Hydrophobic modified chitosan material as well as preparation method and application thereof in wound care and hemostasis

Abstract

The invention provides a hydrophobic modified chitosan material as well as a preparation method and application thereof in wound care and hemostasis. The hydrophobic modified chitosan material provided by the invention comprises chitosan and saturated fatty acid physically crosslinked on a side chain of the chitosan, the deacetylation degree of the chitosan is 75 to 95 percent; the carbon chain length of the saturated fatty acid is 11-18 carbon atoms. The hydrophobic modified chitosan material provided by the invention can be used for stopping arterial bleeding.

Description

Technical Field

[0001] The invention relates to the field of medical technology, and in particular to a hydrophobically modified chitosan material, a preparation method thereof, and applications of the chitosan material in wound care and hemostasis. Background Art

[0002] Fast and efficient hemostatic materials are essential for the rescue of bleeding victims. However, common hemostatic materials such as protein, zeolite, and α-cyanoacrylate materials all have certain defects: protein materials mainly include keratin, silk protein, and collagen, and their animal-derived sources have potential risks of viral infection; zeolite materials release a large amount of heat after absorbing water from the blood, which may cause burns to surrounding tissues; α-cyanoacrylate releases toxic substances such as formaldehyde when it degrades, which is harmful to tissues and the human body.

[0003] As a natural biomass polysaccharide with a wide range of sources, the cationic clusters formed by chitosan can interact with anions on red blood cells, induce red blood cells and platelets to aggregate, and achieve hemostatic effects. It is now widely used in the field of hemostasis. Commercial chitosan products include CELOX, HemCon, etc., which are well-known at home and abroad. However, it has also been reported that its hemostatic effect on the femoral artery cannot meet the purpose of efficient hemostasis, and there is a risk of secondary bleeding. A large number of studies have been devoted to further improving the hemostatic effect of chitosan by introducing hydrophobic interactions. The Chinese invention patent with application publication number CN 105770976 A uses the amino group of chitosan and aldehyde to undergo Schiff base reaction under acidic conditions and then prepare alkylated chitosan through the action of a reducing agent. However, due to the consumption of the amino group, the electrostatic interaction with red blood cells is weakened, which can easily cause the hemostasis time to be prolonged. The Chinese invention patent with authorization announcement number CN 108276506 B also consumes the amino group of chitosan to undergo acylation reaction to graft a substrate containing a hydrophobic group. Although hydrophobic interactions are introduced, the electrostatic interactions are weakened. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. The present invention provides a hydrophobically modified chitosan material, which can retain the amino active sites of chitosan to the greatest extent, while introducing hydrophobic interactions, and through the synergistic hemostasis of the two, is applied in the field of wound care and hemostasis, which is of great significance for stopping severe bleeding and even arterial bleeding.

[0005] In order to make up for the defects and shortcomings of the prior art, the present invention provides the following technical solutions:

[0006] The first aspect of the present invention provides a hydrophobically modified chitosan material, comprising chitosan, and a saturated fatty acid physically cross-linked on the side chain of the chitosan;

[0007] The deacetylation degree of the chitosan is 75-95%;

[0008] The carbon chain length of the saturated fatty acid is 11-18 carbon atoms.

[0009] According to an embodiment of the present invention, the hydrophobically modified chitosan material provided above may further include the following technical features:

[0010] According to an embodiment of the present invention, the mass ratio of the chitosan to the saturated fatty acid is 1:(0.02-0.03).

[0011] According to an embodiment of the present invention, the content of particles with a particle size larger than 20 mesh is not larger than 5%, and the content of particles with a particle size smaller than 65 mesh is not larger than 50%.

[0012] According to an embodiment of the present invention, the saturated fatty acid is selected from at least one of undecanoic acid, lauric acid, pentadecanoic acid and stearic acid.

[0013] According to an embodiment of the present invention, the hydrophobically modified chitosan material can be made into different hemostatic materials, such as powdery, film-shaped, or sponge-shaped hemostatic materials.

[0014] The second aspect of the present invention provides a method for preparing the hydrophobically modified chitosan material according to the first aspect, comprising:

[0015] (1) dissolving chitosan in water and stirring to disperse it uniformly, and then dropping acid to dissolve it to obtain a chitosan solution;

[0016] dissolving saturated fatty acids in anhydrous ethanol to obtain saturated fatty acid ethanol solution;

[0017] (2) adding the saturated fatty acid ethanol solution dropwise to the chitosan solution and stirring for a predetermined time;

[0018] (3) setting the liquid level of the solution obtained in step (2) to 0.1-0.3 mm, heating and drying the solution to form a film; crushing and sieving the film to obtain particles of different particle sizes;

[0019] (4) Mixing the particles with different particle sizes according to a predetermined ratio to obtain a hydrophobically modified chitosan material.

[0020] According to an embodiment of the present invention, the mass ratio of chitosan, acid and water in step (1) is (0.03-0.05):(0.025-0.04):1.

[0021] According to an embodiment of the present invention, the acid is at least one of lactic acid and acetic acid.

[0022] According to an embodiment of the present invention, the stirring rate is 350-500 rpm, and the predetermined time is 2-8 hours.

[0023] According to an embodiment of the present invention, the heating and drying temperature is 50-70° C., and the drying time is 8-15 hours.

[0024] The third aspect of the present invention provides the use of the hydrophobically modified chitosan material described in any one of the first aspects in wound care and hemostasis. For example, it can be prepared into different hemostatic materials for wound care and hemostasis.

[0025] The beneficial effects provided by the present invention are as follows:

[0026] (1) Physical cross-linking is performed by hydrogen bonding between the hydrophilic groups of chitosan and the carboxyl groups of saturated fatty acids. The hydrophobic modified chitosan material formed by physical cross-linking can retain the amino active sites of chitosan to the greatest extent, and utilize the electrostatic interaction between the protonated amino groups and the negatively charged red blood cells to attract the aggregation of red blood cells, thereby avoiding the consumption of the amino groups of chitosan due to acylation reactions, which would result in a decrease in hemostatic performance.

[0027] (2) Saturated fatty acids are introduced into the hydrophobically modified chitosan material, and the hydrophobic long chains of the saturated fatty acids are anchored to the hydrophobic region inside the phospholipid bilayer of blood cells, so that the blood cells and the polymer chain segments form a gel block with a three-dimensional network structure, thereby enhancing the hemostatic effect.

[0028] (3) The in vitro coagulation time is very short, which can effectively stop arterial bleeding. When used for hemostasis, it can form a more solid gel block, which is easier to remove as a whole during debridement. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A diagram showing the mechanism of action of a hydrophobically modified chitosan material provided according to an embodiment of the present invention;

[0030] Figure 2 This is a physical picture of a hydrophobically modified chitosan material prepared according to Example 1 of the present invention;

[0031] Figure 3 This is an infrared spectrum of a hydrophobically modified chitosan material prepared according to Example 1 of the present invention;

[0032] Figure 4 This is a nuclear magnetic hydrogen spectrum of a hydrophobically modified chitosan material prepared according to Example 1 of the present invention;

[0033] Figure 5 A Zeta potential diagram of a hydrophobically modified chitosan material prepared according to Example 1 of the present invention;

[0034] Figure 6 The in vitro coagulation effect diagram of a hydrophobically modified chitosan material prepared according to Example 1 and Comparative Example 1 of the present invention respectively;

[0035] Figure 7 The diagram shows the hemostatic effect of a hydrophobically modified chitosan material prepared according to Example 1 and Comparative Example 1 of the present invention on the femoral artery of pigs;

[0036] Figure 8 The diagram shows the effect of debridement after hemostasis of the porcine femoral artery using a hydrophobically modified chitosan material prepared according to Example 1 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0038] The present invention provides a hydrophobically modified chitosan material, which physically crosslinks saturated fatty acids on the side chains of chitosan. The amino active sites of chitosan can be retained to the greatest extent by physical crosslinking, and the electrostatic interaction between protonated amino groups and negatively charged red blood cells is used to attract red blood cells to aggregate; saturated fatty acids provide hydrophobic long chains to anchor to the hydrophobic regions inside the phospholipid bilayer of blood cells, so that blood cells and polymer chain segments form a gel block with a three-dimensional network structure, thereby enhancing the hemostatic effect. The provided hydrophobically modified chitosan material can be used to stop arterial bleeding without relying on its own coagulation mechanism.

[0039] To this end, the present invention provides a hydrophobically modified chitosan material, comprising chitosan and saturated fatty acids physically cross-linked on the side chains of the chitosan.

[0040] According to a specific embodiment, the deacetylation degree of the chitosan is 75-95%. The deacetylation degree of chitosan is closely related to the number of amino groups on the molecular chain. When the deacetylation degree is low, the number of amino groups of chitosan is small, and the electrostatic interaction with red blood cells is limited, and the hemostatic effect is not good (for example, the coagulation time will be extended, thereby affecting the hemostatic effect of the hydrophobically modified chitosan material); the deacetylation degree of chitosan cannot be too high. When the deacetylation degree of chitosan is too high, the molecules are charged. In the preparation process, the solution viscosity formed by the electrostatic repulsion is too large to be conducive to sufficient reaction, and it will also affect the use and hemostatic effect of the hydrophobically modified chitosan material to a certain extent. According to a preferred embodiment, the deacetylation degree of the chitosan is 85-95%, and according to a more preferred embodiment, the deacetylation degree of the chitosan is 90-95%.

[0041] Physical crosslinking is a process of connecting molecular chains together through non-covalent forces to form a three-dimensional network structure. This crosslinking method does not involve the formation of chemical bonds, but relies on weak interactions between molecules, such as hydrogen bonds, electrostatic interactions, van der Waals forces, hydrophobic interactions, etc. According to a specific embodiment, the "physical crosslinking" mentioned includes but is not limited to hydrogen bonds formed between the carboxyl groups of saturated fatty acids and the amino and hydroxyl groups of chitosan.

[0042] The mechanism of action of the hydrophobically modified chitosan material provided by the present invention is as follows Figure 1 As shown: (1) The chitosan in the hydrophobically modified chitosan material absorbs water from the blood, thereby concentrating the cells and protein components in the blood and promoting blood coagulation. In addition, the volume of chitosan expands after absorbing water, forming a packing effect at the bleeding site, exerting a certain expansion pressure on the tissue to prevent blood from flowing out. (2) Chitosan attracts negatively charged red blood cells to aggregate through its own positive charge, promoting blood coagulation. (3) The long alkyl chains of the hydrophobically modified chitosan are embedded in the cell membrane through hydrophobic action, thereby cross-linking blood cells and forming a more stable blood clot.

[0043] The chitosan mentioned can be obtained by commercial purchase or self-preparation. According to a specific embodiment, the chitosan is a granular or powder product obtained by deacetylation of marine arthropods such as shrimps and crabs. According to a preferred embodiment, the chitosan is chitosan from deep-sea krill. Deep-sea krill feed on phytoplankton and the waters are clean, so they are not easily polluted by mercury, polychlorinated biphenyls and heavy metals. The hydrophobically modified chitosan material prepared from the raw material can be used as a hemostatic material, which is clean and less polluting.

[0044] The saturated fatty acid mentioned is a saturated fatty acid with a carbon chain length of 11-18 carbon atoms. According to a specific embodiment, the saturated fatty acid is one or more of undecanoic acid, lauric acid, pentadecanoic acid, and stearic acid. The number of carbon atoms of these saturated fatty acids is between 11-18. The hydrophobic modified chitosan material formed by these alkyl long chains can pass through the phospholipid bilayer of the cell, that is, firmly anchored in the hydrophobic region of the blood cell to form a three-dimensional network structure, enhancing the hemostatic effect. In addition, it was found during the research process that when the carbon chain length is more than 10, more effective antibacterial activity can be shown, and wound infection can also be prevented when used (when the carbon chain is shorter, the hydrophobic modified chitosan material formed cannot firmly anchor the phospholipid bilayer, and the antibacterial effect is not obvious). However, as the alkyl chain length further increases, the hemolysis rate of the material increases, and the biosafety is reduced. According to a specific embodiment, the carbon chain length of the saturated fatty acid mentioned is C11-C18. According to a preferred embodiment, the saturated fatty acid is lauric acid or undecanoic acid.

[0045] According to a specific embodiment, the mass ratio of chitosan to saturated fatty acid is 1:(0.02-0.03). According to a preferred embodiment, the mass ratio of chitosan to saturated fatty acid is 1:(0.02-0.025).

[0046] The particle size of the hydrophobically modified chitosan material will affect the hemostatic effect of the material to a certain extent. According to a specific embodiment, in the hydrophobically modified chitosan material, the content of particles with a particle size greater than 20 mesh is not greater than 5%, and the content of particles with a particle size less than 65 mesh is not greater than 50%. According to a preferred embodiment, the content of particles with a particle size greater than 20 mesh should be no greater than 3%, and the content of particles with a particle size less than 65 mesh should be no greater than 45%.

[0047] The hydrophobically modified chitosan material can be prepared into various forms according to the needs, including but not limited to powder, film or sponge. For example, the film-like hemostatic material can be obtained by re-dissolving the hydrophobically modified chitosan material and mixing it with pharmaceutical excipients, and then drying it by solvent evaporation; the sponge-like hemostatic material can be obtained by re-dissolving the hydrophobically modified chitosan material and mixing it with pharmaceutical excipients, and then freeze-drying it; products in different forms can meet the needs of different wound hemostasis.

[0048] The present invention also provides a method for preparing a hydrophobically modified chitosan material, comprising:

[0049] (1) dissolving chitosan in water and stirring to disperse it uniformly, and then dropping acid to dissolve it to obtain a chitosan solution;

[0050] dissolving saturated fatty acids in anhydrous ethanol to obtain saturated fatty acid ethanol solution;

[0051] (2) adding the saturated fatty acid ethanol solution dropwise to the chitosan solution and stirring for a predetermined time;

[0052] (3) setting the liquid level of the solution obtained in step (2) to 0.1-0.3 mm, heating and drying the solution to form a film; crushing and sieving the film to obtain particles of different particle sizes;

[0053] (4) Mixing the particles with different particle sizes according to a predetermined ratio to obtain a hydrophobically modified chitosan material.

[0054] When preparing chitosan solution, the acid used is one of lactic acid and acetic acid. The addition of these acids can protonate the amino groups of chitosan through hydrogen ions, making chitosan a water-soluble cationic polyelectrolyte.

[0055] The mass ratio of chitosan: acid: water is (0.03-0.05): (0.025-0.04): 1. According to a preferred embodiment, the mass ratio of chitosan, acid, and water is (0.04-0.05): (0.03-0.035): 1. When the content of chitosan is too low, the production capacity is low; when the content of chitosan is too high, the chitosan dissolves slowly, easily forms a climbing rod phenomenon, and stirring is extremely difficult.

[0056] The stirring is performed at a certain speed. According to a specific implementation manner, the stirring speed is 350-500 rpm, preferably 375-450 rpm.

[0057] In the present invention, the heating and drying temperature is 50-70° C., and the drying time is 8-15 hours, preferably 55-65° C., and the drying time is 10-13 hours.

[0058] Particles with different particle sizes are mixed according to a predetermined ratio, wherein the predetermined ratio requirement is that the content of particles with a particle size greater than 20 mesh should not be greater than 5%, and the content of particles with a particle size less than 65 mesh should not be greater than 50%. According to a preferred embodiment, the predetermined ratio is that the content of particles with a particle size greater than 20 mesh should not be greater than 3%, and the content of particles with a particle size less than 65 mesh should not be greater than 45%.

[0059] It should be noted that the present invention has no special limitation on the instruments for stirring, crushing and screening, and any instrument well known to those skilled in the art may be used.

[0060] It should be noted that the present invention has no particular limitation on the manufacturer of the raw materials, and commercially available products known to those skilled in the art may be used.

[0061] The preparation method provided by the present invention has a simple process and can be carried out without complicated equipment, and the method has universal applicability and can be prepared on a large scale.

[0062] The present invention also provides a hydrophobically modified chitosan material prepared by the preparation method described in the above technical solution. The hydrophobically modified chitosan material provided by the present invention can stop bleeding quickly, does not rely on the self-coagulation mechanism, and is also effective for heparinized blood.

[0063] The provided hydrophobically modified chitosan material can be used in the fields of wound care and hemostasis, for example, to prepare hemostatic materials. The present invention has no special limitation on the application of the hydrophobically modified chitosan material in wound care, and the application operation familiar to those skilled in the art can be used.

[0064] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] Example 1

[0066] Example 1 provides a hydrophobically modified chitosan material, which is prepared by the following method:

[0067] (1) Weigh 9 g of chitosan from deep-sea krill with a deacetylation degree of 93%, dissolve it in 200 mL of deionized water, stir and disperse it evenly, and then drop 6 g of lactic acid to dissolve it to obtain a chitosan solution;

[0068] (2) dissolving 0.2 g of lauric acid in anhydrous ethanol to obtain a lauric acid ethanol solution;

[0069] (3) adding the lauric acid ethanol solution dropwise to the chitosan solution and stirring for 4 hours;

[0070] (4) pouring the solution obtained in step (3) into a stainless steel tray, wherein the liquid level in the tray is 0.18 mm; then placing the stainless steel tray in an oven and heating and drying it at 60° C. for 12 hours, and crushing and sieving the prepared film to obtain particles of different particle sizes;

[0071] (5) Particles of different particle sizes are mixed, wherein the content of particles with a particle size greater than 20 mesh is 2%, and the content of particles with a particle size less than 65 mesh is 42%, thereby obtaining a hydrophobically modified chitosan material.

[0072] Example 2

[0073] Example 2 provides a hydrophobically modified chitosan material, which is prepared by the following method:

[0074] (1) Weigh 10 g of chitosan from deep-sea krill with a deacetylation degree of 85% and dissolve it in 200 mL of deionized water, stir and disperse it evenly, and then drop 7 g of lactic acid to dissolve it to obtain a chitosan solution;

[0075] (2) dissolving 0.23 g of undecanoic acid in anhydrous ethanol to obtain an undecanoic acid ethanol solution;

[0076] (3) adding the undecanoic acid ethanol solution dropwise to the chitosan solution and stirring at 400 rpm for 4 hours;

[0077] (4) pouring the solution obtained in step (3) into a stainless steel tray, wherein the liquid level in the tray is 0.21 mm; then placing the stainless steel tray in an oven and heating and drying it at 65° C. for 10 hours, and crushing and sieving the prepared film to obtain particles of different particle sizes;

[0078] (5) Particles of different particle sizes are mixed, wherein the content of particles with a particle size greater than 20 mesh is 1%, and the content of particles with a particle size less than 65 mesh is 45%, thereby obtaining a hydrophobically modified chitosan material.

[0079] Example 3

[0080] Example 3 provides a hydrophobically modified chitosan material, which is prepared by the following method:

[0081] (1) Weigh 10 g of chitosan from deep-sea krill with a deacetylation degree of 80% and dissolve it in 200 mL of deionized water, stir and disperse it evenly, and then drop 6 g of acetic acid to dissolve it to obtain a chitosan solution;

[0082] (2) dissolving 0.25 g of pentadecanoic acid in anhydrous ethanol to obtain a pentadecanoic acid ethanol solution;

[0083] (3) adding pentadecanoic acid ethanol solution dropwise to the chitosan solution and stirring at 420 rpm for 4 hours;

[0084] (4) pouring the solution obtained in step (3) into a stainless steel tray, wherein the liquid level in the tray is 0.15 mm; then placing the stainless steel tray in an oven and heating and drying it at 55° C. for 13 hours, and crushing and sieving the obtained film to obtain particles of different particle sizes;

[0085] (5) Particles of different particle sizes are mixed, wherein the content of particles with a particle size greater than 20 mesh is 3%, and the content of particles with a particle size less than 65 mesh is 38%, thereby obtaining a hydrophobically modified chitosan material.

[0086] Comparative Example 1

[0087] Comparative Example 1 provides a hydrophobically modified chitosan material, which is prepared by the following method:

[0088] (1) Weigh 9 g of chitosan from deep-sea krill with a deacetylation degree of 93%, dissolve it in 200 mL of deionized water, stir and disperse it evenly, and then drop 6 g of lactic acid to dissolve it to obtain a chitosan solution;

[0089] (2) pouring the solution obtained in step (1) into a stainless steel tray, wherein the liquid level in the tray is 0.18 mm; then placing the stainless steel tray in an oven and heating and drying it at 60° C. for 12 hours, and crushing and sieving the obtained film to obtain particles of different particle sizes;

[0090] (3) Particles of different particle sizes are mixed, wherein the content of particles with a particle size greater than 20 mesh is 2%, and the content of particles with a particle size less than 65 mesh is 42%, to obtain a hydrophobically modified chitosan material.

[0091] The difference between Comparative Example 1 and Example 1 is only that no saturated fatty acid is introduced.

[0092] Comparative Example 2

[0093] Comparative Example 2 provides a hydrophobically modified chitosan material, which is prepared by the following method:

[0094] (1) Weigh 9 g of chitosan from deep-sea krill with a deacetylation degree of 70% and dissolve it in 200 mL of deionized water, stir and disperse it evenly, and then drop 6 g of lactic acid to dissolve it to obtain a chitosan solution;

[0095] (2) dissolving 0.2 g of undecanoic acid in anhydrous ethanol to obtain an undecanoic acid ethanol solution;

[0096] (3) Add the undecanoic acid ethanol solution dropwise to the chitosan solution and stir at 390 rpm for 4 hours;

[0097] (4) pouring the solution obtained in step (3) into a stainless steel tray, wherein the liquid level in the tray is 0.28 mm; then placing the stainless steel tray in an oven and heating and drying at 60° C. for 11 hours, and then crushing and sieving the obtained film;

[0098] (5) Particles of different particle sizes are mixed, wherein the content of particles with a particle size greater than 20 mesh is 6%, and the content of particles with a particle size less than 65 mesh is 56%, to obtain a hydrophobically modified chitosan material.

[0099] The hydrophobically modified chitosan materials prepared in each example are characterized and verified. The product prepared in Example 1 is taken as an example to illustrate the characterization and verification effect of the prepared hydrophobically modified chitosan materials.

[0100] The product prepared in Example 1 is as follows Figure 2 shown. Figure 3 This is an infrared spectrum of a hydrophobically modified chitosan material prepared in Example 1. Figure 3 It can be seen that chitosan has characteristic absorption peaks at the following wave numbers: 3443 cm -1 (Broad peak) is the OH and NH stretching vibration peak, 2927cm -1 The stretching vibration peak of CH, 1574 cm -1 The amide II band, 1317 cm -1 The amide III band, 1090 cm -1 The peak of CO stretching vibration is 1640 cm-1 The peak of the amide I band nearby shifts to the left. In addition to the influence of the water peak, there is also the influence of the characteristic peak of saturated fatty acids. According to the "Chinese Pharmacopoeia" (2020 edition), the material is chitosan.

[0101] Figure 4 This is the nuclear magnetic hydrogen spectrum of a hydrophobically modified chitosan material prepared in Example 1. Figure 4 It can be seen that the solvent peak (D 2 The chemical shift of the chitosan material of embodiment 1 is 2.01ppm.The chemical shift of the acetyl group H-Ac of acetylated chitosan is 2.01ppm, and 3 H chemical shifts of acetyl group are identical because there is no H interference on the adjacent carbon atom.The deacetylation degree of the hydrophobically modified chitosan material prepared by embodiment 1 can be calculated to be 93.46% according to the nuclear magnetic hydrogen spectrum.

[0102] Figure 5 The Zeta potential diagram of the hydrophobically modified chitosan material prepared in Example 1 is shown in FIG. Figure 5 It can be seen that chitosan presents a positive charge in aqueous solution, which is determined by the positive potential of the amino groups in chitosan, which is consistent with what has been reported in the literature.

[0103] At the same time, the water absorption multiples of the hydrophobically modified chitosan materials prepared in each embodiment and comparative example were characterized, as shown in Table 1:

[0104] Table 1 Water absorption multiples

[0105]

[0106] It can be seen from the above table that compared with Comparative Example 2, the hydrophobically modified chitosan material prepared in each embodiment, especially in Example 1, has a higher water absorption multiple, can absorb a large amount of water in a short time, and is helpful to quickly form gel blocks in actual use.

[0107] Then, the in vitro coagulation effect of the hydrophobically modified chitosan material was verified. The specific test method is as follows: ① Weigh 0.04g of sample; make 3 parallel samples for each sample; ② Take a centrifuge tube and preheat fresh anticoagulated rabbit blood (heparin sodium) to 37°C; ③ Pour the weighed 0.04g sample into the centrifuge tube to cover the bottom of the tube, quickly add 1mL of fresh anticoagulated rabbit blood (heparin sodium) and start timing; ③ Put the centrifuge tube upside down. If no blood flows out, it is recorded as coagulation.

[0108] The results of in vitro coagulation time test on the hydrophobically modified chitosan materials prepared in the examples and comparative examples are shown in Table 2:

[0109] Table 2 In vitro coagulation time

[0110] sample In vitro coagulation time (s) Example 1 300 Example 2 337 Example 3 335 Comparative Example 1 752 Comparative Example 2 880

[0111] Figure 6 The in vitro coagulation effect diagram of the hydrophobically modified chitosan materials prepared in Example 1 and Comparative Example 1. It can be seen from the results in Table 2 that the in vitro coagulation time of the hydrophobically modified chitosan materials prepared in each embodiment is significantly lower than that of Comparative Example 1 and Comparative Example 2. Taking the hydrophobically modified chitosan material prepared in Example 1 as an example, its in vitro coagulation time under the experimental conditions is 5 minutes. Under the same conditions, the hydrophobically modified chitosan materials prepared in both Comparative Example 1 and Comparative Example 2 did not coagulate.

[0112] Then, the hemostatic effect of the prepared hydrophobic modified chitosan material on the femoral artery of pigs was verified. The specific test method is as follows: ① After the animal is anesthetized, the skin is cut along the direction of the femoral artery, and the subcutaneous tissue and muscle are separated layer by layer to expose the femoral artery. ② The blood vessel is clamped with an artery clamp at the proximal end, and the femoral artery is cut 1 / 2 vertically with microscissors at the proximal end. After free bleeding for 5 seconds, the excess blood is quickly cleaned with sterile gauze, and the test sample is poured into the wound. A sterile gauze block is immediately placed on it, and continuous pressure is applied for 300 seconds, and the hemostatic effect is recorded. If the bleeding fails to stop after 300 seconds, a second pressure of 300 seconds is applied, and it is repeated up to three times. ③ After 10 minutes of successful hemostasis, the injured hind limb of the animal is pulled, abducted, and adducted three times each with a certain pressure to simulate the transportation and transportation link of the wounded after hemostasis, and loosen to observe whether active bleeding is induced again. The hydrophobically modified chitosan material prepared in Example 1 successfully stopped bleeding after pressing for 300 seconds. After stopping bleeding for 10 minutes, the injured hind limb was stretched, abducted, and adducted, and no secondary bleeding occurred.

[0113] References Figure 7 As shown, the chitosan material prepared by Comparative Example 1 stopped bleeding after pressing for 300 seconds, but after the injured hind limb was pulled, abducted, and adducted 10 minutes after the hemostasis, the wound had secondary bleeding. Compared with Comparative Example 1, the hydrophobically modified chitosan material prepared by Example 1 has better hemostatic firmness, which may be due to the fact that blood cells and polymer segments together form a more solid three-dimensional network structure gel block, which enhances the hemostatic effect.

[0114] The prepared hydrophobic modified chitosan material was further verified for its effect of hemostasis and debridement of porcine femoral artery. The specific operation was as follows: 30-60 minutes after successful hemostasis, the wound site was rinsed with saline until the wound was clean, and the volume of saline used for debridement was recorded.

[0115] The results are as follows Figure 8 As shown, 200 mL of saline solution was used for debridement of the hydrophobically modified chitosan material prepared in Example 1, and 350 mL of saline solution was used for debridement of the hydrophobically modified chitosan material prepared in Comparative Example 1. Compared with Comparative Example 1, the hydrophobically modified chitosan material prepared in Example 1 was easier to debride, and less saline solution was used, because a firmer gel block was formed in Example 1, which was easier to remove as a whole during debridement, while some gel blocks remained in Comparative Example 1 due to its loose structure during debridement.

[0116] In the description of this specification, the description with reference to the terms "some embodiments", "specific implementation methods", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0117] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A hydrophobically modified chitosan material, characterized in that: It comprises chitosan, and saturated fatty acids physically cross-linked on the side chains of the chitosan; The deacetylation degree of the chitosan is 75-95%; The carbon chain length of the saturated fatty acid is 11-18 carbon atoms.

2. The hydrophobically modified chitosan material according to claim 1, characterized in that: The mass ratio of the chitosan to the saturated fatty acid is 1:(0.02-0.03).

3. The hydrophobically modified chitosan material according to claim 1, characterized in that: include: The content of particles with a particle size greater than 20 mesh is not more than 5%, and the content of particles with a particle size less than 65 mesh is not more than 50%.

4. The hydrophobically modified chitosan material according to claim 1, characterized in that: The saturated fatty acid is selected from at least one of undecanoic acid, lauric acid, pentadecanoic acid and stearic acid.

5. A hemostatic material, characterized in that: A hydrophobically modified chitosan material comprising any one of claims 1 to 4; Optionally, the hemostatic material is in at least one of a powdery, film-shaped, and sponge-shaped form.

6. The method for preparing the hydrophobically modified chitosan material according to any one of claims 1 to 4, characterized in that: include: (1) dissolving chitosan in water and stirring to disperse it uniformly, and then dropping acid to dissolve it to obtain a chitosan solution; dissolving saturated fatty acids in anhydrous ethanol to obtain saturated fatty acid ethanol solution; (2) adding the saturated fatty acid ethanol solution dropwise to the chitosan solution and stirring for a predetermined time; (3) setting the liquid level of the solution obtained in step (2) to 0.1-0.3 mm, heating and drying the solution to form a film; crushing and sieving the film to obtain particles of different particle sizes; (4) Mixing the particles with different particle sizes according to a predetermined ratio to obtain a hydrophobically modified chitosan material.

7. The preparation method according to claim 6, characterized in that: The mass ratio of chitosan, acid and water in step (1) is (0.03-0.05):(0.025-0.04):1; Optionally, the acid is at least one of lactic acid and acetic acid.

8. The preparation method according to claim 6, characterized in that: The stirring rate is 350-500 rpm, and the predetermined time is 2-8 hours.

9. The preparation method according to claim 6, characterized in that: The heating and drying temperature is 50-70° C., and the drying time is 8-15 hours.

10. Use of the hydrophobically modified chitosan material according to any one of claims 1 to 4 or the hemostatic material according to claim 5 in wound care and hemostasis.

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