JPH11300169A - Endotoxin adsorptive blood dialysis membrane and dialyzer using the membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blood dialysis membrane preventing the infiltration of endotoxin as a pyrogenous substance into the body at the time of dialyzing, and a dialyzer using the membrane. SOLUTION: The surface of the blood dialysis membrane is coated with a polymer of N,N-dialkylaminoalkyl(meth)acrylamide and/or N,N- dialkylaminoalkyl(meth)acrylate. A copolymer of a hydrophobic monomer, N,N- dialkylaminoalkyl(meth)acrylamide and/or N,N-dialkylaminoalkyl(meth) acrylamide and a hydrophobic monomer can be used instead of the polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel hemodialysis membrane and a dialyzer using the same. Here, a hemodialysis membrane and a dialyzer using the same are HF, HD, and HDF.
1 shows a porous membrane and a dialyzer used in therapy. More specifically, a hemodialysis membrane capable of adsorbing endotoxin in a dialysate (and blood) even in the presence of an anticoagulant at the time of dialysis and preventing endotoxin from being mixed into blood, and a hemodialysis membrane using the same It relates to a dialyzer.

[0002]

2. Description of the Related Art In order to remove low molecular weight proteins such as β2 microglobulin, which is a major related substance of dialysis amyloidosis, a dialysis membrane having a larger pore size than conventionally used dialysis membranes is used. Attempts have been made to remove molecular proteins.

However, by increasing the pore size, endotoxin (a lipopolysaccharide complex present on the cell wall surface of Gram-negative bacteria) present in the dialysate is released by lysis, causing fever, vascular endothelial cell damage, and capillary permeation. Causing a symptom such as hypersexuality), but a new problem has arisen in that it passes through the dialysis membrane and enters the blood.

Therefore, a method is used in which the dialysate is passed through a filter for removing endotoxin to prevent the endotoxin from flowing into the hemodialysis apparatus. However, according to the above method, it is necessary to select a disinfection method that can withstand a filter for removing endotoxin when disinfecting the dialysate supply line, and a simple disinfection method may not be adopted. In addition, it is necessary to periodically replace the endotoxin removal filter, which is a burden on medical sites. Furthermore, there is a possibility that endotoxin may be mixed in between the device position of the filter for removing endotoxin and between the hemodialysis device and when the dialysate supply line and the hemodialysis device are mounted. For this reason, an average pore size of 50 in the dialysate inflow path of a hemodialysis machine (dialyzer) as disclosed in JP-A-7-213603.
There is also proposed a method of preventing an endotoxin in a dialysate from reaching a dialysis membrane by providing an ultrafiltration membrane having an angstrom or less as an endotoxin removal filter.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to
In order to easily prevent endotoxin in the dialysate from entering the blood during hemodialysis, a cationic polymer having endotoxin adsorption performance is adsorbed on at least one outer surface of the hemodialysis membrane and pore surfaces inside the membrane. It is an object of the present invention to provide a hemodialysis membrane which has been used and a dialyzer using the same.

[0006]

The above problems are solved by the present invention described below. (1) In a hemodialysis membrane having an outer surface and a pore wall surface inside the membrane, the outer surface and the pore wall surface are N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N- Dialkylaminoalkyl (meth)
A hemodialysis membrane coated with a polymer comprising acrylate.

(2) The polymer is N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N-
The hemodialysis membrane according to (1), which is a polymer comprising only dialkylaminoalkyl (meth) acrylate.

(3) The polymer is a hydrophobic monomer N, N-
The hemodialysis membrane according to (1), which is a copolymer of dialkylaminoalkyl (meth) acrylamide and / or N, N-dialkylaminoalkyl (meth) acrylate with a hydrophobic monomer.

(4) The hemodialysis membrane according to (3), wherein the hydrophobic monomer is an alkyl (meth) acrylate or styrene.

(5) The composition molar ratio of the N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N-dialkylaminoalkyl (meth) acrylate is 1
The hemodialysis membrane according to (3), wherein, when the composition molar ratio of the hydrophobic monomer is a, 0 <a ≦ 1.

(6) A dialysis device using the hemodialysis membrane according to any one of (1) to (5).

[0012]

DETAILED DESCRIPTION OF THE INVENTION Generally, a hemodialysis membrane is 0.01
It has a pore diameter of about 0.1 μm and is a membrane for removing harmful substances and water in blood and adjusting electrolytes, and is used for patients with renal failure and the like. The shape is a hollow fiber (hollow fiber), and the hemodialyzer is a hemodialysis membrane (hollow fiber) housed in a cylindrical housing having an inlet and an outlet for dialysate. .

[0013] The hemodialysis membrane and hemodialyzer of the present invention include:
Focusing on the fact that endotoxin has an anionic site,
By adsorbing the cationic polymer on the surface of the porous hollow fiber membrane and adsorbing endotoxin by electric charge, it is possible to easily prevent endotoxin in the dialysate from entering the blood side.

Further, since endotoxin is also amphiphilic, the use of a cationic polymer containing a hydrophobic site such as an alkyl chain can further add an adsorption-removing effect due to hydrophobic interaction.

However, during dialysis, an anticoagulant (such as heparin) and proteins in the blood enter the dialysate side, so that the cationic polymer coexists with the anticoagulant (such as heparin) and proteins. Even below, it is desirable that the endotoxin adsorption ability be excellent. A cationic polymer containing a strong anion exchange group such as a quaternary ammonium salt is not suitable for actual dialysis because of its low endotoxin-adsorbing ability because it easily adsorbs proteins and heparin.

Accordingly, the cationic polymer used in the present invention is a polymer containing a tertiary or lower amine.

That is, the cationic polymer used in the present invention is, for example, N, which can be represented by the following general formula (1):
N-dialkylaminoalkyl (meth) acrylamide and / or homopolymer of N, N-dialkylaminoalkyl (meth) acrylate represented by formula (2) or copolymer with one or more other hydrophobic monomers Coalescence is preferred.

[0018]

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[0019]

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(However, in the general formulas (1) and (2), R ₁ represents a hydrogen atom or a methyl group, and R ₂ and R ₃ independently represent the same or different hydrogen atom or lower alkyl group (methyl group) , An ethyl group, a propyl group, a butyl group, etc.), and n represents an integer of 1 to 20.) Examples of N, N-dialkylaminoalkyl (meth) acrylamide of the general formula (1) include N, N -Dimethylaminopropylacrylamide (DMAPAA), N, N-
Dimethylaminopropyl methacrylamide (DMAP
MAA), N, N-dimethylaminoethylacrylamide
(DMAEAA).

The N, N-dialkylaminoalkyl (meth) acrylate of the general formula (2) includes, for example, N, N-
Dimethylaminopropyl acrylate (DMAPA),
N, N-dimethylaminopropyl methacrylate (DM
APMA), N, N-dimethylaminoethyl methacrylate (DMAEMA) and the like.

The cationic polymer is preferably the acrylamide and / or acrylate homopolymer described above, but is more preferably a copolymer with a hydrophobic monomer.

The reason is that the cationic polymer is made water-insoluble by copolymerization with a hydrophobic monomer, and is retained on the surface of the dialysis membrane by coating treatment. Adsorption capacity)
It is because it can increase.

Examples of such a hydrophobic monomer include long-chain alkyl isocyanates such as styrene, acrylonitrile, ethylene, propylene, butadiene and octadecyl isocyanate, and alkyl (meth) acrylates represented by the general formula (3). Alkyl (meth) acrylates that can be copolymerized by a simple synthesis method are preferred.

[0025]

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(However, in the general formula (3), R ₁ represents a hydrogen atom or a lower alkyl group (such as a methyl group), and n represents an integer of 1 to 20.) Alkyl (meth) of the general formula (3) Examples of the acrylate include methyl methacrylate (MMA), butyl acrylate (BA), butyl methacrylate (BMA), and stearyl acrylate (SA).

At this time, the composition molar ratio of N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N-dialkylaminoalkyl (meth) acrylate is 1, and the composition molar ratio of the hydrophobic monomer is a And 0 <
It is preferable to have a relationship of a ≦ 1, more preferably 0 <a ≦ 0.5.

If a exceeds 1, the hydrophilicity is low and the hydrophobicity is high, so that substances other than endotoxin (for example, proteins) are adsorbed and N, N-dialkylaminoalkyl (meth) acrylamide and / or N This is because the endotoxin adsorption ability of N, dialkylaminoalkyl (meth) acrylate is impaired.

The copolymer may be a random copolymer or a block copolymer, and the polymerization reaction itself is not particularly limited, and can be easily polymerized by a known method such as radical polymerization or ionic polymerization.

These cationic polymers are used in such an amount that the function of the porous hollow fiber membrane is not impaired.

The porous hollow fiber membrane for hemodialysis used in the present invention together with the cationic polymer can be used as long as the cationic polymer is adsorbed, and examples thereof include cellulose, cellulose derivatives, polysulfone, and polyamide. Can be

The cationic polymer of the present invention can be used not only for a porous hollow fiber membrane for hemodialysis but also for an endotoxin removal filter installed in a dialysate inflow passage of a hemodialyzer. It can also be used for an endotoxin removal filter installed in a dialysate supply line.

The method of adsorbing the cationic polymer to the hemodialysis membrane is carried out by dissolving or dispersing the cationic polymer in a solvent that does not damage the porous membrane in an amount that does not impair the function of the hemodialysis membrane. And a method of spraying the cationic polymer solution onto a hemodialysis membrane to adsorb it.

It is also possible to use a method in which after the dialyzer is assembled, the cationic polymer solution prepared with a solvent that does not affect the hemodialysis membrane and the dialyzer is filled into the dialyzer to be adsorbed on the hemodialysis membrane. .

The membrane thus obtained can efficiently adsorb endotoxin in the dialysate even in the presence of an anticoagulant, as will be shown in Examples described later. It is useful as a hemodialysis membrane that can prevent contamination with water.

Next, the present invention will be described in more detail with reference to examples.

[0037]

[Examples] (Example 1 and Comparative Examples 1 and 2) Endotoxin removal test in dialysate (To confirm the endotoxin removal effect, a test was performed using a membrane having a pore size larger than that of a dialysis membrane.) As a polymer, a copolymer of N, N-dimethylaminopropyl methacrylamide and stearyl acrylate (DMAPMAA-SA) was synthesized by the following method.

Dioxane (200 g) was placed in a three-necked flask, and dissolved oxygen was replaced with nitrogen while stirring at 80 ° C., followed by N, N-dimethylaminopropyl methacrylamide (DMAPMAA) 25.6 g, stearyl acrylate (SA) 24.4 g and 50 mg of azobisisobutyronitrile (AIBN) were added, and a polymerization reaction was performed at 80 ° C. for 6 hours. ^{In 1} H-NMR, the molar ratio of the copolymer was DM.
It was confirmed that APMAA: SA = 1: 0.5.
Gel permeation chromatography with a molecular weight of 6
I confirmed that it was 10,000.

The synthesized polymer was converted to tetrahydrofuran (T
HF) at a concentration of 1.0 wt%, and the polymer solution was added to a porous polypropylene (PP) membrane (Japanese Patent Publication No. 5-55).
No. 471, and a flat membrane having a pore diameter of 0.45 μm) was immersed therein, and washed with warm water at 60 ° C. for 2 hours.
Dried at 0 ° C. The membrane coated with the cationic polymer was used as Example 1.

After the PP porous film was irradiated with argon plasma (100 W, 0.1 Torr, 15 seconds), methoxyethyl acrylate (MEA) gas (1.
(0 Torr) for 3 minutes to perform surface graft polymerization. This membrane grafted with MEA was used as Comparative Example 1.

A 0.3 wt% aqueous solution of polyethyleneimine (PEI, molecular weight 70,000) (pyridine 0.01 wt%)
% Was prepared, and the PP porous membrane was immersed in the PEI aqueous solution, washed with warm water at 60 ° C. for 2 hours, and dried at 60 ° C. This film coated with PEI was used as Comparative Example 2.

These membranes were cut to a diameter of 25 mm, washed with endotoxin-free distilled water for injection, fixed to a gamma-sterilized filter, and sterilized in an autoclave.

A dialysate prepared with endotoxin-free distilled water for injection (available from Fuso Pharmaceutical Co., Ltd., product name: Kinderly No. 2) and endotoxin-free 0.1M
Endotoxin (Sigma, Escherichia) in Tris-HCl buffer (pH 7.3) at 0.5 ng / ml.
Coli Serotype 0111: lipopolysaccharide of B4) was added to each, and used as a test solution. The test solution was filtered through the membranes of Example 1 and Comparative Examples 1 and 2 at 0.1 ml / min for 10 minutes, and the amount of endotoxin in the test solution before and after filtration was determined by Endospecy and D.
It was measured with an IA-MP set (manufactured by Seikagaku Corporation), and the endotoxin removal rate was determined according to Equation 1 (Table 1).

[0044]

(Equation 1)

[0045]

[Table 1]

From Table 1, it was found that Example 1 removed endotoxin from the dialysate containing buffer and various ions at a high removal rate. Although the MEA of Comparative Example 1 was acrylate, it was found that removal efficiency was low with only acrylate. The PEI of Comparative Example 2 is a cationic polymer, but in the case of a dialysate containing various ions, Example 1 was used.
The removal rate was much lower than that.

(Example 2 and Comparative Examples 3 and 4) Endotoxin removal test in dialysate in the presence of heparin (to confirm endotoxin removal effect, test with a membrane having a larger pore size than dialysis membrane) In the same manner as described above, a copolymer of N, N-dimethylaminopropyl methacrylamide and stearyl acrylate (DMAPMAA-SA, composition molar ratio = 1: 0.5,
Was synthesized and dissolved in a mixed solvent of hexane and methanol (1: 9 volume ratio) at a concentration of 1.0 wt%.
A polysulfone (PS) porous membrane (manufactured by MEMTEC Japan, product name: Membrane Disk Filter SD200, pore diameter 0.20 μm) was added to this polymer solution.
Was washed with warm water of 60 ° C. for 2 hours and dried at 60 ° C. The membrane coated with the cationic polymer was used as Example 2.

On the other hand, a PS porous membrane that was not treated was used as Comparative Example 3, and a cationic polymer containing a quaternary ammonium salt (UX101, manufactured by YAS Corporation) was mixed with a mixed solvent of methanol and water (2: (1 volume ratio) at a concentration of 0.3 wt%, the above-mentioned untreated PS porous membrane was immersed in this solution, washed with 60 ° C warm water for 4 hours, and dried at 60 ° C.
This PS porous membrane on which the cationic polymer was adsorbed was used as Comparative Example 4.

These films are cut to a diameter of 25 mm,
It was fixed to a gamma-sterilized filter, filled with endotoxin-free distilled water for injection, and sterilized in an autoclave.

A dialysate prepared with endotoxin-free distilled water for injection (available from Fuso Pharmaceutical Co., Ltd., product name: Kinderly No. 2) and a dialysate to which 2 U / ml of heparin-pharmaceutical was added. Endotoxin (Sigma, Escheric
hia Coli Serotype 0111: lipopolysaccharide of B4) was added to each of them to prepare test solutions.

The test solution was filtered through the membranes of Example 2 and Comparative Examples 3 and 4 at 0.1 ml / min for 60 minutes and collected every 10 minutes. The amount of endotoxin in the test solution after filtration (recovered solution for 50 to 60 minutes) was measured by Endospecy, DIA-MP set (manufactured by Seikagaku Corporation), and the endotoxin removal rate was determined according to Equation 1 (Table 2). .

[0052]

[Table 2]

From Table 2, it can be seen that Example 2 and Comparative Example 4 in which the cationic polymer was adsorbed adsorb endotoxin in the dialysate more than the untreated PS porous membrane of Comparative Example 3. However, in the presence of heparin, Example 2, which does not have an ionic group, has an ionic group (quaternary ammonium salt).
It was found that endotoxin was adsorbed and removed more efficiently than Comparative Example 4 having

(Example 3 and Comparative Example 5) Endotoxin removal test in dialysate using hemodialyzer 200 g of dioxane, 42.8 g of N, N-dimethylaminopropylacrylamide (DMAPAA), butyl methacrylate (BMA) 7. Using 2 g and 50 mg of azobisisobutyronitrile (AIBN), a cationic polymer (DMAPAA-BMA, composition molar ratio = 1: 0.2, molecular weight 60,000) was synthesized in the same manner as in Example 1.

An alcohol solution (0.1 wt%) of the above cationic polymer was placed in a dialyzer (manufactured by Terumo Corporation, product name: Crilans PS, membrane area 1.5 m ² ) containing a polysulfone (PS) dialysis membrane. From the dialysate inlet, and D
Example 3 was a dialyzer coated with MAPAA-BMA.

A dialyzer without treatment was used as Comparative Example 5.

Each of these dialysers was filled with endotoxin-free distilled water for injection and sterilized in an autoclave.
After sterilization, remove the water inside the dialyzer and replace with 0.5n
g / ml of a dialysate (manufactured by Fuso Pharmaceutical Co., Ltd.) prepared with endotoxin-free distilled water for injection to which endotoxin (a lipopolysaccharide of Escherichia Coli Serotype 0111: B4, manufactured by SIGMA) is added. (Kinderley liquid No. 2) and shaken for 30 minutes. The amount of endotoxin in the test solution after filling is determined by Endospecy, D
It was measured with an IA-MP set (manufactured by Seikagaku Corporation), and the endotoxin removal rate was determined according to Equation 1 (Table 3).

[0058]

[Table 3]

From Table 3, it was found that Example 3, in which the cationic polymer was adsorbed, adsorbed endotoxin in the dialysate more efficiently than the untreated dialyzer of Comparative Example 5.

Example 4-8 Influence of the Ratio of Hydrophobic Monomer of Cationic Polymer on Endotoxin Adsorption in Dialysate (To confirm endotoxin removal effect, pore size is larger than that of dialysis membrane Test with membrane) 200 g of dioxane, azobisisobutyronitrile (A
IBN) 50 mg and the ratio of the hydrophobic monomer was changed in the same manner as in Example 1 except that the ratio of N, N-dimethylaminopropylacrylamide (DMAPAA) and butyl methacrylate (BMA) was changed as follows. Different cationic polymers were synthesized.

[0061]

[Table 4]

Each of the above cationic polymers is added to a mixed solvent of ethanol and water (2: 1 by volume) in a ratio of 1.0% w.
Dissolved at a concentration of t. A polysulfone (PS) porous membrane (flat membrane having a pore diameter of 0.20 μm) was immersed in the polymer solution, washed with warm water at 60 ° C. for 2 hours, and dried at 60 ° C. The membranes coated with these cationic polymers were named Examples 4 to 7, respectively.

Next, 200 g of dioxane, N, N-dimethylaminoethyl methacrylate (DMAEMA) 2
8.2 g, methyl methacrylate (MMA) 9.0 g,
A cationic polymer (DMAEMA-) was prepared in the same manner as in Example 1 using 12.2 g of butyl methacrylate (BMA) and 50 mg of azobisisobutyronitrile (AIBN).
MMA-BMA, composition molar ratio = 1: 0.5: 0.5, molecular weight 150,000) were synthesized.

The obtained cationic polymer was dissolved in a mixed solvent of ethanol and water (3.5: 1 by volume) at a concentration of 1.0% wt. After the PS porous membrane was immersed in this polymer solution, it was dried at 60 ° C. The membrane coated with the cationic polymer was used as Example 8.

These films are cut to a diameter of 25 mm.
It was fixed to a gamma-sterilized filter, filled with endotoxin-free distilled water for injection, and sterilized in an autoclave.

The endotoxin (Escherichia Coli Seroty, manufactured by SIGMA) was adjusted to 0.7 ng / ml in a dialysate (manufactured by Fuso Pharmaceutical Co., Ltd., product name: Kindery No. 2) prepared with endotoxin-free distilled water for injection.
pe 0111: lipopolysaccharide of B4) was added to prepare a test solution.

The test liquid was applied to the membranes of Examples and Comparative Examples by 0.1 m.
The mixture was filtered at 1 / min for 60 minutes and collected every 10 minutes.
The amount of endotoxin in the test solution after filtration (recovered solution for 50-60 minutes) was measured using Endospecy, DIA-MP set (manufactured by Seikagaku Corporation), and the endotoxin removal rate was determined according to Equation 1 (Table 4). .

[0068]

[Table 5]

Table 5 shows that any of the cationic polymers efficiently removed endotoxin in the dialysate.

From Examples 1 to 8, N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N-
When the composition molar ratio of dialkylaminoalkyl (meth) acrylate was set to 1, it was found that the removal ratio of endotoxin was increased when the composition molar ratio of the hydrophobic monomer was 0.5 or less.

[0071]

As described above, the present invention provides a hemodialysis membrane coated with a polymer comprising N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N-dialkylaminoalkyl (meth) acrylate. So that
Endotoxin in the dialysate can be efficiently adsorbed even in the presence of an anticoagulant.

Therefore, by using a dialyzer in which the above-mentioned cationic polymer is coated on the hemodialysis membrane, it is possible to prevent endotoxin in the dialysate from entering the blood during the dialysate.

Claims (5)

[Claims] 1. A hemodialysis membrane having an outer surface and a pore wall surface inside the membrane, wherein the outer surface and the pore wall surface are N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N- A hemodialysis membrane coated with a polymer comprising dialkylaminoalkyl (meth) acrylate. 2. The polymer according to claim 1, wherein said polymer is a polymer consisting only of N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N-dialkylaminoalkyl (meth) acryle. 2. The hemodialysis membrane according to claim 1. 3. The copolymer of claim 1, wherein said polymer is a copolymer of a hydrophobic monomer, N, N-dialkylaminoalkyl (meth) acrylamide and / or N, N-dialkylaminoalkyl (meth) acrylate. The hemodialysis membrane according to claim 1, wherein the membrane is combined. 4. The method according to claim 3, wherein the hydrophobic monomer is an alkyl (meth) acrylate or styrene.
2. The hemodialysis membrane according to claim 1. 5. A dialyzer using the hemodialysis membrane according to any one of claims 1 to 4.