Degradable ureteral stent and preparation method therefor

Abstract

Provided in the present invention are a degradable ureteral stent and a preparation method therefor, which degradable ureteral stent is of a hollow circular tube structure (1), wherein a fixing structure (2) for preventing sliding is disposed on two ends or one end of the degradable ureteral stent, the tube wall of stent is also provided with a plurality of penetrating drainage side holes (3), and the material used for the stent is a composite material formed by at least a glycolide-ε-caprolactone copolymer, an ethylene oxide polymer and a medical developer. In the glycolide-ε-caprolactone copolymer, the weight percentage content of glycolide is 51-58%, such that the copolymer has appropriate mechanical strength and hardness, and the copolymer gradually becomes soft as the time of degradation increases; moreover, a certain proportion of the ethylene oxide polymer is added, and after the degradation thereof, the polymer has a lower modulus at a definite elongation and is softer and smoother, such that degraded fragments are not prone to becoming stuck and are easier to excrete from the body, and is thus more suitable for preparing a degradable ureter.

Description

A degradable ureteral stent and its preparation method Technical Field

[0001] The present invention belongs to the field of biomedical materials and medical devices, and particularly relates to a degradable ureteral stent and a preparation method thereof. Background Art

[0002] Ureteral stents are widely used in urological surgery and are suitable for upper urinary tract surgery, lithotripsy, dilation of ureteral stenosis and other treatment processes. After being implanted in the ureter, they can play an important role in draining urine and preventing ureteral stenosis.

[0003] Existing ureteral stents in clinical use are non-degradable and made of soft polyurethane elastomer or silicone rubber. Polyurethane stents are relatively rigid and easier to place, while silicone rubber stents are relatively soft and offer slightly poorer placement performance. After placement, these two types of non-degradable ureteral stents maintain their rigidity. Once they have completed their drainage function, they must be removed through an invasive procedure, typically cystoscopically. This can be extremely painful for the patient and can lead to complications such as infection. Therefore, the research and development of degradable ureteral stents holds significant clinical value.

[0004] The duration of ureteral stent drainage varies depending on clinical needs. Short-term temporary drainage typically lasts for one to two weeks, such as in cases of mild ureteral injury, simple stones, or pre-placed stents. Common temporary drainage procedures typically last three to six weeks, requiring different biodegradable materials. However, the fundamental requirement for stents is that they possess the mechanical properties of elastic materials and that broken fragments are expelled quickly and completely from the body. Failure to do so increases the risk of complications.

[0005] International literature reports (Lumiaho, J., J. Endourol. 1999, 13, 107–112; Laaksovirta, S. Laurila M. et al. Jurol. 167:1527, 2002) use biodegradable polylactide (PLLA) or lactide / glycolide copolymer (PLGA) as raw materials for ureteral stents. However, PLLA and PLGA are plastics and lack flexibility. Degraded fragments are hard, making them highly likely to become embedded or stuck in the renal pelvis, leading to various complications.

[0006] Chinese patents CN1672739A and CN112516390A disclose a biodegradable ureteral stent, involving a glycolide-ε-caprolactone copolymer material. Within a certain range of composition ratios, this copolymer, composed of a soft-chain monomer (ε-caprolactone) and a hard-chain monomer (glycolide), tends to become increasingly rigid as it degrades in water. This is because the hard-chain structures in the material, such as the glycolide segments, tend to crystallize during degradation, making it prone to becoming stuck or retained in areas such as the renal pelvis.

[0007] In summary, the materials obtained by existing technologies cannot achieve the goal of having both mechanical properties like silicone rubber and polyurethane elastic materials and preventing degraded fragments from getting stuck and being retained in places such as the renal pelvis. This is still the key point restricting the research progress in this field and the main reason why there are currently no commercial degradable ureteral stents on the market.

[0008] Summary of the Invention

[0009] In view of the above deficiencies in the prior art, the present invention provides a degradable ureteral stent having the mechanical strength of elastic material, a high initial hardness (or modulus), and is convenient for catheterization. As it degrades in urine, it gradually becomes softer and easier to be excreted from the body.

[0010] The technical solutions of the present invention are as follows:

[0011] A degradable ureteral stent is made of a composite material. The composite material comprises at least a glycolide-ε-caprolactone copolymer, an ethylene oxide polymer, and barium sulfate, which are blended and formed in the following relative amounts:

[0012] 1) glycolide-ε-caprolactone copolymer, with a weight percentage content of 47%-80%;

[0013] 2) Ethylene oxide polymer, with a weight percentage content of 2%-8%;

[0014] 3) barium sulfate, with a weight percentage of 18% to 45%;

[0015] The glycolide-ε-caprolactone copolymer has a glycolide content of 51%-58% by weight and an ε-caprolactone content of 42%-49% by weight.

[0016] The ureteral stent of the present invention achieves the above purpose by using a composite material formed by blending a degradable glycolide-ε-caprolactone copolymer, an ethylene oxide polymer, and barium sulfate.

[0017] The present invention and related research have found that when the stent tube is too stiff, degraded fragments tend to become stuck in the renal pelvis. Therefore, the hardness of the substrate is a key factor. Conventional biodegradable elastic materials, such as glycolide-ε-caprolactone copolymer and L-lactide / ε-caprolactone copolymer, often become increasingly hard during degradation, making it difficult for degraded fragments or segments to pass through ureteral strictures. However, the present invention has discovered that within an appropriate comonomer ratio and using an appropriate polymerization process, glycolide-ε-caprolactone copolymer gradually softens upon degradation in water or urine, resulting in an elastic material with good mechanical strength and suitable hardness. This appropriate comonomer ratio range is 51%-58% by weight of glycolide. When the glycolide content exceeds 58%, the copolymer exhibits a significant tendency to crystallize and hardens during degradation. When the glycolide content is below 51%, the copolymer exhibits poor mechanical properties and is too soft.

[0018] The present invention also found that adding a certain amount of ethylene oxide polymer, such as polyethylene glycol or polyoxyethylene, to the above-mentioned glycolide-ε-caprolactone copolymer material can further promote the composite material to gradually become softer during degradation, with a smoother surface, easier disintegration and fragmentation, which is beneficial to the discharge of broken fragments of the tubular stent.

[0019] The barium sulfate used in the degradable ureteral stent of the present invention is a commonly used medical developer, has good compatibility with the above materials, and has a certain reinforcing effect.

[0020] In the degradable ureteral stent of the present invention, the glycolide-ε-caprolactone copolymer has an intrinsic viscosity of 1.30-3.00 dl / g when measured at 25±1°C in hexafluoroisopropanol at a concentration of 0.1 g / dl. The greater the viscosity, the longer the degradation duration. Therefore, the drainage time of the stent tube can be regulated by the intrinsic viscosity.

[0021] In the degradable ureteral stent of the present invention, the ethylene oxide polymer is polyethylene glycol, polyethylene glycol monomethyl ether, polyethylene glycol dimethyl ether, or polyoxyethylene.

[0022] Preferably, the weight ratio of the ethylene oxide polymer in the composite material is 2%-8%. The higher the content of the ethylene oxide polymer, the softer the composite material is and the faster it degrades.

[0023] In the degradable ureteral stent of the present invention, the molecular weight of the polyethylene glycol, polyethylene glycol monomethyl ether, polyethylene glycol dimethyl ether and polyoxyethylene is 1000Da-1000000Da.

[0024] Preferably, in the degradable ureteral stent of the present invention, the ethylene oxide polymer is polyethylene glycol, polyethylene glycol monomethyl ether, or polyethylene glycol dimethyl ether, and has a molecular weight of 5000Da-40000Da.

[0025] Preferably, in the degradable ureteral stent of the present invention, the ethylene oxide polymer is polyethylene oxide, and the molecular weight is 50,000 Da-400,000 Da.

[0026] In the degradable ureteral stent of the present invention, barium sulfate can be replaced by other medical developers, including bismuth subcarbonate and metal developers, and the developers used can be one or more.

[0027] The degradable ureteral stent of the present invention, the glycolide-ε-caprolactone copolymer is prepared by the following method:

[0028] Under nitrogen protection, 0.005%-0.1% by mass of stannous octoate, ε-caprolactone and glycolide are added successively to a reactor with a stirrer. Under stirring, the temperature of the reaction system is raised from room temperature to 165°C-200°C within 30 minutes, maintained for 18-30 hours, and then maintained under vacuum for 1-4 hours. The copolymer in the reactor is transferred out, further crushed, and placed in a vacuum oven at 50°C-110°C for vacuum drying for 8-24 hours.

[0029] The degradable ureteral stent of the present invention is a hollow circular tubular structure (1) with a fixing structure (2) at both ends or one end to prevent sliding. The fixing structure is preferably in the shape of a circular tubular coil. There are also several drainage side holes (3) penetrating the tube wall, and the tube diameter is 1.0-4.0 mm.

[0030] The degradable ureteral stent of the present invention is prepared by melt extrusion, and the specific method is as follows:

[0031] A certain amount of glycolide-ε-caprolactone copolymer, ethylene oxide polymer, and medical developer are uniformly mixed and then extruded through an extruder at 120°C-160°C to obtain a degradable elastic tube. The tube is bent at 50°C-80°C to form a fixed structure with a circle at one or both ends, and then punched to obtain the degradable ureteral stent.

[0032] The modulus of the degradable ureteral stent of the present invention at initial 100% deformation is 2MPa-10MPa, and the modulus at 100% deformation after degradation is no greater than the initial value; the initial Shore hardness A of the material used is 70-95, and the Shore hardness A after degradation is no greater than the initial value.

[0033] The degradable ureteral stent of the present invention can be conventionally added with various additives during melt extrusion of the tube to achieve different purposes, including but not limited to plasticizers, lubricants, dyes, antioxidants, anti-hydrolysis agents, melt thickeners, chain extenders, reinforcing agents, and polymer modifiers. These additives help improve the processing performance, degradation performance, surface properties, and mechanical properties of the stent.

[0034] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0035] The present invention controls the content of glycolide monomer in the glycolide-ε-caprolactone copolymer so that the copolymer has suitable mechanical strength and hardness, and gradually becomes softer as the degradation time increases; at the same time, a certain proportion of ethylene oxide polymer is added, so that after degradation, the modulus of elongation is lower and the copolymer is softer and smoother, and therefore is more suitable for preparing degradable ureters. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 shows the imaging observation of the excretion of the degradable ureteral stent of the present invention in an animal body. In Figure 1, (A) is an X-ray film during implantation, (B) is an X-ray film during rupture, (C) is an X-ray film during excretion into the bladder, and (D) is the excreted degraded fragments.

[0037] FIG2 is a schematic diagram of a degradable ureteral stent according to the present invention. DETAILED DESCRIPTION

[0038] Example 1 Preparation of glycolide-ε-caprolactone copolymer 1

[0039] 0.04% stannous octoate catalyst, 570 g of ε-caprolactone monomer (CL) and 580 g of glycolide monomer (GA) were placed in a 3 L reactor. The system temperature was raised to 180° C. under nitrogen protection for 25 minutes. The mixture was stirred at a speed of 10-20 rpm and reacted for 25 hours. The mixture was maintained under vacuum for 2 hours. The copolymer in the reactor was transferred, further crushed, and vacuum-dried in a vacuum oven at 90° C. for 24 hours to obtain glycolide-ε-caprolactone copolymer 1 (PGC1).

[0040] pass 1 The weight percentages of glycolide and ε-caprolactone in the copolymer were determined by H NMR spectroscopy using hexafluoroisopropanol as solvent.

[0041] The above copolymer was prepared into a hexafluoroisopropanol solution with a concentration of 0.1 g / dl, and its intrinsic viscosity was measured at 25° C. using an Ubbelohde viscometer.

[0042] The copolymer was formed into a sheet with a thickness of 2 mm on a flat vulcanizer at 140° C. using a hot pressing method, and the Shore A hardness of the material was tested using a Shore durometer.

[0043] The copolymer was made into a dumbbell plate with a thickness of 2 mm using the same method as above. The tensile strength and elongation at break of the material were tested on a universal mechanical testing machine at a speed of 200 mm / min.

[0044] The in vitro degradation experiment of the material was carried out in simulated urine at 37°C, and the Shore A hardness of the material was measured regularly.

[0045] Example 2 Preparation of glycolide-ε-caprolactone copolymer 2

[0046] 0.02% stannous octoate catalyst, 540 g of ε-caprolactone monomer (CL) and 590 g of glycolide monomer (GA) were placed in a 3 L reactor. The system temperature was raised to 170° C. under nitrogen protection for 20 minutes. The mixture was stirred at a speed of 10-20 rpm and reacted for 28 hours. The mixture was maintained under vacuum for 1 hour. The copolymer in the reactor was transferred, further crushed, and vacuum-dried in a vacuum oven at 90° C. for 24 hours to obtain glycolide-ε-caprolactone copolymer 2 (PGC2).

[0047] The performance test of the above copolymer was carried out using the method described in Example 1. The test results are listed in Table 1.

[0048] Example 3 Preparation of glycolide-ε-caprolactone copolymer 3

[0049] 0.03% stannous octoate catalyst, 530 g of ε-caprolactone monomer (CL), and 600 g of glycolide monomer (GA) were placed in a 3 L reactor. The system temperature was raised to 190° C. under nitrogen protection for 30 minutes. The mixture was stirred at a speed of 10-20 rpm and reacted for 22 hours. The mixture was maintained under vacuum for 4 hours. The copolymer in the reactor was transferred, further crushed, and vacuum-dried in a 90° C. vacuum oven for 24 hours to obtain glycolide-ε-caprolactone copolymer 3 (PGC3).

[0050] The performance test of the above copolymer was carried out using the method described in Example 1. The test results are listed in Table 1.

[0051] Example 4 Preparation of glycolide-ε-caprolactone copolymer 4

[0052] 0.05% stannous octoate catalyst, 480 g of ε-caprolactone monomer (CL) and 600 g of glycolide monomer (GA) were placed in a 3 L reactor. The system temperature was raised to 195°C under nitrogen protection for 30 minutes. The mixture was stirred at a speed of 10-20 rpm and reacted for 18 hours. The mixture was maintained under vacuum for 4 hours. The copolymer in the reactor was transferred, further crushed, and vacuum-dried in a vacuum oven at 90°C for 24 hours to obtain glycolide-ε-caprolactone copolymer 4 (PGC4).

[0053] The performance test of the above copolymer was carried out using the method described in Example 1. The test results are listed in Table 1.

[0054] Example 5 Preparation of glycolide-ε-caprolactone copolymer 5

[0055] 0.01% stannous octoate catalyst, 470 g of ε-caprolactone monomer (CL) and 630 g of glycolide monomer (GA) were placed in a 3 L reactor. The system temperature was raised to 190° C. under nitrogen protection for 30 minutes. The mixture was stirred at a speed of 10-20 rpm and reacted for 20 hours. The mixture was maintained under vacuum for 2 hours. The copolymer in the reactor was transferred, further crushed, and vacuum-dried in a vacuum oven at 90° C. for 24 hours to obtain glycolide-ε-caprolactone copolymer 5 (PGC5).

[0056] The performance test of the above copolymer was carried out using the method described in Example 1. The test results are listed in Table 1.

[0057] Example 6 Preparation of glycolide-ε-caprolactone copolymer 6

[0058] 0.01% stannous octoate catalyst, 470 g of ε-caprolactone monomer (CL) and 660 g of glycolide monomer (GA) were placed in a 3 L reactor. The system temperature was raised to 184°C under nitrogen protection for 26 minutes. The mixture was stirred at a speed of 10-20 rpm and reacted for 23 hours. The mixture was maintained under vacuum for 3 hours. The copolymer in the reactor was transferred, further crushed, and vacuum-dried in a 90°C vacuum oven for 24 hours to obtain glycolide-ε-caprolactone copolymer 6 (PGC6).

[0059] The performance test of the above copolymer was carried out using the method described in Example 1. The test results are listed in Table 1.

[0060] Table 1

[0061] The above results show that the glycolide-ε-caprolactone copolymer described herein has a higher glycolide content, the greater its hardness. When the glycolide content is between 51% and 58% by weight, its Shore A hardness is comparable to that of polyurethane (75-95) and silicone rubber (50-70), making it suitable for use as a ureteral stent. Degradation results in simulated urine at 37°C show that the hardness of PGC1-PGC5 softens during degradation. PGC6, with a glycolide content greater than 58% by weight, exhibits greater hardness, which increases with degradation time. However, when the glycolide content is below 51%, its tensile strength is low.

[0062] Example 7 Preparation of Composite Material of Glycolide-ε-Caprolactone Copolymer, Polyethylene Glycol, and Barium Sulfate

[0063] 200 grams of the glycolide-ε-caprolactone copolymer (PGC) prepared above, a certain amount of polyethylene glycol 20,000 (PEG2) or polyethylene glycol 5,000 (PEG5), and medical barium sulfate (Ba) were mixed uniformly and further blended and pelletized in a twin-screw extruder at a temperature of 120°C-150°C. The resulting composite pellets were then passed through a flat-plate vulcanizer at 140°C to produce 2 mm thick composite sheets of the three materials. These sheets were then tested for tensile strength and hardness. The dynamic coefficient of friction of the composites was tested according to ASTM D1894. The results are shown in Table 2.

[0064] Table 2

[0065] The above results show that the hardness changes of the composite materials containing PEG during the degradation process in simulated urine all decrease significantly with the increase of degradation time. The higher the PEG content, the greater the decrease in hardness; the degree of hardness reduction of composite material 3 without PEG addition is smaller than that of the composite material with PEG addition; the glycolide content in the glycolide-ε-caprolactone copolymer used in composite materials 7 and composite material 8 exceeds 58% by weight, so as the degradation time prolongs, their Shore hardness A increases or changes little; the composite material with PEG addition has a smaller dynamic friction coefficient, indicating that its surface is smoother.

[0066] Example 8 Preparation of Composite Material of Glycolide-ε-Caprolactone Copolymer, Polyethylene Oxide, and Barium Sulfate

[0067] 200 g of the glycolide-ε-caprolactone copolymer (PGC) prepared above, a certain amount of polyoxyethylene (PEO, molecular weight 200,000 Da), and medical barium sulfate (Ba) were mixed uniformly and further blended and pelletized in a twin-screw extruder at an extruder temperature of 120°C-140°C. The resulting composite pellets were then passed through a flat-plate vulcanizer at 140°C to form 2 mm thick sheets for tensile strength and hardness testing. The dynamic coefficient of friction of the composite was tested according to ASTM D1894. The results are shown in Table 3.

[0068] Table 3

[0069] The hardness changes during degradation of the aforementioned composite materials of glycolide-ε-caprolactone copolymer, polyoxyethylene, and medical barium sulfate follow a similar pattern, decreasing significantly with increasing degradation time. The higher the polyoxyethylene content, the greater the decrease in hardness. However, excessive polyoxyethylene content significantly reduces strength, making it difficult to secure the material. Composite materials with polyoxyethylene additions exhibit a lower dynamic coefficient of friction, suggesting a smoother surface.

[0070] Example 9 Preparation of a Composite Material of Glycolide-ε-Caprolactone Copolymer, Polyethylene Glycol, and Bismuth Subcarbonate

[0071] 200 grams of the prepared glycolide-ε-caprolactone copolymer (PGC) were mixed with a certain amount of polyethylene glycol 20,000 (PEG2) or polyethylene glycol 5,000 (PEG5), and medical bismuth subcarbonate (Bi). The mixture was then further blended and pelletized in a twin-screw extruder at a temperature of 120°C to 140°C. The resulting composite pellets were then passed through a flat-plate vulcanizer at 140°C to produce 2 mm thick composite sheets of the three materials. These sheets were then tested for tensile strength and hardness. The dynamic coefficient of friction of the composites was tested according to ASTM D1894. The results are shown in Table 4.

[0072] Table 4

[0073] The performance and change patterns of the above-mentioned composite materials of glycolide-ε-caprolactone copolymer, polyethylene glycol, and bismuth subcarbonate are similar to those of the above-mentioned composite materials, that is, the hardness changes of the composite materials during the degradation process in simulated urine are significantly reduced with increasing degradation time. The composite materials with added PEG have a smaller dynamic friction coefficient. The above pattern is independent of the type of developer used.

[0074] Example 10 Preparation of a degradable ureteral stent

[0075] The composite material prepared in the above embodiment was extruded by an extruder at 120°C-150°C to obtain a degradable elastic tube body 1, wherein the outer diameter of the tube body 1 was 2 mm and the inner diameter was 1.1 mm. The tube body was bent at 50°C-80°C to form a fixed structure with one or both ends of the tube being a curled tubular coil 2. The tube body was then punched with holes (longitudinal pore diameter 1.0 mm) at equal distances (hole spacing 50 mm) by a punching device to form drainage holes 3. The obtained degradable ureteral stent is shown in Figure 2.

[0076] The tensile strength at break and modulus at break (tensile strength at 100% elongation, which characterizes the hardness of the material like Shore hardness) were tested on a universal mechanical testing machine at a speed of 200 mm / min. The change in modulus at break during in vitro degradation in simulated urine at 37°C was also tested. The results are shown in Table 5.

[0077] Example 11 In vivo degradation experiment of degradable ureteral stent in animals

[0078] Under general anesthesia, ureteral stents were implanted in the left and right ureters of miniature pigs using ureteroscopy. The upper tubular coil was fixed to the renal pelvis, and the lower tubular coil was fixed to the bladder. Postoperatively, X-rays were used to observe the ureteral stents at different time points for slippage, fracture, and expulsion. The modulus of elasticity of the stents at different time points was measured using a universal mechanical tester to characterize changes in their hardness and softness. The results are shown in Table 5.

[0079] Table 5

[0080] The above results show that ureteral stents 1, 2, and 3 contain ethylene oxide polymer, while ureteral stents 4 and 5 do not. All degradable stents were able to be completely excreted from the animal's urinary system, with the breakage time depending on factors such as the molecular weight of the material, the ratio of comonomers, the amount of ethylene oxide polymer added, and the processing conditions during the manufacturing process. However, ureteral stents 1, 2, and 3, which contained ethylene oxide polymer, had a lower modulus of tensile strength after degradation, were more flexible, and had a smoother surface. This shortened the time it took to completely excrete the ureteral stents from the body compared to ureteral stents 4 and 5, which did not contain ethylene oxide polymer. Consequently, the likelihood of crusting in the body was reduced. The initial moduli of the ureteral stents in each group varied somewhat, but the differences were not significant, allowing for smooth catheterization. The moduli of commercial silicone rubber and polyurethane stents did not change with degradation time. The degradable ureteral stent of the present invention has a tensile strength and modulus between those of silicone rubber and polyurethane stents, more similar to those of polyurethane stents.

[0081] FIG1 is an imaging observation of the excretion of the degradable ureteral stent of the present invention in an animal body. After degradation, the stent can be excreted smoothly in the renal pelvis, ureter, and bladder without any residual fragments.

Claims

1. A biodegradable ureteral stent, wherein the biodegradable ureteral stent is prepared from a composite material, wherein the composite material is formed by blending at least a glycolide-s-caprolactone copolymer, an ethylene oxide polymer, and barium sulfate with relative contents as follows:1) a weight percentage content of the glycolide-s-caprolactone copolymer is 47-80%;2) a weight percentage content of the ethylene oxide polymer is 2-8%;3) a weight percentage content of the barium sulfate is 18-45%; andin the glycolide-s-caprolactone copolymer, a weight percentage content of glycolide is 5158%, and a weight percentage content of s-caprolactone is 42-49%.

2. The biodegradable ureteral stent according to claim 1, wherein an intrinsic viscosity of the glycolide-s-caprolactone copolymer measured at 25±1°C in hexafluoroisopropanol at a concentration of 0.1 g / dl is 1.30-3.00 dl / g.

3. The biodegradable ureteral stent according to claim 1, wherein the ethylene oxide polymer comprises polyethylene glycol, polyethylene glycol monomethyl ether, polyethylene glycol dimethyl ether, polyoxyethylene, or an ethylene oxide copolymer; anda molecular weight of the polyethylene glycol, the polyethylene glycol monomethyl ether, the polyethylene glycol dimethyl ether, or the polyoxyethylene is 1,000-1,000,000 Da.

4. The biodegradable ureteral stent according to claim 3, wherein the ethylene oxide polymer is the polyethylene glycol or the polyethylene glycol monomethyl ether, and the molecular weight is 5,000-40,000 Da; and alternatively,the ethylene oxide polymer is the polyoxyethylene, and the molecular weight is 50,000400,000 Da.

5. The biodegradable ureteral stent according to claim 1, wherein the barium sulfate is replaced by other medical developers, and the other medical developers comprise one or two of bismuth subcarbonate and a metal developer.

6. The biodegradable ureteral stent according to claim 1, wherein the degradable ureteral stent is of a hollow circular tubular structure (1), a fixing structure (2) for preventing sliding is disposed at two ends or one end, a tube wall is also provided with a plurality of penetrating drainage side holes (3), and an outer diameter of a tube is 1.0-4.0 mm.2023312013   26 Jun 20267. The biodegradable ureteral stent according to claim 1, wherein an initial modulus at 100% deformation of the degradable ureteral stent is 2-10 MPa, and the modulus at 100% deformation after degradation is not greater than an initial value; and an initial Shore hardness (A) of the material used is 70-95, and the Shore hardness (A) after degradation is not greater than an initial value.

8. The biodegradable ureteral stent according to claim 1 or 6, wherein various additives are added to the biodegradable ureteral stent wherein the additives are selected from: a plasticizer, a lubricant, a dye, an antioxidant, an anti-hydrolysis agent, a melt thickener, a chain extender, a reinforcing agent, and a polymer modifier.

9. A preparation method for the biodegradable ureteral stent according to any one of claims 1-8, wherein the preparation method comprises: evenly mixing the glycolide-s-caprolactone copolymer, the ethylene oxide polymer, and the barium sulfate or other medical developer, performing extrusion molding by an extruder at 120-160°C to obtain a degradable elastic tube material, subjecting the tube material to bending shaping at 50-80°C to form a fixing structure with a tubular coil at one end or two ends, and then performing punching to obtain the degradable ureteral stent.

10. The preparation method for the biodegradable ureteral stent according to claim 9, wherein the preparation method further comprises a preparation process of the glycolide-s-caprolactone copolymer:under the protection of nitrogen, sequentially adding stannous octanoate with a mass ratio of 0.005-0.1%, s-caprolactone, and glycolide to a reactor with a stirrer; raising the temperature of a reaction system from room temperature to 165-200°C within 30 minutes under stirring, maintaining the temperature for 18-30 hours, and then holding the system under vacuum for 14 hours; and transferring a copolymer out of the reactor, further breaking the copolymer, and placing the copolymer in a vacuum oven for vacuum drying at 50-110°C for 8-24 hours.

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