JP2001300221A - Leukocyte removing filter material and polymer therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a leukocyte removing filter material for permitting an erythrocyte, a platelet and blood plasma to transmit from a leukocyte-containing liquid represented by whole blood to efficiently remove a leukocyte component, and a polymer useful for this filter material. SOLUTION: The leukocyte removing filter is characterized by that a graft copolymer, which is obtained by polymerizing a graft chain based on a hydrophobia monomer with a main chain being a copolymer containing a monomer having a nonionic hydrophilic group and a monomer having a basic nitrogen- containing functional group as main components, is present at least on the surface of a filter base material. The graft copolymer obtained by polymerizing the graft chain based on the hydrophobic monomer with the main chain being the copolymer containing the monomer having the nonionic hydrophilic group and the monomer having the basic nitrogen-containing functional group as main components is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leukocyte removal filter material. More specifically, the present invention relates to a filter material for transmitting red blood cells, platelets, and plasma from a leukocyte-containing liquid represented by whole blood and efficiently removing leukocytes. The invention also relates to novel polymers useful for such filter media.

[0002]

2. Description of the Related Art Conventionally, in the field of blood transfusion, in addition to so-called whole blood transfusion, a blood donor obtained by adding an anticoagulant to blood collected from a blood donor, the need for a donor from a whole blood product is required. A so-called component blood transfusion in which a blood component is separated and the blood component is infused has been generally performed. Component transfusions include erythrocyte transfusions, platelet transfusions, plasma transfusions, etc., depending on the type of blood component required by the recipient.The blood component preparations used for these transfusions include erythrocyte preparations, platelet preparations, and plasma preparations. and so on.

[0003] In addition, relatively minor side effects such as headache, nausea, chills, and non-hemolytic fever reaction accompanying blood transfusion, alloantigen sensitization that seriously affects the recipient, GVHD after blood transfusion, viral infection, and the like. Serious side effects were found to be caused mainly by leukocytes contaminated in blood products used for blood transfusions. The so-called leukapheresis transfusion has become widespread.

[0004] Methods for removing leukocytes from blood products include:
Broadly classified, centrifugation using the difference in specific gravity of blood components,
There are two types of filter methods using a fiber material or a porous body having continuous pores as a filter medium.The filter method is widely used because of its high leukocyte removal ability, simple operation, and low cost. Have been. On the other hand, if the storage period of blood products is prolonged, it will be difficult to prevent the adverse effects of leukocytes, it will be impossible to prevent the pyrogenic cytokines produced by leukocytes during storage, and white blood cells holding viruses and bacteria It has been pointed out that it is better to remove leukocytes before storage rather than at the time of blood transfusion, because they are killed and crushed, and the pathogenic medium diffuses into blood for transfusion and can not be removed by a leukocyte removal filter. ("Transfusion at a glance" Takayoshi Asai, Kiyoshi Hirama, Takashi Hoshi, co-authored by Medical Science International, p. 77).

However, when connecting a leukocyte removal filter to a blood bag, it is not possible to completely connect the filter under aseptic conditions, so that blood products from which leukocytes have been removed must be used within 24 hours after production. ing.
Since blood products from which leukocytes have not been removed can be stored for a much longer period of time, it goes without saying that a method for removing leukocytes aseptically would be very useful.

[0006] In order to solve this problem, a filter material for permeating red blood cells, platelets and plasma from whole blood and efficiently removing white blood cell components has been required. That is, according to Japanese Patent Publication No. 6-59304, a blood collection bag is connected upstream of a leukocyte removal filter that allows plasma, red blood cells and platelets to pass but not white blood cells, and at least three blood cells are provided downstream of the leukocyte removal filter. Using a blood component separation bag device in which the component separation bag is aseptically connected, the blood collected in the blood collection bag is passed through the leukocyte removal filter to remove white blood cells in advance, and then centrifuged to perform specific gravity. A method of dispensing the blood component separated by the difference into the blood component separation bag is disclosed.

However, the above patent and WO 87/058
No. 12 discloses a leukocyte removal filter that uses a filter material in which the surface portion of the fiber contains a nonionic hydrophilic group and a basic nitrogen-containing functional group to reduce platelet capture and efficiently remove leukocytes. However, there has been a demand for the development of a filter capable of recovering platelets having higher adhesive ability in a higher yield.

Japanese Patent Application Laid-Open No. 55-129755 discloses a method for collecting leukocytes and lymphocytes containing little red blood cells and platelets using a filter having a nonwoven fabric surface coated with an antithrombotic material. However, when this filter is used, the loss of platelets is small, but the leukocyte removal rate is also small and not satisfactory.

Japanese Patent Application Laid-Open No. 5-262656 discloses that a leukocyte is selectively removed using a filter in which a polymer containing an alkoxyalkyl (meth) acrylate monomer as a main component is retained on the surface of a polyurethane porous filter. A technique for performing this is disclosed. Further, Japanese Patent Laid-Open No. 5-1942
No. 43 discloses a technique for selectively removing leukocytes using a filter having both a basic nitrogen-containing functional group and a polyethylene oxide chain introduced into the surface of a polyester nonwoven fabric filter. However, these are examples for a concentrated platelet preparation, and it has been desired to develop a leukocyte-removing filter exhibiting even higher performance on whole blood.

[0010]

DISCLOSURE OF THE INVENTION The present invention relates to a filter material for permeating red blood cells, platelets and plasma from a leukocyte-containing liquid represented by whole blood and efficiently removing leukocyte components, and a filter material useful for the filter material. It is intended to provide a novel polymer.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a conventional monomer having a nonionic hydrophilic group and a monomer having a basic nitrogen-containing functional group are mainly used. When a hydrophobic polymer chain composed mainly of a hydrophobic monomer was introduced as a graft chain into the coating polymer as a component, surprisingly, the platelet recovery rate was improved while maintaining a high leukocyte removal rate. And found the present invention. That is, the present invention provides a method for producing a polymer comprising a monomer having a nonionic hydrophilic group and a monomer having a basic nitrogen-containing functional group on at least the surface of a filter substrate, the main chain being a hydrophobic monomer. The present invention relates to a leukocyte-removing filter material characterized by the presence of a graft copolymer obtained by polymerizing a graft chain containing as a main component, and a novel polymer useful for the leukocyte-removing filter material. The novel polymer of the present invention can be used not only in leukocyte-removing filter materials but also in a wide range of medical materials such as adsorbents, coating agents, permselective membranes or cell adhesion membranes.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The leukocyte removal filter material of the present invention is a filter material that captures leukocytes in blood but does not capture other blood components, that is, red blood cells, platelets, and plasma.

The monomer having a nonionic hydrophilic group of the present invention is a monomer having a hydroxyl group and an amide group, for example, 2-hydroxyethyl (meth) acrylate,
-Hydroxypropyl (meth) acrylate, vinyl alcohol (polymerized as vinyl acetate and then hydrolyzed), (meth) acrylamide, N-vinylpyrrolidone and the like. Here, the description of (meth) acrylate means acrylate or methacrylate. Also,
Examples of the nonionic hydrophilic group include a polyethylene oxide chain in addition to the hydroxyl group and the amide group. A methoxypolyethylene glycol (meth) acrylate or a polyethylene glycol mono (meth) acrylate monomer is used, and the average repetition number of ethylene oxide is preferably 1 to 30. These monomers may be used in a mixture. Among the above monomers, 2-
Hydroxyethyl (meth) acrylate or methoxypolyethylene glycol (meth) acrylate is preferably used.

The monomer having a basic nitrogen-containing functional group of the present invention is allylamine; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl ( Derivatives of (meth) acrylic acid such as (meth) acrylate and 3-dimethylamino-2-hydroxypropyl (meth) acrylate; derivatives of (meth) acrylamide such as 3-dimethylaminopropyl (meth) acrylamide, wherein (meth) The description of acrylamide means acrylamide or methacrylamide. Styrene derivatives such as p-dimethylaminomethylstyrene and p-diethylaminoethylstyrene; vinyl derivatives of nitrogen-containing aromatic compounds such as 2-vinylpyridine, 4-vinylpyridine and 4-vinylimidazole; And quaternary ammonium salts obtained by alkylation. They may also be used in a mixture. Among the above monomers, N, N-dimethylaminoethyl (meth) acrylate or N, N-diethylaminoethyl (meth) acrylate is preferred because of its availability, ease of handling at the time of polymerization, and performance when bleeding blood. Is preferably used.

The hydrophobic monomer of the present invention comprises styrene,
An alkyl ester of (meth) acrylate, for example, styrene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate,
Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like can be mentioned. These may be used in a mixture. Preferably, styrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth)
Acrylates are more preferred, and butyl (meth) acrylate is more preferred.

The hydrophobic graft chain of the present invention desirably has good adhesion to the surface of the filter substrate, and those having a solubility parameter of the graft chain close to the solubility parameter of the substrate are effective. The solubility parameter of the polymer is, for example, a polymer data handbook-basic-,
Edited by The Society of Polymer Science, published by Baifukan (1986), p. 598
To 602. The difference between the solubility parameters of the substrate and the graft chain polymer is preferably 3.0 (cal).
^{1/2 1} / ^{2cm −3/2} ), more preferably less than 2.5, and most preferably less than 2.0.

The graft copolymer of the present invention is obtained by a chain transfer method in which a monomer is polymerized in the presence of a backbone polymer to introduce a graft chain; a macromonomer having a polymerizable group is synthesized in advance and reacted with the monomer to form a backbone. A macromonomer method for forming a polymer; an initiator method for introducing a starting portion into the trunk polymer in advance and polymerizing the monomer therefrom; a trunk polymer having a functional group synthesized separately in advance and capable of reacting with the functional group It is synthesized by a coupling method of reacting a polymer having a functional group and becoming a graft chain; and the like. A preferred method is a macromonomer method or a coupling method because of simplicity of synthesis, control of molecular weight and distribution thereof, control of hydrophobicity and hydrophilicity, and the like. As the polymerization method, known radical polymerization or ionic polymerization can be used, but radical polymerization is preferred in terms of simplicity.

In the synthesis of the macromonomer in the macromonomer method, a method of introducing a polymerizable group using a start reaction or a termination reaction, and / or a method of converting a terminal functional group into a polymerizable group are used. Preferably, a functional group is introduced into the polymer terminal using an initiator having a functional group, and then the terminal functional group is converted into a polymerizable terminal group, or polymerization is carried out in the presence of a chain transfer agent having a functional group. And then converting the terminal functional group to a polymerizable terminal group. The initiator having a functional group is preferably an azo initiator having a functional group, for example, 4,4′-azobis (4
An initiator for introducing a carboxylic acid such as -cyanovaleric acid);
An initiator for introducing a hydroxyl group such as 2,2′-azobis {2-methyl-N- (2-hydroxyethyl) propionamide} is exemplified. As the chain transfer agent having the functional group, a sulfur-containing compound is preferable, and for example, thioglycolic acid, thiomalic acid, α-thioglycerin, 2-mercaptoethanol, 2-mercaptoethylamine hydrochloride, and the like are used. A known method can be used for converting the terminal functional group into a polymerizable terminal group. For example, the reaction can be carried out using glycidyl (meth) acrylate, 2-isocyanatoethyl (meth) acrylate, (meth) acryloyl chloride or the like to introduce a (meth) acryloyl group at the terminal.

The polymer that becomes a graft chain in the coupling method can be prepared by using the above-described method for synthesizing a macromonomer, and has a functional group at a terminal. The functional group is preferably a primary or secondary amino group. The backbone polymer having a functional group capable of reacting with the functional group is obtained by, for example, copolymerizing glycidyl (meth) acrylate or the like.

In the present invention, the nitrogen atom of the basic nitrogen-containing functional group is contained in the main chain, and its content is 0.05% by weight or more and less than 3.0% by weight based on the main chain. It is. Preferably 0.1% by weight or more and less than 2.0% by weight, more preferably 0.2% by weight or more and 1.0% by weight
Is less than. When the content of the nitrogen atom in the basic nitrogen-containing functional group is less than 0.05% by weight, the leukocytes cannot be selectively removed because the leukocytes are hardly adhered together with the platelets. on the other hand,
When the content of the nitrogen atom of the basic nitrogen-containing functional group is 3.0% by weight or more, both platelets and leukocytes tend to adhere to each other, and also in this case, selective leukocyte removal cannot be performed.

The content of nitrogen atoms in the graft copolymer is determined by using the graft polymer before coating.
After coating, the material surface is extracted using an appropriate method, and the extracted component is measured by ¹ H-nuclear magnetic resonance spectroscopy (hereinafter abbreviated as NMR) to determine the amount of the monomer component having a basic nitrogen-containing functional group. And the content of the graft chain containing a hydrophobic monomer as a main component is determined, and the content of the nitrogen atom of the basic nitrogen-containing functional group with respect to the main chain can be calculated from the obtained value.

The graft chain content of the present invention is at least 2% by weight and less than 60% by weight based on the graft copolymer. Preferably, it is at least 5% by weight and less than 50% by weight, more preferably at least 10% by weight and less than 40% by weight. When the graft chain content is less than 2% by weight, the permeability of platelets tends to decrease. On the other hand, when the graft chain content is 60% by weight or more, the hydrophobicity of the coat surface is improved, and both platelets and leukocytes tend to adhere. In addition, the content of the graft chain can be determined by performing NMR measurement as described above.

The graft copolymer of the present invention can be present on the surface of the filter substrate by a coating method. ADVANTAGE OF THE INVENTION According to the method of this invention, since the adhesiveness with the surface of a filter base material improves, the elution amount with respect to a hot water can be reduced conventionally.

In producing the filter material of the present invention, to coat the graft copolymer, the filter substrate is immersed in a solution in which the graft copolymer is dissolved in an appropriate solvent, and then subjected to mechanical compression, gravity, A method of removing excess solution from the fiber by centrifugation or the like, preliminarily drying, and then drying in a gas or a vacuum at room temperature or while heating can be used.

The surface abundance of the graft copolymer with respect to the filter material is preferably 0.001 g /
m ² or more and less than 0.50 g / m ² , more preferably 0.1 g / m ^{2 or} less.
005 g / m ² or more and less than 0.40 g / m ² , most preferably 0.01 g / m ² or more and less than 0.30 g / m ² . If the abundance is less than 0.001 g / m ² , the leukocyte removal rate and platelet recovery rate may be inferior,
If it is 0.50 g / m ² or more, the pore size decreases and the pore structure changes greatly due to swelling when it comes into contact with blood from a dry state, and the leukocyte removal rate and platelet recovery rate may become unstable.

The surface abundance of the graft copolymer with respect to the filter material can be determined by the following method. First, the amount of the graft copolymer per unit weight of the filter material is determined by the difference between the weight before and after the coating, or the polymer present on the substrate surface is extracted using an appropriate method, and the weight of the extracted polymer is measured. Required by Next, the total pore surface area per unit weight of the filter material was measured by a mercury intrusion method, and this value was used to divide the abundance of the graft copolymer per unit weight of the filter material. calculate.

The measurement of the total pore surface area per unit weight of the filter material by the mercury intrusion method is performed by the following method. A part of the filter material is sampled and its weight (W) is measured. The total pore surface area (A) of the sample is measured with a mercury porosimeter in a pressure range of 0.1 to 210 psia, and the total pore surface area per unit weight is determined from the following equation. Total pore surface area per unit weight = A / W In order to determine the total pore surface area per unit weight, it is preferable to sample three or more locations of the filter material and determine the average value. Such materials should be considered to be included in the scope of the present patent if, as a result of the measurement, some portions fall within the range defined by the present invention and the remaining portions deviate from the range.

The filter substrate of the present invention is preferably a fibrous medium such as a nonwoven fabric or a porous body having continuous pores. Also,
These may be used in combination. It is known that the structure of the filter substrate greatly contributes to the capture of leukocytes, and selection of the filter substrate is also an important factor for further improving the leukocyte removal rate.

That is, when a fibrous medium such as a nonwoven fabric is used as the filter substrate, the average fiber diameter is 0.3 μm or more.
Less than 3.0 μm, more preferably 1.0 μm or more,
Desirably less than 2.0 μm. Further, the filling density when the fibrous medium is filled in a container is 0.1 g / cm ³ or more,
Less than 0.3 g / cm ³ is preferred. Average fiber diameter is 0.3
μm, the packing density is 0.3 g / cm ³ or more,
Clogging of blood cells and increase in pressure loss may be caused, and if the average fiber diameter is 3.0 μm or more and the packing density is less than 0.1 g / cm ³ , the leukocyte removal rate may decrease. It is.

The average fiber diameter of the present invention is a value determined according to the following procedure. That is, a part of the filter substrate, which is regarded as substantially uniform, constituting the filter substrate is sampled and photographed using a scanning electron microscope or the like. At the time of sampling, the effective filtration cross-section area of the filter substrate is 0.5 to 1 cm on one side.
, And random sampling is performed at three or more, preferably five or more locations. In order to perform random sampling, for example, after designating an address to each of the sections, a section at a necessary place or more may be selected by a method such as using a random number table. For each sampled section, three or more, preferably five or more locations are photographed.
The diameter of all the fibers in the photograph thus obtained is measured. Here, the diameter refers to the width of the fiber in a direction perpendicular to the fiber axis. The value obtained by dividing the sum of the diameters of all the measured fibers by the number of fibers is defined as the average fiber diameter. However, when multiple fibers are overlapped and the width cannot be measured due to the shadow of other fibers, or when multiple fibers are melted, etc., and become thicker, fibers with significantly different diameters If these are mixed, etc., these data are deleted. By the above method, 1
The average fiber diameter is determined from data of 00 or more, preferably 1,000 or more.

Japanese Patent Application Laid-Open No. 11-42406 discloses a method for improving the leukocyte removal ability in which a porous element having an average pore diameter of 1.0 μm or more and less than 100 μm and an average fiber diameter held by the porous element of 0.1 μm are used. A filter material comprising a fiber structure of not less than 03 μm and less than 1.0 μm, wherein the porosity of the filter material is 50% or more and less than 95%, and the holding amount of the fiber structure with respect to the filter material is 0.01% by weight. %
A leukocyte removal filter in which the ratio of the average pore diameter of the porous element to the average fiber diameter of the fibrous structure is 2 or more and less than 2000, and the fibrous structure forms a network structure. Is disclosed, but it is also preferable to use a filter substrate in which such fine fibers and ultrafine fibers are mixed, as long as clogging of blood cells and increase in pressure loss are not caused.

When the filter substrate is made of fiber, examples of the fiber material include polyamide, aromatic polyamide, polyester, polyacrylonitrile, polytrifluorochloroethylene, polymethyl methacrylate, and the like.
Synthetic fibers such as polystyrene, polyethylene and polypropylene, and recycled fibers such as cellulose acetate, cupra ammonium rayon, viscose rayon, hemp,
Natural fibers such as cotton, silk and wool fibers can be mentioned.
Among them, synthetic fibers such as polyester, polyethylene, and polypropylene are more preferable materials because of their ease of production and handling.

When the filter substrate of the present invention is a porous polymer having continuous pores, the average pore diameter of the porous polymer is preferably 1 μm or more and less than 20 μm, more preferably 1 μm or more. The thickness is more preferably less than 15 μm, and more preferably 2 μm or more and less than 8 μm. If the average pore size is less than 1 μm, it may be difficult to pass red blood cells, which is not preferable.
If it is not less than μm, the frequency of contact between the surface of the porous body and the leukocytes is too low, so that the leukocytes may not be sufficiently removed.

Further, the average porosity of the porous polymer body is as follows:
45% or more and less than 95%, preferably 70%
And more preferably less than 95%, more preferably 80% or less.
% Or more and less than 95%. If the average porosity is less than 45%, there is a possibility that a space for allowing red blood cells to pass therethrough may not be provided sufficiently. Conversely, if the average porosity is 95% or more, the mechanical strength as a filter substrate tends to be insufficient. Not preferred.

The average pore size and average porosity of the present invention are values determined by the mercury intrusion method described below. That is,
A fixed area (S) is sampled at three places at random from the filter base material, and each thickness (t) is measured using a film thickness meter (for example, Peacock thickness meter). From these values, the apparent value of each sample is measured. Determine the volume (V ₁ = S × T). 0.1 to 210 psia for each sample
The total pore volume (V ₂ ) and the total pore surface area (A) measured in the pressure range are determined. Using these values, the porosity and the average pore size are determined from the following equation. Porosity = (V ₂ / V ₁ )
The average value of the porosity at three locations is determined from × 100 (%), and this is defined as the average porosity of the porous body. Average pore size =
From (4 × V ₂ ) / A, the average value of the average pore diameters at three locations is determined, and this is defined as the average pore diameter of the porous body.

When the filter substrate is made of a porous polymer, examples of the porous substrate include polyacrylonitrile, polysulfone, cellulose, cellulose acetate, polyvinyl acetal, polyester, polymethacrylate, and polyurethane. Can be

In the filter substrate of the present invention, a fiber filter substrate having a sequentially smaller average fiber diameter and / or a polymer porous body having a sequentially smaller average pore size are arranged from the inlet side to the outlet side of blood. Is preferred. The fiber filter base material having the smallest average fiber diameter or the polymer porous body having the smallest average pore size is the base material part having the highest leukocyte adsorption efficiency, but is therefore liable to be clogged by the leukocytes adsorbed, and thus has the blood Before reaching the preparation, it is preferable that leukocytes are coarsely removed by a fiber filter substrate having a relatively large average fiber diameter and / or a polymer porous material filter substrate having a relatively large average pore diameter. In general, the leukocyte-containing liquid often contains microaggregates. A prefilter can also be used to remove microaggregates from a leukocyte-containing liquid that is rich in such microaggregates. The prefilter base material is preferably a fiber aggregate having an average fiber diameter of 8 μm to 50 μm or a continuous porous body having an average pore size of 20 μm to 200 μm. The prefilter base material is assembled on the blood entry side of a leukocyte removal filter. It is used by embedding. The prefilter may be used in the presence of the polymer of the present invention on the surface.

The filter material of the present invention may be used by being independently filled in a leukocyte removal filter, but preferably a blood collection bag is connected upstream of the filter, and at least three blood collection bags are connected downstream of the filter. One blood component separation bag is aseptically connected to a filter incorporated in a blood component separation bag device and used.
That is, after the blood collected in the blood collection bag is passed through the leukocyte removal filter to remove white blood cells in advance, centrifugation is performed, and a blood component separated by a specific gravity difference is collected in the blood component separation bag. Used.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on embodiments. Molecular weight is determined by gel permeation chromatography (GP
C), and the number average molecular weight (hereinafter abbreviated as MN) and the weight average molecular weight (hereinafter abbreviated as MW) were determined in terms of the molecular weight in terms of polymethyl methacrylate.

[0040]

[Production Example 1] A macromonomer was synthesized by a known method for introducing a functional group into a polymer terminal using a chain transfer agent having a functional group (for example, Goethals, EJ, edited by Te.
lechelic Polymers: Synthesis and Applications, CRC
Publishing (1989) p. 170; supervised by Tsuyoshi Endo, "Synthesis and Application of Reactive Polymers", see CMC Publishing (1989), Chapter 10.) Methyl methacrylate is polymerized using 2-mercaptoethanol as a chain transfer agent and azobisisobutyronitrile (hereinafter abbreviated as AIBN) as a polymerization initiator.
-Reacted with isocyanatoethyloxy methacrylate to obtain a polymethyl methacrylate macromonomer having a methacryloyl group at a terminal. MN is 10,400, M
W was 21,100. Next, 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA), dimethylaminoethyl methacrylate (hereinafter abbreviated as DM), and the obtained macromonomer were dissolved in dimethylformamide at a ratio of 97: 3: 10 parts by weight, and the initiator was dissolved. AIBN was added in an amount of 1/200 equivalent per monomer, and polymerization was carried out at 80 ° C. in a nitrogen gas atmosphere. After 4 hours, the polymerization solution was poured into water to precipitate a polymer, which was recovered and dried. Purification was performed by dissolving the polymer in ethanol and adding hexane thereto to precipitate the polymer again. The composition of the obtained graft copolymer was measured by NMR, and HEMA: DM: graft chain = 82.6: 2.8:
It was 14.6 (weight composition ratio). Main chain (HEMA-D
The nitrogen atom content of the basic nitrogen-containing functional group with respect to M) is 0.29% by weight, MN is 90,000, and MW is 2%.
It was 31,000.

[0041]

[Production Example 2] A poly-n-butyl methacrylate macromonomer having a methacryloyl group at a terminal was obtained by performing the same reaction as in Production Example 1 except that n-butyl methacrylate (hereinafter abbreviated as BMA) was used instead of methyl methacrylate. I got MN is 12,700, MW is 28,7
00. The composition of the graft copolymer obtained by copolymerization with HEMA and DM was HEMA: DM: graft chain = 81.8: 1.7: 16.4 (weight composition ratio). The content of the nitrogen atom of the basic nitrogen-containing functional group with respect to the main chain (HEMA-DM) was 0.18% by weight.
Was 62,000 and MW was 117,000.

[0042]

Production Example 3 In Production Example 2, methoxypolyethylene glycol methacrylate (average repetition number: 9, hereinafter abbreviated as MPEGMA) was used in place of HEMA, and MP
48. EGMA, DMAEMA, and macromonomer
The same procedure was performed except that the polymerization was carried out at a ratio of 5: 3: 48.5 parts by weight. The composition of the obtained graft copolymer is MPEGM
A: DM: graft chain = 48.5: 2.2: 49.3
(Weight composition ratio). Main chain (MPEGMA-DM)
The content of nitrogen atoms in the basic nitrogen-containing functional group is 0.3
9% by weight, MN: 35,300, MW: 95,5
00.

[0043]

[Production Example 4] A thioglycolic acid as a chain transfer agent and A as a polymerization initiator using a known method as in Production Example 1.
Styrene was polymerized using IBN to introduce a carboxylic acid group at the terminal. Subsequently, it was reacted with glycidyl methacrylate to obtain a polystyrene macromonomer having a methacryloyl group at a terminal. MN is 4,900, MW is 13,2
00. Next, in Production Example 1, except that dimethylformamide was changed to dimethylacetamide,
Copolymerization was performed with HEMA and DM. The composition of the obtained graft copolymer was HEMA: DM: graft chain = 8
2.9: 3.1: 14.0 (weight composition ratio). The content of the nitrogen atom of the basic nitrogen-containing functional group to the main chain (HEMA-DM) was 0.32% by weight, and the MN was 67,3.
00, MW was 177,000.

[0044]

[Production Example 5] In the copolymerization of Production Example 1, HEMA and D
Polymerization was carried out in the same manner except that the charged parts by weight of MAEMA were changed. The composition of the obtained graft copolymer was HEM
A: DM: graft chain = 72.5: 13.0: 14.5
(Weight composition ratio). The nitrogen atom content of the basic nitrogen-containing functional group with respect to the main chain (HEMA-DM) was 1.36% by weight, MN was 56,200, and MW was 131,00.
It was 0.

[0045]

[Production Example 6] In Production 5, HEMA and DMAEMA were used.
The polymerization was carried out in the same manner except that the charged parts by weight were changed. The composition of the obtained graft copolymer was HEMA: DM: graft chain = 85.8: 1.0: 13.2 (weight composition ratio).
Met. The content of the nitrogen atom of the basic nitrogen-containing functional group to the main chain (HEMA-DM) is 0.10% by weight,
N was 59,000 and MW was 137,000.

[0046]

Production Example 7 (Reference) Polymerization was carried out in the same manner as in Production Example 1, except that HEMA and DMAEMA were used, except for the macromonomer. The DMAEMA content of the obtained random copolymer was 3.2% by weight, the nitrogen atom content of the basic nitrogen-containing functional group was 0.29% by weight, and the molecular weights were MN 130,000 and MW 283,000. .

[0047]

Example 1 (Coating method) Average diameter about 1.2 μm
Non-woven fabric (about 40 g / m ² basis weight, about 190 μm thickness) made of polyethylene terephthalate fiber of 25 mm in diameter
And then immersed in a 3% by weight ethanol solution in which the polymer obtained in Production Example 1 was dissolved at 50 ° C. for 5 minutes, and then set in a filter holder at a flow rate of 5 NL / min. Drying was performed by flowing nitrogen for 5 minutes, followed by vacuum drying at 40 ° C. for 8 hours. The coating amount is 0.
It was 14 g / m ² .

(Evaluation of blood performance) 14 mL of CPD solution (composition: sodium citrate 2
6.3 g / L, citric acid 3.27 g / L, glucose 2
3.2 g / L, sodium dihydrogen phosphate dihydrate 2.5
Whole blood prepared by collecting 100 mL of blood into a blood bag containing 1 g / L) is flowed at a constant flow rate of 2.7 mL / min at room temperature using a syringe pump at a flow rate of 2.7 mL / min. 6 mL) were collected.

The leukocyte removal rate (%) and the platelet recovery rate (%) were obtained by measuring the leukocyte concentration and the platelet concentration of the pre-filtration solution and the post-filtration solution, respectively, where A = leukocyte concentration before filtration, and B = leukocyte concentration after filtration. , C = platelet concentration before filtration and D = platelet concentration after filtration, respectively, leukocyte removal rate = (1
−B / A) × 100 (%), platelet recovery rate = (D / C)
It was determined by an equation represented by x100 (%). The leukocyte concentration of the pre-filtration solution was measured by injecting a 10-fold diluted solution by the Turck method into a Bürker-Turk type hemocytometer and measuring the number of leukocytes present in the eight large sections using an optical microscope. did. The leukocyte concentration of the filtered solution was measured using the Nadget method described below. That is, leuc
1 m of collected blood in 9 mL of oplate (SOBIODA)
After adding L and mixing, the mixture was allowed to stand at room temperature for 20 to 30 minutes, centrifuged, the supernatant was removed by a decanting method, and then a solution prepared to 1 mL again by leucoplate was added to a Nadget calculation plate. Was used to determine the number of leukocytes. The platelet concentration was measured with an automatic blood cell counter (Toa Medical Electronics Sysmex K4500). The leukocyte removal rate was measured by combining two fractions, and the platelet recovery rate was measured for each fraction. The hematocrit was measured by placing blood in a glass capillary tube for micro blood test, performing centrifugation, and using a hematocrit reader.

The leukocyte removal rate was 96.6% and the platelet recovery rate was 71.1%, indicating that the leukocyte removal rate and the platelet recovery rate were excellent. Hematocrit was 41.0% before and after filtration, and there was no difference.

(Dissolution test) 200 mg of the filter material produced by the above-mentioned coating method was added to 20 ml of boiling distilled water.
It was immersed in mL for 30 minutes. Next, after cooling, 10 mL of the distilled water was taken, evaporated to dryness, and the residual weight was measured.
Only the uncoated nonwoven fabric used as a comparison was treated in the same manner and the residual weight was measured. The difference is defined as the elution amount,
It was less than 0.1 mg.

[0052]

Example 2 The same procedure as in Example 1 was carried out except that the coating polymer was changed to the polymer of Production Example 2. The coating amount was 0.092 g / m ² . Leukocyte removal rate is 99.
The platelet recovery rate was 18.5% and the platelet recovery rate was 68.5%, indicating that the leukocyte removal rate and the platelet recovery rate were excellent. Hematocrit was 41.0% before and after filtration, and there was no difference. The elution amount is 0.
It was 1 mg or less.

[0053]

Example 3 Example 1 was repeated except that the coating polymer was changed to the polymer of Production Example 3. The coating amount was 0.131 g / m ² . Leukocyte removal rate is 95.
The platelet recovery rate was 72.3%, and the leukocyte removal rate and the platelet recovery rate were excellent. Hematocrit was 41.0% before and after filtration, and there was no difference. The elution amount is 0.
It was 1 mg or less.

[0054]

Example 4 The procedure of Example 1 was repeated except that the coating polymer was changed to the polymer of Production Example 4. The coating amount was 0.097 g / m ² . Leukocyte removal rate is 97.
The platelet collection rate was 24.0% and the leukocyte removal rate and platelet collection rate were excellent. Hematocrit was 41.0% before and after filtration, and there was no difference. The elution amount is 0.
It was 1 mg or less.

[0055]

Example 5 The procedure of Example 1 was repeated, except that the coating polymer was changed to that of Production Example 5. The coating amount was 0.107 g / m ² . Leukocyte removal rate is 99.
The platelet recovery rate was 22.4% and the leukocyte removal rate and the platelet recovery rate were excellent. Hematocrit was 41.0% before and after filtration, and there was no difference. The elution amount is 0.
It was 1 mg or less.

[0056]

Example 6 The procedure of Example 1 was repeated except that the coat polymer was changed to the polymer of Production Example 6. The coating amount was 0.122 g / m ² . Leukocyte removal rate is 97.
The platelet recovery rate was 59.7%, and the leukocyte removal rate and the platelet recovery rate were excellent. Hematocrit was 41.0% before and after filtration, and there was no difference. The elution amount is 0.
It was 1 mg or less.

[0057]

Comparative Example 1 The same procedure as in Example 1 was carried out except that the coating polymer was changed to the polymer of Production Example 7 (reference).
The coating amount was 0.115 g / m ² . The leukocyte removal rate was 95.9% and the platelet recovery rate was the first fraction: 4
4.5%, second fraction: 71.4%, average 5
8.0%, indicating that the platelet collection rate of the first fraction was inferior. The elution amount was 0.3 mg.

[0058]

Comparative Example 2 The same procedure was performed as in Example 1, except that only the nonwoven fabric was used. The leukocyte removal rate was 83.1% and the platelet recovery rate was 11.4%, and the leukocyte removal rate and the platelet recovery rate were inferior.

The results of Examples 1 to 6 and Comparative Examples 1 and 2 are summarized in Table 1.

[Table 1]

[0060]

According to the present invention, there is provided a filter material for permeating red blood cells, platelets and plasma from a leukocyte-containing liquid represented by whole blood and selectively removing leukocyte components efficiently.
And a polymer useful for the filter material.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 291/00 C08F 291/00 (72) Inventor: Shikazu Miura 2111-2, Ojiri, Oita-shi, Oita City, Oita Prefecture Asahi F term in Medical Co., Ltd. (Reference) 4C077 AA12 BB02 BB03 KK13 MM07 MM09 NN02 PP19 4D017 AA11 BA20 CA14 CB05 DA01 DB02 EA05 4D019 AA03 BA12 BA13 BB03 BC05 BD01 CA04 DA03 4G066 AD06B AD15B AE02B AD14B AE02B AD15B AE02B AA19 AA30 AA47 AA48 AA50 AA60 AA61 AC35 AC36 BA05 BA26 BB01 BB09 DB01 GA08 GA10

Claims (4)

[Claims] 1. A hydrophobic monomer is added to at least the surface of a filter base material, which is a copolymer mainly composed of a monomer having a nonionic hydrophilic group and a monomer having a basic nitrogen-containing functional group. 1. A leukocyte removal filter material comprising a graft copolymer obtained by polymerizing a graft chain as a main component. 2. The content of a nitrogen atom of the basic nitrogen-containing functional group is at least 0.05% by weight and less than 3.0% by weight with respect to the main chain, and the content of the graft chain is at least 30% by weight. The filter material according to claim 1, wherein the content is 2% by weight or more and less than 60% by weight based on the copolymer. 3. A graft chain mainly composed of a hydrophobic monomer is polymerized on a main chain composed mainly of a monomer having a nonionic hydrophilic group and a monomer having a basic nitrogen-containing functional group. A graft copolymer comprising: 4. The content of a nitrogen atom of the basic nitrogen-containing functional group is at least 0.05% by weight and less than 3.0% by weight with respect to the main chain, and the content of the graft chain is a graft copolymer. The graft copolymer according to claim 3, wherein the content is 2% by weight or more and less than 60% by weight.