JP2004267368A - Drug release stent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stent having a stable sustained release performance of NF-κB decoy and its stability in the body for a long period. <P>SOLUTION: This drug release stent is so constituted that the surface of a stent base material 11 is covered with a drug retaining layer M composed of a high polymer material containing NF-κB decoy. In this drug release stent, after the surface of the stent base material 11 is treated by primer, the primer layer P is covered with the drug retaining layer M and the drug retaining layer M is covered with a covering layer 12 composed of the high polymer material containing no NF-κB decoy. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement of a stent which can be implanted in a blood vessel or a body cavity and is used for treatment of a stenosis. The present invention relates to a stent that provides a surface for restraint or the like and prevents restenosis.
[0002]
2. Prior Art and Problems to be Solved by the Invention
A stent is a tubular medical device that is placed in a blood vessel or another lumen in a living body when the stenosis or occlusion is obstructed or occluded in order to expand the stenosis or the like and secure a necessary lumen area. The stent is inserted into the body with a small diameter, expanded at a stenosis or the like, and used to expand and hold the lumen by increasing the diameter.
[0003]
For example, in recent years, for the purpose of reconstruction of a stenotic blood vessel, a percutaneous coronary angioplasty (hereinafter referred to as PTCA: Percutaneous Transluminal Angioplasty) is used to perform treatment by dilation with a PTCA balloon catheter and placement of a stent. ing. The stent is intended to prevent / suppress restenosis by sending air to a balloon attached to a catheter and placing the stent in a blood vessel formed by inflation / expansion.
As described above, stent placement has been performed with the expectation of suppressing restenosis for angioplasty by only balloon dilatation, but in fact, the restenosis rate was higher than expected at the beginning. At present, no reduction has been obtained.
This is considered to be one of the causes of inducing formation of thrombus and proliferation of smooth muscle due to vascular damage caused by the stent itself when the stent is expanded and deployed.
[0004]
For this reason, conventionally, in catheters and the like, attempts have been made to incorporate or bind these drugs such as anticoagulants in the polymer constituting the catheter tube and to gradually release these drugs locally. However, in the case of a stent, since the base material is usually a metal, it is difficult to apply a technique such as directly bonding or impregnating the base material to the base material as has been mainly performed with a catheter. Therefore, as for the stent, the only method in which the drug is dissolved and mixed together with the polymer in an organic solvent and applied is practically applicable, but cannot be applied to a drug insoluble in the organic solvent.
[0005]
Although various diseases such as asthma, cancer and heart disease show different symptoms, it has been suggested that one or several types of proteins are mainly caused by overexpression or underexpression. In addition, transcriptional factors such as various transcriptional activators and transcription repressors are involved in protein expression. NF-κB, which is known as one of transcription factors, is composed of p65 and p50 heterodimers. Normally, the inhibitor IκB is present in the cytoplasm in a bound form, and nuclear translocation is prevented. However, when stimuli such as cytokines, ischemia, and reperfusion are applied for some reason, IκB is phosphorylated and degraded, so that NF-κB is activated and translocated into the nucleus. NF-κB promotes transcription of genes downstream thereof by binding to the NF-κB binding site on the chromosome. Genes controlled by NF-κB include, for example, cytokines such as IL-1 and IL-6 and adhesion factors such as VCAM-1 and ICAM-1.
[0006]
Activation of the production of these cytokines and adhesion factors was found to be one of the causes of restenosis after PTCA. As a result of intensive studies, decoys for the nucleic acid binding site of NF-κB, By gradually releasing a compound (NF-κB decoy) that specifically antagonizes the nucleic acid site to which NF-κB binds from the indwelling stent, by suppressing the expression of the gene activated by NF-κB, It was found to be very effective in preventing restenosis after stent placement.
However, since the NF-κB decoy is water-soluble, it has been very difficult to coat the stent with a conventional organic solvent.
[0007]
Patent Document 1 discloses NF-κB decoy as a physiologically active drug, and Patent Documents 2 and 3 disclose coating stents containing the drug. Patent Literature 1 does not disclose application to a stent, Patent Literatures 2 and 3 do not disclose the use of NF-κB decoy as a physiologically active agent. In addition, it is pointed out that sustained release of a drug over a long period of time is difficult, and no specific solution to these is disclosed.
[0008]
[Patent Document 1]
Japanese Patent Application No. 8-533947 (Claims 1 to 22)
[Patent Document 2]
JP-A-2001-293094 (Claims 1 to 3)
[Patent Document 3]
WO 02/13883 A2 (Claims 1 to 7, 10 to 34)
[0009]
[Means for Solving the Problems]
An object of the present invention is to improve the amount of a water-soluble drug retained in a polymer material by improving an improved polymer coating layer (drug holding layer) in a stent that suppresses restenosis by sustained release of the drug. An object of the present invention is to provide a technique for improving sustained release properties and enabling the stent to be stably used in the body for a longer period of time without causing detachment or the like.
NF-κB activated by gradually releasing the decoy for the nucleic acid binding site of NF-κB, that is, the compound (NF-κB decoy) that specifically antagonizes the nucleic acid site to which NF-κB binds, from the indwelling stent It is presumed that suppressing the expression of the gene to be performed is extremely effective in preventing restenosis after stent placement.
According to the present invention, the following inventions are provided.
[1] The present invention provides a drug releasing stent (1) in which the surface of a stent substrate (11) is coated with a drug holding layer (M) made of a polymer material containing NF-κB decoy.
[2] The present invention provides the drug-releasing stent (1) according to [1], wherein the surface of the stent substrate (11) is treated with a primer, and then the primer layer (P) is coated with the drug-retaining layer (M). I will provide a.
[3] The present invention provides the drug-releasing stent according to [1] or [2], wherein the drug holding layer (M) is coated with a coating layer (12) made of a polymer material not containing NF-κB decoy. (1) is provided.
[4] In the present invention, the drug-retaining layer (M) is made of a water-absorbing polymer material that releases the NF-κB decoy in vivo and absorbs at least 100% of its own weight of water [1]. To a drug-releasing stent (1) according to [3].
[5] In the present invention, the primer layer (P) is made of a material having a high affinity for both the stent base material (11) and the water-absorbing polymer material constituting the drug holding layer (M),
The drug release stent (1) according to [2] to [4], wherein the coating layer (12) is made of a polymer material capable of coating the drug holding layer (M).
[6] The present invention provides the drug release stent (1) according to any one of [1] to [5], wherein the polymer material constituting the drug holding layer (M) is a polyether-based polyurethane.
[7] The present invention provides the drug-releasing stent (1) according to [1] to [5], wherein the polymer material constituting the coating layer (12) is a polycarbonate-based polyurethane.
[8] The present invention provides the drug release stent (1) according to any one of [1] to [7], wherein the polymer material constituting the drug holding layer (M) is a bioabsorbable polymer.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The drug-releasing stent 1 of the present invention comprises a drug holding layer M made of a polymer material containing a decoy of NF-κB (hereinafter, referred to as “NF-κB decoy”) on the surface of the stent substrate 11. Coated.
Further, after the surface of the stent substrate 11 is subjected to a primer treatment, the primer layer P is covered with the drug holding layer M.
Further, the drug holding layer M is covered with a coating layer 12 made of a polymer material containing no NF-κB decoy.
As described above, the drug releasing stent 1 of the present invention (hereinafter referred to as “stent 1”) covers the surface of the stent substrate 11 in the order of the primer layer P / the drug holding layer M / the coating layer 12. The “surface” of the stent base material 11 is meant to include both the “outside surface” and the “inside surface” of the stent base material 11 as illustrated in FIG.
The drug holding layer M is made of a water-absorbing polymer material that contains a bioactive drug NF-κB decoy, releases the NF-κB decoy in vivo, and absorbs water at least 100% of its own weight.
The primer layer P is made of a material having a high affinity for both the stent base material 11 and the water-absorbing polymer material constituting the drug holding layer M.
The coating layer 12 is made of a polymer material that can cover the medicine holding layer M.
In the present invention, in forming the drug holding layer M on the stent base material 11, first, a high affinity primer for both the stent base material 11 and the water-absorbing polymer material forming the drug holding layer M, The surface of the stent substrate 11 is treated to form a primer layer P.
Next, a solution in which the water-absorbing polymer material is dissolved is prepared, and the solution is applied or immersed on the surface 11 of the stent base material on which the primer layer P is formed to volatilize the solvent, thereby forming the drug holding layer M. Can be.
In order to introduce a water-soluble drug into the drug holding layer M, the stent substrate 11 on which the drug holding layer M is formed is immersed in an aqueous solution of a desired NF-κB decoy for an arbitrary period of time, and then dried. Can be introduced. Further, the drug holding layer M is covered with a coating layer 12 made of a polymer material. Thus, three coating layers (primer layer P / drug holding layer M / coating layer 12) are formed on the stent substrate 11. The stent 1 itself has a four-layer structure including the stent base material 11.
[0011]
FIG. 1 is a schematic view showing an example of a stent 1 of the present invention, and FIG. 2 is a partially enlarged cross-sectional view of FIG. 1. The stent 1 includes a stent substrate 11 including a stent substrate 11, a primer layer P, and a drug. This is an example in which a four-layer structure of a holding layer M and a coating layer 12 is formed.
The material constituting the base material 11 of the stent may be a material known per se, and is not particularly limited. For example, a stainless steel such as SUS316L, a shape memory alloy such as a Ti-Ni alloy, a Cu-Al-Mn alloy, etc. , Titanium, titanium alloy, tantalum, tantalum alloy, platinum, platinum alloy, tungsten, tungsten alloy, etc. A stitch-like substantially tubular body formed by the above method is used. The shape of the substantially tubular body is not particularly limited as long as desired physical properties can be obtained.
[0012]
Further, the drug holding layer M used in the present invention contains at least NF-κB decoy, and absorbs at least 100% or more of its own weight of water, which can release the NF-κB decoy in vivo, or It is formed from a bioabsorbable material.
In the present invention, as the water-absorbing polymer material, for example, known starch-polyacrylonitrile hydrolyzate, starch-polyacrylate crosslinked product, crosslinked carboxymethylcellulose, saponified vinyl acetate-methyl acrylate copolymer, polyacrylic Sodium acid cross-linked products, cross-linked polyvinyl alcohol, and polyacrylamide-based materials, of which materials having a water absorption of 100% or more of their own weight can be used, the preferred water absorption used in the present invention As the conductive polymer material, a water-absorbing polymer material that is soluble in an organic solvent and can be coated on the stent, and at least does not peel off in accordance with the expansion of the stent, but can be followed, is preferred, and a polypropylene oxide chain, polytetramethylene Polyether chains such as oxide chains in the structure Urethane elastomers and gels or gel-like water absorbent polymer material based on them are preferred.
Examples of the bioabsorbable polymer include polymers such as polylactic acid, polylactic acid-based copolymer, polyglycolic acid, and polyglycolic acid-based copolymer.
[0013]
The water-absorbing polymer material that can be used in the present invention is not limited to those listed above, and is not dissolved in water, blood, or physiological saline, and contains NF-κB decoy efficiently. Can contain water of 100% or more of its own weight (the same amount or more as its own weight), and an effective amount of NF-κB decoy is gradually eluted from the surface through the coating layer 12 in vivo (sustained release). It is possible to use any material having the above characteristics.
Similarly, the bioabsorbable polymer is not limited to those listed above.
[0014]
As a material for the coating layer 12, the stent is not prevented from releasing the NF-κB decoy from the drug holding layer M as a stent, and by controlling the type (material) and thickness of the coating layer 12, a sustained release over a certain period of time is achieved. Is preferable because polyether-based, polycarbonate-based polyurethane, polyester, and polyether polyamide are preferred. More specifically, unlike a medical device that performs a temporary treatment or placement such as a catheter, an intravascular stent to be placed in a blood vessel is placed semipermanently in a body (implant). Polycarbonate polyurethane having high hydrolyzability is most preferable as the material of the coating layer 12 of the intravascular stent of the present invention.
[0015]
As will be described later, the water-absorbing polymer material constituting the drug holding layer M is applied to the stent base material 11 and dried. In the present invention, the stent base material 11 and the stent base material 11 are coated. It is important that the primer layer P is formed on the stent base material 11 by performing a pretreatment in advance with a primer having a high affinity for both of the water-absorbing polymer materials.
That is, the surface of the stent base material 11 is first treated with a primer having an affinity for both the constituent material (metal) of the stent base material 11 and the water-absorbing polymer material to form a primer layer P, Then, after coating with a water-absorbing polymer material to form a drug holding layer M, the stent base material 11 is immersed in an aqueous solution of NF-κB decoy for a predetermined time, and then dried to obtain a drug for NF-κB decoy. It is introduced into the holding layer M, and further forms a coating layer 12 made of a polymer material.
[0016]
In the present invention, various primers can be used as the primer, but most preferably a silane coupling agent having a hydrolyzable group and an organic functional group.
The hydrolyzable group (for example, alkoxy group) of the silane coupling agent forms a silanol group and is bonded to the metallic stent base by a covalent bond or the like, while the organic functional group (for example, epoxy group, amino group, mercapto group) is formed. Group, vinyl group, methacryloxy, etc.) is chemically bonded to a water-absorbing polymer material containing NF-κB decoy, so that the water-absorbing polymer material and the stent substrate 11 are connected via a silane coupling agent. , It is much tighter than when it is not used. Here, an epoxy-based silane coupling agent having an epoxy group as an organic functional group is particularly preferred, but an amino-based or mercapto-based silane coupling agent having the same performance can also be suitably used. .
In addition, a cyanoacrylate-based adhesive and a polyurethane-based paste resin can be appropriately used.
[0017]
As the silane coupling agent, an appropriate one having an organic functional group corresponding thereto may be selected depending on the type of the resin of the water-absorbing polymer material to be used. For example, the following can be suitably used. That is, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, N-phenyl- 3-Aminopropyltrimethoxysilane 3-chloropropyltrimethoxysilane and the like are preferably used.
[0018]
In addition, as the primer, in addition to the silane coupling agent, organic titanium-based cups such as tetrabutoxytitanate, tetrastearyl titanate, tetraisopropoxytitanate, isopropoxytitanium stearate, and titanium lactate having the same function as this. A coupling agent; an aluminum-based coupling agent such as acetoalkoxyaluminum diisopropylate; a chromium-based coupling agent;
[0019]
A primer such as a silane coupling agent having an affinity for both the constituent material (metal) of the stent base material 11 and the water-absorbing polymer material is usually water, a suitable organic solvent, or water and an organic solvent. A pretreatment is performed by dissolving this in a mixed solvent of the above and applying and drying this as a treatment solution on the substrate surface. The organic solvent is not particularly limited, but, for example, methanol, ethanol, isopropanol, a mixed solvent of the alcohol and water, benzene, toluene, xylene and the like are preferably used. As the primer concentration in the treatment solution, a relatively dilute solution is used, and is 0.05 to 2% by mass, preferably 0.1 to 1.0% by mass.
[0020]
In the present invention, by performing such a primer treatment (forming the primer layer P) on the stent base material 11 before coating the water-absorbing polymer material, the stability of the coating of the water-absorbing polymer material is improved. The resulting stent is placed in the body, and is placed in the body for a period sufficient to form an intima, for example, when buried in a blood vessel, for example, for at least one month. Even in this case, the coating layer (drug holding layer M, coating layer 12) can be stably maintained in a water (physiological saline solution, phosphate buffer solution) environment without any peeling or the like. Action and effect can be obtained. In this regard, when the water-absorbing polymer material is directly applied to the metal constituting the stent base material, depending on the conditions, the coating layer (drug holding layer M) can be formed in a water environment in several days to several weeks. It can be said that there is a significant contrast with the fact that it is extremely difficult to place a stent in the body for a long period of time as described above because peeling can occur.
[0021]
In the present invention, the primer layer P is formed on the stent substrate 11 as described above, and the stent substrate 11 is coated with a water-absorbing polymer material that absorbs at least 100% of its own weight of water. After forming the drug holding layer M on the base material 11, the stent base material 11 is immersed in an aqueous solution of NF-κB decoy for a predetermined time, and then dried to introduce the NF-κB decoy into the drug holding layer M. be able to. Further, the stent 1 having a four-layer structure including the stent base material 11 can be obtained by forming the coating layer 12 by coating the drug holding layer M of the stent base material 11 with a polymer material.
Therefore, it is possible to form the stent 1 in which the NF-κB decoy is not bonded to the polymer material, that is, the stent 1 includes the NF-κB decoy in a state of being physically mixed and dispersed in the drug holding layer M. it can. As described above, the thickness of the drug holding layer M and the coating layer 12 formed on the stent base material 11 is arbitrary depending on the concentration of the NF-κB decoy to be contained, the desired elution amount, the change with time of the elution amount, and the like. The thickness is usually 0.1 to 200 μm, preferably 0.1 to 50 μm.
[0022]
Herein, the NF-κB decoy (NF-κB decoy) defined in the present invention may be any compound that specifically antagonizes a nucleic acid binding site of NF-κB present on a chromosome, such as nucleic acid and nucleic acid. Its analogs are included. Any of the currently available products, whether of human, animal or synthetic origin, can be used.
Preferred examples of the NF-κB decoy include an oligonucleotide containing a nucleic acid sequence GGGATTTCCC (8th to 17th from the 5 ′ end of SEQ ID NO: 1 in the sequence listing) or a complement thereof, or a mutant thereof, or a molecule thereof. And the compounds contained therein. The oligonucleotide may be DNA or RNA, and may contain a modified nucleic acid and / or a pseudonucleic acid in the oligonucleotide.
[0023]
In addition, these oligonucleotides, mutants thereof, or compounds containing these in the molecule may be single-stranded or double-stranded, and may be linear or cyclic. The mutant is a nucleic acid in which a part of the above sequence is mutated, substituted, inserted, or deleted and specifically antagonizes a nucleic acid binding site to which NF-κB binds. More preferred NF-κB decoys include double-stranded oligonucleotides containing one or several of the above nucleic acid sequences or variants thereof. The oligonucleotide used in the present invention may be an oligonucleotide having a thiophosphate diester bond in which the oxygen atom of the phosphodiester bond is replaced with a sulfur atom (S-oligo), or a non-charged methyl ester having a phosphodiester bond. Oligonucleotides modified to make the oligonucleotide less susceptible to degradation in vivo, such as oligonucleotides substituted with a phosphate group, are included.
[0024]
Hereinafter, embodiments of the stent of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of the stent of the present invention, as described above. The stent 1 is composed of a stainless steel stent base material 11 as shown in a sectional view of FIG. The outer peripheral surface is sequentially covered with a primer layer P, a medicine holding layer M, and a coating layer 12. In the case of this stent 1, the surface of the stent substrate 11 is first treated with a primer having an affinity for both the metal constituting the stent substrate 11 and the water-absorbing polymer material constituting the drug holding layer M. After the primer layer P is formed, the drug holding layer M is formed by coating with a water-absorbing polymer material, and the NF-κB decoy is introduced into the drug holding layer 4. This is an example of a stent 1 having a four-layer structure including a stent base material 11 by forming a coating layer 12 by coating with a material.
[0025]
As described above, the method of forming the coating layer 12 and the drug holding layer M is to form the coating layer (coating layer 12 and the drug holding layer M) by coating the coating solution by a known method such as spraying or dipping. Is possible. Here, the number of times of spraying or dipping may be one, but the thickness of the coating layer (coating layer 12, drug holding layer M) is adjusted according to the concentration of the polymer material forming the coating layer 12 and drug holding layer M. In order to do so, a method of applying in a plurality of times is usually used.
[0026]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not construed as being limited to these examples.
[0027]
[Example 1]
(1) 1.0 g of an epoxy silane coupling agent (KBM403 (3-glycidoxypropyltrimethoxysilane): manufactured by Shin-Etsu Chemical Co., Ltd.) is dissolved in 100 ml of MeOH / water (50/50), and a 1% by mass solution is prepared. Was adjusted.
(2) Tecophilic HP-93A-100 (polyether type thermoplastic polyurethane, solution (1)) and Carbothane PC-3585A (polycarbonate type thermoplastic polyurethane, solution (2)), which are water-absorbing polymers. 2.0 g) was dissolved in 100 ml of tetrahydrofuran (THF) to prepare a 2% by mass solution (solutions (1) and (2)).
[0028]
(3) First, the solution of (1) is applied to the tubular stent 1 (stent base material 11) having the pattern shown in FIG. 1, the methanol / water is volatilized, and a pretreatment with a silane coupling agent is performed. Layer P was formed. Next, the solution (1) was applied and dried to cover the drug holding layer M, and then the stent 1 was treated with 10% NF-κB decoy [nucleic acid sequence GGGATTTCCC (8 to 17 from the 5 ′ end of SEQ ID NO: 1 in the sequence listing). Third sequence)] After immersion in an aqueous solution for 1 hour, vacuum drying was performed to introduce NF-κB decoy. Thereafter, the solution (2) was applied to form a coating layer 12 to obtain a stent sample. The film thickness was about 20 μm, and the amount of NF-κB decoy introduced was about 200 μg.
[0029]
(4) After the stent sample was expanded, it was placed in a test tube containing 700 μL of a phosphate buffer, and sampled with time at 37 ° C. with shaking at a rate of 60 times / min. (UV detector, OD 260 nm), the sustained release of NF-κB decoy was measured. FIG. 3 shows the measurement results.
[0030]
As a result, in the coating film (drug holding layer M, coating layer 12), sustained release of NF-κB decoy was confirmed for 4 weeks in a phosphate buffer environment.
[0031]
As described above, according to the results of the examples, in the stent of the present invention, the coating film (drug holding layer M, coating layer 12) is formed of NF from stent 1 coated with a water-absorbing polymer material containing NF-κB decoy. Regarding the release behavior of the -κB decoy, it was confirmed that the drug holding layer M and the coating layer 12 could be released from the stent base material 11 without release from the stent substrate 11 even for about 4 weeks. Was.
[0032]
The primer material, the drug holding layer and the coating layer, the specific material used for the stent 1, the design of the stent, and the like presented in the examples are merely examples, and are not particularly limited thereto.
[0033]
Effects of the Invention
According to the present invention, a drug holding layer M made of a water-absorbing polymer is formed, NF-κB decoy is contained and held in the drug holding layer M, and the outermost surface is coated with a polymer material having high in vivo stability. By forming the stent, it is possible to provide a stent having a sustained release property of NF-κB decoy which is stable for a long time and a stability in the body.
Further, according to the stent of the present invention, the sustained release amount and rate of the NF-κB decoy can be controlled by appropriately changing the content of the drug and the thickness of the drug holding layer M and the coating layer 12.
[Brief description of the drawings]
FIG. 1 is a schematic view of a stent of the present invention.
FIG. 2 is a partially enlarged cross-sectional view of the stent of FIG. 1;
FIG. 3 Measurement result of NF-κB decoy elution amount
[Explanation of symbols]
1 stent
11 Substrate (stent substrate)
12 Coating layer
M Drug holding layer
P primer layer

Claims (8)

A drug-releasing stent (1), wherein the surface of a stent substrate (11) is coated with a drug-retaining layer (M) made of a polymer material containing NF-κB decoy. The drug-releasing stent (1) according to claim 1, wherein the surface of the stent substrate (11) is subjected to a primer treatment, and then the primer layer (P) is coated with the drug holding layer (M). The drug releasing stent (1) according to claim 1 or 2, wherein the drug holding layer (M) is coated with a coating layer (12) made of a polymer material not containing NF-κB decoy. ). The said medicine holding | maintenance layer (M) consists of a water-absorbing polymer material which releases the said NF- (kappa) B decoy slowly in a living body, and absorbs at least 100% or more of its own weight of water. Drug release stent (1). The primer layer (P) is made of a material having a high affinity for both the stent base material (11) and the water-absorbing polymer material constituting the drug holding layer (M),
The drug releasing stent (1) according to claim 2, wherein the coating layer (12) is made of a polymer material capable of coating the drug holding layer (M). The drug-releasing stent (1) according to any one of claims 1 to 5, wherein the polymer material constituting the drug holding layer (M) is a polyether-based polyurethane. The drug-releasing stent (1) according to any one of claims 1 to 5, wherein the polymer material constituting the coating layer (12) is a polycarbonate-based polyurethane. The drug-releasing stent (1) according to claim 1, wherein the polymer material constituting the drug holding layer (M) is a bioabsorbable polymer.

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