JPS625922B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel polyelectrolyte complex (hereinafter referred to as PIC) comprising a dextran derivative.

Here, dextran refers to D-glucopyranose, which is produced from sucrose by many bacteria belonging to the Lactobacilliae family, and whose glucose moiety is mainly α-glucopyranose.
It is a polymer with (1→6) bonds and its molecular weight ranges from 800 to several tens of millions. Also, due to α(1→6) coupling,
Compared to other α(1→4) and α(1→3) bonds,
It is stable in the body and gradually degraded by tissue enzymes, so it has extremely good biocompatibility.

In addition, PIC is a substance produced by the reaction of positively and negatively charged polymer substances, and has properties such as ion selective permeability, semipermeability, electrical conductivity, and anticoagulability. Ion exchange membrane, permeability membrane, ultrafiltration membrane,
It is used in electrically conductive coatings, biological membranes, medical materials, etc.

Conventionally, as a PIC with good biocompatibility,
There is a PIC as described in No. 8879, which is made by reacting an anionic partially substituted polysaccharide with a cationic partially substituted polysaccharide other than dextran. At this time,
Depending on the combination of the molecular weight of the polysaccharide and the degree of substitution of the dissociative group, it is often insoluble in water, making it difficult to obtain a PIC with a large molecular weight, and thus with great anticoagulant properties and adequate durability in vivo. However, there were limitations to the PIC design.

In view of the above, it is an object of the present invention to provide a polymer electrolyte complex that has excellent biocompatibility and anticoagulability, can be designed to have any desired durability in vivo, and is particularly useful as an artificial organ material. With the goal.

The gist of this invention is a water-insoluble or sparingly soluble polymer formed by electrostatically bonding a unit generated upon dissociation from a specific anionic derivative of dextran and a unit generated upon dissociation from a specific cationic derivative. It is an electrolyte complex, has excellent biocompatibility and anticoagulability, and can be designed to have any desired durability in vivo, making it particularly useful as an artificial organ material.

This invention will be explained in detail below.

The novel PIC of the present invention consists of a unit generated upon dissociation from an anionic derivative of dextran represented by the following general formula (1) and [C ₆ H ₇ O ₂ (OH) _3-a・(OX) _a ] _x・H ₂ O...(1) [In the formula, X is -SO ^- ₃ , -PO ^-2 ₃ , -(CH ₂ )m
R1 (however, R1 is a group selected from the group consisting of -COO ^- , -SO ^- ₃ , -PO ^-2 ₃ , m = an integer of 1 to 3), O
<a positive number of a≦3, an integer of X≧5] The unit generated upon dissociation from the cationic derivative of dextran represented by the following general formula (2) is [C ₆ H ₇ O ₂ (OH) _3-b・(OY) _b 〕 _y・H ₂ O …(2) [In the formula, Y is -(CH ₂ )nR2 (R2 is -NH ⁺ ₃ ,
―NH ⁺ (CH ₃ ) ₂ , ―NH ⁺ (C ₂ H ₅ ) ₂ , ―N ⁺
( _C2H5 ) ₃ , _-C6H4・NH ⁺ ₃ , -CO・_C6H4・NH ⁺ ₃ , _{n =} an integer from 1 _to 3),
or −CO・R3 (R3 is −CH ₂・NH ⁺ ₃ or −C ₆ H ₄・
NH ⁺ ₃ ), or -CH ₂ CH(OH)・CH ₂ R4 (R4 is -
NH ⁺ ₃ , -NH ⁺ (CH ₃ ) ₂ , -NH ⁺ (C ₂ H ₅ ) ₂ , -N ⁺
(C ₂ H ₅ ) ₃ ), O<b≦
A positive number of 3, an integer of y≧5] This is a PIC that is electrostatically bonded.

Examples of the anionic derivatives of dextran that produce the structural unit represented by the above formula (1) include dextran sulfuric acid ester, phosphoric acid ester, carboxymethyl ether, sulfoethyl ether, sulfopropyl ether, phosphomethyl ether,
Examples include phosphoethyl ether.

In addition, examples of cationic derivatives of dextran that produce the structural unit represented by the above formula (2) include aminoethyl ether, dimethylaminoethyl ether, diethylaminoethyl ether, triethylaminoethyl ether chloride, and p-aminobenzyl ether of dextran. , p-aminophenacyl ether, p-aminophenyl ethyl ether, diethylaminopropyl ether, α-aminoacetic acid ester, p-aminobenzoic acid ester, 3-amino-2oxypropyl ether, 3
-dimethylamino-2oxypropyl ether,
Examples include 3-diethylamino-2oxypropyl ether and 3-triethylamino-2oxypropyl ether chloride.

These compounds are those in which all or part of the hydroxyl groups of dextran are substituted with a dissociable group that dissociates in an aqueous solution and becomes negatively or positively charged, or a dissociable group that can carry a negative or positive charge. It can be obtained by esterification or etherification of.

The PIC of the present invention is produced by reacting an anionic derivative of dextran that produces units of formula (1) above with a cationic derivative of dextran that produces units of formula (2) in an aqueous solution.

That is, generally, when an anionic derivative of dextran or a water-soluble salt thereof and a cationic derivative of dextran or a water-soluble salt thereof are separately dissolved in water and then mixed, preferably with stirring, both The components are electrostatically bound together by Coulomb forces and precipitate out of the solution.

There is no particular limit to the concentration of the anionic derivative of dextran or its water-soluble salt and the cationic derivative of dextran or its water-soluble salt dissolved in water, but if the concentration is high, the reaction product may be dissolved in the solution. Since it may be difficult to separate them from each other, they are dissolved in water at a concentration of 5% or less. The reaction temperature is 0~
The temperature is 100°C, preferably 20-60°C, and the reaction time is within about 1 hour. The generated precipitate is separated from the reaction solution by centrifugation or overoperation, washed thoroughly with water, and dried under reduced pressure to obtain the desired product.

During the reaction, the ratio of the units of the anionic derivative of dextran and the units of the cationic derivative of dextran can be appropriately selected as shown in the examples below. For example, the negative charge of the anionic derivative of dextran and the unit of the cationic derivative of dextran It is possible to produce PICs having compositions with various equivalence ratios, such as those in which the positive charge of the cationic derivative of PIC is apparently neutralized, or those in which positive or negative charges remain.

The PIC of this invention is sparingly soluble or insoluble in water and solvents such as alcohols, ketones, and ethers, but in water, water-miscible organic solvents, and acids.
Soluble in ternary base or salt solvents.

Examples of water-miscible organic solvents that are one component of this ternary solvent include alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, cyclic ethers such as dioxane and tetrahydrofuran, pyridine, and dimethylformamide. Examples of acids, bases and salts include acids such as hydrochloric acid, hydrobromic acid, sulfuric acid or nitric acid, and alkalis such as sodium and potassium. Metal hydroxides or alkaline earth metal hydroxides such as calcium and magnesium, or bases such as ammonia, and halides, sulfates, and nitrates of alkali metals and alkaline earth metals such as chlorine, bromine, iodine, and fluorine. , salts such as perchlorate.

Further, the PIC of the present invention is usually obtained in the form of white powder or granules, but it can be made into a molded article if necessary.

For example, when the PIC powder of the present invention is fed into a mold of a molding machine and vacuum compressed at a pressure of about 10 t/cm ² , various PIC molded products can be obtained.

Further, after applying a solution obtained by dissolving the PIC powder of the present invention in the three-component solvent that dissolves the PIC of the present invention on a glass plate, etc.,
℃, preferably 10 to 50℃, within about 10 hours, preferably 10 to 60 minutes to remove the solvent by air drying or vacuum evaporation, and then preferably after immersion in cold water at 0 to 20℃ for about 10 hours. , a PIC film can be obtained by peeling it off from a glass plate. In this case, if a support is used, a PIC membrane supported on the support can be obtained.

Furthermore, the PIC powder of the present invention is mixed with a resin powder such as polyvinyl chloride, dissolved in tetrahydrofuran or other suitable solvent, applied on a glass plate, etc., and heated at 0 to 100°C, preferably 10 to 50°C.
℃ for about 48 hours, preferably 30 minutes to 10 hours to remove the solvent by vacuum evaporation or air drying to obtain a membrane containing the PIC of the present invention and other resin components.

The PIC of this invention obtained as above is
It has properties such as ion selective permeability, semipermeability, electrical conductivity, and anticoagulability. Therefore, it can be used as a material for ion exchange membranes, membranes, ultrafiltrates, electrically conductive coatings, anticoagulant medical devices, or artificial organs such as artificial blood vessels and corneas.

In particular, it has extremely good affinity for living organisms and can be suitably used as a material for artificial organs. This is presumed to be related to the properties of the dextran derivative that is the constituent unit of the PIC of the present invention, ie, the properties of dextran itself.

Dextran is a glucan mainly composed of α-1,6 bonds, and those with molecular weights of approximately 40,000 and 70,000 are widely used clinically as plasma expanders and have been demonstrated to have extremely good biocompatibility.

Of course, the characteristics of PIC are not simply the sum of the properties inherent to its constituent units, but often appear as different properties, so this invention
Many of the characteristics of PIC are considered to be new to the PIC itself.

Next, the dextran derivative used as a raw material for the PIC of this invention can be obtained by esterification or etherification of dextran as described above, but at this time, various substitutions can be made by changing the reaction conditions. Dextran derivatives with a certain degree of dissociative group can be produced.

Further, the molecular weight of dextran can be arbitrarily selected from about 800 to several tens of millions. For example, native dextran, which is obtained as a fermentation product from sucrose by Leuconostoc mesenteroides, has a molecular weight of several tens of millions, but it is hydrolyzed with acid or alkali and mixed with water and alcohol. By repeating the fractionation operation using a solvent, dextran of various molecular weights and with a sharp molecular weight distribution can be easily prepared.

Furthermore, the dextran derivative used in the present invention is water-soluble at almost any molecular weight and degree of substitution, and as shown in Example 1 below, various combinations of molecular weight and degree of substitution of dissociative groups can be made.

By selecting dextran as the raw material polymer, the PIC of the present invention exhibits the following effects that could not be obtained when conventional polysaccharides (excluding dextran) were used as the raw material polymer.

Dextran is water-soluble at almost any molecular weight (a feature not found in other neutral polysaccharides), so even dextran derivatives with dissociative groups with a low degree of substitution can be reacted in aqueous solution to easily obtain PIC. be able to.

Furthermore, since dextran can be easily obtained in various molecular weights with sharp molecular weight distributions, this combined with the above reason makes it possible to design PICs with combinations of various molecular weights, various substituents, and degrees of substitution.

Therefore, together with the good biocompatibility of dextran, it is possible to arbitrarily design PIC with various desired properties (e.g. biocompatibility, anticoagulability, durability), and it can be used for artificial blood vessels, artificial organs, etc. Applications as a material can be greatly expanded compared to conventional materials.

Examples of the present invention and test data thereof using combinations of various dextran derivatives are shown below.

Note that DEAE is an abbreviation for diethylaminoethyl ether, and the intrinsic viscosity is the value in a 2M NaCl solution at 37°C.

Example 1 A 0.12% aqueous solution of dextran sulfate sodium salt (S content 18.6%, intrinsic viscosity 0.269 dl/g) and a 0.2% aqueous solution of DEAE dextran hydrochloride (N content 4.97%, molecular weight MW 2 million) were mixed in equal amounts. A water-insoluble white precipitate is produced, and this precipitate is separated from the solution, thoroughly washed with water, and then dehydrated with methanol and vacuum-dried to obtain the desired PIC.

The yield was 25%, and the analytical values of this PIC are as follows.

N content 4.55%, S content 8.43%, molar ratio (N/S) 1.2, C content 39.95%, H content 7.37%.

When this PIC is analyzed by infrared absorption spectrum, as shown in Figure 1, the νσ ₀ of the sulfate ester is
The absorption due to (SO ₂ ) was observed at 1230 cm ^-1 , and the absorption due to ν(CN) of the amino group was observed at 1260 cm ^-1 , indicating that both reactive components were included. The reaction product is water-insoluble, Cl is not detected, and Na is only slightly detected.
This indicates that the products are not just a mixture but are electrostatically bound together in aqueous solution due to the attractive force between the negative charge of dextran sulfate sodium salt and the positive charge of DEAE dextran hydrochloride. this
The structure of PIC is presumed to be ionic bonded as shown below.

In addition, this PIC (referred to as PIC(1)) has the same S content as PIC(1) and a smaller intrinsic viscosity (0.027 dl/
PIC (hereinafter referred to as PIC(A)) consisting of dextran sulfate with a small molecular weight and DEAE dextran hydrochloride with the same N content and a small molecular weight (MW = 70,000). ) and the results of a comparison of anticoagulant properties using the following test method.

Test method: 100mg each of PIC(1) and PIC(A) is fed into the mold of a molding machine, vacuum compressed at 10t/ ^cm2 to make a tablet, 0.1ml of ACD blood is placed on the surface of the tablet, and 0.1M chloride is added. Add 0.01 ml of calcium, place it on a watch glass, allow a coagulation reaction to occur in a 37°C water bath for 8 minutes, and then measure the amount of thrombus formed. At this time, the amount of thrombus generated on the glass surface under the same conditions is taken as 100%.

Results PIC(1): 30% PIC(A): 90% From the above, it can be seen that the greater the molecular weight of PIC, the greater the anticoagulant property.

Note that dextran sulfate ester is obtained by sulfuric acid esterification of dextran with, for example, chlorosulfonic acid, and DEAE dextran is obtained by reacting dextran with, for example, diethylaminoethyl chloride.

Example 2 A 0.65% aqueous solution of dextran sulfate sodium salt (S content 5.5%, intrinsic viscosity 0.372 dl/g) and the DEAE dextran hydrochloride aqueous solution of Example 1 were mixed in the same volume to generate a white precipitate, and a white precipitate was produced. 1
Obtain the desired PIC in the same way.

The yield was 20%, and the analytical values of this PIC are as follows.

N content 4.64%, S content 8.11%, molar ratio (N/S) 1.3 Example 3 The dextran sulfate sodium salt of Example 2 was treated with a cation exchange resin (Dowex 50.W-X8 trade name; A 1.5% aqueous solution of DEAE dextran hydrochloride (N content 1.5%,
A white precipitate was produced by mixing the same volume of a 1% aqueous solution of Mw (molecular weight Mw = 1,000,000) made into a base form using an anion exchange resin (Amberlite 400; trade name), and the same procedure as in Example 1 was carried out. to obtain the desired PIC.

The yield was 17%, and the analytical values for this PIC are as follows.

N content 4.46%, S content 8.62%, molar ratio (N/S) 1.2 Example 4 A 0.3% aqueous solution of carboxymethyl dextran sodium salt (degree of carboxymethyl group substitution 0.7 mol/AGU, molecular weight Mw = 1 million) and Example 1
Equal volumes of DEAE dextran hydrochloride aqueous solution are mixed to form a white precipitate, and the desired PIC is obtained in the same manner as in Example 1.

The analytical values of this PIC with a yield of 18% are as follows.

N content 2.6%, -CH ₂ COO ^- content 10.6%, molar ratio (N/-CH ₂ COO ^- ) 1.0 Here, carboxymethyldextran sodium salt is obtained by reacting dextran and monochloroacetic acid in an aqueous solution of caustic soda. , its structural formula is as follows.

Example 5 A 0.2% aqueous solution of carboxymethyl dextran sodium salt (degree of carboxymethyl group substitution 0.3 mol/AGU, molecular weight Mw = 6000) made into an acid form using the above-mentioned cation exchange resin and Example 3
The same volume of 0.3% aqueous solution of DEAE dextran hydrochloride made into a base form using an anion exchange resin is mixed to form a white precipitate, and the desired PIC is obtained in the same manner as in Example 1.

The yield was 20%, and the analytical values of this PIC are as follows.

N content 0.89%, -CH ₂ COO ^- content 4.02%,
Molar ratio (N/-CH ₂ COO ^- ) 0.9

[Brief explanation of the drawing]

FIG. 1 is an infrared absorption spectrum diagram of PIC of Example 1 of the present invention.

Claims (1)

[Scope of Claims] 1. A unit represented by the following formula (a) generated upon dissociation from an anionic derivative of dextran, and [C ₆ H ₇ O ₂ (OH) ₃ - _a
・(OX)a]x・H ₂ O…(a) [In the formula, X is -SO- ₃ ,-PO- ² ₃ ,-(CH ₂ )m
R1 (where R1 is a group selected from the group consisting of -COO ^- , -SO ^- ₃ , -PO ^-2 ₃ , m = an integer of 1 to 3), 0 < a
A positive number of ≦3, an integer of x≧5] The unit represented by the following formula (b) generated upon dissociation from a cationic derivative of dextran is [C ₆ H ₇ O ₂ (OH) ₃ - _b
・(OY)b]y・H ₂ O...(b) [In the formula, Y is -(CH ₂ )nR2 (R2 is -NH ⁺ ₃ , -
NH ⁺ (CH ₃ ) ₂ , ―NH ⁺ (C ₂ H ₅ ) ₂ , ―N ⁺
( _C2H5 ) ₃ , _-C6H4・NH ⁺ ₃ , -CO・_C6H4・NH ⁺ ₃ , _{n =} an integer from 1 _to 3),
Or -COR3 (R3 is -CH ₂・NH ⁺ ₃ or -C ₆ H ₄・
NH ⁺ ₃ ), or -CH ₂ CH(OH)・CH ₂ R4 (R4 is -
NH ⁺ ₃ , -NH ⁺ (CH ₃ ) ₂ , -NH ⁺ (C ₂ H ₅ ) ₂ , -N ⁺
(C ₂ H ₅ ) A group selected from the group consisting of ₃ , 0<b≦3
a positive number, y≧5, an integer of y≧5] A polymer electrolyte complex characterized by being electrostatically bonded.