KR20110056630A - Porous hydrogel and method for preparing the same - Google Patents

Abstract

PURPOSE: A porous hydrogel is provided to control the release and biodegradation of a drug and to offer an environment favorable for tissue regeneration such as cell attachment and proliferation induction. CONSTITUTION: A method for preparing porous hydrogel comprises the steps of: reacting (A) a polysaccharide compound derivative having a (meth)acryl functional group at a side chain with (B) a biocompatible polymer derivative having a thiol functional group at the end the presence of (C) a foaming agent in-situ to form a crosslinked hydrogell; and blowing the foaming agent to obtain poros hydrogel.

Description

Porous Hydrogel and Method for Preparing the Same

The present invention relates to a porous hydrogel and a method for manufacturing the same, and more particularly, to a porous hydrogel and a method for producing the same suitable for use as a support and drug carrier for inducing tissue regeneration.

Generally, tissue support polymer scaffolds should be capable of regenerating patient tissue by biodegradability, cell adhesion and deposition. For example, as a biodegradable polymer material for artificial cartilage polylactide (Polylactide), poly-glycolide (Polyglycolide), polylactide-glycolide copolymer, or a synthetic polymer such as chitosan (Polylactide- co -glycolide copolymers) And natural polymers such as hyaluronic acid are used. Using the polymer to produce a porous biodegradable support to regenerate cartilage to control the size of the micropores or to change the chemical composition of the surface of the support to induce the growth of chondrocytes.

Hydrogel is a widely used material in the field of tissue engineering and drug delivery, and is used for tissue regeneration by incorporating drugs and cells in the hydrogel.

Republic of Korea Patent Registration No. 10-0849185, 10-0737954, 10-0824726 and 10-0671965 is a kind of such hydrogel, it is possible to induce the adhesion of cells and decomposition of the hydrogel to facilitate the tissue regeneration environment The present invention discloses a support for inducing tissue regeneration, but does not have porosity. The reason for the porosity of the support for inducing tissue regeneration is not only useful for controlling the release and biodegradability of the drug contained in the support, but also provides an environment for tissue regeneration through induction of cell adhesion and proliferation. In order to have the advantages of porosity, it is necessary to introduce porosity into the hydrogel, but the hydrogel has a problem that it is not easy to introduce porosity after it is manufactured due to its characteristic of having a three-dimensional crosslinked structure.

Accordingly, the present invention has been made to overcome the above problems and limitations of the prior art. That is, an object of the present invention is not only to control the release and biodegradability of the drug, but also to provide a favorable environment for tissue regeneration, such as induction of cell adhesion and proliferation, porous hydro which can be used as a support for tissue regeneration and drug carrier. It is to provide a gel and a method for producing the same. In other words, the porous hydrogel according to the present invention, by introducing porosity into the hydrogel according to the preceding patents, by introducing a new technology to the existing properties and at the same time to achieve the technology in situ (in situ) process The problem is solved.

The present invention provides a method for producing a porous hydrogel. The production method according to the present invention is (A) a polysaccharide compound derivative having a (meth) acryl functional group in the side chain and (B) a polyethylene oxide derivative having a thiol functional group at the terminal or a polysaccharide compound derivative having a thiol functional group in the side chain (C) reacting in-situ in the presence of a blowing agent to form a crosslinked hydrogel, and foaming the blowing agent included in the hydrogel to obtain a porous hydrogel. .

Here, the polysaccharide compound derivative may be selected from the group consisting of hyaluronic acid derivatives, carboxymethyl cellulose derivatives, chondroitin sulfate derivatives, chitosan derivatives, heparin derivatives, and dermatan sulfate derivatives, the blowing agent is ammonium bicarbonate or carbonic acid Sodium hydrogen. The blowing agent may be provided by coating in advance on the polymer acting as a surfactant, or directly included in the component solution.

In another aspect, the present invention provides a porous hydrogel prepared by the above method.

Porous hydrogel prepared according to the present invention can not only control the release and biodegradability of the drug, but also can provide a favorable environment for tissue regeneration, such as induction of cell adhesion and proliferation can be used as a support for tissue regeneration and drug delivery agent have.

The method for preparing a porous hydrogel according to the present invention firstly comprises (A) a polysaccharide compound derivative having a (meth) acryl functional group in the side chain and (B) a polyethylene oxide derivative having a thiol functional group at the end or a thiol functional group in the side chain. (C) reacting the polysaccharide compound derivative having an in-situ in the presence of a blowing agent to form a crosslinked hydrogel. The polysaccharide compound derivative may be selected from the group consisting of hyaluronic acid derivative, carboxymethyl cellulose derivative, chondroitin sulfate derivative, chitosan derivative, heparin derivative, and dermatan sulfate derivative, and the blowing agent may be ammonium bicarbonate or sodium hydrogen carbonate. Can be.

(A) Polysaccharide compound derivative having a (meth) acrylic functional group in the side chain and (B) Polyethylene oxide derivative having a thiol functional group at the end are registered in Korean Patent Nos. 10-0849185, 10-0737954, 10 -0824726 and 10-0671965 (hereinafter referred to as 'pre-registered patents') in detail. Thus, with regard to the preparation of hydrogels by (A) and (B) compound derivatives and their reactions, the contents described in the pre-registered patents are incorporated herein by reference. Therefore, more details may be referred to here as it may refer to pre-registered patents.

(A) The polysaccharide compound derivative having a (meth) acrylic functional group in the side chain is formed by directly connecting a hydroxy or carboxyl functional group of the polysaccharide compound or a derivative thereof or acting as an intermediate bridge. It may be formed indirectly connected by a compound. In any form, a (meth) acryl functional group is formed at the terminal of the side chain of the polysaccharide compound derivative, which participates in the crosslinking reaction.

As the polymer having a thiol functional group at the end (B), hydrophilic biocompatible polymers such as polysaccharide derivatives and polyethylene oxide derivatives may be used. The polysaccharide derivative may be a natural polymer such as hyaluronic acid, chondroitin sulfate, heparin, dermatan sulfate, chitosan, etc. having a thiol functional group. Such polysaccharide derivatives may have a certain number of thiol functional groups in the repeating unit, and have two or more thiol groups in the entire side chain of the polymer structure. In addition, the polyethylene oxide derivative which is a biocompatible polymer has a thiol functional group at the terminal of the polyethylene oxide having a thiol functional group, and may have two or more thiol functional groups per molecule, preferably four to six.

The thiol functional group of the polyethylene oxide derivative (B) reacts with the (meth) acrylic functional group of the (A) polysaccharide compound derivative. This reaction is known as the Michael type addition reaction, in which a thiol functional group is added to the carbon making up the acrylic functional group. The reaction solvent and the solvent for dissolving the polymers are not particularly limited as long as they can dissolve the polymers and also cause a special reaction with the polymers or otherwise prevent the Michael type addition reaction.

(B) The polysaccharide compound derivative having a thiol in the side chain is a compound in which the hydroxy or carboxyl functional group of the polysaccharide compound or its derivative is chemically linked with a compound having a thiol functional group, or any compound serving as an intermediate bridge. It is a polysaccharide compound which is formed by being indirectly connected by the thiol compound prepared through the media and has a thiol group at the polysaccharide side chain terminal. In any form, a thiol functional group is formed at the terminal of the side chain of the polysaccharide compound derivative, which participates in the crosslinking reaction with the compound having an acrylate terminal functional group.

This reaction of the compound derivatives (A) and (B) forms a crosslinked hydrogel, which is substantially the same as that described in the pre-registered patents. The difference of the present invention compared to the pre-registered patents here is that the above reaction takes place in the presence of (C) blowing agent. Generally, porous polymers are generally prepared by first synthesizing a polymer and then foaming the same by adding a blowing agent to a polymer solution in which the polymer is dissolved. However, the hydrogel has a three-dimensional crosslinked structure, and thus, it is difficult to uniformly mix the blowing agent in the hydrogel solution after the hydrogel is formed. Therefore, it is difficult to obtain a porous hydrogel having uniform porosity with such a method.

In order to solve this problem, the present invention is prepared in-situ by mixing the two solutions in a state in which the (C) blowing agent is included in the polymer derivative having an acrylate or the polymer derivative solution having a thiol. Michael type addition reactions of the compound derivatives (A) and (B) are carried out. (C) A blowing agent may be added to either of these solutions before mixing the (A) compound derivative solution and the (B) polyethylene oxide derivative solution. The blowing agent to be added is added directly to the solution after or without coating with a biocompatible polymer such as poly (ethylene oxide), polyvinyl alcohol, or the like depending on solubility and dispersibility.

Typically, polymers do not add materials other than the solvents and materials necessary for the reaction, because such added materials interfere with the polymer reactions and make it impossible to achieve substantial performance. However, it has been found by the present invention that the polysaccharide compound derivative used in the present invention can perform Michael type addition reaction without being disturbed by the blowing agent used in the present invention, especially ammonium bicarbonate and sodium hydrogen carbonate. Therefore, the hydrogel formed by the step is to contain a blowing agent uniformly therein.

Next, a porous hydrogel having a uniform porosity is obtained by foaming a blowing agent uniformly contained in the hydrogel. The method of foaming the blowing agent here is variously known depending on the type of blowing agent. When ammonium bicarbonate or sodium hydrogen carbonate is used as the blowing agent, foaming may be performed by heating the hydrogel to an appropriate temperature in water, for example, about 40 ° C.

The porous hydrogel obtained in this manner can be used as a support for tissue regeneration and drug delivery agent, for example, it can be prepared in various forms such as disk type, tube type, film type.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only specific examples of the present invention and should not be understood as limiting the scope of the present invention.

Example 1 Synthesis of Porous Chondroitin Sulfate Porous Hydrogels with NaHCO ₃

One-step process:: Chondroitin sulfate-acrylate polymer (meaning chondroitin sulfate polymer having an acrylate functional group in the side chain, similarly applied below) poly (ethylene oxide) derivative having a thiol functional group and a solution at the end or Chondroitin sulfate-thiol polymer (meaning chondroitin sulfate polymer having a thiol functional group in the side chain) A polymer solution was dissolved in a solvent to prepare each polymer solution.

Step 2: Process The gelation by Michael type addition reaction was induced by mixing the two polymer solutions prepared in Step 1 in a ratio (1: 1, molar ratio of acrylate functional group and thiol functional group). NaHCO ₃ was dissolved during the gelation process to prepare porous chondroitin sulfate-poly (ethylene oxide) or porous chondroitin sulfate hydrogel support with pores inside the support.

Example 2: Preparation of Porous Chondroitin Sulfate Hydrogel with Ammonium Bicarbonate (AB)

Step 1: Procedure Chondroitin sulfate-acrylate was dissolved in a solvent to prepare a polymer solution, and in another container, a poly (ethylene oxide) derivative having a thiol functional group was dissolved in a solvent. Each solution was prepared by adding a proportion (12% by weight) of AB to the chondroitin sulfate polymer solution.

Step 2: The two solutions prepared in step 1 were mixed in a certain ratio (1: 1, molar ratio of acrylate functional group and thiol functional group) to induce gelation by Michael type addition reaction (gel containing porogen) formation).

Step 3: After the obtained hydrogel was lyophilized, porous chondroitin sulfate support was prepared by foaming and drying AB in sterile water at 40 ° C.

Example 3 Synthesis of Porous Hyaluronic Acid Hydrogel Induced Pore with NaHCO ₃

Michael type addition reaction between hyaluronic acid-acrylate and polyethylene oxide derivatives synthesized by addition of NaHCO ₃ , using the hyaluronic acid-acrylate instead of the chondroitin sulfate-acrylate of Example 1 Through the porous hyaluronic acid-poly (ethylene oxide) hydrogel support was prepared.

Example 4 Preparation of Porous Hyaluronic Acid Hydrogel Discs by AB

Using the hyaluronic acid acrylate of Example 3, the hyaluronic acid-thiol solution added with AB coated with a poly (ethylene oxide) derivative and the hyaluronic acid-acrylate solution were mixed as in the stepwise experimental method of Example 2 A porous hyaluronic acid support was prepared by inducing a type addition reaction and then foaming AB after freeze drying.

Example 5 Synthesis of Carboxymethyl Cellulose Porous Hydrogel Induced Pore with NaHCO ₃

Michael type of carboxymethylcellulose-acrylate and polyethylene oxide derivative synthesized by addition of NaHCO ₃ as in the stepwise experimental method of Example 1 using carboxymethylcellulose-acrylate instead of the chondroitin sulfate-acrylate of Example 1 A porous carboxymethyl cellulose-polyethylene oxide hydrogel support was prepared through an addition reaction process.

Example 6 Synthesis of Porous Carboxymethylcellulose Hydrogel by AB

Using the carboxymethyl cellulose-acrylate of Example 3 as in the step-by-step experimental method of Example 2, porous carboxy through the Michael type addition reaction of the AB-added polyethylene oxide derivative solution and the synthesized carboxymethyl cellulose-acrylate A methylcellulose-poly (ethylene oxide) hydrogel support was prepared.

Example 7: Synthesis of Porous Chitosan Hydrogels with NaHCO ₃

Using the chitosan-acrylate instead of the chondroitin sulfate-acrylate of Example 1, the Michael-type addition reaction of chitosan-acrylate and polyethylene oxide derivatives synthesized by adding NaHCO ₃ was carried out as in the stepwise experimental method of Example 1. Using a porous chitosan-polyethylene oxide hydrogel support was prepared.

Example 8: Chitosan Porous Hydrogel Synthesis by AB

Using the chitosan-acrylate of Example 3, the Michael type of the synthesized chitosan-acrylate with a hyaluronic acid-thiol solution added AB coated with a poly (ethylene oxide) derivative as in the stepwise experimental method of Example 2 A porous chitosan-poly (ethylene oxide) hydrogel support was prepared through the addition reaction.

Example 9: Analysis

Analysis 1.

The porosity-induced chondroitin sulfate-polyethylene oxide porous hydrogel support with NaHCO ₃ was observed with an optical microscope (10 ×, 40 ×, 100 ×), and it was confirmed that the pore induced by the blowing agent was present in the porous hydrogel support. (FIG. 1).

Analysis 2.

As a result of observing the hyaluronic acid-polyethylene oxide porous hydrogel support inducing pores with AB under an optical microscope (10 ×, 40 ×, 100 ×), it was confirmed that pores induced by the blowing agent were present in the porous hydrogel support ( (B), (c), (d)).

Example 10: Tube Preparation by Michael Type Reaction

Step 1: The polymer solution was prepared by dissolving the chondroitin sulfate-acrylate polymer solution and the poly (ethylene oxide) derivative polymer solution having the thiol functional group in the solvent.

Step 2: Process the two polymer solutions prepared in step 1 by mixing them in the empty space of the tubular mold in a certain ratio (1: 1, molar ratio of acrylate functional group and thiol functional group) to the Michael type addition reaction in the tube mold. Gelation was induced.

Example 11. Analysis

Analysis 1.

The pore-induced chondroitin sulfate-polyethylene oxide porous hydrogel support with NaHCO ₃ was hydrated for 24 hours, cooled with liquefied nitrogen, and lyophilized, and observed by scanning electron microscopy (SEM) and digital images. The gel support was confirmed to have pores induced by the blowing agent.

Analysis 2.

After hydrating the chondroitin sulfate-polyethylene oxide porous hydrogel support with pores with AB for 24 hours and freezing and drying with liquid nitrogen, SEM and digital images showed that the foaming agent inside the hydrogel support foamed the pores. It was confirmed.

Analysis 3.

Hyaluronic acid-polyethylene oxide porous hydrogel support with pores induced by NaHCO ₃ was hydrated for 24 hours, cooled with liquefied nitrogen, freeze-dried and observed by scanning electron microscopy (SEM) and digital images. The gel support was confirmed to have pores induced by the blowing agent.

Analysis 4. The overall shape of the tubular sample prepared by the method of Example 10 was taken by digital image (Fig. 3-a), and the cross-sectional area of the tubular sample (Fig. 3-b) was observed by optical microscope.

Analysis 5.

Hyaluronic acid-polyethylene oxide porous hydrogel support induced by AB was hydrated for 24 hours, and then lyophilized and dried with liquid nitrogen to be observed by SEM (Fig. 2 (a)) and digital images (2-b, c and d). As a result of observing with an optical microscope (Figs. 3-c and d), it was confirmed that the foaming agent was foamed inside the hydrogel support to exist pores (Fig. 4).

Figure 1 shows an optical microscope image of a porous chondroitin sulfate-polyethylene oxide hydrogel prepared by the method of the embodiment of the present invention.

Figure 2 shows a variety of forms of hyaluronic acid-polyethylene oxide porous disk prepared by the manufacturing method of an embodiment of the present invention. (a) porous disk (digital image); Hydrated disc optical microscope images of various magnifications (b: 10 ×), (c; 40 ×) and (d; 100 ×).

Figure 3 shows a digital (a) and optical microscope (b, c, d) images of the porous hyaluronic acid-polyethylene oxide hydrogel prepared by the manufacturing method of an embodiment of the present invention. (a) tubular products free of pores; (b) a tubular cross section without pores; (c) tubular products with pores produced; (d) The cross section of the product in which the pores are formed.

Figure 4 shows an electron microscope (SEM) image of the cross-sectional area of porous chondroitin sulfate-polyethylene oxide disk sample prepared by the method of the embodiment of the present invention.

Claims (6)

(A) a polysaccharide compound derivative having a (meth) acryl functional group at its side chain and (B) a polysaccharide compound derivative having a thiol functional group at its end (C) in-situ in the presence of a blowing agent -situ) to form a crosslinked hydrogel by containing a blowing agent, and Method of producing a porous hydrogel comprising the step of obtaining a porous hydrogel by foaming the blowing agent contained in the hydrogel. (A) a polysaccharide compound derivative having a (meth) acrylic functional group in its side chain and (B) a biocompatible polymer derivative having a thiol functional group at its end (C) in-situ in the presence of a blowing agent (Porogen) reacting with situ) to form a crosslinked hydrogel, and Method of producing a porous hydrogel comprising the step of obtaining a porous hydrogel by foaming the blowing agent contained in the hydrogel. The method of claim 1, The polysaccharide compound derivative is a method of producing a porous hydrogel, characterized in that selected from the group consisting of hyaluronic acid derivatives, carboxymethyl cellulose derivatives, chondroitin sulfate derivatives, chitosan derivatives, heparin derivatives, dermatan sulfate derivatives and alginic acid derivatives. The method of claim 1, The blowing agent is a method for producing a porous hydrogel, characterized in that ammonium bicarbonate or sodium hydrogen carbonate. The method of claim 4, wherein The blowing agents include ammonium bicarbonate or uncoated ammonium bicarbonate coated with polyethylene oxide, polyvinyl alcohol, polypyrrolidone; And sodium hydrogen carbonate. Porous hydrogel prepared by the method according to any one of claims 1 to 5.

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