 has a hollow outer tube 20 and an inner tube 21 which is a hollow internal support. The inner pipe 21 is housed inside the hollow of the outer pipe 20, and the shaft portion 11 has a double pipe structure. A guide wire lumen 23 through which the guide wire 14 is inserted is formed inside the hollow of the inner pipe 21. Further, an expansion lumen 22 for circulating the expansion fluid of the balloon 12 is formed inside the hollow of the outer tube 20 and outside the inner tube 21.

The inner pipe 21 projects further to the tip side than the tip end of the outer pipe 20. The base end side end of the balloon 12 is fixed to the tip end of the outer tube 20, and the tip end side end is fixed to the tip end of the inner tube 21. As a result, the inside of the balloon 12 communicates with the expansion lumen 22. The balloon 12 can be expanded by injecting an expansion fluid into the balloon 12 via the expansion lumen 22. The expansion fluid may be a gas or a liquid, for example, a gas such as helium gas, CO ₂ gas, O ₂ gas, physiological saline, a contrast agent, a cooling liquid (mixed solution of contrast agent and ethanol, liquid nitrogen phosphite, etc.). ) And other liquids can be used.

The outer tube 20 and the inner tube 21 are preferably formed of a material having a certain degree of flexibility. Examples of such a material include polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof, and a soft polyvinyl chloride resin. Examples thereof include fluororesins such as polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane and polytetrafluoroethylene, silicone rubber and latex rubber.

The balloon 12 is formed of a thin-film balloon film, and like the outer tube 20 and the inner tube 21, is formed of a flexible material. In addition, it is required to have enough strength to surely spread the narrowed portion. As the material of the balloon 12, the ones mentioned above for the outer tube 20 and the inner tube 21 can be used, or other materials may be used.

A base layer 30 is formed on the surface of the balloon 12, and a drug layer 31 is formed on the surface of the base layer 30 opposite to the surface facing the balloon 12. The base layer 30 contains a temperature-responsive polymer having a lower critical solution temperature (LCST) lower than the body temperature. The temperature-responsive polymer is a polymer that exhibits hydrophilicity at low temperatures and becomes hydrophobic when the temperature rises above the lower limit seaside solution temperature. As the temperature-responsive polymer, PNIPAAm (poly (N-isopropylacrylamide)) is used in this embodiment. The lower limit critical solution temperature of PNIPAAm is 32 ° C., which is lower than the body temperature. Further, as the other temperature-responsive polymer, poly (2-isopropyl-2-oxazoline) or PIPAAm (poly (N-isopropylacrylamide)) can also be used. The lower limit critical solution temperature of poly (2-isopropyl-2-oxazoline) is 38 ° C, and the lower critical solution temperature of PIPAAm is 37 ° C. In order for the base layer 30 to exhibit hydrophobicity in the living body, it is preferable to use PNIPAAm whose lower limit critical solution temperature is somewhat lower than the body temperature. The temperature-responsive polymer may be other than these, but the lower limit critical solution temperature is preferably in the range of 0 ° C. to 35 ° C., preferably 20 ° C. to 35 ° C.

The drug layer 31 contains a drug and has hydrophobicity. The drug layer 31 is formed by nano / microparticles containing the drug or a coat layer containing the drug. Examples of the drug include immunosuppressive agents, for example, cyclosporines containing cyclosporin, immunoactive agents such as rapamycin, anticancer agents such as paclitaxel, antiviral agents or antibacterial agents, antineoplastic tissue agents, analgesics and anti-inflammatory agents. Agents, antibiotics, antiepileptics, anxiety relievers, antiparasitic agents, antagonists, neuronblocking agents, anticholinergic and cholinergic agents, antimuscariners and muscariners, antiadrenaline agents, antiarrhythmic agents, anti Antihypertensive agents, hormonal agents and nutritional agents can be used. Moreover, the drug may be other than that.

Next, the method and operation of the catheter 10 according to the present embodiment will be described by taking the case of treating a stenotic portion in a blood vessel as an example.

First, the surgeon punctures a blood vessel through the skin by a known method such as the Seldinger method, and indwells an introducer (not shown). Next, the protective sheath (not shown) of the catheter 10 is removed, priming is performed, and then the guide wire 14 is inserted into the guide wire lumen 23. In this state, the guide wire 14 and the catheter 10 are inserted into the blood vessel from the inside of the introducer. Subsequently, the catheter 10 is advanced while the guide wire 14 is preceded, and the balloon 12 is brought to the stenotic portion which is the target site. A guiding catheter may be used to bring the catheter 10 to the stenosis.

When the balloon 12 is inserted to the target site in the living body, the base layer 30 has hydrophobicity because the body temperature is higher than the lower limit critical solution temperature of the temperature-responsive polymer. Since the drug layer 31 also has hydrophobicity as described above, the two are strongly bonded by the hydrophobic interaction. Therefore, the drug layer 31 is in a state where it is difficult to peel off from the base layer 30 even if it is physically affected by blood flow or the like. Therefore, it is possible to reduce the loss of the drug until the balloon 12 reaches the target site.

After arranging the balloon 12 in the narrowed portion, a predetermined amount of the expanding fluid is injected from the hub 13 using an indeflator, a syringe, or the like, and the expanding fluid is sent into the inside of the balloon 12 through the expansion lumen 22. As a result, as shown in FIG. 3, the folded balloon 12 is expanded, and the narrowed portion is expanded by the balloon 12.

The dilation fluid has room temperature or a temperature below room temperature. The temperature of the expansion fluid can be set to, for example, 25 ° C. The temperature of the expansion fluid may be other than that, but is set to at least a temperature lower than the lower limit critical solution temperature of the temperature-responsive polymer of the base layer 30. When the expansion fluid is injected into the balloon 12, the surface temperature of the balloon 12 drops. When the temperature of the balloon 12 becomes lower than the lower limit critical solution temperature of the temperature-responsive polymer, the base layer 30 changes to hydrophilicity. When the base layer 30 has hydrophilicity, it hydrates with the surrounding water and swells, and the hydrophobic interaction with the drug layer 31 disappears. As a result, the drug layer 31 has a higher affinity with the living tissue than the base layer 30, and the drug layer 31 is detached from the balloon 12. When the drug layer 31 is detached from the balloon 12, the transfer of the drug to the living tissue is promoted, and the drug can be effectively transferred to the narrowed portion. Therefore, restenosis of the stenosis is effectively suppressed.

After that, the expansion fluid is sucked and discharged through the expansion lumen 22, and the balloon 12 is contracted to be in a folded state. As a result, the temperature of the balloon 12 rises due to the body temperature. When the temperature of the balloon 12 becomes higher than the lower limit critical solution temperature of the temperature-responsive polymer, the base layer 30 changes to exhibit hydrophobicity. Along with this, the hydrophobic interaction between the drug layer 31 and the base layer 30 occurs again. As shown in FIG. 4, the drug layer 31 that has not migrated to the living tissue is adsorbed on the base layer 30 by hydrophobic interaction. As a result, the drug layer 31 that has not migrated to the living tissue remains around the stenosis, and the drug layer 31 is prevented from falling off from the balloon 12 when the catheter 10 is removed, so that the risk of embolization can be reduced.

In order to change the base layer 30 from hydrophilic to hydrophobic, the expanded balloon 12 may be maintained in the narrowed portion for a while. By keeping the balloon 12 in the living body, the temperature of the expanding fluid rises due to the body temperature. Therefore, the temperature of the balloon 12, which was lower than the lower limit critical solution temperature, rises, and the base layer 30 changes to hydrophobic. As a result, the hydrophobic interaction between the drug layer 31 and the base layer 30 occurs again, and the drug layer 31 that has not migrated to the living tissue can be adsorbed on the base layer 30.

After that, the guide wire 14 and the catheter 10 are removed from the blood vessel via the introducer, and the procedure is completed.

Next, the manufacturing process of the catheter 10 according to the present embodiment will be described. Here, a step of forming the base layer 30 and the drug layer 31 on the balloon 12 and folding them will be described. First, the base layer 30 is formed on the surface of the balloon 12. The base layer 30 is formed by grafting and fixing PNIPAAm to the surface of the balloon 12.

Examples of the method for grafting PNIPAAm include a method of ultraviolet irradiation using a radical polymerization initiator. The method for grafting PNIPAAm may be other than this, and for example, a method such as radical polymerization, covalent bond, or annealing can be used.

After the base layer 30 is formed on the surface of the balloon 12, the base layer 30 is dried. This drying step is performed by natural drying, heating, vacuuming, or the like. As a result, the water contained in the base layer 30 is removed so that the base layer 30 is not hydrated. Then, the drug layer 31 is formed on the surface of the base layer 30. The drug layer 31 is formed by coating the surface of the base layer 30 with a drug or a mixture of the drug and a polymer. As a coating method, a method such as spray coating, pipetting, dipping, or roll coating can be used. It is preferable to use a solvent in which PNIPAAm is not dissolved as the coating liquid. As such a solvent, for example, hexane can be used. The solvent may be other than hexane such as dichloromethane, diethyl ether and acetonitrile.

The coating of the drug layer 31 is performed in a temperature environment higher than the lower limit critical solution temperature of the temperature-responsive polymer. As a result, the drug layer 31 is coated with the base layer 30 in a hydrophobic state, and the two are strongly bonded by the hydrophobic interaction. After coating the drug layer 31, a drying step is performed again to remove water.

After forming the base layer 30 and the drug layer 31 on the surface of the balloon 12, the balloon 12 is folded. As shown in FIG. 5A, the base layer 30 and the drug layer 31 are formed in an expanded state of the balloon 12. As shown in FIG. 5B, a plurality of blade portions 15 are formed on the balloon 12 by a pleating device (not shown). Further, as shown in FIG. 5 (c), the blade portion 15 is laid down by a folding device (not shown) to form a folded balloon 12. In the folded balloon 12, one side of the blade portion 15 and the outer peripheral surface from the tip portion of the blade portion 15 to the root portion of the adjacent blade portion 15 are exposed surfaces 16 exposed outward. In the present embodiment, since the base layer 30 and the drug layer 31 are formed on the surface of the balloon 12 and then the balloon 12 is folded, the base layer 30 and the drug layer 31 are formed on the entire outer surface of the balloon 12.

The formation of the base layer 30 and the drug layer 31 may be performed after the balloon 12 is folded. In the state before folding the balloon 12 shown in FIG. 5 (a), the base layer 30 is formed on the surface of the balloon 12, the balloon 12 is folded as shown in FIG. 5 (c), and then on the surface of the base layer 30. The drug layer 31 may be formed. In this case, the base layer 30 is formed on the entire surface of the balloon 12, and the drug layer 31 is formed only on the exposed surface 16 of the balloon 12. Further, the balloon 12 may be folded as shown in FIG. 5 (c), the base layer 30 may be formed on the surface of the balloon 12, and the drug layer 31 may be formed on the surface thereof. In this case, the base layer 30 and the drug layer 31 are formed only on the exposed surface 16 of the balloon 12.

A modified example of the balloon 12 will be described. As shown in FIG. 6, the outflow portion 12a may be provided on the surface of the balloon 12. The outflow portion 12a is formed as a slit penetrating the inside and outside of the balloon 12. A plurality of outflow portions 12a are formed in the length direction and the radial direction of the balloon 12. When the balloon 12 expands, the outflow portion 12a extends in the width direction as shown in FIG. 7, and a part of the expansion fluid flows out from the inside to the outside of the balloon 12. As a result, the fluid is supplied to the base layer 30 from the inside of the balloon 12, so that the hydrophilization efficiency of the base layer 30 can be improved. The number and shape of the outflow portions 12a are not limited to those shown in FIGS. 6 and 7, and can be arbitrarily set as needed.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Example 1)
(1) Polymerization of temperature-responsive polymer (NIPAAm) and fixation on balloon surface 60 mg of benzophenone was taken and dissolved in 12 mL of acetone (i). The balloon (Φ3.0 mm × 20 mm) of the catheter was immersed in the liquid of (i), pulled up, and air-dried (ii). After taking 3600 mg of NIPAAm and dissolving it in 100 mL of water, the balloon of (ii) was immersed (iii). The container of (iii) was irradiated with UV for 60 minutes. The balloon was removed, washed with water and dried.

(2) Drug coating on balloon L-serine ethyl ester hydrochloride (CAS No. 26348-61-8) (56 mg) and paclitaxel (CAS No. 33069-62-4) (134.4 mg) were weighed. Coating by adding absolute ethanol (1.2 mL), tetrahydrofuran (1.6 mL), RO (Reverse Osmosis, reverse osmosis membrane) treated water (hereinafter referred to as RO water) (0.4 mL) to this and dissolving it. The solution was prepared. By expanding the balloon with warm water to maintain the hydrophobic state of the temperature-responsive polymer, the amount of drug (paclitaxel) per unit area is 3.2 μg / mm ^{2 while keeping the balloon part at 32 ° C or higher.} , Coated by pipetting. After coating, the surface of the balloon was dried to prepare a drug-eluting balloon.

(3) Evaluation of Control of Drug Release from Balloon Surface The prepared drug-eluting balloon was immersed in warm water at 37 ° C. and held for 30 seconds while stirring with a stirrer. While maintaining stirring, the balloon portion was expanded with each of the following expanding solutions.

Condition 1 Cooling liquid (contrast agent: water: ethanol = 1: 1: 1 mixed and stored at -20 ° C)
Condition 2 After holding the expanded state of warm water at 37 ° C. for 60 seconds, the balloon was taken out from the warm water. After the balloon surface was dried, the balloon surface was observed using a digital microscope (KEYENCE, VHX-2000), and the residual state of the drug layer on the balloon surface due to the difference between conditions 1 and 2 was compared.

(4) Evaluation Results FIGS. 8 (a) and 8 (b) show photographs of the appearance of the drug layer before and after the dipping / expanding operation with the expanding solution under Condition 1, respectively. 9 (a) and 9 (b) are photographs of the appearance of the drug layer before and after the dipping / expanding operation with the expanding solution of Condition 2, respectively. In condition 1, from the comparison between FIGS. 8A and 8B, the appearance after the immersion and expansion operations showed almost no drug layer on the balloon surface, and the drug layer was peeled off from the balloon surface. It was seen that it was.

On the other hand, under condition 2, from the comparison between FIGS. 9 (a) and 9 (b), there was almost no change in appearance before and after the immersion and expansion operations, and it was found that the drug layer was held on the balloon surface. It was seen. From the above observation results, the temperature-responsive polymer becomes hydrophilic when expanded with a cooling liquid, so that the drug layer is peeled off from the balloon surface, while when expanded with warm water at 37 ° C, the temperature-responsive polymer becomes hydrophobic. It was confirmed that the drug layer was retained on the balloon surface.

As described above, the catheter 10 according to the present embodiment has a long shaft portion 11 and a balloon 12 arranged on the distal end side of the shaft portion 11 and expandable in the radial direction, and the balloon 12 has a lower limit. The surface has a base layer 30 containing a temperature-responsive polymer whose critical solution temperature is lower than the body temperature, and the base layer 30 has a hydrophobic drug layer 31 containing a drug on the surface opposite to the surface facing the balloon 12. Have. In the catheter 10 configured in this way, the base layer 30 becomes hydrophobic due to body temperature until the balloon 12 reaches the target site in the living body, and the catheter 10 is in a state of being bound to the hydrophobic drug layer 31. It is possible to prevent the drug layer 31 from falling off. Further, in the catheter 10 of the present embodiment, at the target site, the temperature of the balloon 12 becomes lower than the lower limit critical solution temperature due to the expanding fluid that expands the balloon 12, so that the base layer 30 exhibits hydrophilicity and the drug layer 31 becomes hydrophilic. To leave. As a result, the catheter 10 of the present embodiment can reliably release the drug at the target site while protecting the drug layer 31 when the balloon 12 is inserted.

Further, the base layer 30 may have poly (N-isopropylacrylamide) as a temperature-responsive polymer. Since the lower limit critical solution temperature of poly (N-isopropylacrylamide) is 32 ° C., it is possible to ensure that the base layer 30 exhibits hydrophobicity in vivo.

Further, the lower limit critical solution temperature of the temperature-responsive polymer contained in the base layer 30 may be 0 ° C. to 35 ° C. As a result, the base layer 30 can surely perform a function in the living body.

Further, the balloon 12 may have an outflow portion 12a that penetrates inside and outside. As a result, the outflow portion 12a can supply a fluid to the base layer 30 from the inside of the balloon 12 to improve the hydrophilization efficiency of the base layer 30.

Further, the method for manufacturing the catheter 10 according to the present embodiment is a method for manufacturing the catheter 10 having the balloon 12 at the tip of the long shaft portion 11, and the lower limit critical solution temperature on the surface of the balloon 12 is lower than the body temperature. It has a step of forming a base layer 30 containing a temperature-responsive polymer and a step of forming a hydrophobic drug layer 31 containing a drug on the surface of the base layer 30 opposite to the surface facing the balloon 12. The method for manufacturing the catheter 10 configured in this way can manufacture the catheter 10 capable of reliably releasing the drug at the target site while protecting the drug layer 31 when the balloon 12 is inserted.

Further, after the base layer 30 is formed, the base layer 30 may be dried before the drug layer 31 is formed. Thereby, in the production method of the present invention, the drug layer 31 can be formed in a state where the base layer 30 is hydrophobic.

Further, once the drug layer 31 is formed, the drug layer 31 may be dried. Thereby, the production method of the present invention can maintain the base layer 30 in a hydrophobic state after the formation of the drug layer 31, and can maintain the state in which the two are bound by the hydrophobic interaction.

The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, the catheter according to the above-described embodiment is a rapid exchange type, but may be an over-the-wire type (Over-the-wire type).

10 Catheter 11 Shaft 11a Opening 12 Balloon 12a Outflow 13 Hub 14 Guide wire 15 Blade 16 Exposed surface 20 Outer tube 21 Inner tube 22 Expansion lumen 23 Guide wire lumen 30 Base layer 31 Drug layer

Claims (7)

With a long shaft
It has a balloon that is arranged on the tip side of the shaft portion and can be expanded in the radial direction.
The balloon has a base layer on the surface containing a temperature-responsive polymer whose lower limit critical solution temperature is lower than body temperature.
The base layer is a catheter having a hydrophobic drug layer containing a drug on a surface opposite to the surface facing the balloon. The catheter according to claim 1, wherein the base layer has poly (N-isopropylacrylamide) as the temperature-responsive polymer. The catheter according to claim 1 or 2, wherein the lower limit critical solution temperature of the temperature-responsive polymer contained in the base layer is 0 ° C to 35 ° C. The catheter according to any one of claims 1 to 3, wherein the balloon has an outflow portion that penetrates inside and outside. A method for manufacturing a catheter having a balloon at the tip of a long shaft.
A step of forming a base layer containing a temperature-responsive polymer whose lower limit critical solution temperature is lower than body temperature on the surface of the balloon, and
A step of forming a hydrophobic drug layer containing a drug on the surface of the base layer opposite to the surface facing the balloon,
A method for manufacturing a catheter having. The method for manufacturing a catheter according to claim 5, wherein the base layer is formed, the base layer is dried, and then the drug layer is formed. The method for manufacturing a catheter according to claim 5 or 6, wherein the drug layer is formed and then dried.

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