KR20020076662A - Chitosan coated biodegradable polymeric materials for tissue regeneration and their fabrication methods - Google Patents

Abstract

PURPOSE: A process of preparing a surface-treated polymer preparation with chitosan by hydrolyzing an ester bond of a polymer material with sodium hydroxide and coating with chitosan is provided which increases biocompatibility of a polymer matrix. CONSTITUTION: A porous polymer matrix is hydrolyzed with a basic solution such as 0.1 to 2N sodium hydroxide for 0.5 to 100min. A base remaining in the hydrolyzed matrix is neutralized with an acid solution such as hydrochloric acid and then treated with chitosan, wherein the polymer used to form the porous polymer matrix is one or more selected from the group consisting of polylactic acid, polyglycolic acid and a polylactic acid-glycolic acid copolymer.

Description

Chitosan coated biodegradable polymeric materials for tissue regeneration and their fabrication methods

The present invention relates to a biodegradable polymer preparation for tissue regeneration and a method of manufacturing the same, and more particularly, to a biodegradable polymer preparation for tissue regeneration, wherein chitosan is coated on the surface of the hydrolyzate of the porous polymer matrix. It is about.

Poly (α-hydroxyester), ie polylactic acid, polyglycolic acid and polylactic acid-glycolic acid copolymers, have been prepared as carriers for tissue regeneration using biomaterials and tissue engineering techniques. However, they are likely to decrease the pH around the polymer preparation due to lactic acid and glycolic acid generated during hydrolysis, leading to inflammatory reaction and histotoxicity. If the blood vessels are poorly or metabolic and less capable of removing acid breakdown products, they are more likely to be locally toxic.

To reduce these side effects, attempts to introduce hydroxyapatite (HA) and basic salts into the polymer matrix have been described in J. Biomed. Material Res., 38 (2), 105-14 (1997) and Biomaterials 20 (9), 859-77 (1999) and the like. The basic degradation products of hydroxyapatite (HA) and basic salts can enhance the biocompatibility by neutralizing the acid degradation products of the polymer to reduce the toxicity of the tissue due to the reduction of pH. However, these basic salts are eluted from the polymer matrix and cannot maintain acid neutralization effect for a long time. They also do not have a beneficial effect on tissue regeneration.

In contrast, chitosan is structurally similar to the glycosaminoglycan of the extracellular matrix, which shows high histocompatibility and is advantageous for tissue regeneration. In addition, the amine group in the structure can neutralize the acid degradation products, and when combined with the polymer material that produces the acid degradation products, it neutralizes the acid, thereby reducing histotoxicity of the acid, thereby improving biocompatibility.

Therefore, the present inventors conducted a study of coating the chitosan on the surface of the polymer matrix to neutralize the acid of the polymer matrix producing the acid decomposition product and to increase the tissue compatibility. After the hydrolysis of the polymer matrix, the inventors combined the amine group with the chitosan. The method was completed.

Accordingly, it is an object of the present invention to provide a biodegradable polymer preparation for tissue regeneration in which chitosan is coated on a hydrolyzed surface of a porous polymer matrix.

Still another object of the present invention is to provide a method for preparing the biodegradable polymer preparation for tissue regeneration.

1 is a differential scanning micrograph showing a chitosan-coated biodegradable polymer matrix.

2 is a differential scanning micrograph of a biodegradable polymer matrix,

2A is a differential scanning micrograph of a chitosan-free biodegradable polymer matrix,

2B is a differential scanning micrograph of a biodegradable polymer matrix hydrolyzed at a concentration and a hydrolysis time of sodium hydroxide solution in Example 5,

2C is a differential scanning micrograph of a biodegradable polymer matrix hydrolyzed at a concentration and a hydrolysis time of sodium hydroxide solution in Example 6,

FIG. 2D is a differential scanning micrograph of a biodegradable polymer matrix hydrolyzed at a concentration and hydrolysis time of sodium hydroxide solution in Example 7.

Figure 3 is a differential scanning micrograph of the result of differentiation of osteoblasts in the biodegradable polymer matrix for 7 days,

Figure 3a is a differential scanning micrograph of the result of differentiation of osteoblasts to the chitosan-free biodegradable polymer matrix for 7 days,

Figure 3b is a differential scanning micrograph of the result of differentiating osteoblasts for 7 days in the chitosan-coated biodegradable polymer matrix prepared in Example 6.

The biodegradable polymer preparation for tissue regeneration presented in the present invention is a polymer preparation in which chitosan is coated on the hydrolyzed surface of the porous polymer matrix. Such biodegradable polymer preparations can improve the biocompatibility by reducing tissue toxicity by acid because chitosan coated on the surface of the porous polymer matrix neutralizes the acid which is a hydrolysis product of the polymer. Decomposition can increase water uptake.

Examples of the polymer used in the preparation of the porous polymer matrix include poly (α-hydroxyester), more specifically polypolylactic acid, polyglycolic acid and polylactic acid-glycolic acid copolymers.

The biodegradable polymer preparation for tissue regeneration of the present invention as described above may be prepared by a manufacturing method comprising the following steps.

a) treating the porous polymeric matrix with a basic solution to hydrolyze, and

b) neutralization of the remaining base in the hydrolyzed matrix with acid solution followed by surface treatment with chitosan.

When the porous polymer matrix is hydrolyzed by treating with a basic solution, the ester bonds present in the polymer material are broken to give carboxyl groups and hydroxyl groups, and the porous polymer matrix has a negative charge. This negative charge forms an ionic bond with the positive charge of the amine group present in the chitosan, thereby coating the chitosan on the surface of the polymer matrix. Examples of basic solutions that can be used for hydrolysis include, but are not limited to, aqueous solutions such as NaOH, KOH, LiOH, CaOH ₂ , but are not particularly limited so long as they can break the ester bond present in the polymer material. Preferably, sodium hydroxide aqueous solution is mentioned. The concentration of the aqueous sodium hydroxide solution is preferably 0.1 to 2N. If it is 0.1N or less, hydrolysis is very slow, and if it is 2N or more, hydrolysis is too fast, making it difficult to control the speed. The time required for hydrolysis can be appropriately adjusted according to the type, concentration and required physical properties of the polymer preparation used, but is usually 0.5-100 minutes, preferably 0.5-30 minutes.

The polymer matrix hydrolyzed by the basic solution may be neutralized using an acid solution, and examples of the acid solution used for neutralization include, but are not limited to, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and the like. Various acid solutions can be used that do not particularly affect tissue regeneration. In the case of using a hydrochloric acid solution, the concentration is preferably 0.5 to 2N.

In the production method of the present invention, the step of treating with chitosan is performed by an acid solution in which chitosan is dissolved. Examples of the acid solution used for dissolving chitosan include a lactic acid solution of 0.5 to 5 v / v%, and most preferably a lactic acid solution of 1 to 5 w / v%.

Hereinafter, the present invention will be described in more detail with reference to Examples, but these Examples are merely illustrative of the present invention, and the scope of the present invention is not limited to these Examples, and the protection scope of the present invention described in the claims. Various variations and supplements are possible within.

<Example>

Example 1 Preparation of Polymer Formulation Surface-Coated with Chitosan

1 g of polylactic acid-glycolic acid copolymer having a molecular weight of 130,000 Da was dissolved in 6 mL of methylene chloride. 0.1 M phosphate buffer (pH 7.4) was added to this solution as an aqueous phase and emulsified using Span 80 as a surfactant. This was rapidly frozen in liquid nitrogen and lyophilized to obtain a matrix. The obtained matrix was cut into 1 cm wide, 1 cm long and 1 cm high. The matrix thus cut was hydrolyzed by dipping in 50 mL of 0.5 N sodium hydroxide solution for 2 minutes and neutralized in 1 N hydrochloric acid solution. The hydrolyzed polymer matrix was immersed in 3% chitosan solution (dissolved in 1% lactic acid) and left for 10 minutes, and then lyophilized to obtain a chitosan-coated polymer matrix. Differential scanning micrographs of the prepared chitosan coated polymer matrix are shown in FIG. 1 .

<Examples 2-13>

The matrix was prepared from the polymer materials described in Tables 1 and 2 below, and then hydrolyzed with sodium hydroxide solution according to the following hydrolysis time, followed by coating with 3% chitosan solution.

<Example 14>

A glycol 2 producing the acid copolymer with a polymer matrix and it was observed a change in the polymer matrix by varying the treatment time according to hydrolyzed with 0.5 N aqueous sodium hydroxide solution, and also the differential scanning micrograph-polylactic acid Figure 2a (before treatment), Figure 2b (after 1 minute-corresponds to Example 5), Figure 2c (after 2 minutes-corresponds to Example 6) and Figure 2d (after 5 minutes-Example) 7)). As can be seen in Figure 2 , it was observed that as the treatment time elapses, the matrix hydrolyzed along the micropores and the micropores gradually increased. That is, in the treatment of the polymer matrix with sodium hydroxide solution, it can be seen that the degree of hydrolysis increases as the treatment time increases. As a result, the ester bond in the polymer material is broken to generate a negatively charged carboxyl group and a hydroxyl group. It can be seen that. These carboxyl groups and hydroxyl groups become functional groups that form a bond with the chitosan solution having a positive charge.

<Example 15>

The degree of osteoblast differentiation of the biodegradable polymer preparation of the present invention coated with chitosan and the conventional polymer preparation not coated with chitosan was tested, and the results are shown in FIG. 3 . Figure 3a is a differential scanning micrograph showing the results of differentiation of osteoblasts to the chitosan-free biodegradable polymer matrix for 7 days, Figure 3b is a osteoblast to the chitosan-coated biodegradable polymer matrix prepared in Example 7 Differential scanning micrograph of the result of daily differentiation.

As can be seen in Figures 3a and 3b , the chitosan-coated polymer matrix showed unstable cell adhesion and differentiation, and in the case of the chitosan-coated polymer matrix, the expansion of the cytoplasm and the cell center portion Flattening was observed, and it can be observed that these expanded cells layered in layers to form dendritic cell aggregates. Thus, it can be seen that the chitosan coated matrix exhibits increased cell adhesion and biocompatibility compared to the uncoated matrix. This suggests that chitosan can be used as a coating material to increase cell affinity.

The present invention relates to a biodegradable polymer preparation for tissue regeneration and a method of manufacturing the same, by hydrolyzing the ester bond in the polymer material with sodium hydroxide and coating chitosan to increase the water absorption of the polymer material and decomposition of the polymer material Chitosan neutralizes the acid decomposed product produced during the reaction, thereby increasing the biocompatibility of the polymer matrix.

Claims (12)

Biodegradable polymer preparation for tissue regeneration, wherein chitosan is coated on the hydrolyzed surface of the porous polymer matrix. The polymer preparation according to claim 1, wherein the polymer used for forming the porous polymer matrix is at least one selected from the group consisting of polylactic acid, polyglycolic acid, and polylactic acid-glycolic acid copolymers. a) hydrolyzing the porous polymer matrix with a basic solution, and b) neutralizing the remaining base in the hydrolyzed matrix with an acid solution and then treating with chitosan. 4. The polymer preparation according to claim 3, wherein the polymer used for forming the porous polymer matrix is at least one selected from the group consisting of polylactic acid, polyglycolic acid, and polylactic acid-glycolic acid copolymers. The method according to claim 3, wherein the basic solution is a sodium hydroxide solution. The method according to claim 4, wherein the concentration of the sodium hydroxide solution is 0.1 to 2N. The method according to claim 3, wherein the treatment time of the sodium hydroxide solution is 0.5 to 100 minutes. 4. The process according to claim 3, wherein the acid solution used for neutralization is an aqueous hydrochloric acid solution. The production method according to claim 8, wherein the concentration of hydrochloric acid is 0.5 to 2N. 4. A process according to claim 3, wherein said treating with chitosan is accomplished by applying a lactic acid solution in which chitosan is dissolved. The method according to claim 10, wherein the concentration of the lactic acid solution in which the chitosan is dissolved is 0.5 to 5 v / v%. The method according to claim 11, wherein the concentration of the lactic acid solution in which the chitosan is dissolved is 1 to 5 w / v%.