KR101048152B1 - Cyclodextrin hydrogel containing hydrophobicized fibroin and method thereof - Google Patents

Abstract

PURPOSE: A cyclo dextrin hydrogel containing hydrophobic fibroin and a method for preparing the same are provided to actively release wound healing drug to the outside. CONSTITUTION: A cyclo dextrin hydrogel contains hydrophobic fibroin. The cyclo dextrin hydrogel is prepared by cross-linking cyclo dextrin. The dextrin is selected from alpha-cyclo dextrin, beta-cyclo dextrin, and gamma-cyclo dextrin. The hydrophobic fibroin is fixed inside the cyclo dextrin hydrogel. The hydrophobic fibroin is formed by covalent bond of carbon chains.

Description

Cyclodextrin hydrogel containing hydrophobized fibroin and preparation method thereof {Cyclodextrin hydrogel containing hydrophobicized fibroin and method}

FIELD OF THE INVENTION The present invention relates to cyclodextrin hydrogels and methods for their preparation, and more particularly, to cyclodextrin hydrogels containing hydrophobized fibroin and methods for their preparation.

'Hydrogel' is a polymer structure having a three-dimensional network containing an aqueous phase. The polymer constituting the hydrogel must be hydrophilic, and cross-linking bonds must be made between the hydrophilic polymers in order for the hydrophilic polymer to form a three-dimensional network structure.

Hydrophilic polymers used in hydrogels include poly (vinyl alcohol), polyisopropylacrylamide (poly ( N -isopropylacrylamide)), carboxymethyl cellulose, chitosan, gelatin ( gelatin) and alginic acid [Polymer, Volume 49, Issue 8, 15 April 2008, Pages 1993-2007, Todd R. Hoare, Daniel S. Kohane].

Crosslinking between polymers is achieved by physical cross-linking and crosslinking by crystallization, hydrogen bond, ionic bonding, hydrophobic interaction, etc. chemical cross-linking, which covalently crosslinks the polymer chains using a -linker) [Advanced Drug Delivery Reviews, Volume 54, Issue 1, 17 January 2002, Pages 13-36, Hennink, WE, van Nostrum, C. F].

Since hydrogels can contain hydrophilic drugs inside and contain a lot of water, there have been many attempts to use them for wound-dressing (European Journal of Pharmaceutics and Biopharmaceutics, Volume 50, Issue 1 , 3 July 2000, Pages 27-46, Peppas NA, Bures P., Leobandung W., Ichikawa H.).

By the way, the conventional hydrogel has a limitation that can be included only the water-soluble drug therein. Furthermore, conventional hydration gels only exhibit passive drug release properties when dressing on the wound, but the physiological conditions that the wound shows (the "physiological condition of the wound") "exudates the wound. There is a limit that does not show the active drug release characteristics according to the meaning of "is acidic".

Accordingly, the present invention has developed a cyclodextrin hydrogel containing hydrophobized fibroin to hydrate both hydrophobic and hydrophobic (lipophilic) substances and to actively release the drug according to the acidic conditions indicated by the wound. The purpose is to develop and provide a gel.

In order to achieve the above object, the present invention provides a hydrogel capable of encapsulating a target material in a first form, wherein a hydrocarbon chain is covalently bonded and hydrophobized to a cyclodextrin hydrogel prepared by crosslinking cyclodextrin. A hydrogel is provided which is immobilized.

The present invention relates to a fibroin inside a cyclodextrin hydration gel prepared by crosslinking cyclodextrin in a hydration gel capable of inclusion of an inclusion material to provide a hydration gel capable of actively releasing the drug at the wound site. Hydrocarbon chains are covalently bonded to immobilize the hydrophobized fibroin.

In the present invention, the hydrophobized fibroin is a hydrocarbon chain covalently bonded to the fibroin. The reason for hydrophobizing the fibroin is to fix the fibroin in the crosslinked cyclodextrin. That is, the hydrophobized fibroin is immobilized through hydrophobic interaction in the hydrophobic cavity of the cyclodextrin crosslinked by the hydrophobic hydrocarbon chain. At this time, the length of the hydrocarbon chain is preferably C ₆ ~ C ₂₀ . If the length of the hydrocarbon chain is lower than the above range, the hydrocarbon chain is too short to fix the fibroin in the hydrogel, and if it is higher than the above range, the hydrocarbon chain is too long, so that the fibroin does not dissolve in the water phase.

On the other hand, when the fibroin is immobilized on the cyclodextrin hydrogel as in the present invention, it is possible to control the release of the inclusion material from the hydrogel according to the pH change. The physiological condition that a wound presents when it develops is exudates from the wound. Wound exudates, particularly purulent exudates, are acidic and have been reported to reduce pH to 5.4 (Korean Pain Journal 2004: 17: 113-118). The cyclodextrin hydrogels of the invention immobilized with hydrophobized fibroin have a high swelling ratio in acid and a relatively low swelling ratio in neutral. This is because fibroin has a high degree of positive charge in acid, so that strong electrostatic repulsive force acts to swell a relatively large number of hydrated gels, and in neutral, hydrostatic gel swells relatively less due to a decrease in the electrostatic force of fibroin.

The cyclodextrin hydration gel to which the hydrophobized fibroin of the present invention is immobilized absorbs the exudate from the wound, and the fibroin is ionized to swell the hydrated gel. When the hydrated gel swells, the release of the clathrate is promoted to promote the wound healing effect and to protect the wound from external impact. In addition, when the hydrogel is attached to the skin by attaching the hydrogel to the wound, the tension is increased in the skin glue film according to the swelling of the hydrogel, thereby obtaining a compressive effect.

Meanwhile, the cyclodextrin used in the present invention may be any one selected from, for example, α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

Meanwhile, the inclusion material of the present invention may be water-soluble or hydrophobic, and examples of water solubility include sodium fusidate, neomycin sulfate, alllantoin, heparin, and extratum cepae. Diazines include spingosyl phosphoryl choline and beta sitosterol.

On the other hand, the present invention comprises the steps of synthesizing the cross-linked cyclodextrin by adding a crosslinking agent to the cyclodextrin in a second form; Reacting fibroin with a hydrocarbon chain to produce hydrophobized fibroin; Preparing a hydrogel, wherein the hydrophobized fibroin is immobilized therein by adding a crosslinked cyclodextrin to the hydrophobized fibroin prepared above in an aqueous solution state, thereby preparing a hydrogel. Provide a method. Hereinafter, it will be described in detail by dividing step by step.

Step 1: Cyclodextrin Crosslinker  In addition Crosslinked  Synthesis of cyclodextrin

This step is to add a crosslinking agent to the cyclodextrin to synthesize the crosslinked cyclodextrin. The cyclodextrin may use any one selected from α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin, and the crosslinking agent may be, for example, epichlorohydrin, diisocyanates, Any one selected from dichlorides and glutamic dialdehyde may be used.

The crosslinking agent used in the present invention is preferably added to the cyclodextrin such that the ratio of crosslinker: cyclodextrin is 1: 1 to 50: 1 in a molar ratio. When the crosslinking agent addition ratio is lower than the above range, the content of the crosslinking agent is too small to form a gel, and when the crosslinking agent is higher than the above range, the crosslinking density is too high to absorb a lot of water phase and does not exhibit swelling characteristics. The crosslinking reaction proceeds in the alkaline aqueous phase.

Step 2: Fibroin  Hydrophobized by reacting hydrocarbon chains Fibroin  Manufacturing steps

This step is to prepare a hydrophobized fibroin by reacting the fibroin and the hydrocarbon chain. In this step, a hydrocarbon chain is covalently bonded to fibroin to prepare a hydrophobized fibroin, which is intended to be replaced with that described in the first embodiment of the present invention.

On the other hand, the hydrocarbon chain is preferably reacted with the fibroin so that the ratio of the hydrocarbon chain: fibroin is 1: 500 to 1: 2 by weight ratio. If the reaction rate of the hydrocarbon chain is lower than the above range, the content of the hydrocarbon chain is too low to prevent the fibroin from being immobilized on the hydrogel, and if it is higher than the above range, the hydrocarbon chain content is too high and the fibroin does not dissolve in the water phase. This happens.

Step 3: hydrophobized as prepared above Fibroin  After making in aqueous solution, Crosslinked  Hydrophobized by addition of cyclodextrin Fibroin  Internally Fixed Cyclodextrin Hydration Gel  Manufacturing steps

This step is to prepare a cyclodextrin hydrogel in which the hydrophobized fibroin is immobilized therein by adding the crosslinked cyclodextrin to the hydrophobized fibroin prepared above in an aqueous solution state.

The reason for immobilizing the hydrophobized fibroin inside the crosslinked cyclodextrin is intended to be replaced by the one described in the first aspect of the present invention.

On the other hand, the present invention comprises the steps of synthesizing the cross-linked cyclodextrin by adding a crosslinking agent to the cyclodextrin in a third form; Reacting fibroin with a hydrocarbon chain to produce hydrophobized fibroin; Preparing the hydrophobized fibroin to which the hydrophobized fibroin is immobilized, and then drying the hydrophobized fibroin prepared above in an aqueous solution state, and drying the hydrophobized fibroin; Adding a dry powder of a cyclodextrin hydrating gel in which hydrophobized fibroin is immobilized therein to a solution containing the inclusion material; It provides a method for producing a hydrogel, characterized in that it comprises a.

In the third aspect of the present invention, the hydrophobized fibroin prepared in the second aspect of the present invention is a cyclodextrin hydration gel (hereinafter referred to as 'fibroin-cyclodextrin hydration gel') immobilized therein, and then the inclusion material. By adding to the solution containing, the hydrogel containing the clathrate target material is manufactured. In this case, the inclusion material may be water-soluble or hydrophobic.

Fibroin-cyclodextrin hydrogel containing a water-soluble clathrate is prepared by absorbing an aqueous solution in which the hydrophilic clathrate is dissolved in a dried fibroin-cyclodextrin hydrogel. The concentration of the hydrophilic clathrate can not be expressed accurately because the concentration of the drug varies depending on the type of the substance, but the concentration between the lowest and highest concentrations of the drug concentration is selected. The amount of the hydrophilic clathrate aqueous solution used to hydrate the dried fibroin-cyclodextrin gel is used in excess of an aqueous solution sufficient to completely swell the dried fibroin-cyclodextrin gel. Examples of the water-soluble clathrate may be sodium fusidate, neomycin sulfate, alllantoin, heparin, extratum cepae.

Fibroin-cyclodextrin hydrogels containing hydrophobic clathrates are prepared by contacting a suspension of the hydrophobic clathrate with a dried fibroin-cyclodextrin gel, wherein the hydrophobic clathrate is a cyclodextrin hydrophobic cavity. Melt into). The concentration of the hydrophobic clathrate can not be accurately expressed because the concentration of the drug varies depending on the type of the substance, but the concentration between the lowest and highest concentrations of the drug concentration is selected. The amount of hydrophobic clathrate suspension used when contacting the dried fibroin-cyclodextrin gel with the suspension uses an excess of suspension sufficient to completely swell the dried fibroin-cyclodextrin gel. As an example of the hydrophobic clathrate, sulfadiazine may be spingosyl phosphoryl choline or beta cytosterol.

The hydrogel of the present invention is characterized by being able to actively discharge the inclusion material (target material) under acidic conditions. That is, when the hydrogel of the present invention comes into contact with an acidic exudate generated at the wound site, more wound treatment drugs such as anti-inflammatory agents, epithelial formation promoters, angiogenesis agents, and antimicrobial agents encapsulated inside the hydrogel are active. It has an effect that can be released to the outside.

In addition, the hydrogel of the present invention can enclose an active material as well as water soluble.

1 shows an electron micrograph of a cross-linked beta cyclodextrin cross section.

Hereinafter, the content of the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited only to the following examples, but includes modifications of equivalent technical ideas.

Example  1: hydrophobized fibroin  synthesis

3.43 g of fibroin was dissolved in 10 ml distilled water. 0.107 g of N -hexanoic anhydride was dissolved in 10 ml methanol. The hexanoic acid anhydride solution was added to the fibroin aqueous solution and stirred at room temperature for 1 hour. The reaction mixture was poured into 100 ml of methanol / ammonia (7/3, v / v) solution to precipitate the hydrophobized fibroin. The mixture was filtered through filter paper to filter the precipitate and washing the precipitate with methanol and ether to give the final hydrophobized fibroin.

Example  2: Bridged  Cyclodextrin manufacturer

5 g of beta cyclodextrin (β-cyclodextrin) was added to 8 ml of an aqueous NaOH solution (30% w / w) contained in a 50 ml beaker, followed by stirring for 12 hours. Then, EPI (epichlorohydrin), a crosslinking agent, was added to the aqueous solution of beta cyclodextrin maintained at 30 ° C. such that the molar ratio of EPI / beta cyclodextrin was 10/1, followed by reaction at the same temperature for 5 hours.

To remove EPI and beta-cyclodextrin that did not react with excess sodium hydroxide, the cross-linked cyclodextrin was immersed in 500 ml distilled water in a 1000 ml beaker for 3 days, and 500 ml distilled water was changed 10 times for 3 days. .

The dextrin was then lyophilized with crosslinked cycles.

Experimental Example  One: Crosslinked  Electron microscopy observation of the beta cyclodextrin cross section

The cross section of the crosslinked beta cyclodextrin obtained in Example 2 was observed with a scanning electron microscope (JSM-840A, JEOL LTD., Tokyo, Japan). The cross-linked beta cyclodextrin was cut using a blade (No. 10, Feather Safety Razor CO., LTD., Osaka, Japan), and the resulting cross section was coated with gold and then observed its structure.

Figure 1 is an electron micrograph of the cross-linked beta cyclodextrin cross-section, the porous structure was observed in the cross-linked beta cyclodextrin cross-section.

Example  3: fibroin Cyclodextrin Hydrogel Preparation

1 g of the cyclodextrin dry gel prepared in Example 2 was soaked in 30 ml of an aqueous solution of hydrophobized fibroin (2%), and left at room temperature for 24 hours to allow the hydrophobized aqueous solution of fibroin to be absorbed into the crosslinked cyclodextrin. Fibroin-cyclodextrin hydrogels were prepared.

Experimental Example  2: sign language On gel  Absorbed hydrophobized fibroin  Volume measurement

The amount of hydrophobized fibroin absorbed in the hydrogel was confirmed by measuring the amount of hydrophobized fibroin remaining unabsorbed in Example 3, where the amount of hydrophobized fibroin absorbed in unit mass of crosslinked cyclodextrin was 0.01867 g. (Fibroin) / 1 g (cyclodextrin dry gel).

Experimental Example  3: fibroin Cyclodextrin Hydration Gel pH Dependency swelling characteristics

The ability of the fibroin-cyclodextrin hydrogel to absorb water was assessed by measuring the swelling ratio.

The swelling ratio is defined as [(Hydrated Hydrogel Weight-Dry Hydrogel Weight) / Dry Hydrogel Weight], and the physical meaning is the amount of aqueous solution that can be absorbed per dry hydrogel weight.

First, the fibroin-cyclodextrin hydrogel prepared in Example 3 was lyophilized. Thereafter, 0.3 g of the lyophilized gel was 25 ml of citrate buffer (pH 4.0, 10 mM), citrate buffer (pH 5.0, 10 mM), citrate buffer (pH 6.0). , 10 mM), phosphate buffer (phosphate buffer, pH 7.4, 10 mM), and immersed in phosphate buffer (phosphate buffer, pH 8.0, 10 mM) and allowed to stand at room temperature for 24 hours.

Thereafter, the weight of the hydrogel was measured to calculate the swelling ratio, and the results are shown in Table 1.

pH 4.0 5.0 6.0 7.4 8.0 Swelling ratio 651 523 463 355 395

As a result of the measurement (Table 1), the fibroin-cyclodextrin hydrogel had a high swelling ratio in acid and a relatively low swelling ratio in neutral.

It was inferred that this phenomenon occurred because fibroin had a high degree of positive charge in acid, and a strong electrostatic repulsive force was applied to swell the hydrogel relatively, and in neutral, the hydrogel was reduced due to the decrease of the electrostatic force of fibroin.

Example  4: fibroin Cyclodextrin Hydration On gel  Hydrophilic Drug Mount

A hydrophilic neomycin sulfate (anti-inflammatory agent) was dissolved in citrate buffer (pH 4.0, 10 mM) to prepare an aqueous neomycin sulfate solution (1%).

Thereafter, 2 g of the lyophilized fibroin-cyclodextrin hydrogel was immersed in a 20 ml neomycin phosphate aqueous solution and left for 24 hours.

The amount of drug loaded on the hydrogel was calculated by measuring the volume of aqueous solution remaining unabsorbed and the concentration of drug in the aqueous solution using high-performance liquid chromatographic (HPLC).

The amount of drug loaded per dry hydrated gel weight was about 0.05 g (neomycin sulfate) / 1 g (dried fibroin-cyclodextrin hydrated gel).

Example  5: fibroin Cyclodextrin Hydration On gel  Hydrophobic Drug Mount

Beta-cytosterol (anti-inflammatory) was dispersed in citrate buffer (pH 4.0, 10 mM) to prepare a beta-cytosterol suspension (1%).

Thereafter, 2 g of lyophilized fibroin-cyclodextrin hydrogel was immersed in a 20 ml beta sitosterol suspension and stirred for 24 hours.

The amount of beta cytosterol loaded on the hydrogel was calculated by measuring the amount of beta cytosterol remaining in the suspension without melting into the cyclodextrin cavity by HPLC.

The amount of betacytosterol loaded per lyophilized fibroin-cyclodextrin hydrogel weight was about 0.015 g (betacytosterol) / 1 g (dried fibroin-cyclodextrin hydrogel).

Experimental Example  4: fibroin Cyclodextrin Hydration Gel pH  Dependent Release Characterization

0.3 g of the fibroin-cyclo dried gel loaded with the hydrophilic drug prepared in Example 4 were respectively 25 ml of citrate buffer (citrate buffer, pH 4.0), citrate buffer (pH 5.0), and citrate buffer (citrate). buffer, pH 6.0), phosphate buffer (phosphate buffer, pH 7.4), and immersed in phosphate buffer (phosphate buffer, pH 8.0) and left for about 6 hours.

Thereafter, the amount of neomycin sulfate released from the hydrogel to the buffer solution was determined using HPLC to determine the% release.

'Release%' is defined as a percentage of the amount released over 6 hours relative to the amount of neomycin sulfate loaded on the hydrogel, and the results of the calculated release% are shown in Table 2.

pH 4.0 5.0 6.0 7.4 8.0 Swelling ratio 87% 81% 62% 35% 36%

As a result of the measurement (Table 2), the hydrophilic drug loaded fibroin-cyclodextrin hydrogel had a relatively high% release in acid and a relatively low% release in neutral.

This phenomenon was inferred because of the high swelling degree of the hydrogel in acid and low swelling degree of the hydrogel in neutral.

Claims (13)

In a hydrogel that can enclose a target material,
A hydrogel, characterized in that a hydrophobic fibroin is immobilized by covalently bonding a hydrocarbon chain to a cyclodextrin hydrogel prepared by crosslinking cyclodextrin.
The method of claim 1,
The cyclodextrin is,
Hydrating gel, characterized in that any one selected from α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.
The method of claim 1,
The hydrocarbon chain,
Hydrating gel, characterized in that the length of C ₆ ~ C ₂₀ .
The method of claim 1,
The inclusion material,
Method for producing a clathrate-containing hydrous gel, characterized in that the hydrophilic material or hydrophobic material
delete Adding a crosslinking agent to the cyclodextrin to synthesize a crosslinked cyclodextrin;
Reacting fibroin with a hydrocarbon chain to produce hydrophobized fibroin;
Preparing a hydrogel, wherein the hydrophobized fibroin is immobilized therein by adding a crosslinked cyclodextrin to the hydrophobized fibroin prepared above in an aqueous solution state, thereby preparing a hydrogel. Way
The method of claim 6,
The crosslinking agent,
Method for producing a hydrogel, characterized in that any one selected from epichlorohydrin (dipiocyanate), disocyanate, dichloride and glutamic dialdehyde (glutaric dialdehyde).
The method of claim 6,
The crosslinking agent,
Method for producing a hydrogel, characterized in that added to the cyclodextrin such that the ratio of the crosslinking agent: cyclodextrin is 1: 1 to 50: 1 in a molar ratio.
The method of claim 6,
The hydrocarbon chain,
A hydrogel that is reacted with fibroin such that the ratio of hydrocarbon chain: fibroin is 1: 500 to 1: 2 in weight ratio.
delete Adding a crosslinking agent to the cyclodextrin to synthesize a crosslinked cyclodextrin;
Reacting fibroin with a hydrocarbon chain to produce hydrophobized fibroin;
Preparing the hydrophobized fibroin to which the hydrophobized fibroin is immobilized, and then drying the hydrophobized fibroin prepared above in an aqueous solution state, and drying the hydrophobized fibroin;
Adding a dry powder of a cyclodextrin hydrating gel in which hydrophobized fibroin is immobilized therein to a solution containing the inclusion material; Method for producing a hydrogel, characterized in that it comprises a.
The method of claim 11,
The inclusion material,
Method for producing a clathrate-containing hydrous gel, characterized in that the hydrophilic material or hydrophobic material
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