JP2002028461A - Hollow yarn membrane for adsorbing peroxylipid and module using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow yarn membrane for adsorbing peroxylipid which can selectively adsorb and remove the peroxylipid. SOLUTION: The hollow yarn membrane for adsorbing peroxylipid is distinguished by that a cationic polymer is contained in a hollow yarn membrane raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hollow fiber membrane for adsorbing lipid peroxide and a module using the same. In particular, it is suitably used as a plasma separation membrane or an artificial kidney,
The present invention relates to a hollow fiber membrane capable of adsorbing and removing lipid peroxide in blood.

[0002]

2. Description of the Related Art In the field of extracorporeal blood circulation, hollow fiber membrane type blood processors using hollow fiber membranes have been widely used in the field of extracorporeal blood circulation, particularly in hemodialysis and plasma separation. In the field of membranes and the like, polymer hollow fiber membranes are widely used. However, long-term hemodialysis patients have been found to have reduced blood antioxidant activity and high levels of lipid peroxides. Sclerosing diseases and the like are increasing.

[0003] Foam cells, which play an important role in the formation of atherosclerotic plaques, are composed of macrophages as a result of the incorporation of oxidatively altered lipids, especially low-density lipoproteins (hereinafter referred to as LDL), into macrophages. Is foamed.

[0004] In order to solve these problems, a membrane-type blood in which the surface of a dialysis membrane is coated with a vitamin E film having various physiological actions such as an antioxidant action in a living body, a stabilizing action on a biological membrane, and an inhibitory action on platelet aggregation. Although a purifier has been proposed (Japanese Patent Publication No. 62-41738), it is not possible to remove the lipid peroxide once formed in the blood of a patient.

[0005] Among the lipid peroxides, oxidized LDL, in particular, has various biological effects. In addition to the effect of inhibiting the production of nitric oxide (NO) from endothelial cells, monocytes are also transported and accumulated subendothelially. It is important for the onset and progression of arteriosclerosis, such as promoting plaque formation on the arterial wall, promoting endothelial cell and smooth muscle cell damage, etc. Plays a role. Therefore, lipid peroxide from the blood,
It is particularly desirable to remove oxidized LDL.

In the case of hyperlipidemia patients, since the amount of LDL in the blood is large, removing LDL is effective for preventing the progress of arteriosclerosis. Therefore, a liposorber manufactured by Kanegafuchi Chemical is currently used as an adsorption bead column for LDL. It is thought that the use of this adsorbent also removes the oxidized LDL at the same time.
The DL concentration of dialysis patients is the same as that of healthy subjects, and if this column is used, there is a possibility that nutrient deficiency or the like will occur. Therefore, it cannot be used for dialysis patients.

[0007] Further, since high-density lipoprotein (HDL) has a function as an arteriosclerosis protective factor, the HDL concentration in the blood of a dialysis patient must not be lowered.

[0008] The dialysis membrane typified by a commercially available cellulose membrane, polymethyl methacrylate membrane, ethylene-vinyl alcohol membrane, polysulfone / polyvinylpyrrolidone blend membrane, and the like cannot remove lipid peroxide. Rather, the level of lipid peroxide in blood tends to increase after dialysis due to stimulation by a dialysis membrane (Kidney and Dialysis Supplement, 38: 125 (1995)).

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to improve the disadvantages of the prior art and, in particular, to provide a hollow fiber membrane capable of selectively adsorbing and removing lipid peroxide and a module using the same. is there.

[0010]

In order to solve the above problems, the present invention has the following arrangement. "A hollow fiber membrane for adsorbing lipid peroxide, characterized in that the hollow fiber membrane material contains a cationic polymer."

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The hollow fiber membrane of the present invention is characterized in that the hollow fiber membrane material contains a cationic polymer.
Examples of the cationic polymer include an amino group-containing polymer having a primary, secondary, tertiary amino group, and quaternary ammonium salt, a polymer having an aziridine (ethyleneimine) compound, chitin, chitosan, and an acrylamide polymer.
And copolymers of these and nonionics and copolymers with anionic compounds. The polymer may be linear, branched or cyclic. Further, it refers to a compound having a molecular weight of 600 or more.

Examples of the amino group-containing polymer include polyalkyleneimine, polyallylamine, polyvinylamine, those having a substituent introduced therein, and copolymers comprising monomer units constituting these.

Examples of the polyethyleneimine derivative include those obtained by derivatizing polyethyleneimine at various ratios such as alkylation, carboxylation, phenylation, phosphorylation, and sulfonation.

As the polyethyleneimine, a linear or branched one having a molecular weight of 600 or more is used.

Low toxicity among cationic polymers,
Branched polyethyleneimine is preferably used in terms of availability, handling, and the like.

The hollow fiber membrane material of the present invention is not particularly limited, but is preferably a material used for medical purposes.
Examples include polyvinyl chloride, cellulosic polymers, polystyrene, polymethyl methacrylate, polycarbonate, polysulfone, and polyurethane. Among them, polysulfone is particularly preferably used because it is easily formed and has excellent membrane performance when formed into a membrane.

The polysulfone used in the present invention has an aromatic ring, a sulfonyl group and an ether group in the main chain. For example, polysulfone represented by the following formulas (1) and (2) is preferably used. However, the present invention is not limited to these. N in the formula is an integer such as 50 to 80.

[0018]

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Specific examples of polysulfone include Udel polysulfone P-1700, P-3500 (manufactured by Teijin Amoko), Ultrason S3010, S6010 (B
ASF), Victrex (Sumitomo Chemical), Radel A (Teijin Amoko), Ultrason E (BASF)
Polysulfone). In addition, the polysulfone used in the present invention has the above formula (1) and / or (2)
Although a polymer composed of only the repeating unit represented by is preferable, it may be copolymerized with another monomer as long as the effects of the present invention are not impaired. Although not particularly limited, it is preferable that the amount of the other copolymerized monomer be 10% by weight or less.

In the present invention, it is preferable to use polyvinylpyrrolidone. There is no particular limitation on the method of forming and combining polyvinylpyrrolidone and the material serving as the support, and the material serving as the support and polyvinylpyrrolidone may be laminated, but those which are mixed or compatible with each other Is preferred. Further, the material serving as the support is not particularly limited, but is preferably an organic high molecular polymer. Polysulfone is preferred as such an organic polymer.

As polyvinylpyrrolidone, commercially available ones having a weight average molecular weight of 360,000, 160,000, 40,000 and 10,000 are preferably used, but those having other molecular weights may of course be used. Although not particularly limited, the weight average molecular weight of polyvinylpyrrolidone is 20
00 to 200000 is preferable, and 10000 to 150
0000 is more preferred. The molecular weight is the molecular weight at the raw material stage, and in the final product, the molecular weight may be much larger than the above value due to radiation crosslinking or the like. Further, when the polyvinylpyrrolidone used in the present invention is used by blending with a material serving as a support, a homopolymer is preferable, but it may be copolymerized with another monomer within a range not to impair the effects of the present invention. good.
Although not particularly limited, the other comonomer is 1
It is preferably 0% by weight or less.

Incidentally, polymers other than the polyvinylpyrrolidone and the material (eg, polysulfone) serving as a support may be mixed as long as the effects of the present invention are not impaired. Although not particularly limited, such other materials are preferably 10% by weight or less based on the total weight of the hollow fiber membrane.

The thickness of the hollow fiber membrane is preferably from 10 to 80 μm, more preferably from 20 to 60 μm. As for the average pore diameter of the membrane, it is preferable that the albumin permeability in a 1 wt% albumin solution is 0.5% or more,
1% or more is more preferable. The inner diameter is preferably from 100 to 800 μm, more preferably from 150 to 300 μm. Further, the hollow fiber membrane of the present invention preferably has a function as an artificial kidney. Here, having the function as an artificial kidney means that it belongs to the type I or type II in the functional classification of the artificial kidney (Dialysis Society of Japan, 32 (12): 1465-1469, 199).
9).

The hollow fiber membrane of the present invention is produced by appropriately employing the above-described method for introducing a cationic polymer in a conventionally known method for producing a hollow fiber membrane. The following method is an example of a method for manufacturing a hollow fiber membrane.

Polysulfone and polyvinylpyrrolidone (weight ratio 20: 1 to 1: 5, preferably 5: 1 to 1: 1) are mixed with a good solvent (N, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, N
-Methylpyrrolidone, dioxane, etc. are preferable) and a stock solution dissolved in a mixed solution of a good solvent (concentration is 10 to 10).
(Preferably 30% by weight, and more preferably 15% to 25% by weight) is discharged from the double-ringed die, the infusion liquid is flowed inward, and is guided to the coagulation bath after running in the dry section. At this time, since the humidity of the dry part has an influence, the phase separation behavior near the outer surface is accelerated by supplying water from the outer surface of the membrane during running in the dry part, the pore size is enlarged, and as a result, the permeability during dialysis is increased. -It is also possible to reduce the diffusion resistance. However, if the relative humidity is too high, the coagulation of the undiluted solution on the outer surface becomes dominant, and the pore diameter becomes smaller, and as a result, the permeation / diffusion resistance during dialysis tends to increase. Therefore, the relative humidity is preferably from 60 to 90%. Further, it is preferable to use a composition having a composition based on the solvent used for the stock solution from the viewpoint of process suitability. For example, when dimethylacetamide is used,
An aqueous solution of 〜80% by weight, more preferably 60-75% by weight is suitably used.

The method of incorporating a cationic polymer into a material includes mixing a cationic polymer into an undiluted solution of the material before molding, and a method of molding or mixing a material into which a reactive functional group is introduced. After molding the material, the cationic polymer is fixed to the functional group by surface reaction, by immersing the ordinary material in a solution of the cationic polymer and irradiating it with radiation or heat treatment to insolubilize the cationic polymer. Immobilization method, a method of coating a usual material with a cationic polymer and adsorbing and immobilizing the same, and a method of adsorbing and immobilizing and then insolubilizing and immobilizing by radiation irradiation, heat treatment and the like.

The cationic polymer may be immobilized only on the inner surface of the membrane or may be immobilized on the entire surface of the membrane having pores.

The method of manufacturing the module is not particularly limited, but one example is as follows. First, the hollow fiber membrane is cut to a required length, bundled in a required number, and then placed in a cylindrical case. After that, temporary caps are put on both ends, and potting agents are put into both ends of the hollow fiber membrane. At this time, a method of adding the potting agent while rotating the module with a centrifuge is a preferable method because the potting agent is uniformly filled. After the potting agent has solidified, both ends are cut so that both ends of the hollow fiber membrane are open, and a hollow fiber membrane module is obtained.

The hollow fiber membrane of the present invention is suitably used as an extracorporeal circulation module for artificial kidney, plasma separation and the like.
When used for artificial kidneys, large molecules such as LDL and HDL are not dialyzed and filtered. Therefore, if the inner surface of the membrane contains a ligand that selectively interacts with lipid peroxide, the lipid peroxide is adsorbed and removed, and LDL, H
The DL is not adsorbed and is returned to the patient. On the other hand, in the case of a plasma separation membrane, LDL and HDL are filtered, but if the entire membrane contains a ligand that selectively interacts with lipid peroxide, the entire area of the membrane can be used effectively. Therefore, it is effective for efficiently removing lipid peroxide. However, it is preferable to return the filtered LDL or HDL to the body or to replenish fresh plasma.

Hereinafter, conditions for measuring the performance of the membrane adsorber of the present invention will be described. (1) Preparation of antioxidant LDL antibody The one prepared by Itabe et al. Was used (H. Itabe et al.)
al. , J .; Biol. Chem. 269: 1527
4, 1994). That is, a human atherosclerotic lesion homogenate was injected into a mouse and immunized, a hybridoma was prepared from the spleen of the mouse, and a mouse that reacted with copper sulfate-treated LDL was selected. Antibody class is mouse IgM, untreated LDL, acetyl LDL, malondialdehyde LDL
Does not react with Reacts with several phosphatidylcholine peroxidation products, including aldehyde derivatives of phosphatidylcholine and hydroperoxides. 150
10 mM borate buffer (pH 8.
5) was used (protein concentration 0.60 mg /
ml). (2) Preparation of oxidized LDL After desalting commercially available LDL (manufactured by Funakoshi), 0.2 mg
/ Ml after dilution with phosphate buffer (PBS)
1 wt% of 0.5 mM copper sulfate aqueous solution is added, and
The reaction was performed for 6 hours. An oxidized LD was prepared by adding 25 mM ethylenediaminetetraacetic acid (EDTA) to 1 wt%, 10 wt% sodium azide to 0.02 wt%.
The sample was designated as L. (3) Perfusion operation Healthy person plasma (Japanese, 30 years old, LDL (β lipoprotein) concentration 275 mg / dl, HDL-cholesterol concentration 70
mg / dl), the oxidized LDL was added to 2 μg / ml.

From a hollow fiber membrane having an inner diameter of 200 μm and a thickness of 40 μm, mini modules (inner surface area: 53 cm ² ) having a length of 12 cm and 70 pieces were prepared, and an inner diameter of 7 mm (outer diameter: 10 m)
m), 2 cm long silicone tube (product name ARA)
M) and a silicone tube with an inner diameter of 0.8 mm (outer diameter of 1 mm) (product name ARAM, 37
cm at two ends) and the above plasma 1.5m
was perfused into the hollow fiber at a flow rate of 0.5 ml / min at 25 ° C. for 4 hours (the amount of plasma per 1 m ^{2 of} material surface area was 2.8 ×
10 ² ml / m ² ).

Further, a perfusion operation was performed using only a silicone tube without attaching a mini-module.

Oxidized LDL in plasma before and after perfusion, LDL,
By quantifying the HDL concentration, the respective adsorption removal rates were calculated by the following equations.

Adsorption removal rate (%) = Adsorption removal rate (%) using mini-module—Adsorption removal rate using only silicone tube (%) Each adsorption removal rate (%) = 100 × (concentration before perfusion−perfusion) (4) Measurement of oxidized LDL, LDL, and HDL concentrations The antioxidant LDL antibody was diluted to 5 μg / ml with PBS, and
100 μl / well was dispensed into a 6-well plate, shaken at room temperature for 2 hours, and adsorbed to the wall at 4 ° C. overnight or more.

Discard the antibody solution in the well, and add 1 wt% Bo
Tris-HCl buffer (p.p. containing Vine Serum Albumin (BSA, Fraction V, Seikagaku))
H8.0) was dispensed at 200 μl / well at room temperature.
After shaking for hours to block the walls, the BS in the wells
Solution A was discarded, and 100 μl / well of plasma containing oxidized LDL and a standard for preparing a calibration curve (PBS buffer containing 0 to 2 μg / ml of oxidized LDL) were dispensed.
Then, after shaking at room temperature for 30 minutes, it was left at 4 ° C. overnight.

After returning to room temperature, the solution in the well was discarded.
The wells were washed three times with a Tris-HCl buffer (pH 8.0) containing 05 wt% Tween-20 (Katayama Chemical).
Sheep anti-apoB antibody (THE BINDING SITE) 1 diluted 2000-fold with PBS in the washed well
After dispensing 00 μl / well and shaking at room temperature for 2 hours, the anti-apoB antibody in the well was discarded, and a Tris-HCl buffer solution containing 0.05 wt% Tween-20 (pH 8.
The wells were washed three times in 0). 2wt in washed well
Alkaline phosphatase-labeled donkey anti-sheep IgG antibody (CHE) diluted 2,000-fold with Tris-HCl buffer (pH 8.0) containing% Block Ace (Dainippon Pharmaceutical).
MICON) was dispensed at 100 μl / well and shaken at room temperature for 2 hours. Then, discard the labeled antibody in the well,
The wells were washed three times with a Tris-HCl buffer (pH 8.0) containing 0.05 wt% Tween-20, and further washed twice with a Tris-HCl buffer (pH 8.0). Subsequently, p-nitrophenyl phosphate (Boehringer)
100 μl / well of a 1 mg / ml solution (0.0005 M MgCl ₂ , 1 M diethanolamine buffer, pH 9.8) of Mannheim GmbH) was dispensed at 100 μl / well, and allowed to react at room temperature for an appropriate time. It was measured. A calibration curve was drawn from the results of the standard to determine the oxidized LDL concentration.

LDL was quantified using a β-lipo assay kit (Wako Pure Chemical Industries, Ltd.).

Quantification of HDL was performed using an HDL-C measurement kit (Wako Pure Chemical Industries, Ltd.).

[0039]

EXAMPLES Example Polysulfone (Udel P-350 manufactured by Teijin Amoko Co., Ltd.)
0) 18 parts by weight of polyvinylpyrrolidone (K30 manufactured by BASF) 9 parts by weight of N, N-dimethylacetamide 72
In addition to 1 part by weight of water and 1 part by weight of water, the mixture was heated and dissolved at 90 ° C. for 14 hours. This membrane-forming stock solution is discharged from an orifice-type double cylindrical die having an outer diameter of 0.3 mm and an inner diameter of 0.2 mm, and a solution composed of 58 parts by weight of dimethylacetamide and 42 parts by weight of water is discharged as a core liquid. After passing, water 10
The mixture was guided to a 0% coagulation bath to obtain a hollow fiber. Bundle 70 polysulfone hollow fiber separation membranes, fix both ends to the glass tube module case with an epoxy potting agent so as not to block the hollow portion of the hollow fiber, make a mini-module, 1 wt%
Of polyethyleneimine (molecular weight: 10,000, manufactured by Wako Pure Chemical Industries, Ltd.) and irradiated with γ-rays at 25 kGy. The mini-module had a diameter of about 7 mm and a length of 12 cm.
The irradiated membrane was washed again with distilled water at 37 ° C. for 30 minutes and then subjected to an adsorption experiment.

The experimental results are shown in Table 1. Comparative Example 1 A mini-module was prepared in the same manner as in the example, and 1 wt%
Fill with water instead of polyethyleneimine aqueous solution of
What was irradiated with gamma rays at 25 kGy was prepared. Comparative Example 2 Commercially available polymethyl methacrylate dialysis membrane (Toray, BG)
A mini-module was created using. Comparative Example 3 A mini-module was prepared using a commercially available cellulose membrane coated with vitamin E (Exebrene, Terumo, CL-E15N).

Oxidation L in Examples and Comparative Examples 1 to 3
Table 1 shows the results of the adsorption and removal rates of DL, LDL, and HDL.

The water permeability and β ₂ MG clearance of the hollow fiber membrane produced in Example 1 were not different from those of Comparative Example 1.

[0043]

[Table 1]

[0044]

Industrial Applicability According to the present invention, peroxidation is preferably used in applications such as a membrane blood purifier, particularly in the case of preventing the development of arteriosclerosis or preventing its onset in dialysis patients. A hollow fiber membrane for homogeneous adsorption can be provided.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) B01D 71/60 B01D 71/60 71/68 71/68 F term (reference) 4C077 AA05 AA30 BB01 BB02 CC01 KK01 LL05 PP13 PP15 PP18 4D006 GA13 HA01 MA01 MB14 MC51X MC57X MC60X MC62X MC78X NA01 NA26 PB42 PB52 PC44 PC47 4D017 AA09 AA11 BA03 CA13 DA01

Claims (12)

[Claims] 1. A hollow fiber membrane for adsorbing lipid peroxide, wherein the hollow fiber membrane material contains a cationic polymer. 2. A hollow fiber membrane for adsorbing lipid peroxide, wherein the cationic polymer according to claim 1 is an amino group-containing polymer. 3. The hollow fiber membrane for adsorbing lipid peroxide, wherein the amino group-containing polymer according to claim 2 is polyethyleneimine or a derivative thereof. 4. The amount of plasma per 1 m ^{2 of} material surface area is 2.
When a perfusion operation is performed under the condition of 8 × 10 ² ml / m ² , the removal rate of oxidized low-density lipoprotein having an initial concentration of 2 μg / ml contained in the plasma is 20% or more. The hollow fiber membrane for adsorbing lipid peroxide according to any one of claims 1 to 3, characterized in that: 5. The hollow fiber membrane for adsorbing lipid peroxide according to claim 1, wherein the rate of adsorption and removal of low-density lipoprotein is less than 5%. 6. The hollow fiber membrane for adsorbing lipid peroxide according to claim 1, wherein the high-density lipoprotein has an adsorption removal rate of less than 5%. 7. The hollow fiber membrane for adsorbing lipid peroxide according to claim 1, wherein the hollow fiber membrane material is made of polysulfone. 8. The hollow fiber membrane for adsorbing lipid peroxide according to claim 1, wherein the hollow fiber membrane material comprises a blend of polysulfone and polyvinylpyrrolidone. 9. The hollow fiber membrane for adsorbing lipid peroxide according to claim 1, wherein the hollow fiber membrane is used as a module for extracorporeal circulation. 10. The hollow fiber membrane for adsorbing lipid peroxide according to claim 1, which has a function as a plasma separation membrane when used as a hollow fiber membrane module. 11. The hollow fiber membrane for adsorbing lipid peroxide according to claim 1, which has a function as an artificial kidney when used as a hollow fiber membrane module. A module comprising the hollow fiber membrane for adsorbing lipid peroxide according to any one of claims 1 to 8.