CN115010981B

CN115010981B - Solid product containing amino indissolvable polymer, preparation method and application thereof

Info

Publication number: CN115010981B
Application number: CN202210730651.0A
Authority: CN
Inventors: 龙远铸; 赵梦; 陈彬; 白国辉; 刘建国
Original assignee: Oral Hospital Affiliated To Zunyi Medical University
Current assignee: Oral Hospital Affiliated To Zunyi Medical University
Priority date: 2022-06-24
Filing date: 2022-06-24
Publication date: 2023-12-05
Anticipated expiration: 2042-06-24
Also published as: CN115010981A

Abstract

The application provides a preparation method of a solid product containing amino indissolvable polymers in the technical field of material preparation, which comprises the steps of treating chitosan, type I collagen or polyamide and other amino indissolvable polymers into a polymer solution or hydrogel state with amino and weak acid radical ions combined; the treated high molecular solution or hydrogel is not treated by alkali and chemical cross-linking agent, and can be directly frozen and thawed to obtain the sponge product which is recovered to the original high molecular structure. The obtained solid product can reduce the damage of alkaline substances and cross-linking agents to the properties of the high polymer solid product, has lower cost and is beneficial to popularization and use of the product.

Description

Solid product containing amino indissolvable polymer, preparation method and application thereof

Technical Field

The application relates to the technical field of material preparation, in particular to a solid product containing amino indissolvable polymers, a preparation method and application thereof.

Background

The amino group-containing poorly soluble polymer is a polymer containing an amino group which cannot be directly dissolved by water or an organic solvent, and is typically represented by Chitosan (CS), type I collagen (COL-I), linear polyethylenimine, and the like. Wherein CS and COL-I are used as natural degradable materials with biological safety, and are widely applied to various fields of medical treatment, food, beauty treatment, health care, chemical industry, agriculture and the like. CS and COL-I are prepared into solid products such as sponge and hydrogel, are widely applied to CS materials in the form of materials, and can be widely applied to the fields of biomedical materials such as hemostasis and trauma. CS and COL-I solid products have huge application potential, but as amino-containing indissolvable polymers, the CS and COL-I solid products have the problems of poor solubility, complex preparation process of the solid products, high production cost and great popularization difficulty. CS and COL-I have good hydrophilic ability, but have strong hydrogen bonding in their molecular structures, and thus cannot be directly dissolved in water or organic solvents.

The preparation of CS solid products (for example sponge products) requires first a dissolution treatment by means of a dissolution aid, whereas the usual method is to dissolve CS in an acidic solution such as acetic acid or in a mixed solution containing sodium hydroxide. Wherein CS dissolved by acid solution such as acetic acid is subjected to vacuum freeze drying, then is subjected to acid-base neutralization reaction by alkali solution containing organic solvent, and finally is subjected to purification process (extrusion and pure water washing) for more than 3 times to obtain CS spongy solid product. The CS solid product has high production cost and is difficult to popularize and use. CS dissolved in an alkaline solution as a dissolution aid can also be used to prepare a sponge structure using the same principle, and will not be described in detail herein.

The preparation process of CS sponges therefore generally requires to undergo: dissolving, freezing, vacuum freeze drying, post-treatment (treatment with acid/alkali solution containing organic solvent), purifying, and freeze drying time varies according to the size of the product, but usually not less than 48 hours, the time and cost are long, and the organic solvent and reagent required for post-treatment further increase the production cost of CS sponge.

The preparation method of the CS sponge is complex, the time consumption is long, the production cost is high, and the commercialization of CS sponge products is greatly limited. Therefore, the application needs to solve the problems of long preparation time, large reagent consumption and high production cost of CS sponge.

For COL-1, the preparation method has good biocompatibility and high production cost, is often used in the fields of medical use and cosmetology, and alkali can damage the molecular structure and chemical components of the COL-1, so that the biocompatibility of the COL-1 is reduced. Thus, COL-1 products are currently often prepared in a hydrogel state by chemical crosslinking agents, and then sponge products are prepared by freeze-drying and purification processes. Not only is the operation complicated, but also the residual cross-linking agent is easy to reduce the biocompatibility of the solid product. Therefore, COL-1 solid articles are currently being used as tissue-implant materials.

In summary, the current method for preparing the amino group-containing insoluble polymer solid product is complex, high in cost and limited in application range.

Disclosure of Invention

Aiming at the defects of the prior art, the application researches a method for preparing the amino-containing indissolvable polymer solid product without alkali and a chemical crosslinking agent in order to solve the problems that the preparation process is complex and the cost is high in the preparation process of the amino-containing indissolvable polymer solid product, and the use of alkali or the chemical crosslinking agent easily influences the biocompatibility of the amino-containing indissolvable polymer solid product.

The application aims at providing a preparation method of a solid product containing amino indissolvable polymers, which comprises the steps of dissolving the amino indissolvable polymers by using a solutionizer, then adding salt or acid composed of weak acid ions to obtain a solution of combining the weak acid ions with amino in the amino indissolvable polymers, namely a pretreatment solution, forming hydrogel by physical crosslinking of the pretreatment solution, namely a pretreatment hydrogel, and directly preparing the pretreatment solution or the pretreatment hydrogel into the solid product.

Further, the pretreatment solution or the pretreatment hydrogel is subjected to freezing, thawing and washing purification to obtain a polymer sponge-like, flocculent or granular solid product.

Further, the pretreated hydrogel is soaked in aqueous solution for purification, and then the polymer hydrogel solid product which only contains the amino indissolvable polymer and the solvent is directly prepared.

Further, the purified hydrogel solid product is prepared into a solid product by volatilizing and drying a solvent, or is prepared into a spongy solid product by freeze drying.

Further, the pretreatment solution or the pretreatment hydrogel is directly soaked in an aqueous organic solvent solution in a state of containing liquid or dry sponge solid to obtain a purified sponge product.

Through the solvent soaking mode, impurities in the amino group-containing indissoluble polymer solid product can be dissolved in the solvent, and the impurities can be sufficiently removed by replacing the solvent and repeatedly soaking, so that the effect of purifying the amino group-containing indissoluble polymer solid product is achieved.

Further, the dissolution assisting substance is an acid or alkaline solution, when the dissolution assisting substance is an acid, the weak acid radical ion is different from the acid radical ion of the dissolution assisting substance, and the reactivity of the weak acid radical ion is weaker than the acid radical ion.

Further, the solubles include formic acid, hydrochloric acid, acetic acid or a mixture containing sodium hydroxide.

Further, the weak acid radical ion is CO ₃ ^2- 、HCO ₃ ^- 、F ^- 、ClO ^- 、SiO ₃ ^3- 、S ^2- 、CN ^- 、SCN ^- 、NO ₂ ^- 、SO ₃ ^2- 、HPO ₄ ^2- 、HS ^- 、AlO ₂ ^- 、BrO ^- 、BO ₃ ^3- Or one of the other acid ions.

Preferably, the salt composed of weak acid ions is one of sodium bisulfate, sodium fluoride, sodium cyanate, calcium bicarbonate, sodium metaaluminate, ammonium bicarbonate, sodium hypochlorite or sodium stearate, and the acid composed of weak acid ions is one of hydrogen sulfate, hypobromous acid, boric acid, hydrocyanic acid or carbonic acid.

Specifically, the solid product containing the amino group-containing poorly soluble polymer can be prepared by the following steps:

(1) Dissolving amino-containing insoluble polymer in an acid or alkaline solution;

(2) For the amino-containing insoluble polymer dissolved by acid as a solutionizing agent, adding a salt composed of weak acid ions in a temperature range capable of maintaining a solution state, wherein the reaction capacity of the weak acid ions is weaker than that of the acid ions of the solutionizing agent, so that the cations of the salt can be combined with the acid ions of the solutionizing agent, thereby combining the weak acid ions with the amino groups of the amino-containing insoluble polymer and maintaining the solution state; similarly, for the amino group-containing insoluble polymer dissolved in the alkaline solution as the solubilizing agent, an excessive amount of weak acid containing weak acid radical ions is added, the weak acid can react with the alkali to generate a salt with weak acid radical ions, and in addition, the excessive weak acid is combined with the amino group-containing insoluble polymer to obtain a solution state in which the weak acid radical ions are combined with the amino groups; obtaining a pretreatment solution; the pretreatment solution is allowed to stand at room temperature for more than 5 minutes to become a hydrogel formed by physical crosslinking, so that a pretreated hydrogel is obtained.

(3) a, directly freezing the pretreatment solution or the pretreatment hydrogel, naturally thawing in air to obtain spongy solid, squeezing the liquid in the sponge, washing and purifying with pure water to obtain spongy products containing amino indissolvable polymers, regulating the solid content of the amino indissolvable polymers in the pretreatment solution to obtain spongy products with different densities, further reducing the solid content, and even obtaining flocculent or granular solid products.

b. The pretreated hydrogel is soaked in aqueous solution for purification, and then the solid product of the high polymer hydrogel which only contains amino indissolvable high polymer and solvent is directly prepared.

c. The pretreatment solution or the pretreatment hydrogel is directly soaked in an aqueous organic solvent solution in a liquid state or a dry sponge solid state to obtain a sponge product.

d. The purified hydrogel product can be directly dried to obtain solid products in the forms of coating, sheet, block and the like, or can be freeze-dried to obtain spongy solid products.

The amino-containing insoluble polymer comprises glycan, type I collagen, linear polyethylenimine, polypeptide polymer, silk fibroin or polyamide. For different amino-containing insoluble polymers, the selected weak acid radical-containing salt or acid cannot be used as a solubles of the corresponding amino-containing insoluble polymers, and also does not have the property of directly dissolving the amino-containing insoluble polymers, for example, acetic acid can dissolve chitosan, and acetate cannot be used as the weak acid radical-containing salt or acid.

The working principle and the beneficial effects of the application are as follows: in the preparation of the sponge product, taking Chitosan (CS) as an example, the CS sponge solid only needs to undergo the following steps: dissolving, pretreatment, freezing, thawing and purifying, wherein the total steps are 5. The dissolving step of the application is to dissolve by taking acid or alkaline solution as a dissolution assisting substance, and the pretreatment step specifically comprises the following steps: the salt containing weak acid radical is added into CS solution dissolved by acid as the auxiliary solvent, and the acid capable of reacting with amino group on CS to generate weak acid radical is added into CS solution dissolved by alkali as the auxiliary solvent. The CS solution dissolved with acid will be described in detail later, due to similar principles. The pretreatment step takes no more than 1 hour, but the steps of freeze drying and alkaline solution treatment with an organic solvent, which are long in time and high in cost in the conventional preparation method, can be omitted.

The acid is used as a salt which is added in the CS solution dissolved by the solutionizer and consists of weak acid radical ions, wherein the reactivity of the positive charges of the salt is higher than that of the amino group of CS, and the reactivity of the weak acid radical ions is weaker than that of the acid radical ions of the solutionizer. The cations of the added salt are combined with anions formed during dissolution of CS by the acid as a co-solvent, so that the weak acid radical ions are combined with the amino groups of CS and keep CS in solution. The CS solution obtained by salt treatment gradually spontaneously forms a hydrogel state through physical crosslinking along with the time, and the CS solution obtained by salt treatment and the CS hydrogel are all the pretreatment steps of the CS sponge solid. After the CS solution or hydrogel obtained by the pretreatment is frozen and thawed, the weak acid radical ions are separated from amino groups on CS and dissolved into aqueous solution, so that a sponge solid product which is recovered into CS structure is obtained.

Weak acid ions separated from the amino groups on the CS are taken into the aqueous liquid, while CS is insoluble in the aqueous solution, and other non-CS components can be removed by squeezing the liquid in the sponge and washing with pure water.

In conclusion, the CS solution and CS hydrogel obtained in the pretreatment step are quite simple in preparation of CS sponge through freezing and thawing treatment, the time for freezing and thawing the CS solution is far less than that of freeze drying in the prior art, and equipment such as a freeze dryer is not needed. The CS sponge prepared by the application has low input cost, and other substances except the CS sponge can be dissolved in the aqueous solution, so that the purification is very convenient and thorough. The CS sponge obtained by the application has low equipment requirement, short time and low cost, and meets the preparation requirement of low carbon and environmental protection. The method for preparing CS sponge product can also obtain non-sponge solid product in flocculent, granular or other state.

In addition, the following two methods can also be used to prepare CS solid products quite simply without the need for freeze thawing. The first method is that the CS solution and CS hydrogel obtained in the pretreatment step of the application can also be directly placed in an aqueous organic solvent to obtain CS sponge, the principle is that the CS structure is insoluble in the organic solvent, and water can take away weak acid radical ions combined with CS into the solution, thereby obtaining a pure CS sponge structure. Alternatively, the CS solution and CS hydrogel obtained in the "pretreatment" step of the present application are physically or chemically crosslinked to form a stable solid or gel structure. The solid structure or gel structure is immersed in the aqueous solution, and weak acid radical ions combined with CS are slowly released into the solution, so that a purified CS solid product is obtained.

The CS solution or hydrogel prepared by the method directly prepares the pure CS sponge by freezing and thawing, does not need to be subjected to freeze drying treatment, does not need to be treated by alkali and chemical cross-linking agents, and does not need to participate in an organic solvent. Compared with the prior art that the CS sponge is prepared by freeze drying, organic solvent and other treatment steps, the preparation method can save more than 90 percent of preparation time and greatly reduce the production cost. The manufacturing cost of the biocompatible degradable CS sponge is expected to be close to that of traditional wound dressing products such as sterile gauze and the like.

According to the application, the CS hydrogel obtained through the pretreatment step is soaked in pure water to remove impurities, so that a hydrogel solid product only containing CS and a water solvent can be obtained, the purified CS hydrogel is directly dried to obtain a CS solid product with a solid structure, and the purified CS hydrogel is freeze-dried to obtain a CS spongy solid product.

COL-1 or other sponge products and hydrogel solid products containing amino-insoluble polymers are prepared by the same method as CS, so that the amino-insoluble polymer solid products can be prepared by the same method without alkali and chemical crosslinking agents.

The application has the advantages that the amino indissolvable polymer raw material is indissolvable in water and organic solvent, but the amino indissolvable polymer liquid material needs to be in the presence of the auxiliary solvent by adopting the method in the prior art, so that the amino indissolvable polymer liquid material is directly prepared into a solid state (a water-containing gel state) and often contains the auxiliary solvent, so that the material can be dissolved in water or organic solvent, which is obviously disadvantageous to the stability of the properties of a solid product. However, the pretreatment solution provided by the application does not contain a cosolvent after being prepared into a solid product, and does not change the physicochemical properties of the amino-containing insoluble polymer material, and the prepared amino-containing insoluble polymer solid product recovers the property that the amino-containing insoluble polymer product is difficult to dissolve in water or an organic solvent.

It is a further object of the present application to provide the use of solid articles comprising amino-insoluble polymers, including the use in the preparation of biomedical materials and the use in the preparation of carrier materials.

Drawings

FIG. 1 is a schematic flow chart of the preparation method of the application;

FIG. 2 is an infrared spectrum (FTIR) of the product of example 8 at various stages in the preparation of a CS sponge;

FIG. 3 is a schematic representation of the water absorption of CS sponge prepared from the CS solution of examples 1-22 by freezing, thawing and aqueous solvent treatment;

FIG. 4 is a graph showing the water absorption capacity of CS sponges prepared from CS solutions of different solids in examples 10-13;

FIG. 5 is a graph showing the density (A) and tensile strength (B) of the CS sponge prepared in examples 10-13 after 30d composting;

FIG. 6 is a schematic diagram of the cytotoxicity of the CS sponge extract of example 8 on L929 as measured by CCK-8 staining;

FIG. 7 is a schematic diagram of the use of CS sponge as wound dressing in example 8 for wound repair (A) and statistical wound diameter variation (B) in C57BL/6 mice;

FIG. 8 is a schematic diagram of passing electricityMeasurement of calcium ions (Ca) obtained in examples 4 to 6 by inductively coupled plasma emission spectrometry (ICP-OES) ₂ ⁺ ) Modified CS-Ca ₂ ⁺ Ca of sponge ₂ ⁺ Content (A), and hemostatic effect (B) of SD rat tail-breaking experiment;

FIG. 9 is a schematic representation of the sustained release effect of CS sponge on dexamethasone by liquid phase mass spectrometry test example 10-13.

Detailed Description

The following is a further detailed description of the embodiments:

in order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the following specific embodiments. It is to be noted that all of these examples are for further explanation of the present application and should not be construed as limiting the present application. Some insubstantial modifications and adaptations of the application as described above would be within the scope of the application by those skilled in the art in light of the foregoing disclosure.

TABLE 1 list of conditions for preparing solid products containing amino-insoluble Polymer of the present application

Note that: NH-R represents an amino-containing poorly soluble polymer. A sample of the time for preparing the NH-R sponge from the NH-R solution was prepared by placing 50g of the NH-R solution obtained by treatment with a salt or acid containing weak acid groups in a dish having a diameter of 15cm and then freezing and thawing the solution. The number of samples per group was 3.

CS is a typical representation of amino-containing water-insoluble polymers, and CS is used for representing amino-containing water-insoluble polymers for explaining the method for preparing the amino-containing water-insoluble polymer solid product.

Examples 1 to 23

According to the application, CS is dissolved by a traditional method, as shown in figure 1, and salt substances containing acid and alkali are used as a dissolution assisting substance, and then salt or acid consisting of weak acid radical ions is combined with CS, so that CS solution is obtained. Taking CS dissolved in an acidic solution as an example, the specific procedure is as follows.

For examples 1-13, CS was dissolved in an acidic solution, so the principle of CS sponge preparation was the same. The detailed preparation process is described herein by way of example 8. The pretreatment is as follows: 1 part by mole of CS (i.e., CS raw material) was dissolved in an acetic acid solution containing 0.7 part by mole at a temperature of 20℃under stirring at 400 r/min. At this time, the action of acetic acid aqueous solution and CS amino breaks down and dissolves the intramolecular and intermolecular hydrogen bonds of CS. Stirring for 2h, completely dissolving CS, dropwise adding ammonium bicarbonate solution into the dissolved liquid at 5-80deg.C, dropwise adding 0.73 mol of ammonium bicarbonate, stirring for reacting for 20min, and pretreating CS solution. After the reaction is completed, a solution of CS in which carbonate or bicarbonate is combined with the amino groups of CS is obtained.

The pretreatment of the CS solution involves a series of chemical reactions in which the primary amino groups (cations) of the ammonium bicarbonate are more reactive than the secondary amino groups on CS, while the bicarbonate or carbonate (anions) are less reactive than the acetate. It is thus ensured that the primary amino group of the ammonium bicarbonate salt replaces the secondary amino group of CS in combination with the acetate group, thereby enabling the bicarbonate or carbonate anion in the ammonium bicarbonate to combine with the amino group of CS and maintain the dissolved state. The salt-treated CS solution (i.e., CS solution obtained in the "pretreatment" step) may be allowed to stand at room temperature for more than 5 minutes to form a hydrogel by physical crosslinking (i.e., CS gel obtained in the "pretreatment" step).

The molar amount of ammonium bicarbonate used in the preparation of the CS solution may be suitably greater than the molar amount of acetic acid in order to substantially displace acetate bound to the amino groups of CS, which facilitates the final yield of pure CS sponge after the purification step.

The carbonate or bicarbonate groups combine with the amino groups of CS to readily hydrolyze. Thus, after freezing the salt-treated CS solution or hydrogel to a solid, slow formation of CS sponge is observed during thawing. After thawing, the liquid in the sponge can be directly extruded by extrusion. Then soaking in pure water, repeatedly squeezing and washing to remove impurities in the sponge containing CS and obtain pure CS sponge. The chemical formula change throughout the preparation process is illustrated as follows:

the arrows in the formula mark the intramolecular and intermolecular hydrogen bonds of CS. Bicarbonate (-HCO) in the above formula ₃ ) Carbonate is generated in aqueous solutions and is not individually identified herein.

It is noted that the mass of the CS raw material and the aqueous solution during the pretreatment by adding ammonium bicarbonate after dissolving CS in acetic acid solution in example 8 is known, so that the solids content of CS in the liquid can be controlled to be 1.0% (see table 1). The volume of the CS sponge and the volume of the CS solution are almost identical, so that the volume of the pores in the CS sponge can be calculated by controlling the solid content of CS in the solution, and it can be known that the liquid which the CS sponge can absorb at maximum is 100 times (i.e., 10000%) of its own weight in theory.

For examples 14-18, CS was dissolved in an alkaline solution, so the principle of CS sponge preparation was the same. Similar to examples 1-13, according to the proportions of various substances shown in Table 1, after CS is dissolved in an alkaline solution such as sodium hydroxide, and an excessive amount of acid composed of weak acid ions is added, the acid is subjected to acid-base neutralization reaction with the alkaline solution to form a salt, and the excessive acid is combined with CS to form a solution state in which the weak acid ions are combined with amino groups. The same anions bound to CS can be removed by freezing and thawing and pure CS sponge can be obtained.

The method for preparing a solid sponge product by freezing and thawing the solution of non-CS amino group-containing indissolvable polymers in examples 19 to 23 is the same as that for preparing CS sponge in examples 1 to 18.

For examples 1-23, it can be seen from Table 1 that the preparation time of the method for directly preparing the pure amino group-containing insoluble polymer sponge by freezing and thawing the amino group-containing insoluble polymer solution is short, and the time for preparing the amino group-containing insoluble polymer sponge by placing 50g of the pretreated amino group-containing insoluble polymer solution on a 15cm surface dish and freezing and thawing the amino group-containing insoluble polymer solution is less than 3.5 hours. The time required by the conventional method for freeze-drying the amino-containing indissolvable polymer sponge can even exceed 48 hours under the same condition, and the amino-containing indissolvable polymer sponge prepared by the conventional freeze-drying can be removed by the treatment modes such as acid-base reaction and the like, and the water resistance and the solvent resistance of the amino-containing indissolvable polymer sponge can be recovered.

Therefore, the method for preparing the amino-containing indissolvable polymer sponge greatly shortens the preparation time of the amino-containing indissolvable polymer sponge.

It should be noted that, when the amino group-containing insoluble polymer is not directly dissolved in the acidic cosolvent, but is a solution formed by directly combining the amino group of CS with weak acid ions different from the acid ions of the cosolvent, the solution is directly frozen and thawed without adding salts or acids with weak acid groups, and then purified to obtain the amino group-containing insoluble polymer solid.

The "pretreated" hydrogel obtained by standing the "pretreated" solution containing the amino-insoluble polymer in examples 1 to 23 for 5 minutes or longer was water-resistant and solvent-resistant, and impurities such as weak acid ions were removed by immersing to obtain a purified hydrogel containing only the amino-insoluble polymer and the solvent. The purified water gel containing indissoluble amino group is a water gel solid product which is prepared by the method and does not need alkali and chemical cross-linking agent treatment. The purified amino-containing indissoluble polymer hydrogel can also be prepared into solid by directly volatilizing and drying a solvent, and the solid product can be in the forms of blocks, sheets, films, coatings and the like. In addition, the purified amino-containing indissoluble polymer hydrogel can be subjected to solvent removal in a freeze drying mode to obtain an impurity-free amino-containing indissoluble polymer sponge product.

The amino-containing indissolvable polymer solution and the amino-containing indissolvable polymer gel subjected to pretreatment are frozen and thawed to prepare the amino-containing indissolvable polymer sponge solid product, and the amino-containing indissolvable polymer sponge solid product and the purified amino-containing indissolvable polymer hydrogel and the solid product prepared by the purified amino-containing indissolvable polymer hydrogel are all amino-containing indissolvable polymer solid products with the same chemical components. Therefore, the amino group-containing indissoluble polymer sponge solid product is prepared by freezing and thawing the amino group-containing indissoluble polymer solution and the amino group-containing indissoluble polymer hydrogel which are subjected to pretreatment in the follow-up process, and the quality of the solid product obtained by the application is described.

FIG. 2 is an infrared spectrum of the product of the whole process of preparing pure CS sponge directly from CS solution in example 8 by freezing and thawing. Wherein the CS raw material is CS raw material, and CS-HOAc is CS dissolved in acetic acid solution, and CS-NH ₄ HCO ₃ CS-HOAc treated with ammonium bicarbonate, CS sponge CS-NH ₄ HCO ₃ And (5) purifying after freezing and thawing.

In FIG. 2, 3280cm for CS raw material ^-1 The wide peak is formed by overlapping the telescopic vibration absorption peaks of O-H and N-H. 2870 and 2925cm ^-1 C-H stretching vibration absorption peak of methyl or methine on CS. The characteristic peak of CS is 1500-1650 cm ^-1 This is-NH ₂ And a stretching vibration peak of-NH. At 1024cm ^-1 The characteristic absorption peak with a strong front-back range is formed by C-O-C of CS. 1317cm ^-1 Is an absorption peak of amide. With the addition of acetic acid (HOAc) to CS, the amino groups in CS and acetic acid form a carbamate structure, thus forming an absorption peak structure that is significantly different from the CS-starting material. 1649. 1552, 1407 and 1373cm ^-1 Is an amino cation (-N) ⁺ H) C=o for the urethane anion, and symmetrical and asymmetrical vibration absorption peaks for the urethane anion. CS-NH treated with ammonium bicarbonate after dissolution of acetic acid ₄ HCO ₃ The carbamate structure formed in (C) is not obviously different from the structure in CS-HOAc, and can be obtained in infrared spectrogramTo be clearly observed is at 3280cm ^-1 The intensity of the telescopic vibration absorption peaks of O-H and N-H is higher, which indicates that after the ammonium bicarbonate is introduced, CS-NH is enabled to be ₄ HCO ₃ More amino groups in (a). CS-NH was prepared by freezing, thawing and washing ₄ HCO ₃ Preparing into CS sponge. The CS sponge sample showed the disappearance of the carbamate groups and the peak pattern was the same as the CS starting material, indicating that a pure CS structured sponge was obtained.

The infrared spectrum of the CS sponge prepared in examples 1-18 was the same as that of the CS sponge in example 8, indicating that the CS sponge can be prepared by freezing and thawing the CS solution in examples 1-18.

FIG. 3 is a graph showing the water absorption capacity of CS solutions prepared in examples 1-18 by freezing, thawing, and aqueous solvent treatment to form CS sponges. As can be seen in FIG. 3, the CS solutions prepared in examples 1-18 were subjected to a freezing, thawing process and treatment with 95% ethanol solution, respectively, to give a water-insoluble CS sponge. The CS sponge can squeeze and discharge the wrapped liquid, and can quickly absorb the liquid even being soaked in water. The method can be used for removing impurity-containing liquid encapsulated in CS sponge.

Since the dissolution of CS requires removal of substances that aid in its dissolution to restore the CS water-insoluble properties, figure 3 also illustrates that the water-insoluble sponge is a CS sponge.

As shown in fig. 4, the theoretical water uptake of CS sponge is the solids content of CS in the CS solution. The ratio in the figure is the actual water absorption to the theoretical water absorption.

FIG. 4 shows the water absorption capacity of CS sponges prepared from CS solutions of different solids in examples 10-13. The theoretical water uptake of the CS sponge was calculated from the solids content of CS in the CS solution. In fig. 4, it can be seen that after CS becomes a sponge structure, the absorption amount is always lower than the water content of the CS solution state. The CS solution in example 10 has a lower solids content than in examples 11-13, and theoretically and practically has a higher mass of water absorbed per gram of CS sponge. However, the CS solution has low solid content, and the ratio of the actual water absorption capacity to the theoretical water absorption capacity of the CS sponge prepared by the CS solution is lower. This is because the difference in solids content of the CS solution affects the density of the CS sponge and thus the volume of the CS sponge and the ability to absorb moisture at the same mass.

As can be seen from FIG. 4, the CS sponge prepared by the method has extremely high water absorption.

Application example 1

As shown in FIG. 5, the degradability of CS sponge was evaluated according to the national Standard GB/T16716.7-2012 part 7 of packaging and packaging waste, biodegradation and composting.

The CS sponge prepared in the application examples 10-13 is prepared from CS solutions with different solid contents as shown in FIG. 5, so that CS sponges with different densities can be obtained. The higher the density of the CS sponge, the greater its tensile strength. And after the CS sponge is subjected to composting degradation treatment for 30 days according to the 7 th part of the national standard GB/T16716.7-2012 waste packaging and packaging, namely biodegradation and composting, the retained density and tensile strength of the CS sponge are greatly reduced.

Figure 5 illustrates that CS sponges have significant natural degradability properties. Therefore, the CS sponge can be used as an environment-friendly degradable high polymer material, and is beneficial to the development of the environment-friendly industry and the degradable high polymer material industry in China.

Application example 2

FIG. 6 is a comparison of cell viability for different leach liquor concentrations and different time periods in example 8. First, 0.1g of CS sponge was immersed in 10mL of Phosphate Buffered Saline (PBS) at 37℃for 72 hours to obtain a 100% strength leaching solution. The 100% and 50% strength extracts and cell culture media were then used to culture mouse fibroblasts (L929) at a ratio of 1:9, and the biocompatibility of CS sponge to extract for L929 was examined by CCK-8 staining. The L929 group immersed in PBS instead of CS sponge was used as a blank group.

It can be seen from fig. 6 that neither 50% low concentration extract nor 100% high concentration extract was cytotoxic to L929, showing good biocompatibility. Therefore, the CS sponge prepared by the application can be used as biomedical materials.

Application example 3

FIG. 7 shows the change in wound when the CS sponge prepared in example 8 was used as a wound dressing. Specifically, after removing the coat from the C57BL/6 mice, a wound model of about 1cm in diameter was established under aseptic conditions, and then kept in a normal animal house. As can be seen from fig. 7A, both the sterilized gauze and CS sponge as wound dressing can accelerate the healing of mouse wounds to some extent. Comparison of the wound diameter healing statistics of mice in fig. 7B shows that CS sponge can significantly promote wound healing when used as a wound dressing, and the wound repair rate is superior to that of a blank group and a sterilized gauze group. Thus the CS sponge can be used as a wound dressing.

Because the CS sponge has good biocompatibility and is degradable, the CS sponge with low cost can be prepared by the method of the application, which is favorable for the popularization of the CS sponge as a general wound dressing.

Application example 4

As shown in FIG. 8, different Ca ²⁺ Content of CS-Ca ²⁺ Sponge with about equal 3% Ca ²⁺ 、8％Ca ²⁺ And 15% Ca ²⁺ And (3) representing. The method of preparing CS sponge of examples 4-6 herein adds a step to the method of examples 1-13 described above, specifically by stirring at 300r/min for 3 hours at 40℃before freezing the CS solution.

Measurement of Ca in solution by inductively coupled plasma emission Spectrometry (ICP-OES) in FIG. 8A ²⁺ Can be obtained from the reduction of CS sponge-sequestered Ca in examples 4-6 ₂ ⁺ Specific content of (3). In FIG. 8B, for the hemostasis experiment following tail-breaking of SD rats, the hemostasis time using sterile gauze was much longer than that of CS sponge and CS-Ca ²⁺ And (3) a sponge. CS-Ca ²⁺ The sponge is accompanied with Ca ²⁺ The shorter the content is, the better the hemostatic effect is. By counting the blood loss of the tail of the mice, the CS-Ca can be seen ²⁺ The sponge is accompanied with Ca ²⁺ The lower the blood loss of SD rats.

The data in FIG. 8 shows that CS sponge is easily modified and Ca ²⁺ The modified CS sponge can be used as a good hemostatic sponge.

Application example 5

As shown in FIG. 9, the CS sponge has a volume of 1cm ³ Is a slow release profile of dexamethasone loaded with CS sponge obtained from CS solutions of different solids obtained in examples 10-13. The specific practice is to prepare a dry CS sponge of examples 10-13 to a volume of 1cm ³ Then 1mL of a 2mg/mL aqueous solution of dexamethasone was loaded. Drug release was performed in a 100mL beaker containing 100mL of purified water, and the concentration of the released drug was measured by liquid phase mass spectrometry. The earth plug Mi Songshui solution is quickly and evenly dispersed into the solution by directly dripping pure water under the condition of no load. Whereas the CS sponge-loaded dexamethasone drug with different solid contents in FIG. 9 has a very good slow release effect. The higher the solid content of the CS sponge, the higher the density of the sponge, and the better the sustained-release effect of the sponge on dexamethasone. In the course of 6 hours, a CS sponge with a CS solids content of 1% released 87.8% of dexamethasone, whereas a CS sponge with a solids content of 3.5% released only 61.1% of dexamethasone.

Therefore, the CS sponge prepared by the application has good slow release effect on the medicine, and can be used as a carrier for slow release of the medicine.

Claims

1. A preparation method of a solid product containing amino indissolvable polymers is characterized by comprising the following steps: dissolving an amino-containing indissolvable polymer by using a dissolution assisting substance, and then adding salt composed of weak acid ions to obtain a solution of combining the weak acid ions with amino groups in the amino-containing indissolvable polymer, namely a pretreatment solution, wherein the pretreatment solution forms hydrogel through physical crosslinking, namely the pretreatment hydrogel; the pretreatment solution or the pretreatment hydrogel is frozen, thawed and washed for purification to prepare a polymer spongy, flocculent or granular solid product; or soaking the pretreated hydrogel in an aqueous solution for purification to directly prepare a polymer hydrogel solid product which only contains an amino indissolvable polymer and a solvent; or directly soaking the pretreated solution or pretreated hydrogel in aqueous organic solvent solution in the state of liquid or dried sponge solid to obtain extractPure sponge product; the amino-containing indissolvable polymer is any one of chitosan, type I collagen, polypeptide polymer, polyamide 66, linear polyethylenimine or silk fibroin; the solubles are formic acid, hydrochloric acid or acetic acid, and the weak acid radical ion is CO ₃ ^2- 、HCO ₃ ^- 、F ^- 、CNO ^- 、ClO ^- 、CN ^- 、AlO ₂ ^- Or BO ₃ ^3- Any one of them.

2. The method of manufacturing according to claim 1, characterized in that: the purified hydrogel solid product is prepared into a solid product by volatilizing and drying a solvent, or is prepared into a spongy solid product by freeze drying.

3. The preparation method according to claim 2, characterized in that: the weak acid radical ion is different from the acid radical ion of the solubles, and the reactivity of the weak acid radical ion is weaker than the acid radical ion.

4. A solid article comprising an amino-insoluble polymer prepared according to the method of claim 3.

5. The use of a solid preparation comprising an amino-insoluble polymer according to claim 4 for the preparation of a medical material or for the preparation of a carrier material.