阅读说明：本技术 一种壳聚糖衍生物及其制备方法和应用 (Chitosan derivative and preparation method and application thereof ) 是由 余龙江 雷志勇 陈晓娟 刘浩 李�东 徐航 于 2021-11-08 设计创作，主要内容包括：本申请涉及高分子材料领域,尤其涉及一种壳聚糖衍生物及其制备方法和应用,所述壳聚糖衍生物是壳聚糖经过有效基团进行化学修饰得到的；所述方法包括：将壳聚糖粉末溶于甲磺酸中,得到壳聚糖甲磺酸溶液；将笏甲氧羰酰基-6-氨基己酸和二氯亚砜进行第一混合并加热,后进行第一除杂,得到笏甲氧羰酰基-6-氨基己酸-酰氯；将壳聚糖甲磺酸溶液和笏甲氧羰酰基-6-氨基己酸-酰氯进行第二混合,后冷却,得到冷冻混合物；将冷冻混合物进行脱氨基保护,得到脱保护产物；将所述脱保护产物进行第二除杂,后冷冻干燥,得到壳聚糖衍生物；所述应用包括将壳聚糖衍生物用于止血和抗菌的药物中。(The application relates to the field of high polymer materials, in particular to a chitosan derivative, a preparation method and application thereof, wherein the chitosan derivative is obtained by chemically modifying chitosan through an effective group; the method comprises the following steps: dissolving chitosan powder in methanesulfonic acid to obtain a chitosan methanesulfonic acid solution; subjecting fluorenyl methoxycarbonyl acyl-6-aminocaproic acid and thionyl chloride to first mixing and heating, and then carrying out first impurity removal to obtain fluorenyl methoxycarbonyl acyl-6-aminocaproic acid-acyl chloride; secondly, mixing the chitosan methanesulfonic acid solution and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride for the second time, and then cooling to obtain a frozen mixture; carrying out deamination protection on the frozen mixture to obtain a deprotection product; carrying out second impurity removal on the deprotection product, and then carrying out freeze drying to obtain a chitosan derivative; the application comprises the application of the chitosan derivative in hemostatic and antibacterial medicines.)

1. A chitosan derivative is characterized in that the chitosan derivative is obtained by chemically modifying chitosan through an effective group, wherein the effective group comprises 6-aminocaproic acid, and the chemical modification specifically comprises the following steps: and (2) carrying out esterification and/or acylation reaction on the hydroxyl and/or the amino of the chitosan and the carboxyl of the effective group respectively.

2. The derivative of claim 1, wherein the general structural formula of the derivative is shown as formula 1,

wherein n is more than or equal to 2.

3. The derivative of claim 2, wherein the derivative is obtained by esterification and acylation of hydroxyl and amino of chitosan with fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride, respectively.

4. The derivative according to claim 3, wherein the molar ratio of glucosamine unit and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride of chitosan is 1: 1 to 1: 5.

5. A process for the preparation of a derivative according to any one of claims 1 to 4, comprising:

dissolving chitosan powder in methanesulfonic acid to obtain a chitosan methanesulfonic acid solution;

subjecting fluorenyl methoxycarbonyl acyl-6-aminocaproic acid and thionyl chloride to first mixing and heating, and then carrying out first impurity removal to obtain fluorenyl methoxycarbonyl acyl-6-aminocaproic acid-acyl chloride;

secondly, mixing the chitosan methanesulfonic acid solution and the fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride, and then cooling to obtain a frozen mixture;

carrying out deamination protection on the frozen mixture to obtain a deprotection product;

and carrying out second impurity removal on the deprotection product, and then carrying out freeze drying to obtain the chitosan derivative.

6. The method of claim 5, wherein deaminating the frozen mixture to provide a deprotected product comprises:

unfreezing the frozen mixture, adding acetone for precipitation and cleaning to obtain a precipitation mixture;

dissolving the precipitate mixture with N, N-dimethylformamide, adding piperidine for deprotection for 3-12 h to obtain a deprotection reaction solution;

the volume fraction of the end point of the piperidine is 5-30%.

7. The method according to claim 5, wherein the chitosan powder is dissolved in methanesulfonic acid to obtain a chitosan methanesulfonic acid solution, comprising:

adding chitosan powder into methanesulfonic acid under an ice bath condition to obtain a chitosan methanesulfonic acid solution;

the mass volume ratio of the chitosan to the methanesulfonic acid is 1 g: 10 mL-1 g: 30 mL.

8. The method of claim 5, wherein the first dedoping comprises: removing thionyl chloride by rotary evaporation;

the temperature of the first impurity removal is 30-80 ℃, and the time is 60-180 min;

the second impurity removal sequentially comprises: first pH adjustment, water addition and centrifugation, second pH adjustment and dialysis;

the ratio of the water amount of the added water to the volume of the deprotection solution is 3-8;

the dialysis comprises: dialyzing with pure water for 72-150 h, and replacing the dialysate every 12 h;

the end point of the first pH adjustment is 7.0-9.0, and the end point of the second pH adjustment is 2.0-7.0.

9. The method of claim 5, wherein the second mixing comprises: mixing under an ice bath condition, stirring for 0.5-2 h, and standing overnight at-25-5 ℃;

the mass-volume ratio of the first mixed fluorenyl methoxy carbonyl acyl-6-aminocaproic acid and thionyl chloride is 1 g: 2 mL-1 g: 10 mL;

the heating end point temperature is 50-80 ℃, and the time is 120-300 min.

10. Use of a chitosan derivative, comprising the use of a derivative according to claims 1-4 in a hemostatic or antibacterial medicament.

Technical Field

The application relates to the field of high polymer materials, in particular to a chitosan derivative and a preparation method and application thereof.

Background

Traumatic bleeding is one of the most common injuries in various accident sites, wherein uncontrolled bleeding is the leading cause of death of wounded personnel in the site and is also a problem often faced in surgical operations. The existing hemostatic dressings are mainly classified into three types: inorganic materials (such as zeolite, silica, montmorillonite and kaolin), natural polymer materials (such as oxidized cellulose, collagen, chitosan, silk fibroin, calcium alginate, fibrin and starch) and synthetic polymer materials (such as polypeptide, poly (epsilon-caprolactone), polyethylene glycol and polycyanoacrylate). Although these hemostatic materials have a certain hemostatic effect, they all have significant drawbacks, such as:

(1) inorganic materials: poor biocompatibility and easy inflammation initiation; after the heat-generating body contacts with blood, an obvious heat release phenomenon exists, and tissue burns are caused; it is difficult to completely remove the drug in vivo, resulting in fibrosis of organs or formation of thrombus.

(2) Natural polymer material: the hemostatic effect is general; the stability is poor.

(3) Synthesizing a high polymer material: the price is high; the quality control system is imperfect, and the quality difference of products in different batches is large; is difficult to degrade in vivo.

The research and development of the hemostatic material are international research hotspots, the start of China in the field is late, and obvious defects are shown in the rapid development of the hemostatic material. The natural high molecular hemostatic material has large storage amount in nature and low price, and the procoagulant ability of the hemostatic material can be obviously improved after simple chemical modification.

Chitosan is the only natural basic polysaccharide found so far as a traditional hemostatic dressing, and is mainly obtained by deacetylating chitin at the present stage, and is also called chitosan deacetylation. The chitosan is a second largest non-toxic, non-pollution and renewable green material resource which is next to cellulose and has huge inventory in nature.

Chitosan has good biocompatibility and certain hemostatic and antibacterial activities, but clinical application of chitosan still has some unsolved problems: because chitosan itself is insoluble in water and can only be dissolved in a few acidic solutions, chitosan hydrochloride is generally prepared into chitosan hydrochloride clinically so as to be dissolved in water. However, because a large amount of hydroxyl and amino exist in chitosan hydrochloride molecules, intramolecular and intermolecular hydrogen bonds are easily formed, so that the chitosan hydrochloride is rapidly crystallized after being dissolved in water, the viscosity of the solution is rapidly increased, the dissolution rate of the chitosan hydrochloride is slow, the solubility of the chitosan hydrochloride is limited, and the hemostatic effect of the chitosan is limited. Therefore, how to make chitosan have higher solubility and faster dissolution rate in water, thereby improving the hemostatic effect of chitosan, is a technical problem that needs to be solved at present.

Disclosure of Invention

The application provides a chitosan derivative and a preparation method and application thereof, which aim to solve the technical problem that the water solubility and the dissolution rate of chitosan are difficult to improve in the prior art.

In a first aspect, the present application provides a chitosan derivative, wherein the chitosan derivative is obtained by chemically modifying chitosan through an effective group, wherein the effective group includes 6-aminocaproic acid, and the chemical modification specifically includes: and (2) carrying out esterification and/or acylation reaction on the hydroxyl and/or the amino of the chitosan and the carboxyl of the effective group respectively.

Optionally, the structural general formula of the derivative is shown as formula 1,

wherein n is more than or equal to 2.

Optionally, the chitosan derivative is a product obtained after esterification and acylation reactions of hydroxyl and amino of chitosan with fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride respectively.

Optionally, the molar ratio of glucosamine unit and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride of the chitosan is 1: 1-1: 5.

In a second aspect, the present application provides a method for preparing a chitosan derivative, the method comprising:

dissolving chitosan powder in methanesulfonic acid to obtain a chitosan methanesulfonic acid solution;

subjecting fluorenyl methoxycarbonyl acyl-6-aminocaproic acid and thionyl chloride to first mixing and heating, and then carrying out first impurity removal to obtain fluorenyl methoxycarbonyl acyl-6-aminocaproic acid-acyl chloride;

secondly, mixing the chitosan methanesulfonic acid solution and the fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride, and then cooling to obtain a frozen mixture;

carrying out deamination protection on the frozen mixture to obtain a deprotection product;

and carrying out second impurity removal on the deprotection product, and then carrying out freeze drying to obtain the chitosan derivative.

Optionally, the step of performing deamination protection on the frozen mixture to obtain a deprotected product includes:

unfreezing the frozen mixture, adding acetone for precipitation and cleaning to obtain a precipitation mixture;

dissolving the precipitation mixture with N, N-dimethylformamide, adding piperidine for deprotection, and reacting for 3-12 h to obtain a deprotection product;

the volume fraction of the end point of the piperidine is 5-30%.

Optionally, dissolving chitosan powder in methanesulfonic acid to obtain a chitosan methanesulfonic acid solution, including:

adding chitosan powder into methanesulfonic acid under an ice bath condition to obtain a chitosan methanesulfonic acid solution;

the mass volume ratio of the chitosan powder to the methanesulfonic acid is 1 g: 10 mI-1 g: 30 mL.

Optionally, the first impurity removal includes: removing thionyl chloride by rotary evaporation;

the temperature of the first impurity removal is 30-80 ℃, and the time is 60-180 min;

the second impurity removal sequentially comprises: first pH adjustment, water addition and centrifugation, second pH adjustment and dialysis;

the ratio of the water amount of the added water to the volume of the deprotection solution is 3-8;

the dialysis comprises: dialyzing with pure water for 72-150 h, and replacing the dialysate every 12 h;

the end point of the first pH adjustment is 7.0-9.0, and the end point of the second pH adjustment is 2.0-7.0.

Optionally, the second mixing includes: mixing under an ice bath condition, stirring for 0.5-2 h, and standing overnight at-25-5 ℃;

the mass-volume ratio of the first mixed fluorenyl methoxy carbonyl acyl-6-aminocaproic acid and thionyl chloride is 1 g: 2 mL-1 g: 10 mL;

the heating end point temperature is 50-80 ℃, and the time is 120-300 min.

In a third aspect, the present application provides a use of a chitosan derivative, said use comprising the use of a derivative according to the first aspect in a haemostatic and antibacterial medicament.

Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:

according to the chitosan derivative provided by the embodiment of the application, the chitosan is chemically modified by taking 6-aminocaproic acid as an effective group, the 6-aminocaproic acid is activated by carboxyl, and then the hydroxyl and the amino of the chitosan are respectively esterified and acylated with the effective group of the activated 6-aminocaproic acid, so that the chitosan is modified, and part of the hydroxyl and the amino of the chitosan are substituted, so that the formation of hydrogen bonds in molecules and between molecules can be inhibited to a certain extent, the dissolution rate and the solubility of the modified chitosan derivative in water can be improved, and the chitosan derivative is convenient to apply to hemostatic and antibacterial medicines.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a schematic flow chart of a method for preparing chitosan derivatives according to the embodiments of the present application;

FIG. 2 is a detailed flow chart of a method for preparing chitosan derivatives according to the embodiment of the present application;

FIG. 3 is a schematic diagram of a synthetic route of chitosan derivative provided in the examples of the present application;

FIG. 4 is a graph comparing infrared spectra of chitosan and chitosan derivatives provided in examples of the present application;

FIG. 5 is a chart comparing hydrogen nuclear magnetic resonance spectra of chitosan and chitosan derivatives provided in examples of the present application;

FIG. 6 is a graph comparing procoagulant effects of chitosan and chitosan derivatives provided in examples of the present application;

in the figure, CSH represents chitosan hydrochloride, and CSH-AA represents a modified chitosan derivative.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In an embodiment of the present application, there is provided a chitosan derivative obtained by chemically modifying chitosan with an effective group, wherein the effective group includes 6-aminocaproic acid, and the chemical modification specifically includes: and (2) carrying out esterification and/or acylation reaction on the hydroxyl and/or the amino of the chitosan and the carboxyl of the effective group respectively.

As an alternative embodiment, the structural general formula of the derivative is shown as formula 1,

wherein n is more than or equal to 2.

As an alternative embodiment, as shown in fig. 2, the chitosan derivative is a modified product of esterification and acylation reaction of hydroxyl and amino of chitosan with fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride, respectively.

In the application, the positive effect of limiting the chitosan derivative to be the hydroxyl esterification and amino acylation modified substance is to enable the modified substance to have higher solubility and faster dissolution rate, so that the modification of the chitosan is realized.

In an alternative embodiment, the molar ratio of glucosamine unit and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride of the chitosan is 1: 1 to 1: 5.

In the application, the active effect that the molar ratio of glucosamine units and fluorene methoxycarbonyl acyl-6-aminocaproic acid of chitosan is 1: 1-1: 5 is that chitosan derivatives with different substitution degrees can be obtained after reaction in the molar ratio range; when the value range of the molar ratio is too large, a large amount of fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride is wasted, and when the value range of the molar ratio is too small, the unfavorable effect is that the substitution degree of the generated chitosan derivative is too low.

In one embodiment of the present application, as shown in fig. 1, there is provided a method for preparing a chitosan derivative, the method comprising:

s1, dissolving chitosan powder in methanesulfonic acid to obtain a chitosan methanesulfonic acid solution;

s2, carrying out first mixing and heating on fluorenyl methoxycarbonyl acyl-6-aminocaproic acid and thionyl chloride, and then carrying out first impurity removal to obtain fluorenyl methoxycarbonyl acyl-6-aminocaproic acid-acyl chloride;

s3, carrying out second mixing on the chitosan methanesulfonic acid solution and the fluorene methoxycarbonyl acyl-6-aminocaproic acid-acyl chloride, and then cooling to obtain a frozen mixture;

s4, performing deamination protection on the frozen mixture to obtain a deprotection product;

and S5, carrying out second impurity removal on the deprotection product, and then carrying out freeze drying to obtain the chitosan derivative.

As an alternative embodiment, as shown in fig. 2, the deamination protection of the frozen mixture to obtain a deprotected product comprises:

s41, unfreezing the frozen mixture, adding acetone for precipitation and cleaning to obtain a precipitation mixture;

s42, dissolving the precipitation mixture with N, N-dimethylformamide, and then adding piperidine for 3-12 h to obtain a deprotection product;

the end-point volume fraction of the piperidine is 5-30%.

In the application, the reaction time is 3-12 h, and the positive effect is that the deprotection rates of amino groups under different deprotection times can be compared in the reaction time range; when the time range is too large, the reaction time is too long, and when the time range is too small, the reaction time is too short, so that the deprotection rate of the amino group is too low.

The positive effect that the addition amount of the piperidine accounts for 5-30% of the mass of the deprotection reaction liquid is that the deprotection rates of amino groups under different concentrations of piperidine content can be compared in the mass ratio range; when the ratio value range is too large, the adverse effect is that the addition amount of piperidine is too large, so that the synthesis cost is increased, and when the ratio value range is too small, the adverse effect is that the addition amount of piperidine is insufficient, so that the deprotection rate of amino is too low.

As an alternative embodiment, as shown in fig. 2, the chitosan powder is dissolved in methanesulfonic acid to obtain a chitosan methanesulfonic acid solution, comprising:

s11, adding chitosan powder into methanesulfonic acid under an ice bath condition to obtain a chitosan methanesulfonic acid solution;

the mass volume ratio of the chitosan to the methanesulfonic acid is 1 g: 10 mL-1 g: 30 mL.

In the application, the positive effect that the mass-volume ratio of the chitosan to the methanesulfonic acid is 1 g: 10 mL-1 g: 30mL is that the solubility of the chitosan and the uniformity of the solution can be compared in the range of the mass-volume ratio; when the value range of the mass-to-volume ratio is too large, the adverse effect is that the addition amount of chitosan is too large, the dissolution degree of chitosan is low, and the uniformity of the solution is poor.

As an optional embodiment, the first impurity removal comprises: removing thionyl chloride by rotary evaporation;

the temperature of the first impurity removal is 30-80 ℃, and the time is 60-180 min;

the second impurity removal sequentially comprises: first pH adjustment, water addition and centrifugation, second pH adjustment and dialysis;

the ratio of the water amount of the added water to the volume of the deprotection solution is 3-8;

the dialysis comprises: dialyzing with pure water for 72-150 h, and replacing the dialysate every 12 h;

the end point of the first pH adjustment is 7.0-9.0, and the end point of the second pH adjustment is 2.0-7.0.

In the application, the positive effect that the temperature of the first impurity removal is 30-80 ℃ is that the removal rate and the side reaction degree of thionyl chloride at different temperatures can be compared in the temperature range; when the value range of the temperature is too large, the adverse effect is that the side reaction is increased due to the excessively high first impurity removal temperature, and when the value range of the temperature is too small, the adverse effect is that the thionyl chloride removal rate is low due to the excessively low first impurity removal temperature.

The method has the advantages that the first impurity removal time is 60-180 min, and the removal rate of thionyl chloride under different impurity removal times can be compared within the time range; when the value range of the time is too large, the adverse effect is that the time for first impurity removal is too long, the time consumption of the synthesis process is too long, and when the value range of the time is too small, the adverse effect is that the time for first impurity removal is too short, and the removal rate of thionyl chloride is low.

The water adding amount and the volume ratio of the deprotection solution is 3-8, so that water-insoluble impurities in the reaction system can be fully removed; when the value range of the volume ratio is too large, the adverse effect is that the final volume in the reaction stage is too large, the whole reaction is time-consuming and labor-consuming, and when the value range of the volume ratio is too small, the adverse effect is that the product and the impurities cannot be completely separated.

As an optional embodiment, the second mixing comprises: mixing under an ice bath condition, stirring for 0.5-2 h, and standing overnight at-25-5 ℃;

the mass-volume ratio of the first mixed fluorenyl methoxy carbonyl acyl-6-aminocaproic acid and thionyl chloride is 1 g: 2 mL-1 g: 10 mL;

the heating end point temperature is 50-80 ℃, and the time is 120-300 min.

In the application, the positive effect that the heating end point temperature is 50-80 ℃ is that the reaction efficiency and the side reaction degree at different temperatures can be controlled within the range of the end point temperature; when the value range of the temperature is too large, the temperature is too high, which causes side reactions, and when the value range of the temperature is too small, the reaction temperature is too low, which causes insufficient reaction.

The stirring time is 0.5-2 h, so that the uniformity of each area of the reaction system can be increased; when the value range of the time is too large, the adverse effect is that the reaction system absorbs moisture in the air to cause side reaction due to too long stirring time, and when the value range of the time is too small, the adverse effect is that the stirring time of the reaction system is too short and the esterification degree of different parts is not uniform.

The positive effect of staying overnight at-25-5 ℃ is to fully carry out the reaction; when the value range of the temperature is too large, the adverse effect is that a side reaction occurs at an excessively high temperature, and when the value range of the temperature is too small, the adverse effect is that the reaction is insufficient.

The heating time is 120-300 min, which has the positive effect that the degree of fluorenyl methoxy carbonyl acyl-6-aminocaproic acid acyl chloride under different reaction times can be controlled in the heating time; when the value range of the time is too large, the time consumption of the whole synthesis process is too much, and when the value range of the time is too small, the reaction is insufficient.

In one embodiment of the present application, there is provided a use of a chitosan derivative, the use comprising the use of the derivative in hemostatic and antibacterial medicaments.

Example 1

The molar ratio of glucosamine unit and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride of the chitosan is 1: 1.

As shown in fig. 2, a method for preparing a chitosan derivative includes:

weighing 1.61g of chitosan powder with deacetylation degree of 95%;

s11, adding chitosan powder into methanesulfonic acid under an ice bath condition to obtain a chitosan methanesulfonic acid solution;

3.53g of fluorenyl methoxy carbonyl acyl-6-aminocaproic acid is weighed;

s2, carrying out first mixing and heating on fluorenyl methoxy carbonyl acyl-6-aminocaproic acid and thionyl chloride, and then carrying out first impurity removal to obtain an oily yellow substance which is named fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride;

s3, carrying out second mixing on the chitosan methanesulfonic acid solution and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride, and then cooling to obtain a frozen mixture;

s41, unfreezing the frozen mixture at normal temperature, adding 150mL of acetone, stirring, centrifuging for 30min at the centrifugal force of 3000 Xg and the temperature of 4 ℃ to obtain a precipitate, and cleaning the precipitate with acetone again to obtain a precipitate mixture;

s42, dissolving the precipitate mixture with N, N-dimethylformamide, and then adding piperidine for 4h to obtain a deprotection product;

s5, carrying out second impurity removal on the deprotection product, and then carrying out freeze drying to obtain a yellowish final product, namely the chitosan derivative.

The end point volume fraction of piperidine was 7%.

Dissolving chitosan powder in methanesulfonic acid to obtain a chitosan methanesulfonic acid solution, comprising:

the mass-to-volume ratio of chitosan to methanesulfonic acid was 1 g: 20mL, i.e., the volume of methanesulfonic acid added was 32.2 mL.

The first impurity removal comprises: removing thionyl chloride by rotary evaporation;

the temperature of the first impurity removal is 45 ℃ and the time is 120 min.

The second edulcoration includes in proper order: first pH adjustment, adding water and centrifuging, second pH adjustment and dialysis;

the ratio of the water quantity of the added water to the volume of the deprotection solution is 1: 4;

the centrifugation comprises centrifuging at 8000 Xg and 4 deg.C for 30 min.

The dialysis comprises: dialyzing with pure water for 80h, and replacing the dialysate every 12 h;

the end point of the first pH adjustment was pH 8 and the end point of the second pH adjustment was pH 6.

The second mixing includes: mixing under ice bath condition, stirring for 1h, and standing overnight at-10 deg.C;

the mass-to-volume ratio of the first combined fluorenyl methoxy carbonyl acyl-6-aminocaproic acid and thionyl chloride was 1 g: 3 mL.

The heating end temperature was 60 ℃ and the heating time was 240 min.

Example 2

Comparing example 2 with example 1, example 2 differs from example 1 in that:

the molar ratio of glucosamine unit and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride of the chitosan is 1: 3.

1.61g of chitosan powder with deacetylation degree of 95 percent is weighed,

10.60g of fluorenyl methoxycarbonyl acyl-6-aminocaproic acid was weighed,

s41, unfreezing the frozen mixture at normal temperature, adding 200mL of acetone for precipitation, centrifuging for 30min at the centrifugal force of 3000 Xg and the temperature of 4 ℃ to obtain a precipitate, and cleaning the precipitate to obtain a precipitate mixture;

s42, dissolving the precipitate mixture with N, N-dimethylformamide, and then adding piperidine for 6h to obtain a deprotection product;

the mass to volume ratio of chitosan to methanesulfonic acid was 1 g: 15mL, indicating a 24.15mL volume of methanesulfonic acid was added.

The first impurity removal comprises: removing thionyl chloride by rotary evaporation;

the temperature of the first impurity removal is 40 ℃, and the time is 120 min.

The second edulcoration includes in proper order: first pH adjustment, adding water and centrifuging, second pH adjustment and dialysis;

the ratio of the water quantity of the added water to the volume of the deprotection solution is 1: 6;

the centrifugation comprises centrifuging at 8000 Xg and 4 deg.C for 30 min.

The dialysis comprises: dialyzing with pure water for 150h, and replacing the dialysate every 12 h;

the end point of the first pH adjustment was pH 7.5 and the end point of the second pH adjustment was pH 5.5.

The second mixing includes: mixing under ice bath condition, stirring for 1.5h, and standing overnight at-20 deg.C;

the mass-to-volume ratio of the first combined fluorenyl methoxy carbonyl acyl-6-aminocaproic acid and thionyl chloride was 1 g: 6 mL.

The heating end temperature is 55 ℃ and the heating time is 200 min.

Example 3

Comparing example 3 with example 1, example 3 differs from example 1 in that:

the molar ratio of glucosamine unit and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride of the chitosan is 1: 5.

1.61g of chitosan powder with deacetylation degree of 95 percent is weighed,

then 17.67g of fluorenyl methoxycarbonyl acyl-6-aminocaproic acid was weighed,

s41, unfreezing the frozen mixture at normal temperature, adding 180mL of acetone for precipitation, centrifuging for 30min at the centrifugal force of 3000 Xg and the temperature of 4 ℃ to obtain a precipitate, and cleaning the precipitate to obtain a precipitate mixture;

42. dissolving the precipitate mixture with N, N-dimethylformamide, and then adding piperidine for 12h to obtain deprotection reaction liquid;

the mass to volume ratio of chitosan to methanesulfonic acid was 1 g: 30mL, indicating a 48.30mL volume of methanesulfonic acid was added.

The first impurity removal comprises: removing thionyl chloride by rotary evaporation;

the temperature of the first impurity removal is 75 ℃, and the time is 150 min.

The second edulcoration includes in proper order: first pH adjustment, adding water and centrifuging, second pH adjustment and dialysis;

the ratio of the water quantity of the added water to the volume of the deprotection solution is 1: 6;

the centrifugation comprises centrifuging at 8000 Xg and 4 deg.C for 30 min.

The dialysis comprises: dialyzing with pure water for 150h, and replacing the dialysate every 12 h;

the end point of the first pH adjustment was pH 8.5 and the end point of the second pH adjustment was pH 6.5.

The second mixing includes: mixing under ice bath condition, stirring for 1.5h, and standing at-25 deg.C overnight;

the mass-to-volume ratio of the first combined fluorenyl methoxy carbonyl acyl-6-aminocaproic acid and thionyl chloride was 1 g: 9 mL.

The heating was terminated at 65 ℃ for 300 mm.

Comparative example 1

Dissolving chitosan powder with deacetylation degree of 95% in dilute hydrochloric acid with molar concentration of 0.01mol/L, stirring to fully dissolve the chitosan powder, adjusting pH to 6.0 with NaOH solution with molar concentration of 0.01mol/L, dialyzing with pure water for 120h in a dialysis bag, replacing dialysate every 12h, and finally freeze-drying to obtain chitosan hydrochloride.

Related experiments:

the chitosan hydrochloride and the chitosan derivative obtained in the comparative example and the examples 1 to 3 were collected, and water solubility and dissolution rate were measured, and the measurement results are shown in table 1.

The related experimental method comprises the following steps:

solubility test method:

a. for each sample to be tested, 3 glass test tubes are taken, and 1mL of pure water is added into each tube;

b. respectively adding 10mg of chitosan hydrochloride or chitosan derivative into 3 test tubes, stirring to dissolve the chitosan hydrochloride or chitosan derivative, and continuously adding 10mg of solute after the end product is completely dissolved;

c. b, circulating the step b until the end product is added and stirred for 60min, determining the solubility limit if solute still can not be dissolved, respectively recording the addition amount of the end product in 3 test tubes at the moment, obtaining the proportion of the addition amount of the end product and the volume of pure water in the test tubes, and taking an average value (expressed by Mean +/-SD) to obtain the solubility of the chitosan derivative;

d. the solubility of the end products of the comparative examples and examples was obtained after subjecting the chitosan hydrochloride and chitosan derivative chitosan derivatives obtained in the comparative examples and examples to the above tests.

Test method for dissolution rate:

a. respectively pulverizing chitosan hydrochloride and chitosan derivative by a mechanical method, and sieving with a 100-mesh sieve;

b. the powders of chitosan hydrochloride and chitosan derivative obtained in comparative example 1 and examples 1 to 3 after sieving were collected, 50mg were respectively loaded into glass test tubes (6 replicates per set), 1mL of pure water was added to each tube, rapidly stirred for 15s, and left to stand. The time taken for the chitosan hydrochloride and chitosan derivative to dissolve completely was recorded.

TABLE 1

Categories	Solubility (%)	Dissolution time(s)
			Comparative example	9.71±0.32％	2780±320
Example 1	27.91±0.55％	623±64
			Example 2	32.44±0.72％	588±44
Example 3	36.38±0.79％	512±46

Specific analyses in table 1:

solubility refers to the ability of the prepared end product to dissolve in water, and a greater solubility indicates a better water solubility of the end product.

The dissolution time means the dissolution speed of the prepared end product in water, and when the dissolution time is shorter, the dissolution speed of the end product is higher, so that the end product can act on a wound to play a procoagulant function.

From the data of comparative example 1 and examples 1 to 3, it can be seen that:

the water solubility of the chitosan derivative synthesized under each condition is larger than that of chitosan hydrochloride prepared by the conventional method, and the higher the molar ratio of glucosamine unit and fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride of the chitosan is, the stronger the water solubility of the obtained chitosan derivative is.

The chitosan derivative synthesized under each condition has a dissolution rate in water greater than that of chitosan hydrochloride prepared by a conventional method, and the higher the molar ratio of glucosamine unit and fluorenyl methoxycarbonyl acyl-6-aminocaproic acid-acyl chloride of chitosan is, the faster the dissolution rate of the obtained chitosan derivative is.

In order to verify the application of the chitosan hydrochloride and the chitosan derivatives obtained in comparative example 1 and examples 1 to 3 of the present application in practical hemostatic and antibacterial drugs, the present application also performs antibacterial and hemostatic effect experiments on the chitosan hydrochloride and the chitosan derivatives, and the results are shown in table 2.

Methods of the related experiments:

the specific detection method of the Minimum Inhibitory Concentration (MIC) of escherichia coli and the Minimum Inhibitory Concentration (MIC) of staphylococcus aureus is as follows:

a. dissolving chitosan hydrochloride and chitosan derivative in water respectively to prepare solutions with the concentrations of 50 mu g/mL, 100 mu g/mL, 150 mu g/mL, 200 mu g/mL, 250 mu g/mL, 300 mu g/mL, 350 mu g/mL, 400 mu g/mL, 450 mu g/mL and 500 mu g/mL in sequence;

b. filtering each group of solution with a needle filter with the aperture of the filter membrane of 0.22 μm to remove bacteria;

c. 0.5mL of each sterilized solution was taken out of the tube and added to 0.5mL of LB liquid medium (pH 6.0) prepared and sterilized in advance, and each set was repeated 6 times. At this time, the final concentrations of chitosan hydrochloride or chitosan derivative in each group of solutions were 25. mu.g/mL, 50. mu.g/mL, 75. mu.g/mL, 100. mu.g/mL, 125. mu.g/mL, 150. mu.g/mL, 175. mu.g/mL, 200. mu.g/mL, 225. mu.g/mL and 250. mu.g/mL, in that order;

d, setting a zero adjustment group: to 6 shake tubes, 0.5mL of sterile water and 0.5mL of previously prepared and sterilized LB liquid medium (pH 6.0) were added, respectively;

e. setting a positive group: to 6 shake culture tubes, 0.5mL of a chlorhexidine gluconate solution having a concentration of 100 μ g/mL and 0.5mL of a previously prepared and sterilized LB liquid medium (pH 6.0) were added, respectively;

f. to all the shake tubes except the zero-set group, 10. mu.L of E.coli fermentation broth (with a cell concentration of about 10. mu.L) was added⁶CFU/mL), covering a tube cover, and culturing at 28 ℃ and 200rpm for 24 h;

g. measuring the OD600 value of each tube of solution under an enzyme-labeling instrument, and subtracting the average value of the zero-adjusting group to obtain the real OD600 value of the solution in each tube;

h. comparing the OD600 values of the chitosan hydrochloride and the chitosan derivative obtained in the comparative example and the examples 1-3 with the OD600 value of the escherichia coli of the positive group to obtain the Minimum Inhibitory Concentration (MIC) of the chitosan hydrochloride and the chitosan derivative on the escherichia coli;

i. the Minimum Inhibitory Concentrations (MIC) of chitosan hydrochloride and chitosan derivatives obtained in comparative examples and examples 1-3 against Staphylococcus aureus were determined in the same manner, but OD450 values were determined.

The method for detecting procoagulant ability comprises the following steps:

a. taking 36C 57BL/6 mice (each half of male and female) to randomly divide into 6 groups, each group comprises 6 mice, carrying out intraperitoneal injection by using sodium pentobarbital (40mg/mL), fully anaesthetizing the mice after a plurality of minutes, and carrying out subsequent related experiments;

b. fixing the mouse on a dissecting plate, and opening the abdominal cavity to expose the liver after dissecting;

c. wiping tissue fluid around liver with filter paper, placing the filter paper under liver leaf, puncturing liver with G20 needle, and immediately spreading 10mg chitosan hydrochloride or chitosan derivative or zeolite powder (positive drug) on the wound;

d. lifting the dissecting plate by inclining the dissecting plate at 45 degrees, enabling blood to flow downwards and be absorbed by the filter paper sheet, taking down the filter paper sheet after 5min, weighing, and calculating blood flow, wherein the blood flow is the weight of the filter paper sheet after the test-the weight of the filter paper sheet before the test;

e. the above experiment was repeated, each group of samples was subjected to 6 parallel tests, and a blank group (no material was scattered to the wound after puncturing the liver) was set;

g. the average of the amount of liver bleeding of each group of mice was calculated.

TABLE 2

Specific analysis of table 2:

the Minimum Inhibitory Concentration (MIC) is an international standard for measuring the antibacterial performance of an antibacterial drug, and the smaller the MIC, the better the antibacterial performance of the antibacterial drug.

The average value of the amount of bleeding means that the lower the average value of the amount of bleeding after a plurality of parallel experiments, the better the hemostatic effect is.

From the data for the comparative example and examples 1-3, it can be seen that:

the antibacterial performance of the chitosan derivative synthesized under various conditions is superior to that of chitosan hydrochloride prepared by the conventional method. However, the antibacterial abilities of the chitosan derivatives obtained in examples 1 to 3 are not significantly different, which indicates that the molar ratio of the glucosamine unit and the fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride of chitosan is not affected by the continuous increase of the molar ratio in the synthesis process of the chitosan derivative.

The procoagulant capacity of the chitosan derivative synthesized under various conditions is larger than that of chitosan hydrochloride prepared by the conventional method, and the hemostatic effect of the obtained chitosan derivative is improved to a certain extent along with the increase of the molar ratio of glucosamine units and fluorenyl methoxycarbonyl acyl-6-aminocaproic acid-acyl chloride of chitosan.

One or more technical solutions in the embodiments of the present application at least have the following technical effects or advantages:

(1) in the embodiment of the application, fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride is respectively subjected to esterification and acylation reactions with hydroxyl and amino of chitosan, so that the formation of intramolecular and intermolecular hydrogen bonds is inhibited to a certain extent, and the solubility and the dissolution rate of fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride in water are improved;

(2) in the embodiment of the application, the prepared chitosan derivative has stronger antibacterial and hemostatic capabilities, and the application field of chitosan can be better expanded.

(3) In the embodiment of the application, as only simple chemical reaction is needed, the overall modification method is simple and easy to implement, and excessive equipment and reagents are not needed.

The drawings illustrate:

FIG. 3 is a schematic diagram of a synthetic route of a chitosan derivative according to an embodiment of the present invention; as can be seen from FIG. 3, the principle is that fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride and hydroxyl and amino of chitosan are respectively subjected to esterification and acylation reactions, and the hydroxyl is substituted to inhibit the formation of hydrogen bonds in molecules and between molecules, so that the solubility and the dissolution rate of fluorenyl methoxy carbonyl acyl-6-aminocaproic acid-acyl chloride in water are improved.

FIG. 4 is a graph comparing infrared spectra of chitosan and chitosan derivatives provided in examples of the present application; as can be seen from fig. 4, the aminocaproic acid-chitosan ester clearly has a higher absorption peak at a wavelength of 1723.71cm "1, which is the result of stretching vibration of C ═ O in the ester bond or stretching vibration of C ═ O in the amide bond.

FIG. 5 is a chart comparing hydrogen nuclear magnetic resonance spectra of chitosan and chitosan derivatives provided in examples of the present application; in the hydrogen nuclear magnetic resonance spectrum of CSH in fig. 5, δ ═ 1.99ppm is the chemical shift of H in the methyl group on the acetylamino group remaining without complete deacetylation of chitin, δ ═ 3.07ppm is the chemical shift of H in the amino group after deacetylation of chitin, the overlapping peak at δ ═ 3.65 to 3.84ppm is the chemical shift of H on the chitosan ring skeleton, δ ═ 4.70ppm is the chemical shift of H in the solvent peak and the hydroxyl group masked by the solvent peak; in the hydrogen nuclear magnetic resonance spectrum of CSH-AA in fig. 5, δ 1.09 to 1.62ppm and δ 2.16 to 2.25ppm are chemical shifts of H on the carbon skeleton of aminocaproic acid, δ 1.98ppm is a chemical shift of methyl H on the acetylamino group remaining without complete deacetylation of chitin, δ 2.84 to 2.93ppm is a chemical shift of H in the amino group and H in the amide bond, an overlap peak at δ 3.45 to 3.87ppm is a chemical shift of H on the chitosan ring skeleton, and δ 4.57 to 4.79ppm is a chemical shift of H of the solvent peak and the hydroxyl group masked by the solvent peak.

As can be seen from the results of fig. 4 and 5, the chemical structure of the chitosan derivative is consistent with the structure expressed by formula 1.

Fig. 6 is a comparison graph of procoagulant effects of chitosan and chitosan derivative provided by the embodiment of the present application, as can be seen from fig. 6, a large amount of blood flows out from a mouse liver after being punctured by a G20 needle, and a hemostatic material is applied to a bleeding opening to reduce the outflow of blood to a certain extent, the less the amount of bleeding of the mouse liver is, the better the procoagulant effect of the test material is, wherein the hemostatic ability of the chitosan derivative provided by the present application is stronger, and the hemostatic ability increases along with the molar ratio of glucosamine units and fluorene methoxycarbonyl acyl-6-aminocaproic acid-acyl chloride of chitosan.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.