JPH09267419A - Composite tubular composition and medical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand the utilization of a medical device of a composite compsn. capable of holding strength as a tubular compsn. at a time of use and collapsed by artifical chemical treatment after use by constituting one or more hydrogel layer and one or more hydrogel layer of thin-walled suapports different in material quality. SOLUTION: In a composite tubular compsn. 5 of one or more hydrogel layers 1, 2 and one or more thin-walled supports 3, 4, if interfaces are formed between the hydrogel layers and the outside, that is, between the outer or inner layers of the hydrogel layers by the thin-walled supports, the movement of the caught water of the hydrogel layers becomes slow and the caught water is retained with respect to the outside and the water retentivity of the hydrogel layers does not receive the effect of the outside. The ratio R/r of the outer diameter R and inner diameter (r) of the structure thereof is specified to 1.2-10. Especially, this compsn. develops function as a medical device of a conduit such as artificial digestive tract, blood vessel or urinary tract of a human being or an animal and becomes unstable in shape by artificial chemical treatment after use for a definite period to be collapsed and can be safely discharged out of the body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite tubular composition and a medical device composed of one or more hydrogel layers and a thin support made of a material different from that of the one or more hydrogel layers. More specifically, the present invention provides strength reinforcement that provides synergistic effects with support retention during use,
The present invention relates to a composite tubular composition and a medical device that can be easily post-processed.

[0002]

2. Description of the Related Art Hydrogels are widely used in everyday life or in various industrial fields, and can be cited as common cases. However, in terms of shape, tubular articles such as lumps, plates, films, spheres and yarns are scarce. Needless to say, a wide variety of various articles are known as tubular articles, and even in the case of multiple tubes, their structures, shapes, and combinations are various.

[0003] The lack of tubular articles in hydrogels is primarily due to the cumbersome handling of the hydrogel material or raw material having the appropriate moisture content to make it tubular. In addition, many hydrogels have been considered to have inferior processing characteristics in adhesion / bonding, mechanical processing such as bending and stretching, and other so-called post-processing regardless of the water content. In addition, hydrogel itself is considered soft in nature, and there is a preconception that it is impossible to use it in industrial fields. Still, it has been put to practical use without any abnormality in some industrial fields such as the food industry, and in the medical field, it is used for dental impression agents, wound dressing materials, bone reinforcing materials, etc. It is known that the addition of additives and reinforcing agents actually dispels such preconceptions, and adaptation to new industrial fields.

[0004] The tubular composition is used as a medical device and as a stent for digestive tracts, blood vessels and ureters of humans and animals, such as polyvinyl chloride, nylon,
Most of them are made of plastics such as polyurethane and silicone rubber, or materials such as metals. After use, they are removed invasively or remain in the body,
There are problems such as complications. Also, recently, biodegradable plastics such as polyester have been used, but they may decompose during use to lose their strength, block the lumen, and may not function as a medical device. .

On the other hand, since the hydrogel itself has other useful properties, it is hoped that its application will be expanded, but the above-mentioned measures and the like still limit the utilization of the hydrogel to the industrial field. Absent. In addition, tubular articles have properties not found in other materials, such as water retention and flexibility, which are useful properties of hydrogels, as well as many configurations that can be easily treated as waste even if they are disposable after use. In fact, although there is a particularly strong demand for the improvement of the characteristics desired for the expansion of the industrial field in which it is used, the fact is that the improvement does not reach a level higher than that at the known stage.

However, a medical device using these gels, that is, containing an ionically crosslinkable polymer and devised so that the polymer undergoes triggered disintegration (Japanese Patent Laid-Open No. 7-163655) is disclosed. Proposed.
When this gel is used as a medical device for maintaining a lumen, the gel does not have sufficient strength for maintaining a lumen, and, for example, an alkaline component in a living body penetrates into the gel and the gel ages. However, it does not function as a medical device.

After that, a medical device (for example, Japanese Unexamined Patent Publication No. 8-80343) using a gel having improved mechanical performance, that is, strength by lowering the water content of the gel has been proposed. . Similar to the above, this gel also has sufficient initial strength to maintain the lumen when used as a medical device to maintain the lumen, but thereafter, the gel balances the water content in vivo. The gel swells in order to keep it at the same time, and, for example, an alkaline component in the living body permeates the gel, the gel spontaneously disintegrates with time, and it becomes impossible to maintain the lumen, and it does not function as a medical device.

[0008]

SUMMARY OF THE INVENTION The present invention is to provide a composite tubular composition which successfully and easily solves the above-mentioned problems and has the above-mentioned desired properties. . When used, it is possible to maintain strength as a tubular composition, and after use, by artificial chemical treatment, a tubular composition that is easy to treat such that the shape gradually becomes indefinite and collapses is newly added to various industrial fields. Especially, it is intended to expand the use as a medical device in the medical field.

[0009]

[Means for Solving the Problems] When the hydrogel has a certain form, trapped water is incorporated therein. The captured water may exchange free water outside the system,
In some cases, they remain closed. Many tubular objects are used in different atmospheres by separating the inner and outer regions by utilizing the side surface. Therefore, the water content of the trapped water tends to be kept constant inside the hydrogel, but the fluid or fluid encountered on one side is, for example, a liquid containing a surfactant with good permeability or a high degree of permeability. If it is a dried gas, the water content of the trapped water will change drastically, causing a significant dimensional change and composition change in the tube, which makes it unusable for practical use.

The present invention comprises one or more hydrogel layers and a thin-walled support made of a different material from the one or more hydrogel layers in order to prevent the above-mentioned drawbacks caused in the tubular body due to the hydrogel itself. Is a composite tubular composition. Further, in the case of comprising two or more hydrogel layers, at least one layer may have a layer in which the liquid content of the hydrogel is dehydrated to dryness, and the maximum difference in water content of the hydrogel layer is within 10 times. The composite tubular composition is characterized in that the hydrogel layer and the thin support are laminated and formed, or that the thin support is formed by laminating two or more layers of different materials. The hydrogel layer is a polysaccharide or a derivative thereof in which hexose or a hexose substitution product is bonded, and alginic acid, galactomannan, glucomannan, xanthan gum, pectic acid, locust bean gum, guar gum, and salts thereof or K-carrageenan, shran gum, and those thereof. A compound, an intermixture, cross-linked by at least one cation in calcium, barium, strontium, magnesium, iron and chemically by sodium bicarbonate, sodium citrate, sodium gluconate, and inorganic phosphate. It is a composite tubular composition characterized in that its shape becomes indefinite and disintegrates by treatment.

The thin-walled support is composed of cellulose or a derivative thereof, and at least one layer is selected from the group consisting of hydroxypropylcellulose, pyridoxypropylmethylcellulose phthalate, pyridoxypropylmethylcellulose acetate succinate, carboxymethylethylcellulose and cellulose acetate phthalate. A composite tubular composition characterized in that it is a cellulose under alkali infiltration, or a cellulose or a derivative thereof containing 0.3% or more of a binder that is infiltrated under an alkali. Further, the composite tubular composition is characterized in that the ratio of the total thickness of the hydrogel layer to the total thickness of the thin support is 1: 0.06 to 1: 0.8. Further, the size of the composite tubular composition has a structure characterized in that the ratio of the outer diameter (R) to the inner diameter (r) is specified, and folds are provided on the inner surface and / or the outer surface. A medical device characterized in that the composite tubular composition is used as a stent in at least one of the digestive tract, blood vessel and ureter of humans and animals.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. 1A and 1B are views showing an embodiment of the composite tubular composition according to the present invention, wherein FIG. 1A is an external view and FIG. 1B is a sectional view of FIG. FIG. 2 is an external view showing another embodiment. FIG. 3 is a schematic view showing a usage state used as a medical device.

The present invention will be described in detail below. In a composite tubular composition comprising one or more hydrogel layers and one or more thin-walled supports, a multi-layer hydrogel layer can give a hydrogel tubular article which does not change trapped water from the outside and has little change. As shown in FIG. 1, in particular, when an interface is formed between the hydrogel layer and the outside world, that is, the outer or inner layer of the hydrogel with a thin-walled support, the movement of the trapped water of the hydrogel becomes slow, and the trapped water is protected against the outside world. Therefore, the water retention rate of the hydrogel is less likely to be affected by the external environment. Also, by inserting a thin support between the hydrogel layers, a hydrogel tubular product with less change can be obtained. Here, when the hydrogel layer and the thin-walled support are sequentially laminated and formed, the hydrogel layer and the thin-walled support are more closely adhered to each other, so that the gel is less susceptible to the external environment and a hydrogel tubular product with less change can be obtained. You can

Further, if at least one liquid content of the hydrogel layer is dehydrated and dried to dryness, it will not be decomposed during use and the strength will not be maintained and the lumen will not be clogged. It was found that the strength can be maintained and the effect is very effective if the water content is within 1/10 times that of the ordinary gel. If the water content is less than 1/10, the dried gel itself becomes very brittle, and even if a thin support is inserted between the hydrogels, the trapped water of the gel will migrate, so that the water content of the gel The rate changes and it cannot be used.

Further, since it is a tubular body, it is necessary to keep its inner side surface cross-sectional area to the maximum. Therefore, the thickness of the thin-walled support is the same as that of the hydrogel layer in order to maintain strength. Becomes important. The total ratio of the thickness of the hydrogel layer and the thickness of the thin support is 1: 0.
It was found that a desired tubular body could be handled when the ratio was from 06 to 1: 0.8. If this ratio is greater than 1: 0.8, the reinforcing effect is excellent, but the support becomes thick and lacks the flexibility, which is the effect with the hydrogel layer. On the other hand, if the ratio is less than 1: 0.06, the thickness of the support will be too short, and the support will be weakened rather than being used as a support, which makes the use of the hydrogel layer and the composite tubular composition meaningless.

The composite tubular composition according to the present invention may have any shape as long as it has a tubular structure as shown in FIGS. The structure has a ratio R / r of the outer diameter (R) to the inner diameter (r) of 1.2 to 1.
Specified as 0. When the R / r ratio is less than 1.2, the composite tubular composition has a small wall thickness and cannot maintain a tubular shape. On the other hand, when R / r exceeds 10, it can be said that it is rather bulky or rod-shaped, and cannot be called a tubular structure.

Further, one of the present inventions is shown in FIG.
As in (4), it is a composite tubular composition having folds on the outer surface and / or the inner surface. Although the folds are formed continuously on the outer surface and / or the inner surface, they may be discontinuous in the form of protrusions or islands. Such folds are very useful because they can give the tubular shaping composition a unique feel, increase the surface area, and impart strength.

The hydrogel layer contains, as an essential component, a substance which is a polysaccharide or a derivative thereof in which hexose or a hexose substitution product is bound. Such substances are abundant in nature,
In addition, it easily forms hydrogels and is flexible, non-irritating, tasteless, and odorless when used for a specific purpose, so that foods, cosmetics, medicine, tissue culture and bioreactors, microbial immobilization, medical devices, etc. It is effectively used for the member. The above-mentioned substances forming a hydrogel are alginic acid, galactomannan, glucomannan, xanthan gum, locust bean gum, guar gum, pectic acid and salts thereof, or K-carrageenan, shran gum and their compounds, and an intermixture. The hydrogel layer formed by these has a water content of 5 to 98%, and
Calcium, barium, strontium, magnesium, by crosslinking polyvalent cations such as iron, a method of forming a hydrogel is preferred, depending on the intended use,
It is generated by a known method.

Further, the hydrogel layer can retain its shape as a tubular composition and can be used, but it is a structure that can be easily treated after use, such as sodium hydrogen carbonate, sodium citrate, sodium gluconate, and inorganic. It can be said that an important feature is that a chemical reagent that acts by immersing in hydrogel cross-linking ions such as phosphate and that replaces the cross-linking ions causes the shape to become indeterminate and collapse.

In the present invention, the hydrogel layer and the thin-walled support must be made of different materials from the above-mentioned substance forming the hydrogel layer. This is because, if the composition of this thin support is the same as that of the hydrogel, movement such as permeation of external free water and leaching of trapped water is likely to occur, and the original support cannot serve. That is, the support must provide a reasonable barrier effect to prevent such water migration.
Moreover, if the shielding is effective only during use and can be easily treated after use, it is advantageous in handling waste.
In consideration of such circumstances, the composition of the support is mainly composed of cellulose or its derivative. Of the cellulose or its derivatives, a substance that is insoluble in water is naturally effective for blocking water movement. Cellulose is crystalline cellulose, and cellulose derivatives are ethyl cellulose, cellulose acetate, cellulose phthalate, carboxymethyl ethyl cellulose, carboxy. Methyl cellulose calcium, hydroxypropyl cellulose, hydroxypropyl methyl cellulose phthalate, hydroxypropyl methyl cellulose acetate succinate, carboxymethyl ethyl cellulose, cellulose acetate phthalate and the like can be used, and the support is used alone or in any combination thereof.

Further, as described above, what is important in the present invention is that a thin support is laminated with two or more different materials with the aim of providing a support that should be used as a shield to prevent movement of water and can be easily treated after use. Cellulose that is infiltrated under alkaline at least one of these layers, for example, hydroxypropyl cellulose, hydroxypropylmethyl cellulose phthalate, hydroxypropyl methyl cellulose acetate succinate, carboxymethyl ethyl cellulose, cellulose selected from the group of cellulose acetate phthalates is selected under alkaline. When constructed by laminating to non-infiltrated cellulose, after use, upon infiltration under alkaline, the layer will dissolve, leaving only the other uninfiltrated layers under alkaline. At this time, of the thin-walled support, when the layer which is not infiltrated under alkali is made thin, when the thin-walled support is infiltrated under alkali, the layer infiltrated under alkali dissolves and the layer not infiltrated under alkali has a shape. It cannot be held and the shape collapses.
This is an important feature.

Further, similarly to the above, the cellulose which is not infiltrated under alkali can be made to have a constitution in which it can be easily treated after use by including 0.3% or more of a binder in the cellulose or its derivative. it can. If it is 0.3% or less, the effect of infiltration under alkali becomes low, and it becomes impossible to easily treat after use. As such a binder, a resin component that is mainly heat-curable can be used. For example, resole type phenol-formaldehyde condensate, melamine
Formaldehyde condensate, urea-formaldehyde condensate, etc., and natural resins such as cashew, shellac, rosin, terpene, tannin, ligulin, etc., as well as methylcellulose, hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose acetate succinate, hydroxypropylmethylcellulose, carboxy. So-called disintegrants such as methyl cellulose and its sodium salt are used alone or in any combination.

Alkaline infiltration does not require the use of powerful agents. In recent years, such drugs should be avoided because of strict regulations on working environment and discharge of wastewater. Weak base salts of weak acids may be used to meet such regulations and to perform infiltration under alkali. Such salts readily hydrolyze to form any alkali in aqueous solution.

In order to promote infiltration under alkaline,
A poorly water-resistant plasticizer such as triethyl citrate may be added to this support, or a poorly water-resistant and hydrophilic substance such as an oxidation product of sucrose, glucose, fructose, maltose, lactose or sorbitol sugar may be added. A substance may be added.

Further, a reinforcing material is added for temporarily reinforcing the support, for example, embedding of fibers, incorporation of a contrast agent for imparting a contrast property, embedding of a contrasting thread, fluorescent substances, coloring agents, and light-impermeable materials. It is also possible to add a substance such as a permeating agent that does not affect the support itself.

The composition according to the invention is non-irritating, tasteless,
It is odorless, water-retaining, flexible, and easy to cut and work, so its usage is expanded further than conventional hydrogels alone, and it is used for foods, cosmetics, pharmaceuticals, tissue culture, bioreactors, immobilization of microorganisms, medical devices. It is useful not only for sewage and its members, but also for temporary sewage pipes and joints, waste oil treatment equipment, product models, fishing gear, aquaculture materials, fertilizing pipes in soil, and seedling raising pipes.

In particular, the composite tubular composition according to the invention is shown in FIG.
As shown in Fig. 2, used as a medical device for human, animal digestive tract, blood vessels, ureteral conduits such as biliary tract, artificial esophagus, intestinal feeding tract, anastomotic stent, intravascular stent, ureteral stent Is useful for. If it is necessary to remove using a conventional plastic or metal tubular composition, it must be removed invasively, which is costly, time consuming, laborious for a doctor and patient's discomfort. Even when a tubular composition made of biodegradable plastic is used, it has the problem that it decomposes during use and its strength cannot be maintained and the lumen is blocked, making it difficult to exert its function for a certain period of time. there were. When used, it exerts its function as a medical device that retains a lumen as a tubular composition, and after being used for a certain period of time, due to artificial chemical treatment, its shape becomes indefinite and collapses, and it can be safely excreted from the body. You can

[0028]

EXAMPLES Examples will be described below. [Example 1] Triethyl citrate (6 g), crystalline cellulose (12 g) and hydroxypropyl cellulose (1.6 g) were added to ethanol (180 ml), and the mixture was uniformly stirred at room temperature and left overnight for aging. Dip a rod-shaped mold in this liquid and lift it up 33
It was dried at 3K (60 ° C) for 1 hour. The immersion and drying were repeated 2 to 5 times. After that, the composition was removed from the mold to obtain a tubular composition having a uniform thickness. The details are shown in Table 1.

Example 2 In Example 1, ethyl cellulose was used instead of crystalline cellulose, and purified shellac was used instead of hydroxypropyl cellulose. Furthermore, after dipping and drying twice in Example 1, a silk thread was wound, and further dipping and drying was repeated 3 times to embed the thread. Then, it was removed from the mold to obtain a tubular composition having a uniform thickness. The details are shown in Table 1.

[0030]

[Table 1]

Example 3 To 157 ml of ethanol were added 3.4 g of triethyl citrate and 13.7 g of hydroxypropylmethyl cellulose acetate succinate, and the mixture was uniformly stirred at room temperature and aged overnight. A rod-shaped mold was dipped in this solution, lifted, and dried at 338K (65 ° C) for 1 hour. The immersion and drying were repeated 2 to 5 times. After that, they were removed from the mold to obtain tubular compositions having a uniform thickness, respectively.
The details are shown in Table 2.

[0032]

[Table 2]

[Example 4] To 157 ml of acetone, 3.4 g of triethyl citrate and 13.7 g of ethyl cellulose were added, and the mixture was uniformly stirred at room temperature and aged overnight (A).
liquid). Triethyl citrate 3.4 in 157 ml of acetone
g and 13.7 g of hydroxypropylmethylcellulose acetate succinate were added, and the mixture was uniformly stirred at room temperature and left to stand overnight for aging (Liquid B). First, the rod-shaped mold was immersed in the liquid A, lifted, and dried at room temperature 298K (20 ° C) for 1 hour. The immersion and drying were repeated 2 to 5 times. Next, the rod-shaped die is immersed in the liquid B and lifted up, and the room temperature is 298K (20
(° C) for 1 hour. The immersion and drying were repeated 2 to 5 times. Then, it was removed from the mold and each tubular composition having a uniform thickness was obtained. The breakdown is shown in Table 3.

[0034]

[Table 3]

Example 5 5 g of 2 g of glucomannan powder was added.
0 ml of water was added and stirred to form a swollen body. 0.2 g
Immediately after suspending the calcium hydroxide in 10 ml of water, this was kneaded well with the swollen body and pressed into a mold. The mold was placed in a steamer and heated for 40 minutes, then removed from the mold to obtain a tubular composition having a uniform thickness. The breakdown is shown in Table 4.

[0036]

[Table 4]

Example 6 0.02 g of potassium sorbate was added to 120 ml of water and then 4 g of sodium alginate was added and stirred to form a swollen body. This was pressed into a mold and 14 ml of a 15% calcium chloride solution was added to cure it, and the mold was taken out. A tubular composition of uniform thickness was obtained. The breakdown is shown in Table 5.

[0038]

[Table 5]

[Example 7] 0.02 g of potassium sorbate was added to 120 ml of water, and then 4 g of sodium alginate was added and stirred to form a swollen body. This was pressed into a mold and 14 ml of 15% calcium chloride solution was added to cure. The gel was put in a drier, the gel liquid was dehydrated to dryness, and the water absorption was adjusted to 10%, and then taken out from the mold to obtain a composite tubular composition having a uniform thickness. Breakdown is Table 6
Shown in

[0040]

[Table 6]

Example 8 4 g of sodium alginate was added to 120 ml of water and stirred to form a swollen body (solution C). This was pressed into a mold and 14 ml of 15% calcium chloride solution was added to cure. The gel was placed in a drier and the liquid content of the gel was dehydrated and dried to dryness so that the water absorption rate was 10%. Then, the dried gel was immersed in the liquid A (cellulose liquid) of Example 4 and lifted up at room temperature of 298 K (20
(° C) for 1 hour. The immersion and drying were repeated 1 to 5 times. Then, the dried gel with the cellulose membrane was fitted into a mold, and the liquid C was pressed into the mold, 14 ml of a 15% calcium chloride solution was added to cure the liquid C, and the liquid was taken out from the mold. A composite tubular composition of uniform thickness was obtained. The breakdown is shown in Table 7.

[0042]

[Table 7]

[Example 9] A rod-shaped mold was immersed in the liquid A of Example 4 and lifted up, and dried at room temperature of 298K (20 ° C) for 1 hour. The soaking and drying were repeated 1 to 5 times. Next, the rod-shaped mold was dipped in the liquid B, lifted, and dried at room temperature 298K (20 ° C) for 1 hour. The soaking and drying were repeated 1 to 5 times. The rod-shaped mold with the cellulose membrane was fitted into the mold, and the dried gel product, the cellulose and the gel were successively laminated in the same manner as in the procedure of Example 8 and, after the completion, the mold was taken out from the mold and made into a uniform thickness. A composite tubular composition was obtained. The breakdown is shown in Table 8.

[0044]

[Table 8]

[Combination example] Table 9 shows measurement test pieces prepared by the following combinations.

[Table 9]

[Test Example] The test piece according to the above combination example was cut into a length of 10 mm, a load cell of 1 kg weight was used so that a load was applied to the side surface, and 1/30 mm · s -1 (2 mm
The compressive strength of compressing the test piece at a speed of (/ min) was measured.
The load (gram weight) was read as the end point when the test piece was distorted to half the inner diameter (10 mm), that is, 5 mm, and the following results were obtained.

[0047]

[Table 10]

[0048]

As is clear from the comparison of the above test examples with the comparative examples, the composite tubular composition produced according to the present invention maintains the strength of the support during use as compared with the case where the composite tubular composition is not formed. At the same time, the effect of the composition is that it is infiltrated under alkali by the action of the composition and rapidly progresses when there is self-disintegration. Here, when the hydrogel layer is composed of two or more layers, at least one layer of the hydrogel is dehydrated to dryness, and the maximum difference in water content between the hydrogel layers is 10%.
The compressive strength of the composite tubular composition can be increased by having a layer that is within double. In addition, by preparing a composite tubular composition from a thin support and a hydrogel layer, it is possible to save the trouble of conventionally blending various additives and reinforcing agents into the hydrogel layer, and it is preferable to use these substances for the hydrogel layer. Naturally, other property changes such as turbidity and coloring, partial deposition, etc. are naturally avoided, and the original properties of the hydrogel layer can be exerted as they are. Furthermore, by laminating and molding the hydrogel and the thin-walled support, these layers are brought into closer contact with each other, so that the infiltration rate of the gel under alkali becomes slower and the infiltration rate under alkali can be controlled. When this composite tubular composition is used as a stent in the digestive tract, blood vessel, or ureter of humans or animals, it retains its lumen as a tubular composition during use and exerts a function for a certain period of time, and then undergoes artificial chemical treatment. Thus, it is possible to provide a medical device in which the shape is indefinite, collapses, and can be safely excreted from the body.

[Brief description of drawings]

FIG. 1 (a) is a view showing an example of the composite tubular composition according to the present invention. (B) It is sectional drawing which shows one Example of the composite tubular composition by this invention.

FIG. 2 is a view showing another example of the composite tubular composition according to the present invention.

FIG. 3 is a schematic view showing a use state in which the composite tubular composition according to the present invention is used as a medical device.

[Explanation of Codes] Hydrogel layer (1) 2. Hydrogel layer (2) 3. Thin support (1) 4. Thin support (2) 5. Composite tubular composition 6. Esophageal tube 7. stomach

Claims (13)

[Claims] 1. A composite tubular composition comprising one or more hydrogel layers and a thin-walled support made of a different material from the one or more hydrogel layers. 2. A layer comprising two or more hydrogel layers, wherein at least one layer has a layer in which the liquid content of the hydrogel is dehydrated to dryness and the maximum difference in water content of the hydrogel layer is within 10 times. A composite tubular composition. 3. The composite tubular composition according to claim 1, which is formed by laminating a hydrogel and a thin support. 4. The composite tubular composition according to claim 1, 2 or 3, wherein the thin supports are laminated in two or more layers, and at least one layer is made of a material different from that of the other layers. 5. The composite tubular composition according to claim 1, 2, 3 or 4, wherein the hydrogel layer is a polysaccharide or a derivative thereof in which hexose or a hexose substitution product is bonded. 6. The hydrogel layer comprises alginic acid, galactomannan, glucomannan, xanthan gum, pectic acid,
Locust bean gum, guar gum and its salts, or
K-carrageenan, shrangum and their compounds,
6. An intermixture which is cross-linked by at least one cation in calcium, barium, strontium, magnesium, iron and the thin support comprises cellulose or a derivative thereof. A composite tubular composition. 7. The hydrogel layer is deformed by a chemical treatment with sodium hydrogen carbonate, sodium citrate, sodium gluconate, and an inorganic phosphate to have an irregular shape and disintegrate. 7. The composite tubular composition according to 6. 8. At least one layer of the thin-walled support is an alkali-infiltrated cellulose selected from the group consisting of hydroxypropyl cellulose, pyridoxypropylmethylcellulose phthalate, pyridoxypropylmethylcellulose acetate succinate, carboxymethylethylcellulose, cellulose acetate phthalate. Claims 1, 2, 3,
The composite tubular composition according to 4, 5, 6 or 7. 9. The method according to claim 1, wherein at least one layer of the thin support is cellulose or a derivative thereof containing 0.3% or more of a binder that can be infiltrated under alkali. Composite tubular composition. 10. The ratio of the total thickness of the hydrogel layer to the total thickness of the thin support is 1: 0.06 to 1: 0.8, 1, 2, 3, 4, 5, The composite tubular composition according to 6, 7, 8 or 9. 11. A ratio R / r of an outer diameter (R) and an inner diameter (r).
Is 1.2 to 10, Claims 1, 2, 3, 4, 5, 6,
The composite tubular composition according to 7, 8, 9 or 10. 12. The outer surface and / or inner surface having folds according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9,
The composite tubular composition according to 10 or 11. 13. The method of claim 1, 2, 3, 4, 5, 6, 7,
A medical device, characterized in that the composite tubular composition according to 8, 9, 10, 11 or 12 is used as a stent in at least one of human, animal digestive tract, blood vessel, and ureter.