An absorbable material, a preparation method thereof and an absorbable ligating clip

Abstract

The present invention provides an absorbable ligating clip, which comprises an inner clip and an outer clip; the inner clip comprises an inner layer structure and an outer layer structure; the inner layer structure comprises polydioxanone, polyethylene glycol-polydioxanone copolymer and magnesium; the outer layer structure comprises polylactic acid-polydioxanone copolymer. Compared with the prior art, the inner clip of the absorbable ligating clip provided by the present invention comprises two-layer structure, the inner layer part is soft, which can play a role in protecting human blood vessels, avoiding blood vessel injury during surgical clamping, and at the same time adding magnesium powder and polyethylene glycol-polydioxanone copolymer to increase hydrophilicity, greatly shortening the degradation time of the inner clip, making the degradation times of the inner clip and the outer clip tend to be consistent; the outer layer adopts polylactic acid-polydioxanone copolymer, which is harder than the inner layer material, improving the disadvantages of the polydioxanone material such as easy overflow of materials during processing, difficult demolding, and easy strain and deformation of products, achieving the dual effects of easy processing of products and protection of blood vessels.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and particularly relates to an absorbable material, a preparation method thereof, and an absorbable ligating clip. Background Art

[0002] Tissue clips (ligating clips) are commonly used consumables in laparoscopic surgery. Their indications include cholecystectomy, gastrointestinal surgery, appendectomy, liver surgery in general surgery, uterine / ovarian resection in obstetrics and gynecology, kidney resection in urology, etc. during operations to clamp blood vessels and tubular tissues and other general ligation procedures. They are usually used in laparoscopic surgery and are permanently retained after surgery.

[0003] Tissue ligating clips on the market can be classified into three categories according to materials: titanium clips, non-absorbable polymer clips, and absorbable clips.

[0004] The first-generation product, titanium clips, has many drawbacks due to its metal material. For example, when using an electrocoagulator to electrocoagulate and close a lumen less than 3 mm in diameter during the operation, it is easy to conduct current and damage tissues; after the operation, as the edema of the clamped pipeline tissue gradually subsides, the tissue clip is prone to loosening, wandering, premature detachment, etc., failing to play its due ligating and closing role, resulting in leakage or bleeding and causing abdominal cavity infection; it is prone to interference in imaging examinations and affects the diagnostic accuracy; and the potential harm caused by the permanent retention of foreign bodies in the body; the psychological impact on patients, etc. Currently, it is rarely used clinically.

[0005] Non-absorbable polymer clips are currently widely used in clinical practice as integrally formed clips. They are made of a single-layer V-shaped locking structure of polyoxymethylene (POM), with excellent biocompatibility and mechanical properties. They have elasticity, puncture function, and locking structure, forming a fully enclosed state after clamping, and can continue to maintain the clamping force, overcoming most of the drawbacks of titanium metal clips. However, the situation of permanent retention in the body after ligation surgery still cannot be changed.

[0006] Absorbable tissue clips eliminate the use drawbacks of various types of tissue clips in the past. In the ligation of applicable pipeline tissues, they can completely replace non-absorbable ligation clips, achieving degradation on time after surgery and leaving no residue in the body. Absorbable tissue clips can be divided into two types: double clips and single clips according to their structures and materials. Double clips are suitable for ligating pipeline tissues in a non-grasping state, and can close them without completely freeing the pipeline tissues, with simple operation and having advantages in the use of parenchymal internal blood vessels. Although the product morphology and structure of single clips are similar to those of plastic non-absorbable tissue clips, due to the softness of their materials, the clip head cannot achieve the puncture function. Therefore, it requires a higher level of proficiency from the operator. The pipeline tissue to be closed needs to be completely freed and ligated in a non-grasping state, and it cannot be applied to operations such as acute bleeding, closing first and then separating (such as hepatic lobectomy, etc.).

[0007] Commercially available absorbable double clips are divided into inner clips and outer clips. The inner clip is made of trimethyl glycolide-propionate copolymer or poly(p-dioxanone) polymer, and the outer layer is polyglycolide. However, the trimethyl glycolide-propionate copolymer has the disadvantages of poor hydrophilicity and insufficient softness, and sometimes it will damage the tubular tissues or other cavity tissues in the human body; the poly(p-dioxanone) polymer is relatively soft, which can avoid tissue damage, and the degradation period is about 90 days; the outer layer of polyglycolide material has good strength and a relatively fast degradation rate, but the material generates acidic monomer glycolic acid after degradation, causing aseptic inflammation, and the PGA material is extremely easy to degrade during the processing process. Compared with the raw materials, the mechanical properties of the product decline seriously. In order to obtain qualified mechanical properties of the outer clip, PGA raw materials with high intrinsic viscosity and large molecular weight are required, increasing the raw material cost of the product. However, if there is a slight deviation in the product injection molding and post-treatment processes of the double clip, the initial tension of the product will be unqualified, resulting in a low yield. And due to the difference in the inner and outer layer materials, the degradation rate of the product in the human body is inconsistent. After the outer clip is completely degraded, the inner clip is not completely degraded. The product is completely degraded in more than 180 days, and there is still a long postoperative risk period, such as inflammation, adhesion, etc., bringing hidden dangers to the rehabilitation of patients. Summary of the Invention

[0008] In view of this, the technical problem to be solved by the present invention is to provide an absorbable material, a preparation method thereof, and an absorbable ligating clip, which has excellent mechanical properties, the inner clip material is soft, can avoid tissue damage, and the degradation rates of the inner clip and the outer clip are consistent.

[0009] The present invention provides an absorbable ligating clip, including an inner clip and an outer clip; the inner clip includes an inner layer structure and an outer layer structure;

[0010] The inner layer structure includes poly(p-dioxanone), polyethylene glycol-poly(p-dioxanone) copolymer and magnesium;

[0011] The outer layer structure includes a polylactic acid-poly(p-dioxanone) copolymer.

[0012] Preferably, the inner layer structure includes:

[0013] 120-150 parts by weight of poly(p-dioxanone);

[0014] 30-70 parts by weight of polyethylene glycol-poly(p-dioxanone) copolymer;

[0015] 5-30 parts by weight of magnesium.

[0016] Preferably, the inner layer structure further includes 0.1-0.5 parts by weight of a hemostatic drug.

[0017] Preferably, the outer clip includes polyglycolic acid and inorganic filler; the mass ratio of the polyglycolic acid to the inorganic filler is (55-80):(15-40).

[0018] Preferably, the outer clip further comprises plant polyphenols; the mass ratio of polyglycolic acid to plant polyphenols is (55-80):(0.5-2).

[0019] Preferably, the intrinsic viscosity of the polyglycolic acid is 1.1-2.5 dl / g (30 °C, hexafluoroisopropanol);

[0020] The inorganic filler is selected from β-tricalcium phosphate and / or hydroxyapatite;

[0021] The intrinsic viscosity of the poly(p-dioxanone) is 1.5-3.5 dl / g (30 °C, hexafluoroisopropanol);

[0022] In the poly(ethylene glycol)-poly(p-dioxanone) copolymer, the molar ratio of the polyethylene glycol block to the poly(p-dioxanone) block is 1:(10-50);

[0023] The weight-average molecular weight of the poly(ethylene glycol)-poly(p-dioxanone) copolymer is 2000-35000;

[0024] The polylactic acid block in the poly(lactic acid)-poly(p-dioxanone) copolymer is a D-polylactic acid block;

[0025] The intrinsic viscosity of the poly(lactic acid)-poly(p-dioxanone) copolymer is 1.5-3.5 dl / g (25 °C, chloroform).

[0026] The present invention also provides a method for preparing an absorbable ligating clip, comprising the following steps:

[0027] S1) By means of a dual-material co-injection molding process, the inner layer material of the inner clip is injection molded to obtain the inner layer structure of the inner clip, and the outer layer material of the inner clip is injected for outer layer material injection molding. After annealing and shaping, the inner clip is obtained; the inner layer material comprises poly(p-dioxanone), poly(ethylene glycol)-poly(p-dioxanone) copolymer and magnesium; the outer layer material comprises poly(lactic acid)-poly(p-dioxanone) copolymer;

[0028] S2) Assembling the inner clip and the outer clip to obtain the absorbable ligating clip.

[0029] Preferably, the outer clip is prepared according to the following method:

[0030] The outer clip material is injection molded to obtain the outer clip; the outer clip material comprises polyglycolic acid and an inorganic filler;

[0031] The temperature of the injection molding is 220 °C-240 °C; the pressure of the injection molding is 80-100 bar; the time of the injection molding is 20-50 s.

[0032] Preferably, the injection molding temperature of the inner layer material is 105°C to 130°C; the injection molding pressure of the inner layer material is 100 to 120 bar; the injection molding time of the inner layer material is 40 to 80 s;

[0033] The injection molding temperature of the outer layer material is 130°C to 150°C; the injection molding pressure of the outer layer material is 80 to 100 bar; the injection molding time of the outer layer material is 20 to 60 s;

[0034] The annealing temperature is 60°C to 80°C; the annealing time is 5 to 15 h.

[0035] The present invention also provides an absorbable material, comprising an inner layer structure and an outer layer structure compounded on the surface of the inner layer structure;

[0036] The inner layer structure comprises poly(p-dioxanone), poly(ethylene glycol)-poly(p-dioxanone) copolymer and magnesium;

[0037] The outer layer structure comprises poly(lactic acid)-poly(p-dioxanone) copolymer.

[0038] The present invention provides an absorbable ligating clip, comprising an inner clip and an outer clip; the inner clip comprises an inner layer structure and an outer layer structure; the inner layer structure comprises poly(p-dioxanone), poly(ethylene glycol)-poly(p-dioxanone) copolymer and magnesium; the outer layer structure comprises poly(lactic acid)-poly(p-dioxanone) copolymer. Compared with the prior art, the inner clip of the absorbable ligating clip provided by the present invention comprises two layers of structures. The inner layer is soft and can play a role in protecting human blood vessels, avoiding damage to blood vessels during surgical clamping. At the same time, adding magnesium powder and poly(ethylene glycol)-poly(p-dioxanone) copolymer increases the hydrophilicity, greatly shortening the degradation time of the inner clip and making the degradation times of the inner clip and the outer clip tend to be the same; the outer layer uses poly(lactic acid)-poly(p-dioxanone) copolymer, which is harder than the inner layer material, improving the disadvantages of poly(p-dioxanone) material such as easy overflow of materials, difficult demolding and easy strain and deformation of products during the processing process, achieving the dual effects of easy processing of products and protecting blood vessels. Detailed embodiments

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] The present invention provides an absorbable material, comprising an inner layer structure and an outer layer structure compounded on the surface of the inner layer structure; the inner layer structure comprises polydioxanone, polyethylene glycol-polydioxanone copolymer and magnesium; the outer layer structure comprises polylactic acid-polydioxanone copolymer.

[0041] According to the present invention, the inner layer structure preferably comprises 120 to 150 parts by weight of polydioxanone; 30 to 70 parts by weight of polyethylene glycol-polydioxanone copolymer; 5 to 30 parts by weight of magnesium. The polydioxanone material is soft and can avoid pinching the tubular tissues or other intraluminal tissues in the human body; in the present invention, the intrinsic viscosity of the polydioxanone is preferably 1.5 to 3.5 dl / g (30 °C, hexafluoroisopropanol), more preferably 1.7 to 3.4 dl / g (30 °C, hexafluoroisopropanol); in the examples provided by the present invention, the intrinsic viscosity of the polydioxanone is specifically 2.9 dl / g (30 °C, hexafluoroisopropanol), 1.7 dl / g (30 °C, hexafluoroisopropanol) or 3.4 dl / g (30 °C, hexafluoroisopropanol); in the examples provided by the present invention, the content of the polydioxanone in the inner layer structure is specifically 120 parts by weight, 130 parts by weight or 150 parts by weight; the polyethylene glycol block in the polyethylene glycol-polydioxanone copolymer has a large number of hydrophilic groups of hydroxyl, which can shorten the degradation time of the product. In the present invention, the molar ratio of the polyethylene glycol block to the polydioxanone block in the polyethylene glycol-polydioxanone copolymer is preferably 1:(10 to 50), more preferably 1:(20 to 40), still more preferably 1:(25 to 35), and most preferably 1:30; the weight-average molecular weight of the polyethylene glycol-polydioxanone copolymer is preferably 2000 to 35000, more preferably 5000 to 35000, still more preferably 10000 to 35000, still more preferably 20000 to 30000, and most preferably 24000 to 25000; in the examples provided by the present invention, the content of the polyethylene glycol-polydioxanone copolymer in the inner layer structure is specifically 30 parts by weight, 70 parts by weight, 50 parts by weight or 60 parts by weight; the purity of the magnesium is preferably greater than 99.9%; the content of the magnesium in the inner layer structure is preferably 10 to 30 parts by weight; in the examples provided by the present invention, the content of the magnesium in the inner layer structure is specifically 10 parts by weight, 30 parts by weight, 15 parts by weight or 20 parts by weight; adding magnesium to the inner layer structure can, on the one hand, shorten the degradation time of the material, and on the other hand, the generated magnesium hydroxide alkaline substance during degradation can neutralize the acid generated by the degradation of PPDO, reducing or even avoiding the occurrence of inflammation in the tissues around the implant; according to the present invention, the inner layer structure preferably further comprises 0.1 to 0.5 parts by weight of a hemostatic drug, more preferably further comprises 0.1 to 0.3 parts by weight of a hemostatic drug; the hemostatic drug can be a hemostatic drug well-known to those skilled in the art, and there is no special limitation. In the present invention, it is preferably one or more of aminocaproic acid, etamsylate, tranexamic acid and vitamin K.

[0042] According to the present invention, the outer layer structure is a polylactic acid-poly(p-dioxanone) copolymer, which has relatively high hardness and can improve the disadvantages of the poly(p-dioxanone) absorbable material as an inner sandwich, such as difficult soft demolding and easy scratching during demolding; the polylactic acid block in the polylactic acid-poly(p-dioxanone) copolymer is a right-handed polylactic acid block, which is an amorphous polymer and has a short degradation time; the intrinsic viscosity of the polylactic acid-poly(p-dioxanone) copolymer is preferably 1.5 to 3.5 dl / g (25 °C, chloroform), more preferably 1.5 to 3.0 dl / g (25 °C, chloroform), still more preferably 1.5 to 2.5 dl / g (25 °C, chloroform), and most preferably 1.8 to 2.4 dl / g (25 °C, chloroform); in the examples provided by the present invention, the intrinsic viscosity of the polylactic acid-poly(p-dioxanone) copolymer is specifically 2.4 dl / g (25 °C, chloroform), 2.0 dl / g (25 °C, chloroform), 1.8 dl / g (25 °C, chloroform), or 2.2 dl / g (25 °C, chloroform).

[0043] The present invention also provides a preparation method of the above absorbable material, which includes the following steps: adopting a double-material co-injection molding processing method, injection molding the inner layer material to obtain an inner layer structure, injecting the outer layer material for outer layer material injection molding, and after annealing and qualitative determination, obtaining the absorbable material; the inner layer material includes poly(p-dioxanone), a polyethylene glycol-poly(p-dioxanone) copolymer, and magnesium; the outer layer material includes a polylactic acid-poly(p-dioxanone) copolymer.

[0044] Among them, the present invention does not have special restrictions on the sources of all raw materials, and they can be commercially available; the components of the inner layer material and the outer layer material are the same as those described above, and will not be elaborated here.

[0045] In the present invention, it is preferred to first prepare the inner layer material, mix poly(p-dioxanone), a polyethylene glycol-poly(p-dioxanone) copolymer, and magnesium and then extrude and pelletize to obtain the inner layer material; the temperature from the feeding port to the die during the extrusion and pelletization is preferably 90 °C to 130 °C; in the examples provided by the present invention, the temperature from the feeding port to the die during the extrusion and pelletization is specifically 90 °C to 125 °C or 100 °C to 130 °C; the temperature of the die during the extrusion and pelletization is preferably 115 °C to 120 °C; the rotation speed during the extrusion and pelletization is preferably 50 to 100 rpm, more preferably 70 to 90 rpm, still more preferably 80 rpm; after extrusion and pelletization, it is preferably vacuum dried to obtain the inner layer material; the moisture content of the inner layer material is preferably below 500 ppm.

[0046] Adopt the processing method of double - material co - injection molding to injection - mold the inner - layer material to obtain the inner - layer structure; the temperature for injection - molding the inner - layer material is preferably 105°C to 130°C; the pressure for injection - molding the inner - layer material is preferably 100 to 120 bar; the time for injection - molding the inner - layer material is preferably 40 to 80 s, more preferably 50 to 70 s, and still more preferably 60 s; the temperature of the mold during injection - molding the inner - layer material is preferably 35°C to 45°C.

[0047] Then inject the outer - layer material for injection - molding of the outer - layer material; the temperature for injection - molding the outer - layer material is preferably 130°C to 150°C; the pressure for injection - molding the outer - layer material is preferably 80 to 100 bar; the time for injection - molding the outer - layer material is preferably 20 to 60 s, more preferably 30 to 50 s, and still more preferably 40 s; the temperature of the mold during injection - molding the outer - layer material is preferably 45°C to 60°C.

[0048] Then anneal and shape it to obtain the absorbable material; the temperature for annealing is preferably 60°C to 80°C, more preferably 65°C to 75°C, and still more preferably 70°C; the time for annealing is preferably 5 to 15 h, more preferably 8 to 12 h, and still more preferably 10 h.

[0049] The present invention also provides an application of the above - mentioned absorbable material in the preparation of ligating clips.

[0050] The present invention also provides an absorbable ligating clip, comprising an inner clip and an outer clip; the inner clip comprises an inner - layer structure and an outer - layer structure; the inner - layer structure comprises poly(p - dioxanone), poly(ethylene glycol - co - p - dioxanone) copolymer and magnesium; the outer - layer structure comprises poly(lactic acid - co - p - dioxanone) copolymer.

[0051] In the present invention, the inner clip is the above - mentioned absorbable material; the inner - layer structure and the outer - layer structure are the same as those described above and will not be elaborated here.

[0052] The outer clip preferably comprises polyglycolic acid (PGA) and an inorganic filler; preparing the outer clip with a composite material of PGA and an inorganic filler can greatly improve the product tension, and PGA raw materials with relatively low intrinsic viscosity and molecular weight can also be used to reduce the product cost and improve the mechanical properties of the outer clip. The intrinsic viscosity of the polyglycolic acid is preferably 1.1 - 2.5 dl / g (30 °C, hexafluoroisopropanol), more preferably 1.5 - 2.5 dl / g (30 °C, hexafluoroisopropanol), and still more preferably 1.5 - 2.0 dl / g (30 °C, hexafluoroisopropanol); in the examples provided by the present invention, the intrinsic viscosity of the polyglycolic acid is specifically 2.0 dl / g (30 °C, hexafluoroisopropanol), 1.8 dl / g (30 °C, hexafluoroisopropanol), or 1.5 dl / g (30 °C, hexafluoroisopropanol); the inorganic filler can be the inorganic fillers well-known to those skilled in the art without any special limitation, and β-tricalcium phosphate and / or hydroxyapatite are preferably used in the present invention; the particle size of the inorganic filler is preferably 10 - 200 μm; the mass ratio of the polyglycolic acid to the inorganic filler is preferably (55 - 80):(15 - 40), more preferably (60 - 80):(20 - 40), still more preferably (65 - 80):(20 - 40), and most preferably (65 - 80):(20 - 35); in the examples provided by the present invention, the mass ratio of the polyglycolic acid to the inorganic filler is specifically 80:20, 70:30, 65:35, or 75:25.

[0053] According to the present invention, the outer clip preferably further comprises a plant polyphenol; the plant polyphenol can be the plant polyphenols well-known to those skilled in the art without any special limitation, and one or more of tannic acid, gallic acid, and quercetin are preferably used in the present invention; the mass ratio of the polyglycolic acid to the plant polyphenol is preferably (55 - 80):(0.5 - 2), more preferably (60 - 80):(1 - 2), still more preferably (65 - 80):(1 - 1.5); in the examples provided by the present invention, the mass ratio of the polyglycolic acid to the plant polyphenol is specifically 80:1, 70:1.5, 65:1, or 75:1.5.

[0054] The inner clip of the absorbable ligating clip provided by the present invention comprises a two-layer structure. The inner layer is soft and can play a role in protecting human blood vessels, avoiding blood vessel injury during surgical clamping. At the same time, magnesium powder and a polyethylene glycol-poly(p-dioxanone) copolymer are added to increase the hydrophilicity, greatly shortening the degradation time of the inner clip and making the degradation times of the inner clip and the outer clip tend to be consistent; the outer layer uses a poly(lactic acid)-poly(p-dioxanone) copolymer, which is harder than the inner layer material, improving the disadvantages of the poly(p-dioxanone) material having a narrow melting range, being prone to overflow of materials, difficult demolding, and easy pulling and deformation of products during processing, achieving the dual effects of easy processing of the product and protection of blood vessels.

[0055] The present invention also provides a preparation method of the above absorbable ligating clip, comprising the following steps: S1) By means of double-material co-injection molding, the inner layer material of the inner clip is injection molded to obtain the inner layer structure of the inner clip, and the outer layer material of the inner clip is injected for outer layer material injection molding. After annealing and shaping, the inner clip is obtained; the inner layer material includes poly(p-dioxanone), poly(ethylene glycol)-poly(p-dioxanone) copolymer and magnesium; the outer layer material includes poly(lactic acid)-poly(p-dioxanone) copolymer; S2) Assemble the inner clip and the outer clip to obtain the absorbable ligating clip.

[0056] Among them, the preparation steps of the inner clip in step S1) are the same as those of the above absorbable material, and will not be elaborated here.

[0057] The outer clip can be prepared according to the methods well-known to those skilled in the art without any special limitations. In the present invention, it is preferably prepared according to the following method: The outer clip material is injection molded to obtain the outer clip; the outer clip material includes polyglycolic acid and inorganic filler.

[0058] In the present invention, it is preferred to first prepare the outer clip material, mix and extrude polyglycolic acid and inorganic filler to granulate to obtain the outer clip material; in the present invention, the outer clip material preferably further includes plant polyphenols; the plant polyphenols are preferably first mixed and reacted with the inorganic filler to obtain the inorganic filler treated with plant polyphenols, and then the inorganic filler treated with plant polyphenols is mixed and extruded with polyglycolic acid to granulate; the mixing reaction of the plant polyphenols and the inorganic filler is preferably carried out in a liquid phase medium; the liquid phase medium is preferably an aqueous phosphoric acid solution; the volume concentration of phosphoric acid in the aqueous phosphoric acid solution is preferably 0.5% to 1%, specifically 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%; the temperature of the mixing reaction is preferably 40°C to 60°C; the time of the mixing reaction is preferably 1 to 3 h; the method of mixing polyglycolic acid with inorganic filler or polyglycolic acid with the inorganic filler treated with plant polyphenols can be the methods well-known to those skilled in the art without any special limitations. In the present invention, it is preferably grinding, more preferably cryogenic grinding; the time of the cryogenic grinding is preferably 10 to 60 min; the particle size of polyglycolic acid before grinding is preferably 0.4 to 3 mm; the particle size of the inorganic filler before grinding is preferably 10 to 200 μm; the temperature from the feeding port to the die during the extrusion granulation is preferably 140°C to 240°C; in the examples provided by the present invention, the temperature from the feeding port to the die during the extrusion granulation is specifically 140°C to 240°C or 140°C to 235°C; the temperature of the die during the extrusion granulation is preferably 200°C to 230°C, more preferably 220°C; the rotation speed during the extrusion granulation is preferably 50 to 100 rpm, more preferably 70 to 90 rpm, and further preferably 80 rpm; after the extrusion granulation, it is preferably vacuum dried to obtain the outer clip material; the water content of the outer clip material is preferably below 500 ppm.

[0059] The outer clip material is injection molded; the temperature of the injection molding is preferably 220°C to 240°C; the pressure of the injection molding is preferably 80 to 100 bar; the time of the injection molding is preferably 20 to 50 s, more preferably 30 to 40 s, and still more preferably 30 s; the temperature of the mold during the injection molding is preferably 35°C to 45°C.

[0060] After injection molding, annealing treatment is preferably carried out to obtain the outer clip; the temperature of the annealing treatment is preferably 100°C to 150°C, more preferably 110°C to 130°C, and still more preferably 120°C; the time of the annealing treatment is preferably 5 to 15 h, more preferably 8 to 12 h, and still more preferably 10 h.

[0061] The inner clip and the outer clip are assembled to obtain an absorbable ligating clip; during the assembly, in addition to the inner clip and the outer clip, it preferably further includes a tissue ligating clip fitting outer sleeve and a piston that are not implanted into the human body; after the assembly, sterilization treatment is preferably carried out to obtain the absorbable ligating clip; the sterilization preferably uses ethylene oxide sterilization; the temperature of the sterilization is preferably 50°C to 55°C, more preferably 52°C; the time of the sterilization is preferably 5 to 10 h, more preferably 6 to 8 h, and still more preferably 7 h; after the sterilization treatment, drying and analysis are preferably carried out; the temperature of the drying and analysis is preferably 55°C to 65°C, more preferably 60°C; the time of the drying and analysis is preferably 70 to 80 h, more preferably 72 h.

[0062] In order to further illustrate the present invention, the following provides a detailed description of an absorbable material, its preparation method, and an absorbable ligating clip according to the present invention in conjunction with embodiments.

[0063] The reagents used in the following examples are all commercially available; the tannic acid-treated β-tricalcium phosphate in the examples of the present invention is prepared according to the method of Example 1 in the publication number CN110624136A.

[0064] Example 1

[0065] Outer clip:

[0066] 200 g (10 - 200 μm) of dry tannic acid (molecular weight 1701.2)-treated β-tricalcium phosphate is added to 800 g of dry PGA pellets (particle diameter 0.4 - 3 mm, intrinsic viscosity 2.0 dl / g, 30°C, hexafluoroisopropanol), and the two are ground in a cryogenic grinder (in a liquid nitrogen environment) for 30 minutes to be uniformly mixed to obtain a mixed powder.

[0067] The mixed powder was added to the Haake micro co-rotating twin-screw extruder PROCESS 11. The temperature from the feed inlet to the die of the extruder was set at 140°C - 240°C, the die temperature was 220°C, the screw speed was 80 rpm. The sample strips were extruded through the die, air-cooled and pelletized, vacuum-dried until the moisture content was below 500 ppm, and then vacuum-packed in aluminum-plastic bags to obtain the outer clip material for tissue ligating clips.

[0068] The pre-dried outer clip material (dehumidifying dryer, 100°C, 10 hours) was injection-molded on an Italian Babyplast 6 / 12 micro-injection molding machine. The injection temperature was 220 - 240°C, the injection pressure was 80 - 100 bar, the holding pressure time was 30 s, and the mold temperature was 35°C - 45°C to obtain the outer clip product.

[0069] The outer clip product was placed in a tooling mold and annealed and shaped in a forced-air drying oven at an annealing temperature of 120°C and an annealing time of 10 hours, and then vacuum-packed in aluminum-plastic bags.

[0070] Inner layer part of the inner clip:

[0071] 120 g of dry PPDO (particle diameter 0.6 - 3 mm, intrinsic viscosity 2.9 dl / g, 30°C, hexafluoroisopropanol), 30 g of PEG-b-PPDO (block molar ratio PEG:PPDO = 1:30, Mw: 24038), 10 g of magnesium powder, and 0.1 g of the hemostatic drug vitamin K were ground and mixed evenly in a cryogenic grinder (under liquid nitrogen environment) to obtain the mixed powder.

[0072] The mixed powder was added to the Haake micro co-rotating twin-screw extruder PROCESS 11. The temperature from the feed inlet to the die of the extruder was set at 90 - 125°C, the die temperature was 115°C, the screw speed was 80 rpm. The sample strips were extruded through the die, air-cooled and pelletized, vacuum-dried until the moisture content was below 500 ppm, and then vacuum-packed in aluminum-plastic bags to obtain the inner layer material for the inner clip of the tissue ligating clip.

[0073] The pre-dried inner layer material of the inner clip (dehumidifying dryer, 35°C, 12 hours) was injection-molded on an Italian Babyplast 6 / 12 micro-injection molding machine. The injection temperature was 105 - 130°C, the injection pressure was 100 - 120 bar, the holding pressure time was 60 s, and the mold temperature was 35°C - 45°C.

[0074] Rotate the mold, use another injection unit, and adopt a block copolymer of polylactic acid and PPDO (PDLLA-b-PPDO) with an intrinsic viscosity of 2.4 dl / g (25 °C, chloroform) as the inner and outer layer materials. Pre-dry them in a dehumidifying dryer at 80 °C for 6 hours, and then perform inner and outer layer injection molding. The injection molding temperature is 130 - 150 °C, the injection pressure is 80 - 100 bar, the holding pressure time is 40 s, and the mold temperature is 45 °C - 60 °C. Cool, eject and demold to obtain the inner clip of the absorbable tissue ligating clip.

[0075] Place the inner clip in a tooling mold and anneal it in a forced-air drying oven at an annealing temperature of 70 °C for 10 hours, and then vacuum package it in an aluminum-plastic bag.

[0076] Assemble the outer clip, inner clip with the outer sleeve and piston of the tissue ligating clip accessories that are not implanted into the human body, package them in a Tyvek sterilization bag, sterilize them with ethylene oxide (temperature 52 °C, time 7 hours), then dry and desorb them in a vacuum drying oven at 60 °C for 72 hours, and finally vacuum package them in an aluminum-plastic bag to obtain the absorbable tissue ligating clip product.

[0077] Example 2

[0078] Outer clip:

[0079] Add 300 grams (10 - 200 μm) of β-tricalcium phosphate treated with 15 grams of tannic acid (molecular weight 1701.2) that has been dried to 700 grams of PGA pellets that have been dried (particle diameter 0.4 - 3 mm, intrinsic viscosity 1.8 dl / g, 30 °C, hexafluoroisopropanol). Grind and mix the two evenly in a cryogenic grinder (under liquid nitrogen environment) for 30 minutes to obtain a mixed powder.

[0080] Add the mixed powder to the Haake micro co-rotating twin-screw extruder PROCESS 11, set the temperature from the feed port to the die of the extruder to be 140 °C - 240 °C, the die temperature to be 220 °C, the screw speed to be 80 rpm. The sample is extruded through the die, air-cooled and pelletized, vacuum-dried until the moisture content is below 500 ppm, and then vacuum packaged in an aluminum-plastic bag to obtain the outer clip material of the tissue ligating clip.

[0081] Perform product injection molding on the pre-dried outer clip material (in a dehumidifying dryer, 110 °C, 12 hours) on an Italian Babyplast 6 / 12 micro injection molding machine. The injection molding temperature is 225 °C - 245 °C, the injection pressure is 90 - 110 bar, the holding pressure time is 30 s, and the mold temperature is 35 °C - 45 °C to obtain the outer clip product.

[0082] Place the outer clip in a tooling mold and anneal it in a forced-air drying oven at an annealing temperature of 110 °C for 12 hours, and then vacuum package it in an aluminum-plastic bag.

[0083] Inner layer part of the inner clip:

[0084] 130 g of dry PPDO (particle diameter 0.6 - 3 mm, intrinsic viscosity 2.9 dl / g, 30 °C, hexafluoroisopropanol), 70 g of PEG-b-PPDO (block molar ratio PEG:PPDO = 1:30, Mw: 24038), 30 g of magnesium powder, and 0.2 g of the hemostatic drug aminocaproic acid were ground and mixed evenly in a cryogenic grinder (under liquid nitrogen environment) to obtain a mixed powder.

[0085] The mixed powder was added to a Haake micro co-rotating twin-screw extruder PROCESS 11. The temperature from the feeding port to the die of the extruder was set at 90 °C - 125 °C, the die temperature was 115 °C, the screw speed was 80 rpm. The sample strips were extruded through the die, air-cooled and pelletized, vacuum-dried until the moisture content was below 500 ppm, and vacuum-packed in an aluminum-plastic bag to obtain the inner-layer material of the tissue ligating clip.

[0086] The pre-dried inner-layer material of the inner clip (dehumidifying dryer, 35 °C, 15 hours) was injection-molded on an Italian Babyplast 6 / 12 micro-injection molding machine. The injection temperature was 110 °C - 130 °C, the injection pressure was 110 - 120 bar, the holding pressure time was 60 s, and the mold temperature was 35 °C - 45 °C.

[0087] The mold was rotated, and another injection unit was used. A block copolymer of polylactic acid and PPDO (PDLLA-b-PPDO) with an intrinsic viscosity of 2.0 dl / g (25 °C, chloroform) was used as the outer-layer material of the inner clip. It was pre-dried in a dehumidifying dryer at 80 °C for 6 hours, and then the outer-layer injection molding of the inner clip was carried out. The injection temperature was 130 °C - 145 °C, the injection pressure was 80 - 100 bar, the holding pressure time was 40 s, and the mold temperature was 45 °C - 60 °C. After cooling and ejection, the absorbable tissue ligating clip inner clip was obtained.

[0088] The inner clip was placed in a tooling mold and annealed and shaped in a forced-air drying oven at an annealing temperature of 90 °C for 6 hours, and then vacuum-packed in an aluminum-plastic bag.

[0089] The outer clip, inner clip were assembled with the outer sleeve and piston of the tissue ligating clip fittings that are not implanted into the human body, and packaged in a Tyvek sterilization bag. After ethylene oxide sterilization (temperature 52 °C, time 7 hours), it was dried and analyzed in a vacuum drying oven at 60 °C for 72 hours, and then vacuum-packed in an aluminum-plastic bag to obtain the absorbable tissue ligating clip product.

[0090] Example 3

[0091] Outer clip:

[0092] 350 g of β-tricalcium phosphate (10 - 200 μm) treated with 10 g of dry tannic acid (molecular weight 1701.2) was added to 650 g of dry PGA pellets (particle diameter 0.4 - 3 mm, intrinsic viscosity 1.5 dl / g, 30 °C, hexafluoroisopropanol). The two were ground and mixed evenly in a cryogenic grinder (under liquid nitrogen environment) for 30 minutes to obtain a mixed powder.

[0093] The mixed powder was added to a Haake Mini-Compounder PROCESS 11. The temperature from the feeder to the die of the extruder was set at 140 °C - 235 °C, the die temperature was 220 °C, the screw speed was 80 rpm. The sample strips were extruded through the die, air-cooled and pelletized, vacuum-dried until the moisture content was below 500 ppm, and vacuum-packed in an aluminum-plastic bag to obtain the outer clip material for tissue ligating clips.

[0094] The pre-dried outer clip material (in a dehumidifying dryer, 100 °C, 10 hours) was injection-molded on an Italian Babyplast 6 / 12 Mini Injection Molding Machine. The injection temperature was 220 °C - 240 °C, the injection pressure was 90 - 110 bar, the holding pressure time was 30 s, and the mold temperature was 35 °C - 45 °C. The outer clip product was obtained.

[0095] The outer clips were placed in a tooling mold and annealed and shaped in a forced-air drying oven at an annealing temperature of 120 °C and an annealing time of 10 hours, and then vacuum-packed in an aluminum-plastic bag.

[0096] Inner layer of the inner clip:

[0097] 150 g of dry PPDO (particle diameter 0.6 - 3 mm, intrinsic viscosity 1.7 dl / g, 30 °C, hexafluoroisopropanol), 50 g of PEG-b-PPDO (block molar ratio PEG:PPDO = 1:30, Mw: 24038), 15 g of magnesium powder, and 0.3 g of the hemostatic drug etamsylate were ground and mixed evenly in a cryogenic grinder (under liquid nitrogen environment) to obtain a mixed powder.

[0098] The mixed powder was added to a Haake Mini-Compounder PROCESS 11. The temperature from the feeder to the die of the extruder was set at 100 °C - 130 °C, the die temperature was 120 °C, the screw speed was 80 rpm. The sample strips were extruded through the die, air-cooled and pelletized, vacuum-dried until the moisture content was below 500 ppm, and vacuum-packed in an aluminum-plastic bag to obtain the inner layer material of the tissue ligating clip inner clip.

[0099] The pre-dried (in a dehumidifying dryer, 35 °C, 12 hours) inner layer material of the inner clip was injection-molded on an Italian Babyplast 6 / 12 Mini Injection Molding Machine. The injection temperature was 105 °C - 130 °C, the injection pressure was 100 - 120 bar, the holding pressure time was 60 s, and the mold temperature was 35 °C - 45 °C.

[0100] Rotate the mold, use another injection unit, and adopt a block copolymer of polylactic acid and PPDO (PDLLA-b-PPDO) with an intrinsic viscosity of 1.8 dl / g (25 °C, chloroform) as the inner and outer layer materials. Pre-dry it at 80 °C for 6 hours using a dehumidifying dryer, and then perform inner and outer layer injection molding. The injection molding temperature is 130 °C to 145 °C, the injection molding pressure is 80 to 100 bar, the holding pressure time is 40 s, and the mold temperature is 45 °C to 60 °C. Cool and eject the mold. Obtain the inner clip of the absorbable tissue ligating clip.

[0101] Place the inner clip in the tooling mold and anneal it in a forced-air drying oven at an annealing temperature of 70 °C for 10 hours, and then vacuum package it in an aluminum-plastic bag.

[0102] Assemble the outer clip, inner clip with the outer sleeve and piston of the tissue ligating clip fitting that is not implanted into the human body, package it with a Tyvek sterilization bag, sterilize it with ethylene oxide (temperature 52 °C, time 7 hours), then dry and desorb it in a vacuum drying oven at 60 °C for 72 hours, and finally vacuum package it in an aluminum-plastic bag to obtain the absorbable tissue ligating clip product.

[0103] Example 4

[0104] Outer clip:

[0105] Add 250 grams (10 - 200 μm) of β-tricalcium phosphate treated with 15 grams of tannic acid (molecular weight 1701.2) that has been dried to 750 grams of pre-dried PGA pellets (particle diameter 0.4 - 3 mm, intrinsic viscosity 2.0 dl / g, 30 °C, hexafluoroisopropanol). Grind and mix the two evenly in a cryogenic grinder (under liquid nitrogen environment) for 30 minutes to obtain a mixed powder.

[0106] Add the mixed powder into the Haake micro co-rotating twin-screw extruder PROCESS 11, set the temperature from the feeding port to the die of the extruder to be 140 °C to 240 °C, the die temperature to be 220 °C, the screw speed to be 80 rpm. The sample is extruded through the die, air-cooled and pelletized, vacuum dried until the moisture content is below 500 ppm, and then vacuum packaged in an aluminum-plastic bag to obtain the outer clip material of the tissue ligating clip.

[0107] Perform product injection molding on the pre-dried (using a dehumidifying dryer at 100 °C for 10 hours) outer clip material on the Italian Babyplast 6 / 12 micro injection molding machine. The injection molding temperature is 220 °C to 240 °C, the injection molding pressure is 90 to 110 bar, the holding pressure time is 30 s, and the mold temperature is 35 °C to 45 °C. Obtain the outer clip product.

[0108] Place the outer clip in the tooling mold and anneal it in a forced-air drying oven at an annealing temperature of 120 °C for 10 hours, and then vacuum package it in an aluminum-plastic bag.

[0109] Inner layer part of the inner clip:

[0110] 120 g of dry PPDO (particle diameter 0.6 - 3 mm, intrinsic viscosity 3.4 dl / g, 30 °C, hexafluoroisopropanol), 60 g of PEG-b-PPDO (block molar ratio PEG:PPDO = 1:30, Mw: 24038), 20 g of magnesium powder, and 0.2 g of the hemostatic drug tranexamic acid were ground and mixed evenly in a cryogenic grinder (under liquid nitrogen environment) to obtain a mixed powder.

[0111] The mixed powder was added to a Haake micro co-rotating twin-screw extruder PROCESS 11. The temperature from the feed port to the die of the extruder was set at 90 °C - 125 °C, the die temperature was 115 °C, the screw speed was 80 rpm. The sample strips were extruded through the die, air-cooled and pelletized, vacuum dried until the moisture content was below 500 ppm, and then vacuum-packed in an aluminum-plastic bag to obtain the inner layer material of the tissue ligating clip.

[0112] The pre-dried (in a dehumidifying dryer, 35 °C, 12 hours) inner layer material was injection-molded on an Italian Babyplast 6 / 12 micro-injection molding machine. The injection temperature was 105 °C - 130 °C, the injection pressure was 100 - 120 bar, the holding pressure time was 60 s, and the mold temperature was 35 - 45 °C.

[0113] The mold was rotated, and another injection unit was used. A block copolymer of polylactic acid and PPDO (PDLLA-b-PPDO) with an intrinsic viscosity of 2.2 dl / g (25 °C, chloroform) was used as the outer layer material of the inner clip. It was pre-dried in a dehumidifying dryer at 80 °C for 6 hours, and then the outer layer of the inner clip was injection-molded. The injection temperature was 130 °C - 150 °C, the injection pressure was 80 - 100 bar, the holding pressure time was 40 s, and the mold temperature was 45 °C - 60 °C. After cooling, it was ejected from the mold. The absorbable tissue ligating clip inner clip was obtained.

[0114] The inner clip was placed in a tooling mold and annealed and shaped in a forced-air drying oven at an annealing temperature of 70 °C and an annealing time of 10 hours, and then vacuum-packed in an aluminum-plastic bag.

[0115] The outer clip, inner clip were assembled with the outer sleeve and piston of the tissue ligating clip fitting that is not implanted into the human body, and packaged with a Tyvek sterilization bag. After ethylene oxide sterilization (temperature 52 °C, time 7 hours), it was dried and analyzed in a vacuum drying oven at 60 °C for 72 hours, and then vacuum-packed in an aluminum-plastic bag to obtain the absorbable tissue ligating clip product.

[0116] Comparative Example 1

[0117] Outer clip:

[0118] The pre-dried (dehumidifying dryer, 100 °C, 10 hours) outer clip material PGA (particle diameter 0.4 - 3 mm, intrinsic viscosity 1.5 dl / g, 30 °C, hexafluoroisopropanol) was injection molded into products on an Italian Babyplast 6 / 12 micro-injection molding machine at an injection temperature of 220 - 238 °C, an injection pressure of 90 - 110 bar, a holding pressure time of 30 s, and a mold temperature of 35 - 45 °C. The outer clip products were obtained.

[0119] The outer clip was placed in a tooling mold and annealed and shaped in a forced-air drying oven at an annealing temperature of 120 °C for 10 hours, and then vacuum-packed in an aluminum-plastic bag.

[0120] Inner clip:

[0121] The pre-dried (dehumidifying dryer, 35 °C, 12 hours) inner clip material PPDO (particle diameter 0.6 - 3 mm, intrinsic viscosity 1.7 dl / g, 30 °C, hexafluoroisopropanol) was injection molded on an Italian Babyplast 6 / 12 micro-injection molding machine at an injection temperature of 105 °C - 130 °C, an injection pressure of 100 - 120 bar, a holding pressure time of 60 s, and a mold temperature of 35 - 45 °C.

[0122] The inner clip was placed in a tooling mold and annealed and shaped in a forced-air drying oven at an annealing temperature of 70 °C for 10 hours, and then vacuum-packed in an aluminum-plastic bag.

[0123] The outer clip, inner clip were assembled with the outer sleeve and piston of the tissue ligating clip fitting that is not implanted into the human body, and packaged in a Tyvek sterilization bag. After ethylene oxide sterilization (temperature 52 °C, time 7 hours), it was dried and desorbed in a vacuum drying oven at 60 °C for 72 hours, and then vacuum-packed in an aluminum-plastic bag to obtain the absorbable tissue ligating clip product.

[0124] Comparative Example 2

[0125] Outer clip:

[0126] The pre-dried (dehumidifying dryer, 100 °C, 10 hours) outer clip material PGA (particle diameter 0.4 - 3 mm, intrinsic viscosity 2.0 dl / g, 30 °C, hexafluoroisopropanol) was injection molded into products on an Italian Babyplast 6 / 12 micro-injection molding machine at an injection temperature of 220 °C - 238 °C, an injection pressure of 90 - 110 bar, a holding pressure time of 30 s, and a mold temperature of 35 °C - 45 °C. The outer clip products were obtained.

[0127] The outer clip was placed in a tooling mold and annealed and shaped in a forced-air drying oven at an annealing temperature of 120 °C for 10 hours, and then vacuum-packed in an aluminum-plastic bag.

[0128] Inner clip:

[0129] Pre-dry the inner clamping material PPDO (particle diameter 0.6 - 3 mm, intrinsic viscosity 3.4 dl / g, 30 °C, hexafluoroisopropanol) in a dehumidifying dryer at 35 °C for 12 hours, and then inject it on an Italian Babyplast 6 / 12 micro-injection molding machine. The injection temperature is 105 °C - 130 °C, the injection pressure is 100 - 120 bar, the holding pressure time is 60 s, and the mold temperature is 35 °C - 45 °C.

[0130] Place the inner clamping in a tooling mold and anneal it in a forced-air drying oven at 70 °C for 10 hours, then vacuum package it in an aluminum-plastic bag.

[0131] Assemble the outer clamping, inner clamping, the outer sleeve of the tissue ligating clip fitting that does not implant into the human body, and the piston, package them in a Tyvek sterilization bag, sterilize them with ethylene oxide (temperature 52 °C, time 7 hours), then dry and desorb them in a vacuum drying oven at 60 °C for 72 hours, and finally vacuum package them in an aluminum-plastic bag to obtain the absorbable tissue ligating clip product.

[0132] Performance Testing

[0133] Perform performance testing on the degradable outer clamping medical materials and tissue ligating clips prepared in Examples 1 - 4 and Comparative Examples 1 - 2. The results are shown in Table 1, and Table 1 is the performance testing data table of the tissue ligating clips provided by the present invention.

[0134] Table 1 Performance Testing Data Table of Absorbable Tissue Ligating Clips

[0135]

[0136]

[0137] From the above performance testing, it can be seen that the tensile strength of the modified β-TCP / PGA composite material has been significantly improved, far higher than that of the PGA material. The opening force of the outer clamping injection molded with the modified β-TCP / PGA composite material is significantly higher than that of the outer clamping injection molded with the pure PGA material. Through two-color injection molding of the inner clamping and material modification, the appearance of the inner clamping has been significantly improved compared with that of the pure PPDO material, and the qualified rate of the inner clamping has been significantly increased. The complete degradation time of the inner clamping has been significantly reduced.

[0138] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An absorbable ligating clip, characterized in that, It includes an inner clip and an outer clip; the inner clip includes an inner layer structure and an outer layer structure; The outer layer structure is a poly(lactic acid)-poly(p-dioxanone) copolymer; The inner layer structure includes: 120 - 150 parts by weight of poly(p-dioxanone); 30 - 70 parts by weight of a polyethylene glycol-poly(p-dioxanone) copolymer; 5 - 30 parts by weight of magnesium; The outer clip includes poly(glycolic acid) and an inorganic filler; the mass ratio of poly(glycolic acid) to the inorganic filler is (55 - 80):(15 - 40); In the polyethylene glycol-poly(p-dioxanone) copolymer, the molar ratio of the polyethylene glycol block to the poly(p-dioxanone) block is 1:(10 - 50).

2. The absorbable ligating clip according to claim 1, wherein, The inner layer structure further includes 0.1 - 0.5 parts by weight of a hemostatic drug.

3. The absorbable ligating clip according to claim 1, wherein, The outer clip further includes plant polyphenols; the mass ratio of poly(glycolic acid) to plant polyphenols is (55 - 80):(0.5 - 2).

4. The absorbable ligating clip according to claim 1, wherein The intrinsic viscosity of poly(glycolic acid) in hexafluoroisopropanol at 30 °C is 1.1 - 2.5 dl / g; The inorganic filler is selected from β-tricalcium phosphate and / or hydroxyapatite; The intrinsic viscosity of poly(p-dioxanone) in hexafluoroisopropanol at 30 °C is 1.5 - 3.5 dl / g; The weight-average molecular weight of the polyethylene glycol-poly(p-dioxanone) copolymer is 2000 - 35000; The polylactic acid block in the poly(lactic acid)-poly(p-dioxanone) copolymer is a dextrorotatory polylactic acid block; The intrinsic viscosity of the poly(lactic acid)-poly(p-dioxanone) copolymer in chloroform at 25 °C is 1.5 - 3.5 dl / g.

5. A method for preparing the absorbable ligating clip according to claim 1, characterized in that, It includes the following steps: S1) Adopting a double-material co-injection molding process, the inner layer material of the inner clip is injection molded to obtain the inner layer structure of the inner clip, and the outer layer material of the inner clip is injected for outer layer material injection molding. After annealing and shaping, the inner clip is obtained; The inner layer material includes: 120 - 150 parts by weight of poly(p-dioxanone); 30 - 70 parts by weight of a polyethylene glycol-poly(p-dioxanone) copolymer; 5 - 30 parts by weight of magnesium; The outer layer material is a poly(lactic acid)-poly(p-dioxanone) copolymer; In the polyethylene glycol-poly(p-dioxanone) copolymer, the molar ratio of the polyethylene glycol block to the poly(p-dioxanone) block is 1:(10 - 50); S2) Assembling the inner clip and the outer clip to obtain an absorbable ligating clip; the outer clip material includes poly(glycolic acid) and an inorganic filler; the mass ratio of poly(glycolic acid) to the inorganic filler is (55 - 80):(15 - 40).

6. The preparation method according to claim 5, characterized in that, The outer clip is prepared according to the following method: The outer clip material is injection molded to obtain the outer clip; The temperature of the injection molding is 220 °C - 240 °C; the pressure of the injection molding is 80 - 100 bar; the time of the injection molding is 20 - 50 s.

7. The preparation method according to claim 5, wherein The temperature of the injection molding of the inner layer material is 105 °C - 130 °C; the pressure of the injection molding of the inner layer material is 100 - 120 bar; the time of the injection molding of the inner layer material is 40 - 80 s; The temperature of the injection molding of the outer layer material is 130 °C - 150 °C; the pressure of the injection molding of the outer layer material is 80 - 100 bar; the time of the injection molding of the outer layer material is 20 - 60 s; The annealing temperature is 60°C to 80°C; the annealing time is 5 to 15 h.

8. An absorbable material, characterized in that, It includes an inner structure and an outer structure covering the surface of the inner structure. The inner structure includes 120 to 150 parts by weight of poly(p-dioxanone); 30 to 70 parts by weight of polyethylene glycol-poly(p-dioxanone) copolymer; 5 to 30 parts by weight of magnesium. The outer structure is a poly(lactic acid)-poly(p-dioxanone) copolymer. In the polyethylene glycol-poly(p-dioxanone) copolymer, the molar ratio of the polyethylene glycol block to the poly(p-dioxanone) block is 1:(10 to 50).

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