Medical soft tissue adhesive as well as preparation method and application thereof

Abstract

The invention relates to a medical soft tissue adhesive. The medical soft tissue adhesive comprises at least one adhesive layer and at least one anti-adhesion layer arranged on the adhesive layer, the bonding layer at least comprises a component A, and the component A is a polymer with one or more reactive functional groups; the reactive functional group is selected from one or more of a hydroxyl group, an aldehyde group, a carboxyl group, a pyrrolidone group, an amide group, a maleimide ester group and a succinimide ester group; the anti-adhesion layer at least comprises a component B, and the component B is an alkaline polymer with film-forming property. During preparation, the anti-adhesion layer and the bonding layer are alternately coated to prepare the medical soft tissue adhesive, and the medical soft tissue adhesive is widely applied to medical adhesives.

Description

Technical Field

[0001] The present invention relates to the field of biomedical technologies, and particularly to a medical soft tissue adhesive and its preparation method and application. Background Art

[0002] In clinical practice, after soft tissues such as the heart, blood vessels, dura mater, lungs, and pancreas have lesions, defects, or are traumatized, surgery is usually required to repair or excise the wound surface. In order to further promote the repair of the lesion site or prevent tissue fluid / blood leakage, soft tissue adhesives or soft tissue adhesive patches are used during the operation for sealing or reinforcement.

[0003] For the above diseases, there are currently various types of soft tissue adhesives in clinical practice, which are mainly divided into two categories: bio-derived materials and polymer synthetic materials. Among them, bio-derived materials are represented by PEG hydrogels. PEG adhesives have good biocompatibility, but have low bonding strength, fast degradation rate, and do not have the effect of preventing adhesion. For soft tissues of the cardiovascular and cerebrovascular systems, they are prone to cause adhesion and affect tissue repair. Polymer synthetic materials are mainly adhesives containing -NHS groups. -NHS adhesives have the advantage of high bonding strength. However, when this substance interacts with tissues, the acidic -NHS degradation products generated cannot maintain the tissue acid-base balance, have poor biocompatibility, are prone to cause tissue inflammation, are not conducive to tissue healing, and this substance is relatively brittle, making the surgical operability poor. Summary of the Invention

[0004] The object of the present invention is to provide a medical soft tissue adhesive and its preparation method and application, which improve the tissue adhesion and biocompatibility of the adhesive based on soft tissue bonding in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a medical soft tissue adhesive, comprising: at least one adhesive layer and at least one anti-adhesion layer provided on the adhesive layer;

[0007] The adhesive layer at least comprises component A, and component A is a polymer having one or more reactive functional groups; the reactive functional groups are one or more selected from hydroxyl group, aldehyde group, carboxyl group, pyrrolidone group, amide group, maleimide ester group, and succinimide ester group;

[0008] The anti-adhesion layer at least comprises component B, and component B is a basic polymer with film-forming property.

[0009] Further, in Component A, the polymerizable monomer providing the carboxyl group is acrylic acid, the polymerizable monomer providing the pyrrolidinone group is N-vinylpyrrolidone, the polymerizable monomer providing the maleimide ester group is maleimide acrylate, and the polymerizable monomer providing the succinimide ester group is succinimide acrylate.

[0010] Further, the polymerizable monomer can also be selected from carboxyl groups, isocyanate groups, N-hydroxysuccinimide, N-hydroxythiobuccinimide, N-hydroxy-3,3-cyclopentanepentanedicarboximide or N-hydroxyphthalimide that react with tissues, or can also be selected from groups such as hydroxyl groups, carboxyl groups and amino groups that can form hydrogen bonds with tissues.

[0011] Further, Component A is copolymerized from the polymerizable monomers N-vinylpyrrolidone, acrylic acid and succinimide acrylate, and the molar ratio of N-vinylpyrrolidone, acrylic acid and succinimide acrylate is (6 - 14):(3 - 8):(3 - 8).

[0012] Further, the film-forming basic polymer is chitin and its modified derivatives, chitosan and its modified derivatives, or cellulose and its modified derivatives.

[0013] Further, the chitosan modified derivative is prepared by reacting chitosan with a modifier. The chitosan is α-chitosan, β-chitosan or γ-chitosan, the modifier is a carboxylic acid, an alkyl acid, an acyl chloride or an acid anhydride, and the alkyl acid is stearic acid or palmitic acid.

[0014] Further, the relative molecular mass of the chitosan is 5×10 4 ~1×10 5 .

[0015] Further, the number of layers of the adhesive layer is 1 - 5 layers, and the number of layers of the anti-adhesion layer is 1 - 3 layers.

[0016] Further, the thickness of the medical soft tissue adhesive is 0.02 - 0.10 mm, preferably 0.03 - 0.06 mm.

[0017] The second aspect of the present invention provides a preparation method of a medical soft tissue adhesive, comprising the following steps:

[0018] (1) Chitosan and a modifier are heated under reflux under the action of a catalyst to obtain Component B;

[0019] (2) Under an N 2 atmosphere, N-vinylpyrrolidone, acrylic acid and an initiator are placed in a first solvent and mixed and heated;

[0020] (3) Cool the reaction system in step (2) to room temperature, and then add N-hydroxysuccinimide and a condensing agent to the reaction system, and mix them for reaction to obtain component A;

[0021] (4) Dissolve component B described in step (1) in a second solvent, and then perform coating to form an anti-adhesion layer;

[0022] (5) Dissolve component A described in step (3) in a third solvent, and then perform coating to form an adhesive layer;

[0023] (6) Coat the anti-adhesion layer and the adhesive layer alternately, and dry them to obtain the medical soft tissue adhesive.

[0024] Further, in step (1), the catalyst is EDC, DCC or DIC; the heating temperature is 60 °C, the reaction duration is 4-10 h; the molar ratio of chitosan, the modifier and the catalyst is 3:(1-1.3):2.5.

[0025] Further, in step (2), the dosage of the initiator is 0.01%-0.03% of the total amount of N-vinylpyrrolidone and acrylic acid, the initiator is azobisisobutyronitrile, the first solvent is dimethyl sulfoxide, the heating temperature is 70-85 °C, and the heating duration is 16-26 h;

[0026] In step (3), the molar ratio of N-hydroxysuccinimide, the condensing agent and acrylic acid is (1-1.5):(1-1.2):1, the condensing agent is DCC or EDC, and the reaction duration is 48-72 h.

[0027] Further, in step (4), the second solvent is dichloromethane; in step (5), the third solvent is a mixed solution of dichloromethane and methanol.

[0028] Further, in step (6), the drying temperature is 30 °C to 150 °C, more preferably 60 °C to 120 °C.

[0029] The third aspect of the present invention provides an application of a medical soft tissue adhesive in a medical adhesive.

[0030] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0031] The present invention enhances the mechanical strength and flexibility of the adhesive by introducing a film-forming alkaline polymer and a carboxyl-containing adhesive layer polymer to construct a hydrolyzable ester bond. At the same time, by constructing the ester bond, the release rate of the -NHS groups in the film-forming alkaline polymer and the adhesive layer polymer is regulated, and the tissue repair cycle is matched, solving the problems of low mechanical strength and high brittleness of -NHS adhesives and low mechanical properties and fast degradation rate of hydrogel adhesives in the prior art.

[0032] In addition, a film-forming alkaline polymer is introduced onto the anti-adhesion layer, making it have a good anti-adhesion effect, which can effectively prevent adhesion between tissues and avoid secondary tissue damage. Detailed implementation manners

[0033] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] Example 1:

[0035] This example provides a medical soft tissue adhesive and its preparation method, including the following steps:

[0036] (1) Weigh 72.5 g of chitosan and 42.6 g of stearic acid and add them to a reactor. Add 57.3 g of EDC catalyst, and mix evenly in a PBS buffer solution at room temperature and pH = 6 to obtain a mixed solution. Heat and react at 60 °C, while stirring and refluxing for 8 h. After the reaction is completed, naturally cool to room temperature, filter by suction to obtain a modified product, wash the modified product with ethanol, and dry to obtain stearic acid-modified chitosan;

[0037] (2) Add 1000 mL of dimethyl sulfoxide to a reaction kettle, heat it to 75 °C in an oil bath, and simultaneously purge with nitrogen to remove oxygen in the solvent system. Add 55.8 g of N-vinylpyrrolidone, 36.2 g of acrylic acid, and 0.6 g of azobisisobutyronitrile to the reaction kettle, and continuously react for 24 h;

[0038] After the reaction is cooled to room temperature, add 28.8 g of N-hydroxysuccinimide and 61.9 g of dicyclohexylcarbodiimide to the reaction kettle, and continue to react for 48 h; after the reaction is completed, add 6000 mL of isopropanol to precipitate the polymer, and filter and separate. The obtained polymer is washed 3 times in isopropanol, and then the polymer is freeze-dried to obtain component A.

[0039] (3) Dissolve 2.5 g of the above stearic acid-modified chitosan in 25 mL of dichloromethane (concentration 10% w / v), stir for 2 h at room temperature. After complete dissolution, cast it onto a high-density polyethylene plate, coat it on a coater, and dry at room temperature to obtain a uniform anti-adhesion layer;

[0040] Dissolve 1.88 g of the above component A in 25 mL of dichloromethane / methanol solution (mass ratio 5:1), stir for 2 h at room temperature. After complete dissolution, cast it onto the above anti-adhesion layer, coat it on a coater, and dry at room temperature to obtain a uniform adhesive layer;

[0041] Coat in the order of anti-adhesion layer - adhesive layer - anti-adhesion layer - adhesive layer - adhesive layer to obtain a 5-layer composite film; then place the composite film in a vacuum drying oven and dry at 120 °C for 72 h to obtain a medical soft tissue adhesive.

[0042] Example 2:

[0043] This example provides a medical soft tissue adhesive and its preparation method. The only difference from Example 1 is that the alkanoic acid used in step (1) is palmitic acid, and the feeding amount is 38.5 g. Finally, a medical soft tissue adhesive is also prepared.

[0044] Example 3:

[0045] This example provides a medical soft tissue adhesive and its preparation method. The only difference from Example 1 is that the coating order is anti-adhesion layer - anti-adhesion layer - adhesive layer - adhesive layer - adhesive layer. Finally, a medical soft tissue adhesive is also prepared.

[0046] Example 4:

[0047] This example provides a medical soft tissue adhesive and its preparation method. The only difference from Example 1 is that the feeding amount of stearic acid in step (1) is 56.9 g. Finally, a medical soft tissue adhesive is also prepared.

[0048] Example 5:

[0049] This example provides a medical soft tissue adhesive and its preparation method. The only difference from Example 1 is that the feeding amount of stearic acid-modified chitosan in step (3) is 1.25 g. Finally, a medical soft tissue adhesive is also prepared.

[0050] Example 6:

[0051] This example provides a medical soft tissue adhesive and its preparation method. The only difference from Example 1 is that the feeding amount of stearic acid-modified chitosan in step (3) is 3.0 g. Finally, a medical soft tissue adhesive is also prepared.

[0052] Comparative Example 1

[0053] This example provides a medical soft tissue adhesive and its preparation method. The difference from Example 1 is only that a film-forming alkaline polymer is not used, and the reaction is carried out with a lactide-glycolide copolymer instead of Component B. The specific preparation method includes the following steps:

[0054] (1) Add 1000 mL of dimethyl sulfoxide to the reaction kettle, heat it in an oil bath to 75 °C, and simultaneously purge with nitrogen to remove oxygen in the solvent system. Add 55.8 g of N-vinylpyrrolidone, 36.2 g of acrylic acid, and 0.6 g of azobisisobutyronitrile to the reaction kettle, and react continuously for 24 h;

[0055] After the reaction drops to room temperature, add 28.8 g of N-hydroxysuccinimide and 61.9 g of dicyclohexylcarbodiimide to the reaction kettle, and continue to react for 48 h; after the reaction is completed, add 6000 mL of isopropanol to precipitate the polymer, and filter and separate. The obtained polymer is washed 3 times in isopropanol, and then the polymer is freeze-dried to obtain Component A.

[0056] (2) Take 2.5 g of lactide-glycolide copolymer (containing 50% lactide and 50% glycolide, Mw = 100 kDa) and dissolve it in 25 mL of dichloromethane (concentration 10% w / v). Stir at room temperature for 2 h. After complete dissolution, cast it onto a high-density polyethylene plate and coat it on a coater, and dry it at room temperature to obtain a uniform anti-adhesion layer;

[0057] Take 1.88 g of the above Component A and dissolve it in 25 mL of dichloromethane / methanol solution (mass ratio 5:1). Stir at room temperature for 2 h. After complete dissolution, cast it onto the above anti-adhesion layer and coat it on a coater, and dry it at room temperature to obtain a uniform adhesive layer;

[0058] Coat in the order of anti-adhesion layer - adhesive layer - anti-adhesion layer - adhesive layer - adhesive layer to obtain a 5-layer composite film; then place the composite film in a vacuum drying oven and dry it at 120 °C for 72 h to prepare the medical soft tissue adhesive.

[0059] In the present invention, the performance of the product prepared above is characterized as follows:

[0060] 1. pH of in vitro degradation solution

[0061] According to the characteristics of the product, PBS buffer solution is used as the in vitro degradation reagent, and the degradation experiment is carried out under the extraction condition of 37 °C, and 72 h, 1 w, 4 w, and 12 w are set respectively. The specific pH data of the degradation solution are as follows:

[0062] Table 1 pH data of in vitro degradation solution

[0063] Example Degradation for 72 h Degradation for 1 week Degradation for 4 weeks Degradation for 12 weeks Example 1 7.1 7.2 7.3 7.2 Example 2 6.9 7.1 7.0 7.1 Example 3 5.9 6.1 6.7 7.0 Example 4 6.8 6.9 7.1 7.1 Example 5 6.5 6.5 6.6 6.6 Example 6 7.1 7.1 7.2 7.2 Comparative Example 1 5.2 4.5 4.3 4.3

[0064] As can be seen from Table 1, the pH of the degradation solution of the adhesives provided in Examples 1, 2, 4, 5, and 6 basically remained at 6.5 - 7.3, while the pH of the degradation solution in Comparative Example 1 was in the range of 4.3 - 5.2. In the examples of the present invention, by introducing different proportions of -NH 2 groups, the pH was adjusted to regulate the acidic environment generated when the -NHS groups act on tissues, and the acid-base balance at the tissue repair site was maintained. Through Example 3, it can be seen that the adhesive obtained by alternating coating can more effectively regulate the acid-base balance during the tissue repair process.

[0065] 2. Mechanical strength research

[0066] 2.1 Adhesive tensile strength

[0067] Table 2 Adhesive tensile strength

[0068] Example number Adhesion tensile strength (Mpa) Example 1 45 Example 2 43 Example 3 25 Example 4 42 Example 5 35 Example 6 44 Comparative Example 1 21

[0069] As can be seen from Table 2, the adhesive tensile strengths of the adhesives provided in Examples 1, 2, 4, and 6 are much greater than that of Comparative Example 1. From the tensile strength values, it can be known that in the examples of the present invention, the adhesives involved improve the bonding strength through the introduction of -NHS bonding functional groups and the abundant hydroxyl groups in chitosan, and can have good adhesion to the wound surface tissue to seal the wound surface.

[0070] 2.2 Rupture strength

[0071] Table 3 Rupture strength

[0072] Example number Burst strength (Kpa) Example 1 18.38 Example 2 17.67 Example 3 12.93 Example 4 16.29 Example 5 14.25 Example 6 19.81 Comparative Example 1 6.37

[0073] As can be seen from Table 3, the rupture strengths of the adhesives provided in Examples 1 - 5 are much greater than that of Comparative Example 1. The modified chitosan and the carboxyl-containing adhesive layer polymer construct easily hydrolyzable ester bonds, enhancing the rupture strength of the adhesive. It can better seal the wound surface and prevent air or liquid leakage from the tissue. From the comparison of Examples 1 - 5, it can be seen that the concentration, number of layers, drying parameters, etc. of the modified chitosan in the forming process also have a greater impact on the rupture strength.

[0074] 2.3 Elongation at break

[0075] Table 4 Elongation at break

[0076] Example number Elongation at break (%) Example 1 4.3 Example 2 4.2 Example 3 2.8 Example 4 3.8 Example 5 3.2 Example 6 5.0 Comparative Example 1 1.2

[0077] As can be seen from Table 4, the elongation at break of the adhesives provided in Examples 1-6 is much greater than that of Comparative Example 1. The introduction of modified chitosan and the formation of strong forces between the modified chitosan and the adhesive layer enhance the flexibility of the adhesive patch and make the surgical operability strong.

[0078] 3. In vitro cytotoxicity study

[0079] According to the in vitro cytotoxicity test of GB / T 16886.5, the in vitro cytotoxicity tests (MTT method) were carried out on Examples 1-5 and Comparative Example 1.

[0080] 3.1 MTT results of relative cell viability

[0081] Table 5 Relative cell viability

[0082]

[0083]

[0084] 3.2 Cell pictures of sample extracts

[0085] Table 6 Cell status of 100% sample extracts

[0086]

[0087] As can be seen from Table 5 and Table 6, the cell viability of the adhesives provided in Examples 1 and 2 is much greater than that of Comparative Example 1. For the adhesives involved in the examples of the present invention, the anti-adhesive layer is coated with modified chitosan, and the alkaline hydrophobic structure can neutralize the acidic functional groups of the adhesion layer, neutralize the acidic environment generated by -COOH and NHS groups during tissue repair, reduce the irritation of the tissue patch to the tissue, and is beneficial to cell growth, reproduction or survival.

[0088] 4. In vivo implantation study

[0089] In vivo implantation studies were carried out using Example 1, Example 2 and Comparative Example 1, and HE section observations were set at three time points of 1 month, 3 months and 6 months.

[0090] Table 7 Status of HE sections

[0091]

[0092] As can be seen from Table 7, there is no obvious inflammatory reaction in the sections of Examples 1 and 2. The adhesives involved in the examples of the present invention have good biocompatibility, while there are a large number of inflammatory cells around the tissue in Comparative Example 1, which affects tissue repair.

[0093] In summary, a medical soft tissue adhesive provided in the present invention is composed of modified chitosan and a polymer containing active - NHS groups. The adhesive layer is a synthetic organic polymer active material with abundant active groups, which can covalently bond with tissues instantaneously during fitting, showing good tissue adhesion and high bonding strength. The introduction of - NH 2 groups in the modified chitosan solves the problem that the degradation products of existing adhesives containing active - NHS are acidic, which easily causes acid - base imbalance at the tissue repair site and leads to local inflammation.

[0094] The modified chitosan and the adhesive layer polymer containing carboxyl groups form easily hydrolyzable ester bonds, enhancing the mechanical strength and flexibility of the adhesive. At the same time, through the construction of ester bonds, the release rates of the modified chitosan and - NHS groups are regulated to match the tissue repair cycle, solving the problems of low mechanical strength and high brittleness of existing - NHS - based adhesives, and low mechanical properties and fast degradation rate of hydrogel - based adhesives.

[0095] The above - mentioned embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. However, the protection scope of the present invention cannot be limited thereby. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A medical soft tissue adhesive, characterized in that: include: at least one adhesive layer and at least one anti-adhesion layer disposed on the adhesive layer; The adhesive layer comprises at least component A, wherein component A is a polymer having one or more reactive functional groups; the reactive functional groups are one or more selected from hydroxyl, aldehyde, carboxyl, pyrrolidone, amide, maleimide ester, and succinimide ester. The anti-adhesion layer at least comprises component B, and the component B is a basic polymer with film-forming property.

2. A medical soft tissue adhesive according to claim 1, characterized in that: In component A, the polymerizable monomer providing the carboxyl group is acrylic acid, the polymerizable monomer providing the pyrrolidone group is N-vinyl pyrrolidone, the polymerizable monomer providing the maleimide ester group is maleimide acrylate, and the polymerizable monomer providing the succinimide ester group is succinimide acrylate.

3. A medical soft tissue adhesive according to claim 2, characterized in that: The component A is copolymerized by polymerizing monomers N-vinyl pyrrolidone, acrylic acid and succinimide acrylate, and the molar ratio of N-vinyl pyrrolidone, acrylic acid and succinimide acrylate is (6-14): (3-8): (3-8).

4. The medical soft tissue adhesive according to claim 1, characterized in that: The alkaline polymer with film-forming property is chitin and its modified derivatives, chitosan and its modified derivatives or cellulose and its modified derivatives.

5. The medical soft tissue adhesive according to claim 4, characterized in that: The chitosan modified derivative is prepared by reacting chitosan and a modifier, wherein the chitosan is alpha-chitosan, beta-chitosan or gamma-chitosan, the modifier is carboxylic acid, alkyl acid, acyl chloride or anhydride, and the alkyl acid is stearic acid or palmitic acid.

6. A method for preparing a medical soft tissue adhesive according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) The chitosan and the modifier are heated to reflux under the action of a catalyst to obtain component B; (2) Under a nitrogen atmosphere, placing N-vinyl pyrrolidone, acrylic acid and an initiator in a first solvent and mixing and heating; (3) The reaction system in step (2) is cooled to room temperature, and then N-hydroxysuccinimide and a condensing agent are added to the reaction system, and mixed to react to obtain component A; (4) dissolving the component B in step (1) in a second solvent, and then coating to form an anti-adhesion layer; (5) dissolving the component A in step (3) in a third solvent, followed by coating to form an adhesive layer; (6) The anti-adhesion layer and the adhesive layer are alternately coated and dried to obtain the medical soft tissue adhesive.

7. The method for preparing a medical soft tissue adhesive according to claim 6, characterized in that: In step (1), the catalyst is EDC, DCC or DIC; the heating temperature is 60° C., the reaction time is 4 to 10 hours; and the molar ratio of the chitosan, the modifier and the catalyst is 3:(1 to 1.3):2.

5.

8. The method for preparing a medical soft tissue adhesive according to claim 6, characterized in that: In step (2), the amount of the initiator is 0.01% to 0.03% of the total amount of the N-vinyl pyrrolidone and the acrylic acid, the initiator is azobisisobutyronitrile, the first solvent is dimethyl sulfoxide, the heating temperature is 70 to 85° C., and the heating time is 16 to 26 hours; In step (3), the molar ratio of the N-hydroxysuccinimide, the condensing agent and the acrylic acid is (1-1.5): (1-1.2): 1, the condensing agent is DCC or EDC, and the reaction time is 48-72 hours.

9. The method for preparing a medical soft tissue adhesive according to claim 6, characterized in that: In step (4), the second solvent is dichloromethane; in step (5), the third solvent is a mixed solution of dichloromethane and methanol.

10. Use of the medical soft tissue adhesive according to any one of claims 1 to 5 in medical adhesives.

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