Elongated medical device and method for producing elongated medical device

Abstract

Provided is an elongated medical device 1 comprising an elongated body 10 which extends from the distal end side to the proximal end side and a swellable coating layer 20 which is provided on at least part of the surface of the elongated body 10, wherein: the swellable coating layer 20 is provided with a first portion 21 and a second portion 22 that is disposed closer to the proximal end side in comparison to the first portion 21; the thickness of the first portion 21 is greater than the thickness of the second portion 22 after the swellable coating layer 20 is caused to swell by immersing the elongated medical device 1 in water at 37°C for 120 minutes; and the degree of swelling of the swellable coating layer 20 defined by equation (1) below in the second portion 22 is smaller than the degree of swelling of the swellable coating layer 20 defined by equation (1) below in the first portion 21.　(1): Degree of swelling = (thickness after swelling) ÷ (thickness before swelling). The elongated medical device 1 exhibits excellent lubricity and is capable of suppressing the generation of fine particles.

Description

Long medical device and method for manufacturing long medical device

[0001] The present invention relates to elongated medical devices and methods for manufacturing elongated medical devices.

[0002] Long medical devices such as guide wires, stents, and catheters that are inserted into the body are required to have lubricity toward biological tissue in order to prevent damage to the biological tissues, such as blood vessels, that they come into contact with in the body, and to improve the operability of the long medical devices.

[0003] For this reason, coatings made of hydrophilic polymers or the like are formed on the surfaces of such elongated medical devices. For example, Patent Document 1 discloses an endoscopic device provided with a lubricating coating material that is thicker at the distal end than at the proximal end. Patent Document 2 also discloses a guidewire provided with a lubricating resin coating that has a lubricating resin density gradient so that frictional resistance decreases from the proximal end to the distal end.

[0004] JP 2006-150040 A JP 2006-192294 A

[0005] However, in conventional elongated medical devices equipped with the above-described coating, friction occurs between the coating and the living tissue when the device is inserted into a body cavity, which can cause part of the coating to be scraped off, resulting in the generation of fine particles.

[0006] An object of the present invention is to provide a long medical device that exhibits excellent lubricity and is capable of suppressing the generation of fine particles.

[0007] In order to achieve the above-mentioned object, firstly, the present invention provides a long medical device comprising a long body extending from a distal end side to a proximal end side, and a swellable coating layer provided on at least a part of the surface of the long body, wherein the swellable coating layer comprises a first portion and a second portion located on the proximal end side of the first portion, and wherein, after the long medical device is immersed in water at 37°C for 120 minutes to cause the swellable coating layer to swell, the thickness of the first portion is thicker than the thickness of the second portion, and the swelling degree of the swellable coating layer in the second portion, as defined by the following formula (1), is smaller than the swelling degree of the swellable coating layer in the first portion, as defined by the following formula (1) (Invention 1).

[0008] In the above invention (Invention 1), it is preferable that the swellable coating layer has a third portion located closer to the base end than the second portion, and that after swelling, the thickness of the second portion is thicker than the thickness of the third portion, and the swelling degree of the swellable coating layer defined by formula (1) in the third portion is smaller than the swelling degree of the swellable coating layer defined by formula (1) in the second portion (Invention 2).

[0009] Secondly, the present invention provides a method for manufacturing a long medical device having a long body extending from the distal end to the proximal end, the method comprising the steps of: preparing a long body in which a first long body part (I) made of a first resin (I) and a second long body part (II) made of a second resin (II) arranged on the proximal end side of the first long body part (I) and having a smaller swelling degree in a first solvent (A) than the first resin (I) are directly or indirectly connected; and applying a coating material containing a crosslinking agent and the first solvent (A) to at least a portion of the surface of the first long body part (I) and the second long body part (II) (Invention 3).

[0010] In the above invention (Invention 3), in the coating process, it is preferable to form a swellable coating layer by applying a paint containing a hydrophilic polymer, a crosslinking agent and a first solvent (A) to at least a portion of the surface of the first elongated body part (I) and the second elongated body part (II) (Invention 4).

[0011] In the above invention (Invention 3), it is also preferable that the coating step includes a step of forming a base layer by applying a paint containing a base polymer, a crosslinking agent, and a first solvent (A) to at least a portion of the surface of the first elongated body part (I) and the second elongated body part (II), and after the coating step, a step of forming a swellable coating layer by applying a paint containing a hydrophilic polymer and a second solvent (B) to at least a portion of the surface of the base layer opposite the elongated body (Invention 5).

[0012] In the above invention (Invention 3), it is also preferable that the coating step includes a step of forming an adhesive layer by applying a paint containing a crosslinking agent and the first solvent (A) to at least a portion of the surface of the first elongated body part (I) and the second elongated body part (II), and after the coating step, a step of forming a swellable coating layer by applying a paint containing a hydrophilic polymer and a second solvent (B) to at least a portion of the surface of the adhesive layer opposite the elongated body (Invention 6).

[0013] The elongated medical device according to the present invention exhibits excellent lubricity and can suppress the generation of fine particles.

[0014] 1A and 1B are schematic cross-sectional views of an elongated medical device according to one embodiment of the present invention, a schematic cross-sectional view of an elongated medical device according to another embodiment of the present invention, and a schematic cross-sectional view of an elongated medical device according to yet another embodiment of the present invention.

[0015] An embodiment of the present invention will now be described. Fig. 1 shows a schematic cross-sectional view of a long medical device according to one embodiment of the present invention. The long medical device 1 shown in Fig. 1 comprises a long body 10 extending from the distal end (left side of the page) to the proximal end (right side of the page) and a swellable coating layer 20 provided on at least a portion of the surface of the long body 10. The swellable coating layer 20 comprises a first portion 21 and a second portion 22 located closer to the proximal end than the first portion 21. In the long medical device 1 shown in Fig. 1, the long body 10 is depicted as having a tubular shape.

[0016] In the elongated medical device 1 according to this embodiment, after the elongated medical device 1 is immersed in water at 37°C for 120 minutes to swell the swellable coating layer 20, the thickness of the first portion 21 is greater than the thickness of the second portion 22. Note that the elongated medical device 1 shown in Figure 1 is immersed under the above conditions, and is depicted in a state in which the swellable coating layer 20 is fully expanded. This also applies to Figures 2 and 3, which will be described later.

[0017] The degree of swelling of the swellable coating layer 20 in the second portion 22, as defined by the following formula (1), is smaller than the degree of swelling of the swellable coating layer 20 in the first portion 21, as defined by the following formula (1): Swelling degree = (thickness after swelling) ÷ (thickness before swelling) (1)

[0018] In the elongated medical device 1 of this embodiment, the thickness of the first portion 21 located at the tip end is thicker than the thickness of the second portion 22 located at the base end, so that the amount of water contributing to lubrication is greater at the tip end, improving the lubricity at the tip end and resulting in excellent passability through body cavities.

[0019] Furthermore, because the thickness of the second portion 22 is thinner than that of the first portion 21, the contact between the swellable coating layer 20 and the body cavity is reduced at the position of the second portion 22, where lubricity is less required than at the distal end. Furthermore, because the degree of swelling of the second portion 22 is smaller than that of the first portion 21, i.e., the cross-linking density is higher, the second portion 22 has greater strength, and wear of the swellable coating layer 20 at the position of the second portion 22 is less likely to occur. As a result, it is possible to suppress the generation of fine particles from the swellable coating layer 20.

[0020] Furthermore, since the thickness of the second portion 22 is thinner than that of the first portion 21, the lubricity of the swellable coating layer 20 is lower at the base end side than at the tip end side, which makes it easier to support the elongated medical device 1 inserted into the body cavity (improved backup force) and provides excellent operability.

[0021] As described above, the elongated medical device 1 according to this embodiment has excellent lubricity at the distal end and is less likely to damage the body cavity, and is less likely to generate fine particles at the proximal end.

[0022] The elongated medical device according to the present invention is not limited to the one shown in FIG. 1 and may have other shapes and configurations. For example, FIG. 2 shows a elongated medical device 2 according to another embodiment. The elongated medical device 2 shown in FIG. 2 includes a elongated body 10 and a swellable coating layer 20, similar to the elongated medical device 1, but further includes a base layer 30 between the elongated body 10 and the swellable coating layer 20. As described below, the base layer 30 serves to improve the adhesion of the swellable coating layer 20 to the elongated body 10. Furthermore, the elongated medical device according to the present invention may include not only the elongated body 10 and the swellable coating layer 20, but also an adhesive layer provided therebetween. Like the base layer 30, the adhesive layer also serves to improve the adhesion of the swellable coating layer 20 to the elongated body 10.

[0023] Fig. 3 also shows an elongated medical device 3 according to another embodiment. The elongated medical device 3 shown in Fig. 3 includes an elongated body 10 and a swellable coating layer 20, similar to the elongated medical device 1. However, the swellable coating layer 20 includes, in addition to a first portion 21 and a second portion 22, a third portion 23 that is disposed proximally of the second portion 22. The thickness of the third portion 23 after swelling is thinner than the thickness of the second portion 22 after swelling. Furthermore, the swelling degree of the third portion 23, as defined by the above formula (1), is smaller than that of the second portion.

[0024] Like the elongated medical device 1 shown in Fig. 1, the elongated medical devices 2 and 3 shown in Fig. 2 and 3 exhibit excellent lubricity while suppressing the generation of fine particles. The elongated medical devices 1 and 2 shown in Fig. 1 and 2 may also include a third portion 23. The elongated medical device 3 shown in Fig. 3 may also include a base layer 30 or an adhesive layer. Furthermore, these elongated medical devices may also include a fourth portion (and further portions beyond) located closer to the base end than the third portion.

[0025] 1. Long Body The long body 10 in this embodiment is not particularly limited as long as it has a configuration extending from the distal end to the proximal end. The long body 10 may have a solid internal structure or a hollow internal structure. In particular, in the latter case, the long body 10 may be a tubular body having an internal structure in which a cavity extends in the longitudinal direction, as shown in Figures 1 to 3.

[0026] The material of the elongated body 10 is not particularly limited and can be appropriately selected depending on the elongated medical devices 1, 2, and 3 to be manufactured. Examples of such materials include resin, metal, glass, and ceramic, and among these, resin is preferred.

[0027] The resin constituting the elongated body 10 is not particularly limited, and examples thereof include nylon resins such as polyamide, polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyesters such as polyethylene terephthalate, thermoplastic resins such as polyvinyl chloride, ethylene-vinyl acetate copolymer, cross-linked ethylene-vinyl acetate copolymer, and polyurethane, polyamide elastomers, polyolefin elastomers, polyurethane elastomers, polystyrene elastomers, silicone rubber, and latex rubber.

[0028] In the elongated medical devices 1, 2, and 3 according to the present embodiment, as described below, the first portion 21 and the second portion 22 may be separately produced by using different resins for the portions of the elongated body 10 corresponding to the first portion 21 and the second portion 22. In this case, the elongated body 10 may include a first elongated body part disposed at the position where the first portion 21 is to be provided and a second elongated body part disposed at the position where the second portion 22 is to be provided. Furthermore, as in the elongated medical device 3 shown in FIG. 3 , when the swellable coating layer 20 includes a third portion 23, the elongated body 10 may include a third elongated body part disposed at the position where the third portion 23 is to be provided. The first elongated body part, second elongated body part, and third elongated body part may be directly or indirectly connected to each other.

[0029] The first to third elongate body components may be made of the same or different polymers. For example, even when the same polymer is used for each elongate body component, the degree of swelling of each elongate body component in a solvent can be varied by adjusting the monomer composition ratio in the polymer. In this way, even when the same polymer is used, the elongate body can have different degrees of swelling in a specific solvent from the distal end to the proximal end.

[0030] As described above, when the elongated body 10 is composed of a first elongated body part and a second elongated body part (and even a third elongated body part), the materials for the first to third elongated body parts are not particularly limited, and polyurethane elastomers, polyolefin elastomers, polyester elastomers, polystyrene elastomers, polyamide elastomers, etc. are preferred, with polyurethane elastomers or polyamide elastomers being particularly preferred.

[0031] Furthermore, even if the first elongated body part and the second elongated body part (and even the third elongated body part) are made of the same type of resin, the first part 21 and the second part 22 (and even the third part 23) can be made differently by, for example, changing the composition ratio of the monomers that make up the resin.

[0032] 2. Swellable Coating Layer The material constituting the swellable coating layer 20 in this embodiment is not particularly limited as long as it can exhibit swelling properties and can constitute the first portion 21 and the second portion 22 described above.

[0033] In particular, the swellable coating layer 20 is preferably composed of a resin that exhibits swelling properties. Examples of such resins include polymers having reactive functional groups (e.g., hydroxyl, carboxyl, amino, and epoxy groups), particularly known hydrophilic substances such as polysaccharide-based polymers (e.g., hyaluronic acid-based polymers, cellulose-based polymers), polyethylene oxide-based polymers, maleic acid-based polymers, acrylamide-based copolymers, water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone-based copolymers, hydroxyl-containing acrylic copolymers, and amphoteric polymers having hydrophilic groups (e.g., polymers having a betaine structure). Among these, hydroxyl-containing acrylic copolymers are preferred. These polymers can be used alone or in combination.

[0034] It is also preferable to use a crosslinking agent together with the resin described above. In particular, since the degree of swelling of the swellable coating layer 20 can be adjusted by the degree of crosslinking of the polymer described above, the use of a crosslinking agent makes it easier to achieve the desired degree of swelling.

[0035] Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, amine-based crosslinking agents, melamine-based crosslinking agents, aziridine-based crosslinking agents, hydrazine-based crosslinking agents, aldehyde-based crosslinking agents, oxazoline-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, ammonium salt-based crosslinking agents, etc. The crosslinking agents may be used alone or in combination of two or more.

[0036] When the polymer has a hydroxyl group as a reactive group, it is preferable to use an isocyanate-based crosslinking agent, which has excellent reactivity with the hydroxyl group, as the crosslinking agent.

[0037] The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as pentamethylene diisocyanate and hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; and biuret, isocyanurate, and allophanate forms thereof, as well as adducts obtained by reaction with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among these, hexamethylene diisocyanate is preferably used.

[0038] When a crosslinking agent is used, the amount used is preferably 1 to 100 parts by mass, more preferably 5 to 80 parts by mass, and even more preferably 10 to 50 parts by mass, relative to 100 parts by mass of the above-mentioned resin.

[0039] The method for forming the swellable coating layer 20 in this embodiment is not particularly limited, and can be, for example, by mixing the above-mentioned resin and, if desired, a crosslinking agent in a predetermined solvent to form a paint, and then applying the paint to the elongated body 10 (or the base layer 30, if present), and drying the paint. Examples of drying conditions include drying at a temperature of room temperature to 150°C, preferably 40 to 100°C, for 1 to 1,440 minutes, preferably 20 to 800 minutes.

[0040] Examples of the solvent include a mixed solvent of water and ethanol, water alone, ethanol alone, isopropanol, etc., and among these, a mixed solvent of water and ethanol is preferred.

[0041] The thickness of the swellable coating layer 20 in this embodiment before swelling is preferably 0.1 to 100 μm, more preferably 0.5 to 20 μm, and even more preferably 1 to 10 μm. Note that, before swelling, there may be no difference in thickness between the first portion 21 and the second portion 22 (and the second portion 23, if present).

[0042] On the other hand, after swelling the swellable coating layer 20 in this embodiment, the thickness of the first portion 21 is preferably 1 to 200 μm, particularly preferably 5 to 100 μm, and even more preferably 10 to 50 μm. The thickness of the second portion 22 is preferably 0.5 to 100 μm, particularly preferably 2 to 80 μm, and even more preferably 3 to 30 μm. Furthermore, if the third portion 23 is present, its thickness is preferably 0.1 to 80 μm, particularly preferably 1 to 50 μm, and even more preferably 1 to 30 μm.

[0043] In the swellable coating layer 20 of this embodiment, the swelling degree of the swellable coating layer 20 defined by the following formula (1) is preferably 10 to 2000, particularly preferably 13 to 200, and even more preferably 15 to 100, for the first portion 21. Furthermore, for the second portion 22, it is preferably 5 to 1000, particularly preferably 7 to 800, and even more preferably 8 to 300. Furthermore, when the third portion 23 is present, it is preferably 1 to 800, particularly preferably 2 to 500, and even more preferably 3 to 300, for the third portion 23. Swelling degree = (thickness after swelling) ÷ (thickness before swelling) (1)

[0044] In this specification, unless otherwise specified, the conditions for swelling the swellable coating layer 20 are to immerse the long medical devices 1, 2, and 3 in water at 37°C for two hours to allow them to swell sufficiently.

[0045] 3. Base Layer The material constituting the base layer 30 in this embodiment is not particularly limited as long as it is capable of adhering the swellable coating layer 20 and the elongated body 10 to each other. Preferred examples of such materials include (meth)acrylic resins, polyvinyl alcohol resins, polyhydroxyethyl methacrylate resins, polyethylene glycol resins, acrylic acid resins, and maleic acid resins. The (meth)acrylic resins are those containing an acryloyl group (H ２ C=CH-C(=O)-) or methacryloyl group (H ２ C=C(CH ３ Any resin having polymerization units based on a monomer having the formula (III)-C(═O)-) may be used.

[0046] A crosslinking agent may be added to the resin constituting the base layer 30. The crosslinking agent may be used to crosslink the resin constituting the base layer 30, or may be used to crosslink the resin constituting the swellable coating layer 20. In the latter case, when a paint for forming the swellable coating layer 20 is applied onto the base layer 30, the crosslinking agent migrates from the base layer 30 toward the paint and crosslinks the resin constituting the swellable coating layer 20.

[0047] Examples of the crosslinking agent include the same crosslinking agent as the material of the swellable coating layer 20. When a crosslinking agent is added to the resin for constituting the base layer 30, the amount used is preferably 1 to 100 parts by mass, more preferably 5 to 80 parts by mass, and even more preferably 10 to 50 parts by mass, per 100 parts by mass of the resin.

[0048] The method for forming the base layer 30 in this embodiment is not particularly limited, and can be, for example, a coating material prepared by mixing the above-described resin and, if desired, a crosslinking agent in a predetermined solvent, and then applying the coating material to the elongated body 10 and drying it. Examples of drying conditions include drying at a temperature of room temperature to 150°C, preferably 40 to 100°C, for 1 to 1440 minutes, preferably 20 to 800 minutes.

[0049] Examples of the solvent include propylene glycol monomethyl ether acetate (PGMEA), ethyl acetate, butyl acetate, toluene, etc., and among these, propylene glycol monomethyl ether acetate (PGMEA) is preferred.

[0050] In this embodiment, the thickness of the base layer 30 (before swelling) is preferably 0.1 to 100 μm, more preferably 0.5 to 50 μm, and even more preferably 1 to 10 μm.

[0051] 4. The material constituting the adhesive layer in this embodiment is not particularly limited as long as it is capable of adhering the swellable coating layer 20 and the elongated body 10. However, the adhesive layer differs from the base layer 30 in that, while it contains a crosslinking agent as a main material, it does not contain a polymer component as a main material.

[0052] As a preferred example of the crosslinking agent, for example, the same crosslinking agent as the material of the swellable coating layer 20 can be used.

[0053] The method for forming the adhesive layer in this embodiment is not particularly limited, and for example, the adhesive layer can be formed by mixing a crosslinking agent in a predetermined solvent to form a coating material, applying the coating material to the elongated body 10, and drying the coating material. Examples of drying conditions include drying at a temperature of room temperature to 150°C, preferably 40 to 100°C, for 1 to 1440 minutes, preferably 20 to 800 minutes.

[0054] As an example of the solvent, the same solvent as that used as the material of the base layer 30 can be used.

[0055] 5. Long Medical Device The types of long medical devices 1, 2, and 3 according to the present embodiment are not particularly limited as long as they require lubricity relative to biological tissue, but typically, long medical devices that are inserted or placed inside a living body are preferred, and guidewires or catheters are particularly preferred.

[0056] Examples of the catheter are not particularly limited and include, for example, a guiding catheter, a penetration catheter, a microcatheter, a balloon catheter, a foreign body removal catheter, a contrast catheter, a bile duct catheter, a urethral catheter, an endoscope, a dilator, etc. The catheter preferably comprises a tubular elongated body made of resin and extending from the distal end to the proximal end, and a swellable coating layer provided on the outer periphery of the tubular elongated body, and the above-mentioned base layer may be provided between the tubular elongated body and the swellable coating layer. Furthermore, the resin forming the tubular elongated body on which the first portion of the swellable coating layer is disposed may be different from the resin forming the tubular elongated body on which the second portion is disposed.

[0057] Furthermore, examples of the guidewire are not particularly limited, and include, for example, a PCI guidewire for coronary artery treatment, a PTA guidewire for lower limb vascular treatment, an IVR guidewire for peripheral vascular treatment, an INR guidewire for cerebrovascular treatment, and a CAG guidewire for angiography.

[0058] 6. Manufacturing Method of Elongated Medical Device The elongated medical devices 1, 2, and 3 according to the present embodiment can be manufactured, for example, by preparing an elongated body 10 and sequentially laminating, as desired, a base layer 30 or an adhesive layer and a swellable coating layer 20 onto at least a portion of the surface of the elongated body 10.

[0059] There are no particular limitations on the method for separately creating the first portion 21 and the second portion 22 (and even the third portion 23) in the swellable coating layer 20; for example, they can be formed by preparing paint containing the materials for each portion and applying them individually to the surface of the elongated body 10 (or base layer 30).

[0060] As mentioned above, the first portion 21 and the second portion 22 (and also the third portion 23) have different thicknesses and swelling degrees when swollen, but these differences can be created by changing the crosslinking density of the resin that makes up each portion.

[0061] For example, when the swellable coating layer 20 is formed using a paint obtained by mixing a hydrophilic polymer and a crosslinking agent in a solvent, increasing the amount of crosslinking agent relative to the hydrophilic polymer can increase the number of crosslinking points, thereby reducing the degree of swelling and the thickness of the swollen layer. Conversely, decreasing the amount of crosslinking agent relative to the hydrophilic polymer can decrease the number of crosslinking points, thereby increasing the degree of swelling and the thickness of the swollen layer.

[0062] Therefore, by adding the same amount of hydrophilic polymer to the paint for forming the first portion 21 and the second portion 22, but adding a smaller amount of crosslinking agent to the paint for the first portion 21 and a larger amount to the paint for the second portion 22, the crosslink density of the first portion 21 is reduced compared to the second portion 22, and as a result, it is possible to form the first portion 21 with a greater degree of swelling and a greater thickness when swollen.

[0063] The amount of the crosslinking agent can also be adjusted by adjusting the swelling (absorbency) of the elongated body 10 (or the base layer 30) with respect to a solvent.

[0064] For example, by forming the portion (first elongated body part) that forms the first portion 21 of the elongated body 10 using a resin that easily swells in the solvent of the paint, the crosslinking agent can be migrated into the resin together with the solvent from the paint applied thereon, thereby reducing the amount of crosslinking agent in the first portion 21. On the other hand, by forming the portion (second elongated body part) that forms the second portion 22 using a resin that does not easily swell in the solvent of the paint, the above-mentioned migration of the crosslinking agent can be suppressed, thereby reducing the amount of crosslinking agent in the second portion 22.

[0065] From the viewpoint of easier manufacturing, the elongated medical devices 1, 2, and 3 according to the present embodiment are preferably manufactured by a method utilizing the above-described adjustment of the amount of crosslinking agent depending on the elongated body 10. A suitable example of such a manufacturing method includes the steps of: preparing a elongated body in which a first elongated body part (I) made of a first resin (I) and a second elongated body part (II) made of a second resin (II) that is arranged on the proximal end side of the first elongated body part (I) and has a smaller swelling degree in a first solvent (A) than the first resin (I) are directly or indirectly connected; and applying a coating material containing a crosslinking agent and the first solvent (A) to at least a portion of the surface of the first elongated body part (I) and the second elongated body part (II).

[0066] In the above manufacturing method, one preferred embodiment is that the coating step involves applying a paint containing a hydrophilic polymer, a crosslinking agent, and the first solvent (A) to at least a portion of the surface of the first elongated body part (I) and the second elongated body part (II) to form a swellable coating layer.

[0067] In addition, for a long medical device 2 having a base layer 30, the amount of crosslinking agent in the swellable coating layer 20 can be adjusted by adding a crosslinking agent to the paint used to form the base layer 30 and transferring the crosslinking agent to the paint of the swellable coating layer 20.

[0068] In this case, too, the portion of the elongated body 10 that forms the first portion 21 is formed from a resin that swells easily in solvents, and the portion that forms the second portion 22 is formed from a resin that does not swell easily in solvents, so that the crosslinking agent in the paint used to form the base layer 30 migrates to these resins, and the difference in the amount of migration causes a difference in the amount of crosslinking agent between the first portion 21 and the second portion 22 formed on the base layer 30, resulting in a difference in crosslink density.

[0069] A preferred example of a method for manufacturing a long medical device 2 having a base layer 30 includes a manufacturing method including the steps of: preparing a long body in which a first long body part (I) made of a first resin (I) and a second long body part (II) made of a second resin (II) that is arranged on the base end side of the first long body part (I) and has a smaller swelling degree in a first solvent (A) than the first resin (I) are directly or indirectly connected; forming a base layer by applying a paint containing a base polymer, a crosslinking agent, and the first solvent (A) to at least a portion of the surface of the first long body part (I) and the second long body part (II); and forming a swellable coating layer by applying a paint containing a hydrophilic polymer and a second solvent (B) to at least a portion of the surface of the base layer opposite the long body.

[0070] Furthermore, for long medical devices having an adhesive layer, as with long medical devices 2 having a base layer 30, the amount of crosslinking agent in the swellable coating layer 20 can be adjusted by adding a crosslinking agent to the paint used to form the adhesive layer and transferring the crosslinking agent to the paint of the swellable coating layer 20.

[0071] A preferred example of a method for manufacturing a long medical device having an adhesive layer includes the following manufacturing method: preparing a long body in which a first long body part (I) made of a first resin (I) and a second long body part (II) made of a second resin (II) that is arranged on the base end side of the first long body part (I) and has a smaller swelling degree in a first solvent (A) than the first resin (I) are directly or indirectly connected; applying a paint containing a crosslinking agent and the first solvent (A) to at least a portion of the surface of the first long body part (I) and the second long body part (II) to form an adhesive layer; and applying a paint containing a hydrophilic polymer and a second solvent (B) to at least a portion of the surface of the adhesive layer opposite the long body to form a swellable coating layer.

[0072] The paint for forming the swellable coating layer 20, the paint for forming the base layer 30, and the paint for forming the adhesive layer can be applied by a general method.

[0073] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0074] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0075] [Experimental Example 1] (1) Confirmation of Swelling Property A resin plate made of an ether-based polyurethane elastomer was cut into a size of 10 mm in length, 10 mm in width, and 0.1 mm in thickness to prepare a first resin plate. The first resin plate was immersed overnight in propylene glycol monomethyl ether acetate (PGMEA) at 23°C, and its length and width increased by 1.4 times.

[0076] A resin plate made of polyamide elastomer was cut into a size of 10 mm in length, 10 mm in width, and 0.1 mm in thickness to prepare a second resin plate. When the second resin plate was immersed in PGMEA overnight at 23° C., it did not substantially swell.

[0077] (2) Sample Preparation A base layer coating material was prepared by mixing 10.58% by mass of a hydrophobic acrylic polyol resin and 3.63% by mass of hexamethylene diisocyanate as a crosslinking agent in 85.79% by mass of PGMEA as a solvent.

[0078] Also, a paint for a swellable coating layer was prepared by dissolving 10% by mass of a water-soluble hydroxyl group-containing acrylic resin in 90% by mass of a mixed solvent of water and ethanol.

[0079] Next, the base layer paint prepared as described above was applied onto a resin tube made of the above-mentioned ether-based polyurethane elastomer resin, and dried by heating at 60°C for 30 minutes to form a base layer with a thickness of 4 μm.

[0080] Furthermore, the paint for the swellable coating layer prepared as described above was applied onto the formed base layer, and dried by heating at 70°C for 90 minutes to form a swellable coating layer with a thickness of 1 μm.

[0081] This resulted in a first sample in which the base layer and the swellable coating layer were laminated in this order on a resin tube made of an ether-based polyurethane elastomer resin.

[0082] In addition, a base layer and a swellable coating layer were formed in the same manner as in Sample 1, except that the resin tube made of ether-based polyurethane elastomer resin was replaced with a resin tube made of the above-mentioned polyamide elastomer resin, thereby obtaining Sample 2, which was composed of a resin tube made of polyamide elastomer resin and a base layer and a swellable coating layer laminated in this order on the resin tube.

[0083] [Test Example 1] (Measurement of the amount of crosslinking agent on the surface of the base layer) As described above, during the preparation of the first and second samples, the amount of crosslinking agent on the surface of the base layer was measured by Fourier transform infrared spectroscopy (FT-IR) immediately after the base layer was formed. As a result, it was found that the amount of crosslinking agent in the second sample was 1.2 times that of the first sample.

[0084] [Test Example 2] (Measurement of the thickness of the swellable coating layer after swelling) The thickness of the swellable coating layer after swelling was measured for the prepared first and second samples. Specifically, the first and second samples were immersed in water at a temperature of 27°C for 120 minutes to allow the respective swellable coating layers to swell sufficiently. Then, the thickness of the swellable coating layer after swelling was measured.

[0085] As a result, the thickness of the swellable coating layer after swelling in the first sample was 34 μm, whereas the thickness of the swellable coating layer after swelling in the second sample was 12 μm. That is, the thickness of the swellable coating layer after swelling in the first sample was approximately three times that of the second sample.

[0086] The swelling degree of the swellable coating layer of each of the first and second samples was calculated based on the following formula (1), and was found to be 34 for the first sample and 12 for the second sample: Swelling degree = (thickness after swelling) ÷ (thickness before swelling) (1)

[0087] The results of the above test examples show that by changing the material of the resin tube, the amount of crosslinking agent in the base layer can be changed, and further, the thickness and swelling degree of the swellable coating layer after swelling can be changed.

[0088] Therefore, it can be seen that the elongated medical device of this embodiment can be manufactured by forming the first part in the same manner as the first sample and forming the second part in the same manner as the second sample.

[0089] The elongated medical device according to the present invention is suitable as, for example, a guide wire, a catheter, or the like.

[0090] REFERENCE SIGNS LIST 1, 2, 3... Long medical device 10... Long body 20... Swellable coating layer 21... First portion 22... Second portion 23... Third portion 30... Base layer

Claims

1. A long medical device comprising: a long body extending from a distal end to a proximal end; and a swellable coating layer provided on at least a portion of the surface of the long body, wherein the swellable coating layer comprises a first portion and a second portion located on the proximal end side of the first portion; and after the long medical device is immersed in 37°C water for 120 minutes to cause the swellable coating layer to swell, the thickness of the first portion is thicker than the thickness of the second portion, and the swelling degree of the swellable coating layer in the second portion, as defined by the following formula (1), is smaller than the swelling degree of the swellable coating layer in the first portion, as defined by the following formula (1): Swelling degree = (thickness after swelling) ÷ (thickness before swelling) ... (1).

2. The long medical device described in claim 1, characterized in that the swellable coating layer has a third portion located on the base end side of the second portion, the thickness of the second portion after swelling is thicker than the thickness of the third portion, and the swelling degree of the swellable coating layer defined by formula (1) in the third portion is smaller than the swelling degree of the swellable coating layer defined by formula (1) in the second portion.

3. A method for manufacturing a long medical device having a long body extending from a distal end to a proximal end, comprising: a step of preparing a long body in which a first long body part (I) made of a first resin (I) and a second long body part (II) made of a second resin (II) that is arranged on the proximal end side of the first long body part (I) and has a smaller swelling degree in a first solvent (A) than the first resin (I) are connected directly or indirectly; and a coating step of coating at least a portion of the surface of the first long body part (I) and the second long body part (II) with a paint containing a crosslinking agent and the first solvent (A).

4. A method for manufacturing a long medical device as described in claim 3, wherein in the coating process, a paint containing a hydrophilic polymer, a crosslinking agent and the first solvent (A) is applied to at least a portion of the surface of the first long body part (I) and the second long body part (II) to form a swellable coating layer.

5. A method for manufacturing a long medical device as described in claim 3, wherein the coating step includes forming a base layer by applying a paint containing a base polymer, a crosslinking agent and the first solvent (A) to at least a portion of the surface of the first long body part (I) and the second long body part (II), and after the coating step, forming a swellable coating layer by applying a paint containing a hydrophilic polymer and a second solvent (B) to at least a portion of the surface of the base layer opposite the long body.

6. A method for manufacturing a long medical device as described in claim 3, comprising the steps of: in the coating step, forming an adhesive layer by coating a paint containing a crosslinking agent and the first solvent (A) on at least a portion of the surface of the first long body part (I) and the second long body part (II); and after the coating step, forming a swellable coating layer by further coating a paint containing a hydrophilic polymer and a second solvent (B) on at least a portion of the surface of the adhesive layer opposite the long body.

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