Balloon for balloon catheter, balloon catheter, and method for manufacturing balloon catheter

Abstract

A balloon (10) for a balloon catheter, the balloon (10) comprising: a straight tube section (13); a near-position-side tapered part positioned closer to the position side than the straight pipe part (13); and a distal-side tapered section positioned further toward the distal side than the straight tube section (13), the straight tube section (13) having: a cylindrical balloon main body section (16); and a bead (17) protruding radially outward from the outer surface of the balloon main body section (16), a drug layer (31) being provided on the outer surface of the straight tube section (13) including the side surface (18) of the bead (17), and a slit (32) extending along the base section (17B) of the bead (17) being formed on the surface of the drug layer (31).

Description

Technical Field

[0001] The present invention relates to a balloon for a balloon catheter having a drug held on its surface, a balloon catheter having the balloon, and a method for manufacturing the balloon catheter having the balloon. Background Art

[0002] It is well-known that stenosis occurs in blood vessels, which are flow paths for blood to circulate in the body, resulting in stagnation of blood circulation and various diseases. In particular, if stenosis occurs in the coronary arteries that supply blood to the heart, there is a concern of serious diseases such as angina pectoris and myocardial infarction. As one of the methods for treating such stenotic portions of blood vessels, there is angioplasty (PTA, PTCA, etc.) using a balloon catheter to dilate the stenotic portion.

[0003] Among balloon catheters, a balloon catheter having ridges provided on the surface of the balloon is well-known (for example, Patent Documents 1 to 5). When using such a balloon catheter, when the balloon is expanded, the ridges of the balloon can bite into the stenotic portion to effectively dilate the stenotic portion. On the other hand, in the case of angioplasty, restenosis sometimes occurs in the dilated stenotic portion. In order to reduce the frequency (restenosis rate) of such restenosis, a balloon catheter having a drug held on the surface of the balloon is also well-known (for example, Patent Documents 4 to 7). When using such a balloon catheter having a drug held thereon, the drug can be transferred to the inner wall of the body cavity such as the blood vessel wall by expanding the balloon in the stenotic portion or diseased portion of the body cavity such as a blood vessel, and it is possible to expect suppression of the occurrence of restenosis and the like.

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-112361

[0005] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2017-12678

[0006] Patent Document 3: International Publication No. 2020 / 250611

[0007] Patent Document 4: Japanese Patent Application Laid-Open No. 2008-539959

[0008] Patent Document 5: Japanese Unexamined Patent Application Publication No. 2013-176507

[0009] Patent Document 6: Japanese Patent Application Laid-Open No. 2008-529740

[0010] Patent Document 7: Japanese Unexamined Patent Application Publication No. 2015-217260 Summary of the Invention

[0011] It is desired that a balloon catheter having a drug on the surface of the balloon can efficiently transfer the drug to the inner wall of a body cavity such as a blood vessel wall by expanding the balloon at a stenotic part or a diseased part of a body cavity such as a blood vessel. The present invention has been completed in view of the above circumstances, and an object thereof is to provide a balloon for a balloon catheter and a balloon catheter having the balloon, which can efficiently transfer a drug to a stenotic part, a diseased part, etc. of a body cavity such as a blood vessel. The present invention further provides a method for manufacturing a balloon catheter having the balloon of the present invention.

[0012] The balloon for a balloon catheter and the balloon catheter having the balloon of the present invention, which can solve the above problems, are as follows.

[0013] [1] A balloon for a balloon catheter has a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction, wherein

[0014] the balloon has: a straight tube portion; a proximal side tapered portion located on the proximal side of the straight tube portion; and a distal side tapered portion located on the distal side of the straight tube portion,

[0015] the straight tube portion has: a cylindrical balloon main body portion; and a rib protruding outward in the radial direction on the outer surface of the balloon main body portion,

[0016] a drug layer is provided on the outer surface of the straight tube portion including the side surface of the rib,

[0017] a crack extending along the base of the rib is formed on the surface of the drug layer.

[0018] [2] A balloon for a balloon catheter has a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction, wherein

[0019] the balloon has: a straight tube portion; a proximal side tapered portion located on the proximal side of the straight tube portion; and a distal side tapered portion located on the distal side of the straight tube portion,

[0020] the straight tube portion has: a cylindrical balloon main body portion; and a multi-stage rib protruding outward in the radial direction on the outer surface of the balloon main body portion,

[0021] a drug layer is provided on the outer surface of the straight tube portion including the side surface of the rib,

[0022] a crack extending along the base of any stage of the multi-stage rib is formed on the surface of the drug layer.

[0023] [3] The balloon according to [1] or [2], wherein

[0024] the rib extends in the longitudinal direction of the balloon.

[0025] [4] The balloon according to any one of [1] to [3], wherein,

[0026] The outer surface of the straight tube portion has: a rib presence region where the above-mentioned ribs exist; and a rib non-existence region where the above-mentioned ribs do not exist. In a vertical cross-section in the longitudinal direction of the straight tube portion, the thickness of the above-mentioned medicament layer at the base of the above-mentioned rib (except for the portion where the above-mentioned crack is formed) is thicker than the thickness of the above-mentioned medicament layer at the farthest point from the above-mentioned rib in the above-mentioned rib non-existence region.

[0027] [5] The balloon according to any one of [1] to [4], wherein,

[0028] The medicament constituting the above-mentioned medicament layer is crystalline.

[0029] [6] The balloon according to any one of [1] to [5], wherein,

[0030] The above-mentioned rib is made of resin, metal, or a combination thereof.

[0031] [7] The balloon according to any one of [1] to [6], wherein,

[0032] The outer surface of the straight tube portion has: a rib presence region where the above-mentioned ribs exist; and a rib non-existence region where the above-mentioned ribs do not exist. In the contracted state of the above-mentioned balloon, the straight tube portion folds the inner surface of the above-mentioned balloon main body portion to the inside and is folded back in the above-mentioned rib non-existence region, forming a folded blade portion formed by overlapping the above-mentioned rib non-existence regions. The above-mentioned folded blade portion is overlapped and arranged on the outer surface of the above-mentioned straight tube portion and covers the top of the above-mentioned rib.

[0033] [8] The balloon according to any one of [1] to [6], wherein,

[0034] The outer surface of the straight tube portion has: a rib presence region where the above-mentioned ribs exist; and a rib non-existence region where the above-mentioned ribs do not exist. In the contracted state of the above-mentioned balloon, the straight tube portion folds the inner surface of the above-mentioned balloon main body portion to the inside and is folded back in the above-mentioned rib non-existence region, forming a folded blade portion formed by overlapping the above-mentioned rib non-existence regions. The above-mentioned folded blade portion is overlapped and arranged on the outer surface of the above-mentioned straight tube portion in a manner that does not cover the top of the above-mentioned rib.

[0035] [9] A balloon catheter, wherein,

[0036] It includes the balloon according to any one of [1] to [8].

[0037] The manufacturing method of the balloon catheter of the present invention is as follows.

[0038]

[10] A manufacturing method of a balloon catheter, which has:

[0039] A process for preparing a balloon, the balloon having a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction, and having a straight tube portion, a proximal conical portion located at a position closer to the proximal side than the straight tube portion, and a distal conical portion located at a position closer to the distal side than the straight tube portion. The straight tube portion has a cylindrical balloon main body portion and a rib protruding outward in the radial direction on the outer surface of the balloon main body portion;

[0040] A process of coating a liquid medicine on the outer surface of the straight tube portion of the balloon including the side surface of the rib to form a medicine layer; and

[0041] A process of bending the rib relative to the outer surface of the balloon main body portion after the process of forming the medicine layer.

[0042] The balloon for a balloon catheter of the present invention has a rib provided on the outer surface of the straight tube portion of the balloon, a medicine layer provided on the outer surface of the straight tube portion including the side surface of the rib, and a crack extending along the base of the rib formed on the surface of the medicine layer. Therefore, when using a balloon catheter equipped with the balloon of the present invention to expand the balloon at a stenosis or lesion in a body cavity such as a blood vessel, the rib can bite into the stenosis or lesion and expand effectively. And when the medicine layer contacts the inner surface of the inner wall of the body cavity, the medicine layer is easily peeled off from the side surface of the rib starting from the crack, and the medicine layer is easily transferred from the surface of the balloon to the blood vessel wall side. As a result, the medicine can be efficiently transferred to the inner wall of the body cavity such as the blood vessel wall. In addition, according to the manufacturing method of the balloon catheter of the present invention, the balloon catheter of the present invention can be easily manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A configuration example of a balloon catheter showing an embodiment of the present invention, a side view of the balloon catheter except for the medicine layer on the balloon surface.

[0044] Figure 2 Showing Figure 1 A perspective view of the balloon included in the shown balloon catheter.

[0045] Figure 3 Showing Figure 1 A cross-sectional view taken along line III-III of the shown balloon catheter.

[0046] Figure 4 Showing Figure 1 A cross-sectional view taken along line IV-IV of the shown balloon catheter.

[0047] Figure 5 An example of a vertical cross-sectional view in the longitudinal direction of the straight tube portion of the balloon having a medicine layer.

[0048] Figure 6Another example of a vertical cross-sectional view in the longitudinal direction of the straight tube portion of a balloon having a medicament layer.

[0049] Figure 7 Partial perspective view showing the appearance of the straight tube portion of a balloon having a medicament layer.

[0050] Figure 8 Shows Figure 5 and Figure 6 An enlarged cross-sectional view around the rib of the balloon shown.

[0051] Figure 9 An example of an enlarged cross-sectional view around the rib of a balloon having a medicament layer.

[0052] Figure 10 Another example of an enlarged cross-sectional view around the rib of a balloon having a medicament layer.

[0053] Figure 11 Another example of an enlarged cross-sectional view around the rib of a balloon having a medicament layer.

[0054] Figure 12 Shows the Figure 5 An example of a vertical cross-sectional view in the longitudinal direction of the state in which the balloon shown is contracted and folded.

[0055] Figure 13 Shows the Figure 5 Another example of a vertical cross-sectional view in the longitudinal direction of the state in which the balloon shown is contracted and folded.

[0056] Figure 14 Schematic diagram showing a method of forming a medicament layer on the balloon surface. Detailed implementation mode

[0057] Hereinafter, the present invention will be specifically described based on the following embodiments. However, the present invention is of course not limited by the following embodiments, and can of course be appropriately modified and implemented within the scope that can conform to the gist described above / below, and they are all included in the technical scope of the present invention. In addition, in each drawing, there are cases where hatching, component reference numerals, etc. are omitted for convenience. In such cases, please refer to the specification and other drawings. In addition, the sizes of various components in the drawings are preferably conducive to understanding the features of the present invention, and thus there are cases where they are different from the actual sizes.

[0058] A configuration example of a balloon for a balloon catheter and a balloon catheter having the balloon according to an embodiment of the present invention will be described with reference to the drawings. In Figures 1 to 4 A configuration example of a balloon catheter excluding the medicament layer of the balloon is shown. Figure 1 Shows a side view of the balloon catheter, Figure 2 Shows Figure 1Stereogram of the balloon provided in the balloon catheter shown Figure 3 indicating Figure 1 III-III cross-sectional view of the balloon catheter shown Figure 4 indicating Figure 1 IV-IV cross-sectional view of the balloon catheter shown. In Figure 1 a configuration example of a rapid exchange type balloon catheter is shown.

[0059] The balloon catheter 1 has a shaft 2 and a balloon 10 provided on the outer side of the shaft 2. The balloon catheter 1 has a proximal side and a distal side, and the balloon 10 is provided at the distal portion of the shaft 2. The proximal side of the balloon catheter 1 refers to the direction on the side of the user (operator) with respect to the extending direction of the balloon catheter 1, and the distal side refers to the opposite direction of the proximal side, that is, the direction of the treatment target side. In addition, the direction from the proximal side to the distal side of the balloon catheter 1 is referred to as the longitudinal direction.

[0060] The balloon catheter 1 is configured to supply fluid into the balloon 10 through the shaft 2, and the inflation and deflation of the balloon 10 can be controlled using an inflator (balloon pressure regulator). The fluid may also be a pressurized fluid pressurized by a pump or the like. Hereinafter, the fluid supplied into the balloon 10 is referred to as "balloon expansion fluid".

[0061] The shaft 2 is composed of, for example, an inner shaft 3 and an outer shaft 4. The inner shaft 3 is disposed in the inner cavity of the outer shaft 4. The inner shaft 3 can function as an insertion path for a guide wire that guides the advancement of the shaft 2, and when using the balloon catheter 1, the guide wire is inserted through the inner cavity of the inner shaft 3. The space between the inner shaft 3 and the outer shaft 4 can function as a flow path for the balloon expansion fluid.

[0062] In the rapid exchange type balloon catheter 1, a guide wire port 7 is provided midway from the distal side to the proximal side of the shaft 2, and the proximal end of the inner shaft 3 is connected to the guide wire port 7, and the distal end of the inner shaft 3 extends to the distal portion of the shaft 2, thereby forming a guide wire insertion path extending from the guide wire port 7 to the distal portion of the shaft 2.

[0063] The outer shaft 4 may also have a proximal side outer shaft 4A and a distal side outer shaft 4B. In this case, it is preferable to dispose the inner shaft 3 in the inner cavity of the distal side outer shaft 4B. The proximal side outer shaft 4A and the distal side outer shaft 4B may be made of the same material or may be made of different materials from each other. For example, it is preferable that the proximal side outer shaft 4A is made of resin or metal, and the distal side outer shaft 4B is made of resin. In addition, the outer shaft 4 may not be divided into the proximal side outer shaft 4A and the distal side outer shaft 4B, but may be composed of one component, and the proximal side outer shaft 4A and the distal side outer shaft 4B may also be composed of a plurality of tube components.

[0064] Preferably, a hub 5 is provided on the proximal side of the shaft 2. Preferably, the hub 5 has a fluid injection portion 6 communicating with the flow path of the balloon-expandable fluid of the shaft 2. The joining of the balloon 10, the shaft 2 (inner shaft 3, outer shaft 4), and the hub 5 can be performed by using conventionally known joining means such as adhesives and heat welding.

[0065] In addition, although not shown in the drawings, the balloon catheter may also be an over-the-wire exchange type balloon catheter in which the inner shaft extends from the distal portion to the proximal portion of the shaft and a guide wire insertion path is formed from the distal side to the proximal side of the shaft. In this case, preferably, the flow path of the balloon-expandable fluid provided in the shaft and the guide wire insertion path extend to the hub, and the hub is configured to have a fluid injection portion communicating with the flow path of the balloon-expandable fluid and a treatment portion communicating with the guide wire insertion path. Preferably, the hub has a structure branched into two branches, with a fluid injection portion provided on one of the two branches and a treatment portion provided on the other.

[0066] Preferably, the outer surface of the shaft 2 is coated. In the rapid exchange type balloon catheter 1, preferably, the outer surface of one or both of the proximal outer shaft 4A and the distal outer shaft 4B is coated, and more preferably, the outer surfaces of both the proximal outer shaft 4A and the distal outer shaft 4B are coated. In the over-the-wire exchange type balloon catheter, preferably, the outer surface of the outer shaft is appropriately coated.

[0067] The coating can be a hydrophilic coating or a hydrophobic coating according to the purpose. The outer surface of the shaft 2 can be coated by immersing the shaft 2 in a hydrophilic coating agent or a hydrophobic coating agent, or by coating a hydrophilic coating agent or a hydrophobic coating agent on the outer surface of the shaft 2, or by covering the outer surface of the shaft 2 with a hydrophilic coating agent or a hydrophobic coating agent. The coating agent may also include drugs and additives.

[0068] Examples of the hydrophilic coating agent include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether maleic anhydride copolymer, or hydrophilic coating agents prepared by any combination thereof.

[0069] Examples of the hydrophobic coating agent include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy alkane (PFA), silicone oil, hydrophobic polyurethane resin, carbon coating, diamond coating, diamond-like carbon (DLC) coating, ceramic coating, and substances with a small surface free energy capped with an alkyl or perfluoroalkyl group.

[0070] Preferably, a tip 8 is provided at the distal end of the balloon catheter 1. The tip 8 can be provided as a component separate from the inner shaft 3 on the distal side of the distal end of the inner shaft 3, or the distal end of the inner shaft 3 can extend to the distal side of the distal end of the balloon 10, so that the distal end portion of the inner shaft 3 functions as the tip 8.

[0071] In the shaft 2, in order to be able to confirm the position of the balloon 10 under fluoroscopy, an X-ray impermeable marker 9 may also be disposed at a portion of the balloon 10 with respect to the longitudinal direction. The X-ray impermeable marker 9 can be disposed, for example, on the inner shaft 3 disposed inside the balloon 10, preferably at positions corresponding to both ends of the straight tube portion of the balloon 10, or may also be disposed at a position corresponding to the center of the straight tube portion of the balloon 10.

[0072] The balloon 10 has a longitudinal direction and a radial direction, and is formed in a cylindrical shape having openings at the proximal side and the distal side (refer to Figure 2 ). The radial direction of the balloon 10 refers to a direction perpendicular to the longitudinal direction, and is a direction extending from the center of the balloon 10 toward the radial direction. The balloon 10 also has a circumferential direction in a vertical cross-section in the longitudinal direction of the balloon 10, as a direction along the outer circumference of the expanded balloon 10.

[0073] The balloon 10 has a straight tube portion 13 with respect to the longitudinal direction, a proximal side tapered portion 12 located closer to the proximal side than the straight tube portion 13, and a distal side tapered portion 14 located closer to the distal side than the straight tube portion 13. The straight tube portion 13 is formed in a substantially cylindrical shape extending along the longitudinal direction, and the length in the radial direction (outer diameter) is formed to be the largest in the balloon 10. The proximal side tapered portion 12 is located on the proximal side of the straight tube portion 13 and is connected to the proximal end of the straight tube portion 13. The proximal side tapered portion 12 is formed such that the outer diameter becomes smaller as it moves away from the straight tube portion 13. The distal side tapered portion 14 is located on the distal side of the straight tube portion 13 and is connected to the distal end of the straight tube portion 13. The distal side tapered portion 14 is formed such that the outer diameter becomes smaller as it moves away from the straight tube portion 13. Preferably, the balloon 10 further has: a proximal side sleeve portion 11, located at a position closer to the proximal side than the proximal side tapered portion 12; and a distal side sleeve portion 15, located at a position closer to the distal side than the distal side tapered portion 14. The proximal side sleeve portion 11 is located on the proximal side of the proximal side tapered portion 12 and is connected to the proximal end of the proximal side sleeve portion 11. The proximal side sleeve portion 11 is formed in a substantially cylindrical shape. The distal side sleeve portion 15 is located on the distal side of the distal side tapered portion 14 and is connected to the distal end of the distal side sleeve portion 15. The distal side sleeve portion 15 is formed in a substantially cylindrical shape.

[0074] By configuring the balloon 10 as described above, when the balloon 10 is expanded in the stenotic portion, the straight tube portion 13 comes into sufficient contact with the stenotic portion, and it is easy to perform treatments such as dilation of the stenotic portion. In addition, the balloon 10 has a proximal side tapered portion 12 and a distal side tapered portion 14, so that when the balloon 10 is contracted, the outer diameters of the proximal end portion and the distal end portion of the balloon 10 can be reduced to reduce the step difference between the shaft 2 and the balloon 10, and the balloon 10 can be easily inserted through the body cavity and the forceps channel of the endoscope.

[0075] At the distal portion of the shaft 2, preferably, the inner shaft 3 extends and protrudes distally from the distal end of the outer shaft 4. The inner shaft 3 extends from the proximal side sleeve portion 11 to the distal side sleeve portion 15 within the internal space of the balloon 10. Further, preferably, the outer surface of the inner shaft 3 engages with the inner surface of the distal side sleeve portion 15 of the balloon 10, and the outer surface of the outer shaft 4 engages with the inner surface of the proximal side sleeve portion 11 of the balloon 10. By configuring the distal portion of the shaft 2 in this manner, balloon expansion fluid can be supplied to the internal space of the balloon 10 through the space between the inner shaft 3 and the outer shaft 4.

[0076] The balloon 10 is preferably made of resin, more preferably made of a thermoplastic resin. Thereby, it becomes easy to manufacture the balloon 10 by molding. As the resin constituting the balloon 10, for example, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyester resins such as polyethylene terephthalate and polyester elastomer, polyurethane resins such as polyurethane and polyurethane elastomer, polyphenylene sulfide resin, polyamide resins such as polyamide and polyamide elastomer, fluorine-based resins, silicone resins, natural rubbers such as latex rubber, etc. can be cited. These can be used alone or in combination of two or more. Among them, polyamide resins, polyester resins, and polyurethane resins are preferably used. In particular, from the viewpoints of thinning of the balloon 10 and flexibility, an elastomer resin is preferably used. For example, among polyamide resins, as materials suitable for the balloon 10, nylon 12, nylon 11, etc. can be cited, and nylon 12 is preferably used from the viewpoint of being relatively easy to mold during blow molding. In addition, from the viewpoints of thinning of the balloon 10 and flexibility, polyamide elastomers such as polyether ester amide elastomer and polyamide ether elastomer are preferably used. Among them, from the viewpoints of high yield strength and good dimensional stability of the balloon 10, polyether ester amide elastomer is preferably used.

[0077] The balloon 10 has a rib 17 on the outer surface of the straight tube portion 13. By providing the rib 17 on the outer surface of the straight tube portion 13, the balloon 10 has a scoring function, and when the balloon 10 is expanded in the stenotic portion of the blood vessel, it can bite into the calcified stenotic portion and introduce a crack in the stenotic portion. Therefore, it is possible to expand the stenotic portion while suppressing the dissociation of the vascular intima. In addition, it is also possible to achieve high strength of the balloon 10 and suppression of overexpansion during pressurization. Further, the balloon 10 can also be used in the treatment of stenotic portions and diseased portions in body cavities other than blood vessels, but the following description will focus on the case where the balloon 10 is applied to the stenotic portion of a blood vessel.

[0078] Refer to Figures 5 to 11 A detailed description will be given of the rib 17 of the balloon 10. In Figure 5 and Figure 6 a vertical cross-sectional view in the longitudinal direction of the straight tube portion 13 of the balloon 10 is shown, and in Figure 7 a partial perspective view of the appearance of the straight tube portion 13 of the balloon 10 is shown, and in Figures 8 to 11An enlarged cross-sectional view around the rib 17 of the balloon 10 is shown. In Figures 5 to 11 it, a balloon 10 having a medicament layer 31 provided on the outer surface of the straight tube portion 13 is shown. In Figure 5 it is shown in Figure 2 and Figure 4 a structural example in which a medicament layer 31 is provided on the outer surface of the balloon 10 shown, and ribs 17 are provided at three positions in the circumferential direction of the straight tube portion 13. In Figure 6 it is shown a structural example of a balloon 10 in which a rib 17 is provided at one position in the circumferential direction of the straight tube portion 13 and a medicament layer 31 is provided on the outer surface.

[0079] The straight tube portion 13 of the balloon 10 has a cylindrical balloon main body portion 16, and ribs 17 are provided on the outer surface of the balloon main body portion 16. The ribs 17 are provided to protrude radially outward from the outer surface of the balloon main body portion 16. By providing the ribs 17, a rib presence region 21 and a rib non-presence region 22 are formed on the outer surface of the straight tube portion 13 of the balloon 10.

[0080] The rib 17 has a top portion 17A and a base portion 17B (refer to Figures 8 to 11 ). In the rib 17, the top portion 17A refers to the front end of the rib 17, that is, the portion located on the outermost side in the radial direction of the rib 17, and the base portion 17B refers to the boundary with the balloon main body portion 16 in the side surface 18 of the rib 17, that is, the portion located on the innermost side in the radial direction of the rib 17.

[0081] The rib 17 can be made of resin, for example. If the rib 17 is made of resin, the balloon 10 having the rib 17 can be manufactured by resin molding, and the manufacturing becomes easy. In this case, it is preferable that the rib 17 and the balloon main body portion 16 are made of the same resin, and it is preferable that the rib 17 and the balloon main body portion 16 are integrally formed. The balloon main body portion 16 may also have an inner layer and an outer layer. In this case, it is preferable that the rib 17 is made of the same resin as the outer layer of the balloon main body portion 16. Thereby, it is less likely that the rib 17 accidentally detaches from the balloon main body portion 16. Or, as long as the resin constituting the rib 17 has a certain degree of compatibility with the resin constituting the balloon main body portion 16, the rib 17 and the balloon main body portion 16 may also be made of mutually different resins.

[0082] The rib 17 can be made of metal, or can also be made of a combination of metal and resin. In this case, it is preferable that the portion of the rib 17 including the top portion 17A is made of metal. Thereby, when the balloon 10 is expanded, it is easy to introduce a crack or cut the stenosis portion through the rib 17. For example, the entire rib 17 may be made of metal, or the portion of the rib 17 including the base portion 17B may be made of resin, and the portion of the rib 17 including the top portion 17A may be made of metal. Therefore, it is preferable that the rib 17 is resin-made, metal-made, or a combination thereof.

[0083] In the straight tube portion 13, the balloon main body portion 16 is defined as the portion having a cylindrical shape. In the straight tube portion 13, the portion other than the rib 17 protruding outward in the radial direction becomes the balloon main body portion 16. The outer surface of the balloon main body portion 16 can be regarded as being formed in a cylindrical shape. Therefore, in the vertical cross-section in the longitudinal direction of the straight tube portion 13, the outer shape of the balloon main body portion 16 is substantially formed in a circular shape, whereby the balloon main body portion 16 can be distinguished from the rib 17. In Figures 8 to 11 it, the balloon main body portion 16 and the rib 17 are shown separately by a dashed line. The rib existing region 21 is composed of the balloon main body portion 16 and the rib 17, and the rib non-existing region 22 is composed of the balloon main body portion 16.

[0084] The rib 17 is provided on the outer surface of the straight tube portion 13 so as to extend in a ridge shape. Preferably, the rib 17 is provided to extend in the longitudinal direction. In this case, the rib 17 may extend substantially parallel to the longitudinal direction of the balloon 10, or may extend in a spiral shape in the longitudinal direction. In addition, from the viewpoints of improving the scoring function of the balloon 10 and facilitating the manufacture of the balloon 10 having the rib 17, it is preferable that the rib 17 extends substantially parallel to the longitudinal direction of the balloon 10.

[0085] In the vertical cross-section in the longitudinal direction of the straight tube portion 13, the rib 17 may be provided only one, or may be provided multiple. When only one rib 17 is provided in the straight tube portion 13, only one rib non-existing region 22 is formed in the straight tube portion 13. When multiple ribs 17 are provided in the straight tube portion 13, multiple rib non-existing regions 22 are formed in the straight tube portion 13. The number of rib non-existing regions 22 formed is equal to the number of the ribs 17. In Figure 5 it, the rib 17 is provided at three positions in the circumferential direction of the straight tube portion 13 of the balloon 10. In Figure 6 it, the rib 17 is provided only at one position in the circumferential direction of the straight tube portion 13 of the balloon 10.

[0086] Preferably, multiple ribs 17 are provided at different positions in the circumferential direction of the straight tube portion 13 of the balloon 10. That is, it is preferable that the ribs 17 are provided at multiple positions in the circumferential direction of the balloon 10. In this case, it is preferable that the ribs 17 are arranged at substantially equal intervals in the circumferential direction of the straight tube portion 13 of the balloon 10. Thereby, when the balloon 10 is expanded, cracks can be introduced at multiple positions in the stenosis portion. Preferably, the ribs 17 are provided at positions of two or more in the circumferential direction of the balloon 10, more preferably three or more, and preferably eight or less, more preferably six or less. In addition, it is preferable that the circumferential interval of the ribs 17 in this case is longer than the circumferential length of one rib 17.

[0087] The cross-sectional shape of the rib 17 is not particularly limited. For example, as the shape of the vertical cross-section in the length direction of the straight tube portion 13 of the rib 17, there can be cited polygons such as triangles and quadrilaterals, partial shapes of circles such as semi-circles and sectors, approximately circular shapes, wedge shapes, convex shapes, spindle shapes, irregular shapes, etc. In addition to the shape where the vertices of the corners are clear and the sides are straight lines, the polygon also includes a rounded polygon with rounded corners and a shape where at least a part of the side is a curve. Further, it is preferable that the rib 17 is formed to be narrower toward the top portion 17A.

[0088] Figures 8 to 10 Examples of various cross-sectional shapes of the rib 17 are shown. In Figure 8 the rib 17 is formed such that the width gradually narrows toward the top portion 17A without steps. In Figure 9 the rib 17 is formed in multiple steps and the width is formed to narrow stepwise toward the top portion 17A. In Figure 10 the rib 17 is formed to have a portion where the width widens toward the top portion 17A and a portion where the width narrows toward the top portion 17A. Details of each form of the rib 17 shown in Figures 8 to 10 will be described later.

[0089] In the vertical cross-section in the length direction of the straight tube portion 13, the height of the rib 17 can be set to be 0.2 times or more of the width (maximum width) of the rib 17, for example. If the rib 17 is formed in this way, when the balloon 10 is expanded in the narrow portion, the rib 17 easily bites into the narrow portion, and the notching function based on the rib 17 can be improved. The width of the rib 17 described here refers to the circumferential length of the rib 17. The rib 17 can also be formed to have the maximum width at the base portion 17B, whereby the rib 17 is stably provided on the outer surface of the balloon main body portion 16. Further, when a drug layer 31 is provided on the side surface 18 of the rib 17 as described later, considering the point that it is easy to form a crack extending along the base portion 17B of the rib 17, the height of the rib 17 is more preferably 0.4 times or more of the width of the rib 17, and further preferably 0.7 times or more. On the other hand, considering the point that the rib 17 is stably formed on the outer surface of the straight tube portion 13, the height of the rib 17 is preferably 2.0 times or less of the width of the rib 17, more preferably 1.8 times or less, and further preferably 1.5 times or less.

[0090] In the straight tube portion 13, the wall thickness of the portion where the rib 17 is preferably provided, that is, the wall thickness of the rib existing region 21, is formed to be thicker than the wall thickness of the portion where the rib 17 is not provided, that is, the wall thickness of the rib non-existing region 22. Thereby, the scoring function based on the rib 17 can be improved. The wall thickness (maximum wall thickness) of the rib existing region 21 is preferably 1.5 times or more, more preferably 2.0 times or more, and further preferably 2.5 times or more of the wall thickness (maximum wall thickness) of the rib non-existing region 22. The upper limit of the wall thickness of the rib existing region 21 is not particularly limited. For example, it may be 30 times or less, 20 times or less, or 10 times or less of the wall thickness of the rib non-existing region 22.

[0091] In the balloon 10, the rib 17 is preferably provided in a range of 1 / 2 or more in the longitudinal direction of the straight tube portion 13, more preferably in a range of 2 / 3 or more, and further preferably in a range of 3 / 4 or more. Thereby, when the balloon 10 is expanded, cracks can be introduced in a large range of the stenosis portion. The rib 17 may also be provided on the outer surface of the proximal cone portion 12 and / or the distal cone portion 14. In Figure 1 and Figure 2 the rib 17 is provided to extend from the proximal cone portion 12 through the straight tube portion 13 to the distal cone portion 14.

[0092] The balloon 10 may also have an inner rib that protrudes inward in the radial direction on the inner surface of the balloon 10 (not shown). The rib 17 and the inner rib may be arranged at the same position in the longitudinal direction and circumferentially of the balloon 10, and preferably they are integrally formed, whereby a part of the balloon 10 can be formed into a thick wall.

[0093] A drug layer 31 is provided on the outer surface of the straight tube portion 13 of the balloon 10. The drug included in the drug layer 31 is not particularly limited as long as it is a pharmacologically active substance. For example, gene therapy drugs, non-gene therapy drugs, small molecules, cells, etc. can be cited as drugs permitted in medicine. In particular, when the balloon catheter 1 is used for the purpose of suppressing restenosis of the blood vessel after treatment in angioplasty, anti-restenosis agents such as anti-proliferative agents and immunosuppressive agents can be preferably used as the drug. Specifically, drugs such as paclitaxel, sirolimus (rapamycin), everolimus, and zotarolimus can be used. These drugs can be used alone or in combination of two or more.

[0094] In the medicament layer 31, together with the pharmacologically active substance, an auxiliary agent for improving the dispersibility, solubility, transferability to the blood vessel wall, and storage stability of the medicament may also be included. As the auxiliary agent, a stabilizer, a binder, a disintegrant, a moisture-proof agent, a preservative, a solubilizing agent, etc. are used. Specifically, lactose, sucrose, maltose, dextrin, xylitol, erythritol, mannitol, ethylenediamine, potassium iodide, urea, polysorbate, dibutylhydroxytoluene, polyethylene glycol, lipid, sodium metabisulfite, ascorbic acid, tocopherol, benzoic acid, p-hydroxybenzoate, polyacrylic acid, polylactic acid, polyglycolic acid, hyaluronic acid, chitosan, gelatin, etc. may be mentioned.

[0095] In order to inhibit the dissolution or detachment of the medicament into the blood during the delivery of the medicament to the stenosis (during transportation), the medicament layer 31 may also have a protective layer. Preferably, the protective layer is included in a part of the medicament layer 31 and constitutes the outermost layer of the medicament layer 31. The protective layer is formed of a water-soluble polymer, for example, and can be formed of carboxymethyl cellulose, hydroxypropyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, alginic acid, pectin, gum arabic, gellan gum, guar gum, xanthan gum, carrageenan, gelatin, etc.

[0096] Preferably, the medicament constituting the medicament layer 31 is crystalline, for example, preferably the pharmacologically active substance is crystalline. As the crystalline pharmacologically active substance, examples include paclitaxel, sirolimus (rapamycin), everolimus, zotarolimus, etc. Thereby, the brittleness of the medicament layer 31 is increased, and when the balloon 10 is expanded, the medicament layer 31 is easily peeled off from the outer surface of the balloon 10. In addition, it is also preferable that the auxiliary agent and the protective agent included together with the pharmacologically active substance are crystalline. As the crystalline auxiliary agent and protective agent, sugars, salts such as urea and potassium iodide, ascorbic acid, polylactic acid, polyglycolic acid, etc. may be mentioned.

[0097] The medicament layer 31 is provided on the outer surface of the straight tube portion 13 including the side surface 18 of the rib 17. By providing the medicament layer 31 in this way, when the balloon 10 is expanded at the stenosis, the medicament can be efficiently transferred from the inner surface of the blood vessel wall to the inside of the blood vessel wall. That is, when the balloon 10 is expanded at the stenosis, the rib 17 can bite into the stenosis to effectively expand the stenosis, and the medicament layer 31 provided on the side surface 18 of the rib 17 can be transferred to the blood vessel wall side at the expanded stenosis. Preferably, the medicament layer 31 is provided from the rib non-existent region 22 to the side surface 18 of the rib 17.

[0098] As Figure 7 、 Figure 8 、 Figure 10 、 Figure 11As shown, the balloon 10 has a crack 32 formed on the surface of the medicament layer 31 and extending along the base 17B of the rib 17. By forming the crack 32 on the surface of the medicament layer 31 in this way, when the medicament layer 31 contacts the inner surface of the blood vessel wall when the balloon 10 expands in the stenosis, the medicament layer 31 provided on the side surface 18 of the rib 17 is likely to peel off from the surface of the balloon 10 starting from the crack 32, and the medicament layer 31 is likely to transfer from the surface of the balloon 10 to the blood vessel wall side.

[0099] As Figure 9 shown, when the rib 17 is formed in a multi-stage shape, it is only necessary to form a crack 32 on the surface of the medicament layer 31 extending along the base of any stage of the multi-stage rib 17. In Figure 9 , the multi-stage rib 17 has a first-stage portion 19 adjacent to the outer surface of the balloon main body portion 16 and a second-stage portion 20 on the side closer to the top 17A than the first-stage portion 19. It is only necessary to form a crack 32 on the surface of the medicament layer 31 extending along at least one of the bases of the base 19B of the first-stage portion 19 and the base 20B of the second-stage portion 20. In Figure 9 , an example is shown in which a crack 32 extending along the base 20B of the second-stage portion is formed on the surface of the medicament layer 31. In addition, the base 19B of the first-stage portion 19 of the rib 17 corresponds to the base 17B of the rib 17.

[0100] Hereinafter, taking the case where the crack 32 is formed on the surface of the medicament layer 31 along the base 17B of the rib 17 as an example, the crack 32 of the medicament layer 31 will be described in detail, but the following description also applies equally to the case where the crack 32 is formed on the surface of the medicament layer 31 along the base of any stage of the multi-stage rib 17.

[0101] Viewing the balloon 10 from the outside, the crack 32 is formed to extend on the surface of the medicament layer 31 along the extending direction of the base 17B, that is, the extending direction of the boundary between the rib existing region 21 and the rib non-existing region 22 (see Figure 7 ). The crack 32 can be formed to extend parallel to the extending direction of the base 17B, or can be formed such that at least a part of the crack 32 extends obliquely with respect to the extending direction of the base 17B. As long as the crack 32 as a whole is formed to extend along the extending direction of the base 17B. The crack 32 can extend continuously along the base 17B, or can extend intermittently. In addition, a plurality of cracks 32 extending along the base 17 can also be formed to be arranged in the circumferential direction, that is, to overlap in the length direction. For example, a part of one crack 32 among the plurality of cracks 32 can be formed to overlap with a part of the other crack 32 in the length direction of the balloon 10.

[0102] Preferably, the crack 32 is formed within a range of more than 1 / 2 of the length direction of the medicament layer 31 in the straight tube portion 13, more preferably within a range of more than 2 / 3, and further preferably within a range of more than 3 / 4. The crack 32 may also be formed in the entire length direction of the medicament layer 31 in the straight tube portion 13.

[0103] Preferably, in a vertical section in the length direction of the straight tube portion 13, the crack 32 is formed at or near the shortest point 33 from the base portion 17B on the surface of the medicament layer 31. Specifically, preferably, in a vertical section in the length direction of the straight tube portion 13, when a straight line connecting the shortest point 33 on the surface of the medicament layer 31 is drawn from the base portion 17B of the rib 17 and the length from the base portion 17B to the shortest point 33 of this straight line is set as R, in the vertical section in the length direction of the straight tube portion 13, the crack 32 on the surface of the medicament layer 31 is located inside a virtual circle 34 with a radius of 1.5R centered on the base portion 17B. More preferably, in the vertical section in the length direction of the straight tube portion 13, the entire crack 32 is accommodated inside a virtual circle 34 with a radius of 1.5R centered on the base portion 17B. In Figures 8 to 11 Figure, a part of the virtual circle 34 with a radius of 1.5R centered on the base portion 17B is shown by a one-dot chain line. More preferably, the radius of the virtual circle 34 is 1.3R.

[0104] In a vertical section in the length direction of the straight tube portion 13, the crack 32 may be formed to extend from the surface of the medicament layer 31 to the outer surface of the straight tube portion 13 of the balloon 10, or may be formed to extend from the surface of the medicament layer 31 to the inside of the medicament layer 31 as the end point.

[0105] The number of the base portions 17B of the ribs 17 in a vertical section in the length direction of the straight tube portion 13 is twice the number of the ribs 17, that is, there are amounts corresponding to the base portion 17B of the first side surface 18A and the base portion 17B of the second side surface 18B of each rib 17. However, in the straight tube portion 13 of the balloon, as long as the crack 32 is formed in the medicament layer 31 along at least one of the base portions 17B where a plurality of ribs 17 exist. In addition, for the first side surface 18A and the second side surface 18B of the rib 17, in a vertical section in the length direction of the straight tube portion 13, the side surface 18 located on one side with respect to a virtual straight line 17L passing through the top portion 17A of the rib 17 and extending in the radial direction becomes the first side surface 18A, and the side surface 18 located on the other side becomes the second side surface 18B. For example, when observing the balloon 10 from the distal side, the left side surface 18 of the rib 17 can be set as the first side surface 18A, and the right side surface 18 can be set as the second side surface 18B.

[0106] When there are a plurality of ridges 17 provided in a vertical section in the longitudinal direction of the straight tube portion 13, a plurality of ridge non - existent regions 22 are formed on the outer surface of the straight tube portion 13 by the plurality of ridges 17, but it is sufficient to form a crack 32 in the medicament layer 31 along at least one of the bases 17B of the plurality of ridges 17. It is preferable to form a crack 32 in the medicament layer 31 along the base 17B of at least one of the first side surface 18A and the second side surface 18B of each ridge 17, and more preferably to form a crack 32 in the medicament layer 31 along the bases 17B of both the first side surface 18A and the second side surface 18B of each ridge 17.

[0107] Preferably, the medicament layer 31 is set to be relatively thick at the base 17B of the ridge 17. For example, the balloon 10 preferably has the thickness of the medicament layer 31 at the base 17B of the ridge 17 in a vertical section in the longitudinal direction of the straight tube portion 13 formed thicker than the thickness of the medicament layer 31 at the farthest point 22F from the ridge 17 in the ridge non - existent region 22. By setting the medicament layer 31 in this way, a thick medicament layer 31 exists at the base 17B of the ridge 17. Thus, when the balloon 10 is expanded in the stenosis, more medicament can be delivered from the inner surface of the blood vessel wall to the inside of the blood vessel wall in the expanded stenosis.

[0108] The thickness of the medicament layer 31 at the base 17B of the ridge 17 refers to the length of the straight line from the base 17B of the ridge 17 to the shortest point 33 connecting the surface of the medicament layer 31 when the straight line is drawn in a vertical section in the longitudinal direction of the straight tube portion 13. In addition, the shortest point 33 refers to the shortest point from the base 17B to the surface of the medicament layer 31 except for the portion where the crack 32 is formed. Therefore, the thickness of the medicament layer 31 at the base 17B of the ridge 17 refers to the thickness of the medicament layer 31 except for the portion where the crack 32 is formed.

[0109] The thickness of the medicament layer 31 at the farthest point 22F from the ridge 17 in the ridge non - existent region 22 refers to the radial length from the outer surface of the balloon main body portion 16 to the surface of the medicament layer 31 at the farthest point 22F. When there is no medicament layer 31 at the farthest point 22F from the ridge 17 in the ridge non - existent region 22, the thickness of the medicament layer 31 at this farthest point 22F is 0.

[0110] The farthest point 22F from the ridge 17 in the ridge non - existent region 22 is determined as follows. As Figure 6 shown, when there is only one ridge 17 provided in a vertical section in the longitudinal direction of the straight tube portion 13, the symmetric point of the ridge 17 in the circumferential direction of the straight tube portion 13 (the symmetric point with respect to the center of the cylindrical balloon main body portion 16) becomes the farthest point 22F from the ridge 17 in the ridge non - existent region 22. As Figure 5As shown, when there are a plurality of ridges 17 in the vertical section in the longitudinal direction of the straight tube portion 13, the midpoints in the circumferential direction of the ridges 17 adjacent in the circumferential direction of the straight tube portion 13 become the farthest points 22F from the ridges 17 in the ridge non-existence region 22.

[0111] A further detailed description will be given thereof. In the ridge 17, the base portions 17B of the ridge 17 are present on the first side surface 18A and the second side surface 18B respectively, but as Figure 6 shown, when only one ridge 17 is provided in the vertical section in the longitudinal direction of the straight tube portion 13, the midpoint between the base portion 17B of the first side surface 18A of the ridge 17 and the base portion 17B of the second side surface 18B of the ridge 17 in the ridge non-existence region 22 becomes the farthest point 22F from the ridge 17 in the ridge non-existence region 22. As Figure 5 shown, when a plurality of ridges 17 are provided in the vertical section in the longitudinal direction of the straight tube portion 13, the midpoint between the base portion 17B of the first side surface 18A of one ridge 17 and the base portion 17B of the second side surface 18B of the ridge 17 adjacent to the first side surface 18A of the ridge 17 with the ridge non-existence region 22 therebetween becomes the farthest point 22F from the ridge 17 in the ridge non-existence region 22.

[0112] In the straight tube portion 13 of the balloon, it is preferable that the thickness of the drug layer 31 at at least one of the base portions 17B of the plurality of ridges 17 is formed to be thicker than the thickness of the drug layer 31 at the farthest point 22F from the ridge 17 in the ridge non-existence region 22. When a plurality of ridges 17 are provided in the vertical section in the longitudinal direction of the straight tube portion 13, a plurality of ridge non-existence regions 22 are formed on the outer surface of the straight tube portion 13 by providing the plurality of ridges 17, but it is preferable that the thickness of the drug layer 31 at at least one of the base portions 17B of the plurality of ridges 17 is formed to be thicker than the average value of the thicknesses of the drug layer 31 at the farthest points 22F from the ridge 17 in the plurality of ridge non-existence regions 22, and more preferably formed to be thicker than each of the thicknesses of the drug layer 31 at the farthest points 22F from the ridge 17 in the plurality of ridge non-existence regions 22. Further, it is preferable that the thickness of the drug layer 31 at the base portion 17B of at least one of the first side surface 18A and the second side surface 18B of each ridge 17 is formed to be thicker than the average value of the thicknesses of the drug layer 31 at the farthest points 22F from the ridge 17 in the plurality of ridge non-existence regions 22, and more preferably formed to be thicker than each of the thicknesses of the drug layer 31 at the farthest points 22F from the ridge 17 in the plurality of ridge non-existence regions 22.

[0113] The thickness of the medicament layer 31 at the base 17B of the rib 17 and the thickness of the medicament layer 31 at the farthest point 22F from the rib 17 in the rib non-existence region 22 can be obtained, for example, as follows. The balloon 10 is cut in the vertical direction along the length of the straight tube portion 13, and the balloon main body portion 16 is maintained in a substantially circular state. In this state, the thickness of the medicament layer 31 at the base 17B of the rib 17 and the thickness of the medicament layer 31 at the farthest point 22F from the rib 17 in the rib non-existence region 22 are measured. Alternatively, the folded balloon 10 can be cut in the vertical direction along the length of the straight tube portion 13, the outer circumference of the rib non-existence region 22 between the ribs 17 of the folded balloon 10 can be measured, the midpoint of the outer circumference between the ribs 17 can be determined as the farthest point 22F, and the thickness of the medicament layer 31 at the base 17B of the rib 17 and the thickness of the medicament layer 31 at the farthest point 22F from the rib 17 in the rib non-existence region 22 can be measured.

[0114] The thickness of the medicament layer 31 at the base 17B of the rib 17 is preferably 1.5 times or more, more preferably 2.0 times or more, and further preferably 2.5 times or more the thickness of the medicament layer 31 at the farthest point 22F from the rib 17 in the rib non-existence region 22. The upper limit value of the ratio of the thickness of the medicament layer 31 at the base 17B of the rib 17 to the thickness of the medicament layer 31 at the farthest point 22F from the rib 17 in the rib non-existence region 22 is not particularly limited. The medicament layer 31 may not exist at the farthest point 22F from the rib 17 in the rib non-existence region 22, or may exist with a very thin thickness. For example, the thickness of the medicament layer 31 at the base 17B of the rib 17 may be 100 times or less, 50 times or less, 30 times or less, 20 times or less, or 10 times or less the thickness of the medicament layer 31 at the farthest point 22F from the rib 17 in the rib non-existence region 22.

[0115] In the above-described case, it is sufficient that the thickness of the drug layer 31 at the base 17B of the convex strip 17 is thicker than the thickness of the drug layer 31 at the farthest point 22F from the convex strip 17 in the convex-strip non-existent region 22 in at least a part of the length direction of the straight tube portion 13. It is preferable to form the drug layer 31 in that manner in at least a part of the central 1 / 2 region in the length direction of the straight tube portion 13, more preferably in more than half of the central 1 / 2 region in the length direction of the straight tube portion 13, and still more preferably in more than 2 / 3 of the central 1 / 2 region in the length direction of the straight tube portion 13. For example, when the proximal end of the straight tube portion 13 is set to 0% and the distal end is set to 100% as the relative positions in the length direction of the straight tube portion 13, it is preferable to cut the straight tube portion 13 radially at six positions in units of 10% within the range of 25% to 75%, measure the thickness of the drug layer 31 at each cut cross section, and form it in three or more positions in that manner. Thereby, it can be determined that in more than half of the central 1 / 2 region in the length direction of the straight tube portion 13, the thickness of the drug layer 31 at the base 17B of the convex strip 17 is formed thicker than the thickness of the drug layer 31 at the farthest point 22F from the convex strip 17 in the convex-strip non-existent region 22. The drug layer 31 may be formed in the entire central 1 / 2 region in the length direction of the straight tube portion 13 such that the thickness of the drug layer 31 at the base 17B of the convex strip 17 is formed thicker than the thickness of the drug layer 31 at the farthest point 22F from the convex strip 17 in the convex-strip non-existent region 22, or the drug layer 31 may be formed in that manner in the entire length direction of the straight tube portion 13.

[0116] In the following various descriptions regarding the formation of the drug layer 31 in the vertical cross section perpendicular to the length direction of the straight tube portion 13, the description regarding the formation of the drug layer 31 in the length direction of the straight tube portion 13 is also referred to.

[0117] It is also preferably that, in a vertical cross-section in the longitudinal direction of the straight tube portion 13, the thickness of the medicine layer 31 at the base portion 17B of the rib 17 is thicker than the average thickness of the medicine layer 31 in the central 1 / 2 region 22M in the circumferential direction of the rib non-existence region 22. The central 1 / 2 region 22M in the circumferential direction of the rib non-existence region 22 means the region of the two central intervals when the rib non-existence region 22 is divided into four equal parts in the circumferential direction in one rib non-existence region 22. When a plurality of ribs 17 are provided in the vertical cross-section in the longitudinal direction of the straight tube portion 13, it is preferably that the thickness of the medicine layer 31 at the base portion 17B (the base portion 17B of at least one of the first side surface 18A and the second side surface 18B) of at least one rib 17 is formed to be thicker than the average value of the average thicknesses of the medicine layer 31 in the central 1 / 2 region 22M in the circumferential direction of the plurality of rib non-existence regions 22, and more preferably formed to be thicker than each average thickness of the medicine layer 31 in the central 1 / 2 region 22M in the circumferential direction of the plurality of rib non-existence regions 22. In addition, it is preferably that the thickness of the medicine layer 31 at the base portion 17B of at least one of the first side surface 18A and the second side surface 18B of each rib 17 is formed to be thicker than the average value of the average thicknesses of the medicine layer 31 in the central 1 / 2 region 22M in the circumferential direction of the plurality of rib non-existence regions 22, and more preferably formed to be thicker than each average thickness of the medicine layer 31 in the central 1 / 2 region 22M in the circumferential direction of the plurality of rib non-existence regions 22.

[0118] The average thickness of the medicine layer 31 in the central 1 / 2 region 22M in the circumferential direction of the rib non-existence region 22 is obtained by dividing the area of the medicine layer 31 in the central 1 / 2 region 22M in the circumferential direction of the rib non-existence region 22 when observing the straight tube portion 13 in the vertical cross-section in the longitudinal direction by the circumferential length of the central 1 / 2 region 22M in the circumferential direction of the rib non-existence region 22. It is convenient to obtain the average thickness of the medicine layer 31 in the central 1 / 2 region 22M in the circumferential direction of the rib non-existence region 22 by cutting the balloon in the direction perpendicular to the longitudinal direction of the straight tube portion 13, photographing a photo of the cut cross-section, and performing image processing.

[0119] The thickness of the medicament layer 31 at the base 17B of the rib 17 is preferably 1.3 times or more, more preferably 1.5 times or more, and further preferably 2.0 times or more the average thickness of the medicament layer 31 in the region 22M which is the central 1 / 2 in the circumferential direction of the rib non-existence region 22. The upper limit value of the ratio of the thickness of the medicament layer 31 at the base 17B of the rib 17 to the average thickness of the medicament layer 31 in the region 22M which is the central 1 / 2 in the circumferential direction of the rib non-existence region 22 is not particularly limited. For example, the thickness of the medicament layer 31 at the base 17B of the rib 17 may be 100 times or less, 50 times or less, 30 times or less, 20 times or less, or 10 times or less the average thickness of the medicament layer 31 in the region 22M which is the central 1 / 2 in the circumferential direction of the rib non-existence region 22.

[0120] Preferably, on the outer surface of the straight tube portion 13, a medicament layer 31 is also provided in the rib non-existence region 22 together with the rib existence region 21 (i.e., the side surface 18 of the rib 17). For example, preferably, a medicament layer 31 is provided in at least a part of the region 22M which is the central 1 / 2 in the circumferential direction of the rib non-existence region 22, and preferably, a medicament layer 31 is provided at the farthest point 22F from the rib 17 in the rib non-existence region 22. If a medicament layer 31 is also provided in the rib non-existence region 22, when the balloon 10 is expanded in the stenosis, the medicament can be delivered to a wide range of the inner surface of the blood vessel in the stenosis.

[0121] As an embodiment, as Figure 8 and Figure 9 shown, the rib 17 may also be formed to have a portion where the width narrows toward the top 17A and not to have a portion where the width widens toward the top 17A. That is, the side surface 18 of the rib 17 may be formed to have a portion that approaches the imaginary straight line 17L toward the top 17A with respect to the imaginary straight line 17L that passes through the top 17A of the rib 17 and extends in the radial direction, and not to have a portion that moves away from the imaginary straight line 17L toward the top 17A. If the rib 17 is formed in this way, when the balloon 10 is expanded in the stenosis, even if the rib 17 is strongly pressed against the inner surface of the blood vessel, the rib 17 will not bend and is likely to bite into the stenosis. The rib 17 may also be formed such that the width as a whole from the base 17B to the top 17A narrows toward the top 17A. That is, the side surface 18 of the rib 17 may be formed to approach the imaginary straight line 17L toward the top 17A as a whole from the base 17B to the top 17A of the rib 17.

[0122] The rib 17 may be formed, as Figure 8 shown, such that the width narrows continuously toward the top 17A, or may be formed, as Figure 9As shown, it is formed to be stepped and narrowed in width toward the top 17A. In the former case, the side surface 18 of the rib 17 only needs to be formed as a straight line that extends obliquely with respect to the imaginary straight line 17L in the vertical section in the longitudinal direction of the straight tube portion 13, or as a curved line that bulges outward in the radial direction (a part may include a straight line portion), or as a curved line that bulges inward in the radial direction (a part may include a straight line portion). In the latter case, the rib 17 only needs to have a portion that is stepped and narrowed in width toward the top 17A at least in part from the base 17B to the top 17A.

[0123] As another embodiment, as Figure 10 shown, the rib 17 may also be formed to have a portion where the width widens toward the top 17A and a portion where the width narrows toward the top 17A on the side closer to the top 17A than this portion. For example, in the vertical section in the longitudinal direction of the straight tube portion 13, the side surface 18 of the rib 17 may be formed to have a portion 18R that is away from the imaginary straight line 17L toward the top 17A with respect to the imaginary straight line 17L that passes through the top 17A of the rib 17 and extends in the radial direction, and a portion 18S that is closer to the imaginary straight line 17L toward the top 17A on the side closer to the top 17A than this portion. In this case, a part of the side surface 18 of the rib 17 is recessed. Therefore, more medicament can be held in the recessed portion of the side surface 18 of the rib 17. In the rib 17, the portion where the width widens toward the top 17A, or the portion 18R of the side surface 18 of the rib 17 that is away from the imaginary straight line 17L toward the top 17A is preferably formed in at least a part of the range of at least 0% to 30% of the height of the rib 17, and is preferably not formed in the range of 50% to 100% of the height of the rib 17. Thereby, more medicament can be held in the base 17B of the rib 17.

[0124] As Figure 11 shown, in the vertical section in the longitudinal direction of the straight tube portion 13, the thickness of the medicament layer 31 at the base 17B of the first side surface 18A of the rib 17 may also be formed to be thicker than the thickness of the medicament layer 31 at the base 17B of the second side surface 18B of the rib 17. If the medicament layer 31 is formed on the side surface 18 of the rib 17 in this way, the biting performance at the narrow portion is ensured on the second side surface 18B of the rib 17, and more medicament is held on the first side surface 18A of the rib 17. Therefore, when the balloon 10 is expanded at the narrow portion, the medicament can be efficiently delivered to the narrow portion.

[0125] Preferably, when the balloon 10 is delivered to a treatment target portion such as a stenosis in a blood vessel, it is inserted through a guiding catheter and a sheath in a contracted state. At this time, the balloon 10 is preferably appropriately folded so that its radial size becomes smaller.

[0126] Figure 12 andFigure 13 illustrates an example in which the Figure 5 shown balloon 10 is contracted and folded. As Figure 12 well as Figure 13 shown, preferably in the contracted state of the balloon 10, the straight tube portion 13 turns the inner surface of the balloon main body portion 16 to the inside and is folded back in the ridge non-existing region 22 to form a folded blade portion 23 formed by overlapping of the ridge non-existing regions 22, and the folded blade portion 23 is overlapped and arranged on the outer surface of the straight tube portion 13. The folded blade portion 23 is formed by the ridge non-existing regions 22 of the balloon main body portion 16 being folded back at the fold line 24, and the ridge non-existing regions 22 overlap each other. At the fold line 24, the ridge non-existing region 22 turns the inner surface of the balloon main body portion 16 to the inside and is folded back. Therefore, when observed from the outside of the balloon 10, the fold line 24 is formed as a convex fold. The folded blade portion 23 is preferably formed only by the ridge non-existing regions 22 of the balloon main body portion 16 and is not formed to include the ridge existing regions 21.

[0127] Preferably, the fold line 24 is formed to extend substantially parallel to the extending direction of the ridge 17. The ridge non-existing region 22 can be folded back in such a way as to form a clear crease at the fold line 24, or can be folded back in a way with a smooth front end. In addition, the ridge non-existing regions 22 of the balloon main body portion 16 generally have a certain thickness and elasticity, so the ridge non-existing regions 22 are folded back at the fold line 24 in a way with a smooth front end. In this case, when observed from a vertical cross-section in the longitudinal direction of the straight tube portion 13, the front end portion formed by folding back the ridge non-existing region 22 becomes the fold line 24.

[0128] In the straight tube portion 13, a fold line (a concave fold line when observed from the outside of the balloon 10) can be formed in which the outer surface of the balloon main body portion 16 is turned to the inside and folded back with respect to one side and / or the other side in the circumferential direction of the fold line 24. In this case, preferably, the fold line that becomes a concave fold line forms the base of the folded blade portion 23.

[0129] One fold line 24 can be formed only in one ridge non-existing region 22, or two or more fold lines 24 can be formed. Preferably, one or two fold lines 24 are formed in one ridge non-existing region 22. In Figure 12 it, one fold line 24 is formed in one ridge non-existing region 22, and in Figure 13In [the above], two bent lines 24 are formed in a non - rib region 22. When one bent line 24 is formed in a non - rib region 22, preferably, when observed from a vertical cross - section in the longitudinal direction of the straight tube portion 13, the folded blade portion 23 tilts toward one side in the circumferential direction. When two bent lines 24 are formed in a non - rib region 22, preferably, when observed from a vertical cross - section in the longitudinal direction of the straight tube portion 13, the two folded blade portions 23 tilt in opposite directions to each other in the circumferential direction and tilt toward the rib 17 side. Thus, in the contracted state of the balloon 10, the rib 17 is easily protected by the folded blade portion 23.

[0130] As an embodiment, it is also possible that in the contracted state of the balloon 10, the folded blade portion 23 is arranged to cover the top 17A of the rib 17. In this case, the drug layer 31 provided on the rib 17 is protected by the folded blade portion 23. For example, the drug layer 31 near the top 17A of the rib 17 is easily protected. Therefore, before the balloon 10 is delivered to the treatment target site, the drug layer 31 is not easily detached from the balloon 10.

[0131] As another embodiment, it is also possible that in the contracted state of the balloon 10, the folded blade portions 23 are overlapped and arranged on the outer surface of the straight tube portion 13 in such a way as not to cover the top 17A of the rib 17. In this case, when the balloon 10 is expanded at the stenosis, the rib 17 quickly bites into the stenosis, and it is easy to effectively expand the stenosis by the balloon 10.

[0132] In Figure 12 one non - rib region 22, one folded blade portion 23 is formed, and the folded blade portion 23 is arranged to cover the top 17A of the rib 17, but in Figure 12 it is also possible that the folded blade portion 23 is overlapped and arranged on the outer surface of the straight tube portion 13 in such a way as not to cover the top 17A of the rib 17. In Figure 13 two folded blade portions 23 are formed in one non - rib region 22, and the folded blade portions 23 are overlapped and arranged on the outer surface of the straight tube portion 13 in such a way as not to cover the top 17A of the rib 17, but the folded blade portions 23 can also be arranged to cover the top 17A of the rib 17.

[0133] Next, a method for manufacturing the balloon catheter of the present invention will be described. The method for manufacturing the balloon catheter according to the embodiment of the present invention includes: a step of preparing a balloon having ribs on its outer surface (hereinafter referred to as "balloon preparation step"); a step of applying a liquid medicine on the outer surface of the balloon to form a drug layer (hereinafter referred to as "drug layer formation step"); and a step of bending the ribs relative to the outer surface of the balloon main body portion (hereinafter referred to as "rib bending step").

[0134] In the balloon preparation step, the balloon 10 described above is prepared. That is, the balloon 10 having a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction is prepared. The balloon 10 includes: a straight tube portion 13; a proximal conical portion 12 located on the proximal side of the straight tube portion 13; and a distal conical portion 14 located on the distal side of the straight tube portion 13. The straight tube portion 13 includes: a cylindrical balloon main body portion 16; and a rib 17 protruding outward in the radial direction on the outer surface of the balloon main body portion 16 and extending in the longitudinal direction. For the details of the structure and preferred mode of the balloon 10, refer to the above description.

[0135] In the pharmaceutical layer formation step, a pharmaceutical solution is applied to the outer surface of the straight tube portion 13 including the side surface 18 of the rib 17 to form a pharmaceutical layer 31. The method of applying the pharmaceutical solution is not particularly limited. For example, the pharmaceutical solution can be applied to the outer surface of the straight tube portion 13 by a brush, a sprayer, a coater, etc., or the pharmaceutical solution can be applied to the outer surface of the straight tube portion 13 by immersing the balloon 10 in the pharmaceutical solution. As needed, the pharmaceutical solution can also be applied to the outer surface of the straight tube portion 13 on the basis of masking the portion where the pharmaceutical layer 31 is not formed.

[0136] From the point of view of easily forming the pharmaceutical layer 31 on the side surface 18 of the rib 17, in the pharmaceutical layer formation step, as Figure 14 shown, the pharmaceutical solution 35 can be applied to the outer surface of the straight tube portion 13 of the balloon 10, and the balloon 10 can be rotated about a central axis extending in the longitudinal direction. Figure 14 is shown in Figure 2 a vertical cross-sectional view of the balloon 10 in the longitudinal direction, showing the state where the pharmaceutical solution 35 is applied to the outer surface of the straight tube portion 13 of the balloon 10. The pharmaceutical solution 35 is applied to the outer surface of the straight tube portion 13, and the balloon 10 is rotated about a central axis extending in the longitudinal direction. As a result, the pharmaceutical solution 35 applied to the outer surface of the straight tube portion 13, particularly the non-rib region 22, moves circumferentially on the surface of the straight tube portion 13 and accumulates on the side surface 18 of the rib 17, and a thicker pharmaceutical layer 31 can be formed on the side surface 18 and the base portion 17B of the rib 17.

[0137] The pharmaceutical agent included in the pharmaceutical solution 35 refers to the above description. Preferably, the pharmaceutical solution 35 includes a solvent in which the pharmaceutical agent is dissolved or dispersed. The pharmaceutical concentration of the pharmaceutical solution 35 is not particularly limited, as long as the concentration is appropriately adjusted so that it can be applied to the outer surface of the straight tube portion 13 and ensure fluidity on the surface of the straight tube portion 13.

[0138] The method of applying the pharmaceutical solution 35 is not particularly limited, but preferably, as Figure 14 shown, the pharmaceutical solution 35 is applied to the outer surface of the straight tube portion 13 by a sprayer, whereby it is easy to widely apply an arbitrary amount of the pharmaceutical solution 35 to the outer surface of the straight tube portion 13. In addition, it is easy to form the pharmaceutical layer 31 on the outer surface of the straight tube portion 13.

[0139] In the pharmaceutical layer forming step, it is preferable to coat the liquid medicine 35 on the outer surface of the straight tube portion 13 in a state where the balloon 10 is expanded. Further, it is preferable to rotate the balloon 10 about a central axis extending in the longitudinal direction in a state where the balloon 10 is expanded. Thereby, the liquid medicine 35 coated on the non-existence region 22 of the ridges of the straight tube portion 13 easily moves circumferentially on the surface of the straight tube portion 13 and accumulates on the side surface 18 of the ridge 17.

[0140] In the pharmaceutical layer forming step, the liquid medicine 35 can be coated on the outer surface of the straight tube portion 13 while rotating the balloon 10 about a central axis extending in the longitudinal direction, or the balloon 10 can be rotated about a central axis extending in the longitudinal direction after coating the liquid medicine 35 on the outer surface of the straight tube portion 13. In either case, the liquid medicine 35 coated on the outer surface of the straight tube portion 13 can move circumferentially on the surface of the straight tube portion 13 and accumulate on the base portion 17B of the ridge 17.

[0141] In the pharmaceutical layer forming step, the balloon 10 can rotate only in one direction about a central axis extending in the longitudinal direction, or can rotate in two directions, one direction and the opposite direction, in sequence. By appropriately setting the rotation direction of the balloon 10, it is possible to easily adjust the thickness of the pharmaceutical layer 31 formed on the base portion 17B of the first side surface 18A and the base portion 17B of the second side surface 18B of the ridge 17.

[0142] In the pharmaceutical layer forming step, it is preferable to evaporate at least a part of the solvent included in the liquid medicine 35 while rotating the balloon 10. Thereby, it is easy to form the pharmaceutical layer 31 on the outer surface of the straight tube portion 13. The evaporation of the solvent can be performed by heating the balloon 10 coated with the liquid medicine 35, or can be performed by placing the balloon 10 coated with the liquid medicine 35 in a reduced pressure state, or can be performed by blowing air on the balloon 10 coated with the liquid medicine 35. Further, the solvent can be naturally evaporated while rotating the balloon 10 by selecting a solvent having an appropriate vapor pressure as the solvent.

[0143] After the pharmaceutical layer forming step, a ridge bending step of bending the ridge 17 with respect to the outer surface of the balloon main body portion 16 is performed. In the ridge bending step, the ridge 17 is tilted circumferentially with respect to the outer surface of the balloon main body portion 16 to be bent. Thereby, a crack 32 extending along the base portion 17B of the ridge 17 can be formed on the surface of the pharmaceutical layer 31. The ridge 17 can be tilted only in one direction in the circumferential direction, or can be tilted in one direction and the other direction in the circumferential direction in sequence. Further, in the ridge bending step, from the viewpoint of easily bending the ridge 17, it is preferable that the height of the ridge 17 is 0.2 times or more, more preferably 0.4 times or more, and further preferably 0.7 times or more of the width of the ridge 17.

[0144] This application claims the benefit of priority based on Japanese Patent Application No. 2022-183695 filed on November 16, 2022. The entire contents of the specification of Japanese Patent Application No. 2022-183695 filed on November 16, 2022 are incorporated herein by reference.

[0145] Explanation of Reference Numerals

[0146] 1... balloon catheter; 2... shaft; 5... pivot portion; 10... balloon; 11... proximal sleeve portion; 12... proximal tapered portion; 13... straight tube portion; 14... distal tapered portion; 15... distal sleeve portion; 16... balloon main body portion; 17... rib; 17A... top; 17B... base; 18... side surface; 18A... first side surface; 18B... second side surface; 19... first stage portion; 20... second stage portion; 21... rib present area; 22... rib absent area; 23... folding blade portion; 24... fold line; 31... medicament layer; 32... crack; 35... liquid medicine.

Claims

1. A balloon for a balloon catheter, having a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction, characterized in that, The balloon has: a straight tube portion; a proximal cone portion located on the proximal side of the straight tube portion; and a distal cone portion located on the distal side of the straight tube portion. The straight tube portion has: a balloon main body portion having a cylindrical shape; and a rib protruding outward in the radial direction on the outer surface of the balloon main body portion. A medicament layer is provided on the outer surface of the straight tube portion including the side surface of the rib. A crack extending along the base of the rib is formed on the surface of the medicament layer.

2. A balloon for a balloon catheter, having a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction, characterized in that, The balloon has: a straight tube portion; a proximal cone portion located on the proximal side of the straight tube portion; and a distal cone portion located on the distal side of the straight tube portion. The straight tube portion has: a balloon main body portion having a cylindrical shape; and a multi-stage rib protruding outward in the radial direction on the outer surface of the balloon main body portion. A medicament layer is provided on the outer surface of the straight tube portion including the side surface of the rib. A crack extending along the base of any stage of the multi-stage rib is formed on the surface of the medicament layer.

3. The balloon according to claim 1 or 2, characterized in that, The rib extends in the longitudinal direction of the balloon.

4. The balloon according to claim 1 or 2, characterized in that, The outer surface of the straight tube portion has: a rib presence region where the rib exists; and a rib non-presence region where the rib does not exist. In a vertical cross-section in the longitudinal direction of the straight tube portion, the thickness of the medicament layer at the base of the rib, except for the portion where the crack is formed, is thicker than the thickness of the medicament layer at the farthest point from the rib in the rib non-presence region.

5. The balloon according to claim 1 or 2, characterized in that, The medicament constituting the medicament layer is crystalline.

6. The balloon according to claim 1 or 2, characterized in that, The rib is made of resin, metal, or a combination thereof.

7. The balloon according to claim 1 or 2, characterized in that, The outer surface of the straight tube portion has: a rib presence region where the rib exists; and a rib non-presence region where the rib does not exist. In the contracted state of the balloon, the straight tube portion folds the inner surface of the balloon main body portion inward and is folded back in the rib non-presence region to form a folded blade portion formed by overlapping the rib non-presence regions. The folded blade portion is overlapped and arranged on the outer surface of the straight tube portion and covers the top of the rib.

8. The balloon according to claim 1 or 2, characterized in that, The outer surface of the straight tube portion has: a rib presence region where the rib exists; and a rib non-presence region where the rib does not exist. In the contracted state of the balloon, the straight tube portion folds the inner surface of the balloon main body portion inward and is folded back in the rib non-presence region to form a folded blade portion formed by overlapping the rib non-presence regions. The folded blade portion is overlapped and arranged on the outer surface of the straight tube portion in a manner that does not cover the top of the rib.

9. A balloon catheter, characterized in that, The balloon according to claim 1 or 2 is provided.

10. A method for manufacturing a balloon catheter, characterized in that, Has: A step of preparing a balloon, the balloon having a longitudinal direction extending from the proximal side to the distal side and a radial direction perpendicular to the longitudinal direction, and having a straight tube portion, a proximal cone portion located on the proximal side of the straight tube portion, and a distal cone portion located on the distal side of the straight tube portion, the straight tube portion having a balloon main body portion having a cylindrical shape and a rib protruding outward in the radial direction on the outer surface of the balloon main body portion; A step of coating a liquid medicine on the outer surface of the straight tube portion including the side surface of the rib to form a medicament layer; and A step of bending the rib with respect to the outer surface of the balloon main body after the step of forming the agent layer.

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