Absorbable composite hemostatic membrane as well as preparation method and application thereof

Abstract

The invention relates to an absorbable composite hemostatic membrane as well as a preparation method and application thereof, and relates to the field of medical materials. The preparation method of the composite hemostatic membrane comprises the following steps: dividing a carboxymethyl chitosan and carboxymethyl cellulose blended solution into a first solution and a second solution; mixing the first solution and a cross-linking agent, and performing cross-linking to obtain a cross-linked substance; cleaning the cross-linked substance by adopting a water-soluble metal ion solution to obtain a primary mixture; mixing the second solution and the primary mixture, and stirring to prepare a film forming solution; the film forming liquid is freeze-dried, the hemostatic membrane is prepared, the prepared absorbable composite hemostatic membrane has good toughness, the degradation rate of the absorbable composite hemostatic membrane in the body can be increased, and then the early-stage hemostatic effect is improved.

Description

Technical Field

[0001] This invention belongs to the field of medical materials, and more specifically relates to an absorbable composite hemostatic membrane, its preparation method, and its uses. Background Technology

[0002] Surgical bleeding is the most common clinical manifestation after surgical trauma. Therefore, efficient and safe hemostasis is essential for the safety of surgical patients. When surgeons cannot control bleeding using conventional hemostasis techniques, they must use hemostatic materials for auxiliary hemostasis. With the increasing sophistication of surgical procedures, the increase in surgical methods, and the aging population, more and more demands are being placed on the quality of hemostasis. Traditional hemostatic materials are insufficient to meet the hemostasis needs of all surgeries. For example, for delicate surgical procedures and some laparoscopic surgeries, hemostatic materials must have good toughness, be able to be inserted into the endoscope through a puncture for hemostasis, be rapidly absorbed by the body while promoting wound healing, and be completely degraded and absorbed within 4-6 weeks. They must also have good tissue compatibility and be very safe.

[0003] Common hemostatic materials mainly include polyvinyl alcohol, polyurethane, oxidized cellulose, chitosan, carboxymethyl polysaccharide, starch (polysaccharide), collagen, gelatin, etc. Conventional hemostatic materials are usually prepared by crosslinking at least one of the above raw materials with an amino activator such as 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and then obtaining them through subsequent processes such as film formation.

[0004] However, currently available hemostatic materials are fragile, lack toughness, and cannot be bent, thus limiting their application in laparoscopic and other endoscopic surgeries. Therefore, developing hemostatic materials that offer early hemostasis while possessing better toughness and accelerating their degradation rate in vivo is of significant practical importance. Summary of the Invention

[0005] In view of the above-mentioned defects and problems of the prior art, the present invention develops an absorbable composite hemostatic membrane, its preparation method and its uses.

[0006] The first aspect of this invention provides a method for preparing a composite hemostatic membrane, comprising the following steps: The blend of carboxymethyl chitosan and carboxymethyl cellulose was divided into a first solution and a second solution. The first solution and the crosslinking agent are mixed and crosslinked to obtain a crosslinked product; The crosslinked material was washed with a water-soluble metal ion solution to obtain a preliminary mixture; The second solution and the initial mixture are mixed and stirred to obtain a film-forming solution; The film-forming solution was freeze-dried to obtain the hemostatic film.

[0007] Optionally, the metal ion solution has one or more of the following characteristics: (a) The metal ions include at least one of calcium ions or magnesium ions; (b) The mass fraction of metal ions is 0.2% to 0.6%.

[0008] Preferably, the step of cleaning the crosslinked material with a water-soluble metal ion solution has one or more of the following characteristics: (a) The mass ratio of the crosslinked material to the metal ion solution is 1:10 to 1:45; (b) The cleaning time is 3~10 hours; (c) Add water to the washed crosslinked material to twice the weight of the crosslinked material before washing, and granulate to obtain the initial mixture.

[0009] Preferably, the crosslinked material is cleaned by oscillation cleaning for 5-8 hours; preferably, the rotation speed is 80-200 rpm.

[0010] Optionally, the mass ratio of the initial mixture to the second solution is 0.1:1 to 6:1.

[0011] Optionally, after the second solution is evenly dispersed with calcium chloride, it is then mixed with the initial mixture.

[0012] Optionally, it has one or more of the following features: (a) The mass fraction of all solutes in the blend is 0.5% to 5%; (b) The preparation process of the blend includes: The carboxymethyl chitosan and the carboxymethyl cellulose were placed in water and dispersed evenly by electric stirring to obtain mixture A; The mixture A is emulsified at a speed of 80-200 rpm for 15-30 minutes to obtain mixture B; The mixture B is placed in an environment of 2-8°C to swell for 12-20 hours, and then stirred a second time at a speed of 80-120 rpm for 20-40 minutes to obtain the blend. (c) The cross-linking process includes: The first solution and the crosslinking agent were emulsified at a stirring speed of 80-120 rpm for 4-8 minutes; then, the mixture was sealed and allowed to stand for 5-10 hours to obtain the crosslinked product. (d) The process of mixing the second solution and the initial mixture includes: emulsifying the second solution and the initial mixture under vacuum conditions for 5 to 15 minutes, wherein the rotation speed is 80 to 120 rpm; (e) The freeze-drying step of the film-forming solution includes: adding the film-forming solution into a freeze-drying mold by casting to freeze-dry and obtain the hemostatic film.

[0013] Optionally, the mass ratio of the carboxymethyl chitosan to the carboxymethyl cellulose is 1.5:1 to 5:1.

[0014] In another aspect, the present invention provides an absorbable composite hemostatic membrane prepared by any of the preparation methods described in the first aspect above.

[0015] In another aspect, the present invention also provides the application of the above-mentioned absorbable composite hemostatic membrane in the preparation of wound repair products.

[0016] In summary, the present invention has at least one of the following beneficial effects: 1. By using a water-soluble metal ion solution to clean the crosslinked material, the mutual repulsion between carboxyl groups in the crosslinked material can be reduced, allowing the molecular chains to extend. This makes it easier to obtain a hemostatic membrane product that can be repeatedly folded and rolled up without affecting its hemostatic effect. It also accelerates its degradation rate in vivo to a certain extent, meeting the requirements for clinical use. 2. By adjusting the mass ratio of the initial mixture to the second solution, it is helpful to further improve the toughness of the absorbable composite hemostatic membrane and accelerate its degradation rate in vivo. 3. By optimizing the stirring method during the cleaning of cross-linked materials with water-soluble metal ion solution, the toughness of the composite hemostatic membrane can be further improved, and its degradation rate in vivo can be accelerated. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0018] Figure 1 This is a schematic diagram showing the bending of the composite hemostatic membranes prepared in Example 1 and Comparative Example 1 when they are artificially bent. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer, and the raw materials used in the following embodiments are all commercially available unless otherwise specified.

[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] In this invention, terms such as "first aspect," "second aspect," and "third aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first," "second," and "third" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0022] In this invention, "optionally," "optionally," and "optional" mean that they are optional, that is, they are selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent.

[0023] In this invention, when multiple ranges are provided to describe a feature or characteristic, these ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0024] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0025] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items. The term "multiple" in this invention means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

[0026] To facilitate the explanation of the technical solution of the present invention, the following materials and steps will be described before starting the experiment of the present invention: (1) The main raw materials in this invention are sourced from the following sources: Carboxymethyl chitosan: purchased from Qingdao Haidefeng Biotechnology Co., Ltd., with a molecular weight of 10,000 Da-500,000 Da; Carboxymethyl cellulose: purchased from Azeres International Trading (Shanghai) Co., Ltd., with a molecular weight of 1 million Da-5 million Da; 1-Ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC): Shanghai Aladdin Biochemical Technology Co., Ltd.; Calcium chloride and magnesium chloride: purchased from Chengdu Huayi Pharmaceutical Excipients Manufacturing Co., Ltd.

[0027] In this invention, the preparation method of the absorbable composite hemostatic membrane mainly includes the following steps: Step 1: Divide the carboxymethyl chitosan and carboxymethyl cellulose blend into a first solution and a second solution.

[0028] Step 2: Mix the first solution and the crosslinking agent to carry out crosslinking and obtain the crosslinked product.

[0029] Step 3: Wash the cross-linked material with a water-soluble metal ion solution to obtain the initial mixture.

[0030] Step 4: Mix the second solution and the initial mixture, stir, and obtain the film-forming solution.

[0031] Step 5: Freeze-dry the film-forming solution to obtain a hemostatic film.

[0032] It should be noted that the preparation method of the carboxymethyl chitosan and carboxymethyl cellulose blend can be any method that ensures the blend is homogeneous and stable. As an example, carboxymethyl chitosan and carboxymethyl cellulose can be placed in water and dispersed evenly by electric stirring to obtain mixture A, wherein the mass ratio of carboxymethyl chitosan to carboxymethyl cellulose is 1.5:1 to 5:1. Mixture A is emulsified at a speed of 80 to 200 rpm for 15 to 30 minutes to obtain mixture B. Mixture B is placed in an environment of 2 to 8°C for swelling for 12 to 20 hours, and then stirred a second time at a speed of 80 to 120 rpm for 20 to 40 minutes to obtain the blend, wherein the mass fraction of all solutes in the blend is 0.5% to 5%.

[0033] After obtaining the blend, the blend is divided into a first solution and a second solution. The volume ratio of the first solution and the second solution can be 0.5:1 to 3:1. As a specific example, in the following embodiments, the volume ratio of the first solution and the second solution is 1:1.

[0034] In step two above, the crosslinking agent can be any amino-based activator selected from 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, dimethylaminopropylethylcarbodiimide, and phenylene ethylcarbodiimide. As a specific example, in the following embodiments, the crosslinking agent is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC). The specific crosslinking process can be as follows: emulsify the first solution and the crosslinking agent at a stirring speed of 80~120 rpm for 4~8 min; then, seal and let stand for 5~10 h to obtain the crosslinked product.

[0035] In step three, it is understood that the mass fraction of metal ions in the water-soluble metal ion solution can be 0.2% to 0.6%, and the metal ions can be human-friendly ions, such as calcium ions, magnesium ions, or titanium ions. The anions in the metal ion solution can be human-friendly ions such as chloride ions or phosphate ions. During the process of cleaning the crosslinked material with the metal ion solution, the mass ratio of the crosslinked material to the metal ion solution is 1:10 to 1:45; the cleaning time is 3 to 10 hours; water is added to the cleaned crosslinked material to twice the weight of the crosslinked material before cleaning, and then granulated to obtain the initial mixture.

[0036] The cleaning method can be flowing liquid circulation cleaning, stirring cleaning, or oscillation cleaning. When oscillation cleaning is used, the cleaning time can be 5 to 8 hours and the rotation speed can be 80 to 200 rpm. Subsequent experimental tests show that when oscillation cleaning is used, the resulting composite hemostatic membrane has better toughness.

[0037] In step four above, to improve the toughness of the final product, the second solution and calcium chloride can be evenly dispersed before being mixed with the initial mixture. During the dispersion of the second solution and calcium chloride, the mass ratio of the second solution to calcium chloride is 100:0.05 to 100:0.5. The second solution and calcium chloride are placed in an emulsifier and emulsified at a stirring speed of 60-100 rpm for 5-15 minutes to obtain the treated second solution. The mixing process of the second solution and the initial mixture includes: mixing the initial mixture and the second solution at a mass ratio of 0.1:1 to 6:1, and emulsifying the treated second solution and the initial mixture under vacuum conditions for 5-15 minutes at a stirring speed of 80-120 rpm. After emulsification, a film-forming liquid is obtained. Because calcium chloride is used in this step, it can further promote the hemostatic effect of the final product and enhance the viscosity of the entire film-forming liquid, facilitating subsequent casting.

[0038] In step five, the film-forming liquid can be added to the freeze-drying mold by casting to obtain a hemostatic film. This invention does not specifically limit the film-forming method.

[0039] It should be noted that granulation and crushing are routine operations in the entire preparation process described above, performed only to ensure sufficient contact between substances, and are not essential steps. In this invention, numerical ranges are involved; unless otherwise specified, these ranges are considered continuous and include the minimum and maximum values ​​within the range, as well as every value between these minimum and maximum values.

[0040] The absorbable composite hemostatic membrane prepared by the above method has a thickness of 0.5~1.5mm (which can be measured by a thickness gauge). It has excellent hemostatic performance, high tensile strength and elongation at break, high degree of curling, good flexibility, and can pass through the puncture card intact. It is suitable for narrow luminal environments and has excellent applications in the preparation of wound repair products.

[0041] Example 1 A method for preparing an absorbable composite hemostatic membrane includes the following steps: (1) Preparation of a blend of carboxymethyl chitosan (CMCS) and carboxymethyl cellulose (CMC): Carboxymethyl chitosan (CMCS) and carboxymethyl cellulose (CMC) were weighed and dissolved in water for injection at a mass ratio of 2.5:1. The materials were slowly dispersed using an electric stirrer to obtain mixture A. Mixture A was placed in an emulsifier and stirred at a speed of 95±5 rpm for 20±2 min to obtain mixture B. Mixture B was placed in a pharmaceutical cooler at 6℃ for 18 h to swell. After swelling, it was stirred a second time at a speed of 95±5 rpm for 30±2 min. Through the above steps, a blend of carboxymethyl chitosan and carboxymethyl cellulose was prepared. The total mass fraction of methyl chitosan and carboxymethyl cellulose in the blend was 1%.

[0042] (2) The CMC and CMCS mixture is divided into a first solution and a second solution, labeled and placed in a cool medicine cabinet for later use. The volume ratio of the first solution to the second solution is 1:1.

[0043] (3) Preparation of cross-linked materials: The first solution and EDC were added to a vacuum emulsifier and emulsified for 6±1 min at a stirring speed of 95±5 rpm. The vacuum homogenizing emulsifier tank was then sealed and allowed to stand for 7 h to activate, resulting in the crosslinked material.

[0044] (4) Place the crosslinked material obtained in step (3) into an emulsifier and stir and crush it. The stirring time is 2 min ± 30 s and the stirring speed is 45 ± 5 rpm to obtain the crushed crosslinked material.

[0045] (5) Cleaning cross-linked substances The crushed crosslinked material was placed in a 0.45% calcium chloride solution and washed by shaking at 25°C for 6 hours, with a shaking speed of 180 rpm. The mass ratio of the crushed crosslinked material to the calcium chloride solution was 1:20. Water for injection was added to the washed crosslinked material until it reached twice its original weight. The water-added crosslinked material was then granulated using a double-layer 150-mesh sieve in a granulator to obtain the granulated initial mixture.

[0046] (6) Treatment of the second solution The second solution and calcium chloride were placed in an emulsifier at a mass ratio of 50:0.1, and the stirring speed was 95±5 rpm for 8±1 min to obtain the treated second solution.

[0047] (7) Mixing of the second solution and the initial mixture: The initial mixture obtained in step (5) and the second solution obtained in step (6) are mixed in a vacuum homogenizer (vacuum degree of 0.08 MPa) at a mass ratio of 1:1, with an allowable deviation of ±1 g in the amount added. Emulsification is carried out at a stirring speed of 95±5 rpm for 9±1 min. After the emulsification is completed, the film-forming solution is obtained.

[0048] (8) Film formation: Using a casting method, the film-forming liquid obtained in step (7) is applied in a ratio of 5g:10cm² between the mass of the film-forming liquid and the bottom area of ​​the film-forming mold. 2 The mixture is spread evenly in a freeze-drying mold and freeze-dried. The allowable deviation of the amount of film-forming solution added is ±1g, resulting in an absorbable composite hemostatic membrane.

[0049] Example 2 The difference from Example 1 is that in step (5), the calcium chloride solution is replaced with a magnesium chloride solution of the same concentration, while the other steps are the same.

[0050] Example 3 The difference from Example 1 is that in step (5), a calcium chloride solution with a mass fraction of 0.6% is used, while the other steps are the same.

[0051] Example 4 The difference from Example 1 is that in step (5), electromagnetic stirring is used, with a stirring speed of 180 rpm and a stirring time of 6 hours. The other steps are the same.

[0052] Example 5 In step (7), the initial mixture obtained in step (5) and the second solution obtained in step (6) are in a mass ratio of 6:1, and the remaining steps are the same.

[0053] Example 6 In step (7), the initial mixture obtained in step (5) and the second solution obtained in step (6) are in a mass ratio of 0.1:1, and the other steps are the same.

[0054] Example 7 The difference from Example 1 is that step (6) is omitted, and in step (7), the second solution is directly mixed with the initial mixture obtained in step (5), while the other steps are the same.

[0055] Example 8 Step (4) is omitted, and in step (5), the crosslinked material obtained in step (3) is directly placed in a calcium chloride solution for washing, and the washed crosslinked material is not granulated again. The remaining steps are the same.

[0056] Comparative Example 1 The difference from Example 1 is that in step (5), the broken crosslinked material is placed in water for injection (the mass of water for injection is 20 times the mass of the broken crosslinked material), and shaken and washed at 25°C for 3 hours. After that, the waste liquid after washing is discarded, and then placed in the same volume of water for injection, and shaken and washed at 25°C for 3 hours. The remaining steps are the same, and the shaking parameters are the same.

[0057] Comparative Example 2 The difference from Example 1 is that in step (5), the broken crosslinked material is placed in a PBS solution with a pH of 7.0 (the mass ratio of the broken crosslinked material to the PBS solution is 1:20), and shaken and washed at 25°C for 3 hours; then, the waste liquid after washing is discarded, and the product is placed in the same volume of water for injection, and shaken and washed at 25°C for 3 hours. The remaining steps are the same. The shaking speed is also the same.

[0058] Comparative Example 3 The difference from Example 1 is that in step (5), the broken crosslinked material is placed in a PBS solution with a pH of 7.0 (the mass ratio of the broken crosslinked material to the PBS solution is 1:20), and shaken and washed at 25°C for 6 hours. The remaining steps are the same. The shaking speed is also the same.

[0059] Comparative Example 4 The difference from Example 1 is that the cleaning step in step (5) is not performed, and in step (7), the broken crosslinked material obtained in step (4) is directly mixed with the second solution.

[0060] Comparative Example 5 A method for preparing an absorbable composite hemostatic membrane includes the following steps: Steps (1)-(5) are the same as steps (1)-(5) in Example 1. The difference from Example 1 is that after step (5), the following steps (6) and (7) are performed: (6) The initial mixture obtained in step (5) is mixed with an equal mass of water for injection in a vacuum homogenizer (vacuum degree is 0.08 MPa), and the allowable deviation of the amount added is ±1 g. Emulsify for 9 ± 1 min at a stirring speed of 95 ± 5 rpm. After the emulsification is completed, the film-forming solution is obtained.

[0061] (7) Using a casting method, the film-forming liquid obtained in step (6) is applied in a ratio of 5g:10cm² between the mass of the film-forming liquid and the bottom area of ​​the film-forming mold. 2 The mixture was spread evenly in a freeze-drying mold and freeze-dried. The allowable deviation of the amount of film-forming liquid added was ±1g, and the corresponding sample was obtained.

[0062] Comparative Example 6 A method for preparing an absorbable composite hemostatic membrane includes the following steps: Steps (1)-(2) are the same as steps (1)-(2) in Example 1. The difference from Example 1 is that after step (2), the following steps (3) and (4) are performed: (3) The second solution and calcium chloride were placed in an emulsifier at a mass ratio of 50:0.1, and the stirring speed was 95±5 rpm. The emulsification was carried out for 8±1 min to obtain the treated second solution. The treated second solution was used as the film-forming solution.

[0063] (4) Using a casting method, the second solution is applied in a ratio of 5g:10cm² between the mass of the film-forming solution and the bottom area of ​​the film-forming mold. 2 The mixture was spread evenly in a freeze-drying mold and freeze-dried. The allowable deviation of the amount of film-forming liquid added was ±1g, and the corresponding sample was obtained.

[0064] Performance testing Performance Test 1: Flexibility Test Example 1: Mechanical Property Test

[0065] Test method: The composite hemostatic membrane prepared in the examples and preparation examples was cut into 10mm×40mm specimens and tested using a microcomputer-controlled electronic universal testing machine of model STD500. The clamping distance between the two ends of the specimen length direction of the microcomputer-controlled electronic universal testing machine was 10mm, and the experimental length in the middle of the specimen clamp was 20mm. The two clamps were moved in opposite directions at a speed of 20mm / min, and the maximum load (N) and the displacement (mm) corresponding to the maximum load of each specimen were recorded. The tensile breaking strength of each specimen was calculated according to the following formula (1), and the elongation at break of each specimen was calculated according to the following formula (2). The test results are shown in Table 1.

[0066] Formula (1): Tensile breaking strength (MPa) = Maximum load (N) / (Width (mm) × Thickness (mm)); Formula (2): Elongation at break = Displacement corresponding to maximum load (mm) / Experimental length (mm) × 100%.

[0067] It should be noted that the greater the tensile strength at break and the higher the elongation at break, the better the strength and ductility of the product, which is a concentrated manifestation of the product's excellent toughness.

[0068] Table 1. Mechanical property data of composite hemostatic membranes prepared in the examples and comparative examples Grouping Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Tensile breaking strength (MPa) 0.39 0.38 0.36 0.33 0.30 0.28 0.35 0.37 0.14 0.17 0.16 0.11 0.09 0.05 Elongation at break (%) 10.15 10.12 10.09 9.95 9.82 9.73 10.00 10.05 2.76 3.26 3.17 2.25 2.07 1.98

[0069] As shown in Table 1, the tensile strength and elongation at break of the products prepared in Comparative Examples 1-6 are all poor, indicating to some extent that the toughness of these products is also poor. It should be noted that the data for the sample prepared in Comparative Example 4 are listed here for comparison with other data to illustrate that the cleaning step and the reagents used in the cleaning step have a significant impact on the mechanical properties of the prepared products. When the crosslinking agent is not cleaned or is cleaned with water or a buffer solution, the mechanical properties of the prepared products are very poor. In fact, because the product prepared in Comparative Example 4 did not undergo a cleaning step, the residual crosslinking agent content would render it unsuitable for practical application due to safety concerns.

[0070] A comparison of the data from Examples 1 and 4 shows that the stirring method also affects the flexibility of the product during the cleaning of the crosslinked material. This may be because the stirring method affects the microstructure of the material, resulting in differences in the toughness of the product.

[0071] By comparing the data from Examples 1, 5, and 6, and Comparative Examples 5 and 6, it can be seen that mixing the initial mixture with the second solution is necessary, and the mixing ratio between the initial mixture and the second solution has a certain influence on the mechanical properties of the prepared composite hemostatic membrane.

[0072] A comparison of the data from Examples 1 and 7 shows that the absence of treatment on the second solution also affects the mechanical properties to some extent. This may be due to calcium chloride affecting the viscosity of the final product and its influence on the internal structure of the composite hemostatic membrane.

[0073] Test Example 2: Card Stamping Experiment This invention utilizes a medical trocar to conduct trocar experiments on samples prepared in Examples 1-8 and Comparative Examples 1-6. The medical trocar is a medical device used in laparoscopic surgery to establish access to the abdominal cavity. It typically consists of a long, thin metal tube and a disc. During laparoscopic surgery, the surgeon makes a small incision in the patient's abdomen and inserts the trocar into the abdominal cavity. The disc of the trocar remains outside the abdominal wall, while the long, thin metal tube enters the abdominal cavity to facilitate the insertion of the laparoscope and surgical instruments. An absorbable hemostatic membrane is bent into a cylindrical shape and enters the cavity through the metal tube.

[0074] The puncture test showed that the samples prepared in Examples 1-8 of this invention could pass through the puncture completely, meaning that the bent samples were not easily cracked or broken. However, the samples prepared in Comparative Examples 1, 2, and 3 cracked after bending, making them unsuitable for clinical use. The samples prepared in Comparative Examples 4 and 5 started to crumble immediately after bending, making them unsuitable for clinical use. The sample prepared in Comparative Example 6 not only had poor film-forming properties, but also cracked after bending, making it unsuitable for clinical use.

[0075] To facilitate a more intuitive understanding, the products obtained in Examples 1-8 and Comparative Examples 1-6 were cut to the same specifications and manually bent by the same operator. As a specific example, some data are listed below. Figure 1 .according to Figure 1 It is evident that the absorbable composite hemostatic membrane prepared in the embodiments of the present invention has good toughness and can be completely rolled up to be suitable for different trauma environments, thus having strong clinical applicability.

[0076] Combining Table 1 and Figure 1 It is evident that the absorbable composite hemostatic membrane prepared by the method of this invention exhibits superior mechanical properties, significantly enhancing the product's toughness. This is likely due to the fact that the present invention, through washing with a water-soluble metal solution such as calcium chloride, can control the gel's water absorption, maintain its internal osmotic pressure, and prevent the gel from becoming too brittle due to water absorption. Furthermore, the addition of inorganic salts reduces the mutual repulsion of carboxyl groups on the CMC molecules, allowing their molecular chains to extend, resulting in a tough absorbable composite hemostatic membrane. This flexibility makes the absorbable composite hemostatic membrane suitable for confined cavities, thus improving its clinical applicability.

[0077] Performance Test 2: Degradation Performance The method for testing the degradation performance of the composite hemostatic membranes prepared in the examples and comparative examples is as follows: Take a 2g sample measuring 3cm × 4cm, cut each piece into 6 uniform pieces, mix well, and divide the sample into 2 portions. Take 0.1g of each portion and determine the loss on drying of this product according to the method specified in General Chapter 0831 of Part IV of the Pharmacopoeia of the People's Republic of China (2020 Edition). Weigh 0.1g of each portion (accurate to 0.0001g) according to m 样品 V PBS A phosphate buffer containing lysozyme was added to each sample at a ratio of 1 g / 200 mL. After gently shaking to ensure sufficient contact between the material and the lysozyme in the phosphate buffer, the samples were simulated for degradation at 37°C and 120 rpm. Samples were collected at 1 h and 24 h, centrifuged at 4000 rpm for 15 minutes, and then poured into Buchner funnels lined with pre-weighed filter paper. The samples were then filtered using a vacuum pump. After filtration, the pre-weighed filter paper and remaining residue were collected in a weighing bottle, dried at 105°C to constant weight, and the mass was recorded as W. i The degradation rate (%) of the material is calculated using the following formula: Degradation rate = [W0 * (1-w) - W] i ] / [W0*(1-w)]*100%, where W o W represents the weight of each sample after drying (g), and w represents the weight loss rate of each sample during drying (%). i The values ​​represent the dried weight (g) of each sample after degradation. The test results are shown in Table 2.

[0078] Table 2. Degradation performance of products prepared in the examples and comparative examples

[0079] As shown in Table 2, the absorbable composite hemostatic membrane prepared by the method of this invention exhibits good degradation performance, thus improving safety. This may be because a suitable cross-linking cleaning method can reduce the mutual repulsion of carboxyl groups on CMC molecules, promoting degradation. Furthermore, the appropriate ratio between the initial mixture and the second solution also helps to weaken the rigid structure of the final product, accelerating the degradation rate.

[0080] In addition, the hemostatic effect of the composite hemostatic membranes prepared in Examples 1-8 of the present invention was tested in animal experiments. The test results showed that the hemostatic effect of the composite hemostatic membranes prepared in Examples 1-8 of the present invention was excellent.

[0081] It should be understood that the disclosed invention is not limited to the specific methods, schemes, and substances described, as these are all subject to variation. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of the invention, which is limited only by the appended claims.

[0082] Those skilled in the art will also recognize, or be able to identify, many equivalents of the specific embodiments of the invention described herein using no more than conventional experiments. These equivalents are also included in the appended claims.

Claims

1. A method for preparing an absorbable composite hemostatic membrane, characterized in that, Includes the following steps: The blend of carboxymethyl chitosan and carboxymethyl cellulose was divided into a first solution and a second solution. The first solution and the crosslinking agent are mixed and crosslinked to obtain a crosslinked product; The crosslinked material was washed with a water-soluble metal ion solution to obtain a preliminary mixture; The second solution and the initial mixture are mixed and stirred to obtain a film-forming solution; The film-forming solution was freeze-dried to obtain the hemostatic film.

2. The preparation method according to claim 1, characterized in that, The metal ion solution has one or more of the following characteristics: (a) The metal ions include at least one of calcium ions or magnesium ions; (b) The mass fraction of metal ions is 0.2% to 0.6%.

3. The preparation method according to claim 1, characterized in that, The step of cleaning the crosslinked material with a water-soluble metal ion solution has one or more of the following characteristics: (a) The mass ratio of the crosslinked material to the metal ion solution is 1:10 to 1:45; (b) The cleaning time is 3~10 hours; (c) Add water to the washed crosslinked material to twice the weight of the crosslinked material before washing, and granulate to obtain the initial mixture.

4. The preparation method according to claim 3, characterized in that, The crosslinked material is cleaned by oscillation cleaning for 5-8 hours; preferably, the rotation speed is 80-200 rpm.

5. The preparation method according to claim 1, characterized in that, The mass ratio of the initial mixture to the second solution is 0.1:1 to 6:

1.

6. The preparation method according to claim 1, characterized in that, After the second solution is evenly dispersed with calcium chloride, it is then mixed with the initial mixture.

7. The preparation method according to claim 1, characterized in that, It has one or more of the following characteristics: (a) The mass fraction of all solutes in the blend is 0.5% to 5%; (b) The preparation process of the blend includes: The carboxymethyl chitosan and the carboxymethyl cellulose were placed in water and dispersed evenly by electric stirring to obtain mixture A; The mixture A is emulsified at a speed of 80-200 rpm for 15-30 minutes to obtain mixture B; The mixture B is placed in an environment of 2-8°C to swell for 12-20 hours, and then stirred a second time at a speed of 80-120 rpm for 20-40 minutes to obtain the blend. (c) The cross-linking process includes: The first solution and the crosslinking agent were emulsified at a stirring speed of 80-120 rpm for 4-8 minutes; then, the mixture was sealed and allowed to stand for 5-10 hours to obtain the crosslinked product. (d) The process of mixing the second solution and the initial mixture includes: emulsifying the second solution and the initial mixture under vacuum conditions for 5 to 15 minutes, wherein the rotation speed is 80 to 120 rpm; (e) The freeze-drying step of the film-forming solution includes: adding the film-forming solution into a freeze-drying mold by casting to freeze-dry and obtain the hemostatic film.

8. The preparation method according to claim 1, characterized in that, The mass ratio of the carboxymethyl chitosan to the carboxymethyl cellulose is 1.5:1 to 5:

1.

9. An absorbable composite hemostatic membrane, characterized in that, It is prepared by any one of the preparation methods described in claims 1-8.

10. The application of the absorbable composite hemostatic membrane according to claim 9 in the preparation of wound repair products.

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