JP2003070905A - Coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material for a leukocyte selective removing filter by passing blood platelets in particular at a high rate through the filter from a blood suspension containing both of the leukocyte and the platelets. SOLUTION: The coating material for the leukocyte selective removing filter consists of a water-soluble unit derived from a nonionic water-soluble monomer, a basic group-containing unit derived from a basic group-containing monomer and a water-insoluble copolymer unit in which the content of basic nitrogen atoms is 0.1 to 1.0 wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating material used for medical devices. More specifically, the present invention relates to a coating material for a leukocyte selective removal filter that selectively and efficiently removes only leukocytes from a blood cell suspension represented by whole blood and recovers platelets at a high passage rate.

[0002]

2. Description of the Related Art In recent years, in the field of blood transfusion, attention has been paid to the importance of removing leukocytes from blood products for blood transfusion in order to reduce the physical burden on patients to whom blood transfusion therapy is applied. One of the reasons for this is side effects such as post-transfusion headache, non-hemolytic fever reaction, and graft body host disease (GVH).
D), alloantigen sensitization, virus infection, and other more serious blood transfusion side effects are considered to be mainly derived from leukocytes mixed in blood products. There is a need to remove leukocytes to a sufficiently low level that they are not considered to be triggered.

Under such circumstances, various removal techniques for removing leukocytes have been studied. As a method for removing white blood cells, there are a centrifugal separation method utilizing a difference in specific gravity of blood components, a filter method for filtering blood using a fibrous base material or a porous body as a filter material, and the like. Among these,
A filter method having advantages such as simple operation, low cost, and excellent adsorption / removal performance for leukocytes has been widely practiced.

Various reports have been made so far on leukocyte removal filters. For example, WO87 / 05
In Japanese Patent No. 812, a nonionic hydrophilic group and a basic nitrogen-containing functional group are provided on the peripheral surface portion for the purpose of efficiently removing leukocytes from a cell suspension containing both platelets and leukocytes with less loss of platelets. A leukocyte removal filter material containing is disclosed. However, when this filter material was used for treating whole blood, the passage rate of platelets was not satisfactory, and it was found that further improvement was necessary.

Further, Japanese Patent Laid-Open No. 7-25776 discloses that
With the objective of providing a leukocyte selective removal filter material that efficiently removes leukocytes while suppressing the loss of platelets and that has almost no eluate, the surface of the filter substrate has both a hydrophobic portion and a polyethylene oxide chain. A leukocyte selective removal filter material in which a multimer is introduced by coating is disclosed. This multimer is constituted by introducing a hydrophobic part into a monomer having a polyethylene oxide chain, which is an excellent material having antithrombogenicity, for the purpose of enhancing adhesion with a filter material and suppressing elution. ing. However, this filter material also did not have a satisfactory platelet passage rate when whole blood was treated, and further improvement was necessary.

[0006]

An object of the present invention is to selectively remove only leukocytes from a blood cell suspension containing both leukocytes and platelets, which is represented by whole blood, at a high rate of passage of platelets. It is to provide a coating material used for a leukocyte selective removal filter.

[0007]

Means for Solving the Problems As a result of intensive research for solving the above problems, the present inventors have completed the present invention. That is, the present invention is a water-insoluble copolymer composed of a water-soluble unit derived from a nonionic water-soluble monomer, a basic group-containing unit derived from a basic group-containing monomer, and a water-insoluble unit, and a basic group The coating material has a nitrogen atom content of 0.1 to 1.0 wt%.

When the coating material of the present invention is used as a coating material for a leukocyte selective removal filter, surprisingly, only leukocytes are selectively selected from a hemocyte suspension containing both leukocytes and platelets typified by whole blood. It has a great effect on the removal of the platelets, especially the improvement of the passage rate of platelets.

It is not clear why the coating material of the present invention selectively removes only leukocytes and exerts a tremendous effect particularly in improving the passage rate of platelets, but the present inventors presume as follows. is doing. As described in WO87 / 05812, a material having a basic nitrogen atom comes to have a positive charge on the material surface in a physiological liquid such as a cell suspension. When leukocytes and platelets having a negative charge are brought into contact with the positively charged material surface in this way, both leukocytes and platelets adhere well, but if the basic nitrogen atom is in an appropriate amount, the platelets will adhere. Although it is difficult, leukocytes have a unique property of being easily adhered, so that leukocytes can be efficiently removed. The coating material of the present invention selectively removes only leukocytes from the conventional one and can exert a great effect particularly in improving the passage rate of platelets because the copolymer according to the present invention is filtered by a water-insoluble unit. It is presumed that the basic nitrogen atom fixed to the base material and having an appropriate amount introduced into the water-soluble part composed of the water-soluble unit is effectively present in the liquid layer capable of interacting with blood components. There is. The present inventors presume that the presence of the basic nitrogen atom in the liquid layer effectively acts on the selective removal of leukocytes.

The water-soluble unit derived from a nonionic water-soluble monomer in the present invention is a water-soluble unit which is derived from a monomer having a nonionic hydrophilic group and which is a homopolymer having a molecular weight of about 20,000 to 100,000 and is described later. When water / water-insoluble is evaluated, it is water-soluble.

The unit in the present invention is defined as the minimum unit of the repeating structure derived from each monomer in the copolymer. For example, the general formula CH ₂ = C
The unit derived from the vinyl monomer represented by XY (X: H or a substituent other than H, Y: a substituent other than X) is the minimum unit of the repeating structure — (CH ₂ —CX).
Y)-.

The basic group-containing unit derived from the basic group-containing monomer in the present invention is characterized by being derived from a monomer having a basic group and having a positive charge in a physiological fluid such as blood. Further, a homopolymer having a molecular weight of about 20,000 to 100,000 was synthesized to evaluate water solubility / water insolubility (

Those which are water-soluble when () is carried out are preferred. The water-insoluble unit in the present invention is water-insoluble when a homopolymer having a molecular weight of about 20,000 to 100,000 is synthesized using a monomer forming the unit and water-soluble / water-insoluble evaluation described below is carried out. Say something. Regarding the above-mentioned basic group-containing unit, even if the homopolymer having a molecular weight of about 20,000 to 100,000 is water-insoluble, it is excluded from the water-insoluble unit in the present invention. In the present invention, the portion excluding the water-insoluble unit is preferably water-soluble. The portion excluding the water-insoluble unit is water-soluble. A copolymer having the same composition as that of the portion excluding the water-insoluble unit and having a molecular weight of about 20,000 to 100,000 was synthesized and evaluated for water-solubility / water-insolubility described later. Sometimes it is water-soluble.

The content of basic nitrogen atom in the water-insoluble copolymer composed of the water-soluble unit, the basic group-containing unit and the water-insoluble unit in the present invention is 0.1.
˜1.0 wt%, preferably 0.2 to 0.8 wt%. If the content of basic nitrogen atoms is less than 0.1 wt%, the amount of positive charge is insufficient and leukocyte-removing ability is not improved, which is not preferable. The basic nitrogen atom content is 1.0w
If t% is exceeded, platelets are also removed by adhesion, which is also not preferable. The content of basic nitrogen atom can be measured by a known method, for example, elemental analysis, infrared absorption spectrum, nuclear magnetic resonance spectrum (hereinafter abbreviated as NMR).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The nonionic water-soluble monomer forming the water-soluble unit of the present invention is a monomer having a nonionic hydrophilic group, and examples of the nonionic hydrophilic group include a hydroxyl group,
Examples thereof include an amide group and a polyoxyethylene group having about 1 to 4 repeating units.

As the monomer having a nonionic hydrophilic group, vinyl alcohol (polyvinyl alcohol which is a polymer of this monomer is obtained by polymerizing vinyl acetate and then hydrolyzing the obtained polyvinyl acetate). ) Etc. having a hydroxyl group (meth) acrylic acid derivative;
(Meth) acrylamides having an amide group, such as (meth) acrylamides, N-monosubstituted (meth) acrylamides, N, N'-disubstituted (meth) acrylamides; polyoxy with about 1 to 4 repeating units in the side chain Examples include alkoxypolyethylene glycol (meth) acrylates having an ethylene group. Among these monomers, (meth) acrylamides having an amide group, such as (meth) acrylamide, N-monosubstituted (meth) acrylamide, N, N′-disubstituted (meth) acrylamide,
Water solubility is preferable, and N-monosubstituted (meth) acrylamides and N, N′-disubstituted (meth) acrylamides are more preferable. Among them, because of easy availability, easy handling, good performance when filtering blood, etc.
Particularly preferred are N, N′-disubstituted (meth) acrylamides such as N, N′-dimethylacrylamide, N, N′-diethylacrylamide.

The nonionic water-soluble monomer according to the present invention is a water-soluble monomer when a homopolymer having a molecular weight of about 20,000 to 100,000 is synthesized using the monomer and the water-soluble / water-insoluble evaluation described below is carried out. is there. In the present invention, these nonionic water-soluble monomers may be used alone or in combination of two or more as required.

The molecular weight of the monomer forming the water-soluble unit in the present invention is preferably 400 or less, and further 3
00 or less, most preferably 180 or less. The molecular weight of the monomer is preferably 40 or more. When the molecular weight of the monomer forming the water-soluble unit is 400 or less, the passage of platelets is better, which is particularly suitable for carrying out the present invention.

The basic group-containing monomer forming the basic group-containing unit of the present invention is a monomer having a basic group, and examples of the basic group include a basic nitrogen-containing functional group, As such a basic nitrogen-containing functional group,
Examples thereof include primary amino groups, secondary amino groups, tertiary amino groups, quaternary ammonium groups, and nitrogen-containing aromatic groups such as pyridyl groups and imidazolyl groups.

Examples of the monomer having a basic nitrogen-containing functional group include allylamine; N, N'-dimethylaminoethyl (meth) acrylate, N, N'-diethylaminoethyl (meth) acrylate, N, N'-dimethylaminopropyl. (Meth) acrylate, 3-dimethylamino-2
-(Meth) acrylic acid derivatives such as hydroxypropyl (meth) acrylate; styrene derivatives such as p (para) -dimethylaminostyrene, p (para) -dimethylaminoethylstyrene; 2-vinylpyridine, 4-vinylpyridine, 4 A vinyl derivative of a nitrogen-containing aromatic compound such as vinylimidazole; and a derivative of the above vinyl compound converted to a quaternary ammonium salt by reaction with an alkyl halide. Among these, N, N'-
Dialkylaminoalkyl (meth) acrylates are preferable, and specifically, N, N′-dimethylaminoethyl methacrylate, N, N′-diethylaminoethyl methacrylate, etc. are more preferable in view of easy availability and easy handling. .

The molecular weight of the monomer forming the basic group-containing unit in the present invention is preferably 500 or less, more preferably 300 or less, and most preferably 200 or less. The molecular weight of the monomer is preferably 40 or more. If the monomer forming the basic group-containing unit has a molecular weight of 500 or less, the passage of platelets is better,
It is particularly suitable for carrying out the present invention.

As the monomer forming the water-insoluble unit of the present invention, a molecular weight of about 20,000 to 10 is obtained using the monomer.
Any homopolymer can be used as long as it has been confirmed to be water-insoluble when water-soluble / water-insoluble evaluation described below is carried out. Examples of such a monomer include methyl (meth) acrylate, Alkyl (meth) acrylates such as ethyl (meth) acrylate and n-butyl (meth) acrylate, hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate (Meth) acrylic acid derivatives may be mentioned. Among these monomers, the solubility in water at a temperature of 20 ° C is 1
It is preferable that the amount exceeds 2 (g / 100 g of water) in terms of passage of platelets. For the measurement of the solubility, when the monomer is a solid, a known measurement method such as a dew point method or a thermal analysis method can be used, and when the monomer is a liquid, the same measurement method as that for the solid can be used. Further, it can be measured by a known measuring method such as a capacitance method, a light scattering method, a vapor pressure method or the like. Among such monomers, hydroxyalkyl (meth) acrylates having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate are more preferable in terms of passage of platelets. Among these, 2-hydroxypropyl (meth) acrylate is particularly preferable.

The water-soluble unit content of the copolymer of the present invention is 20 wt% or more and 85 wt% or less, the water-insoluble unit content is 10 wt% or more and 70 wt% or less, and the basic group-containing unit content is 1 wt% or more,
It is preferably 10 wt% or less.

The weight average molecular weight of the copolymer used in the coating material of the present invention is preferably 20,000 or more and 1,000,000 or less. If the weight average molecular weight is less than 20,000, elution of the coating material becomes unacceptable, which is not preferable as a medical material. When the weight average molecular weight exceeds 1,000,000, the coating material becomes difficult to dissolve in the solvent for preparing the coating solution, and it tends to be difficult to coat the filter substrate.

The polymerization form of the copolymer used in the coating material of the present invention is not particularly limited, and examples thereof include a random copolymer, a graft copolymer and a block copolymer. The method for producing the copolymer is not particularly limited, and radical polymerization, ring-opening polymerization, polycondensation, etc.
A known polymerization method can be used. Among these polymerization methods, radical polymerization is mentioned as a polymerization method which is less susceptible to impurities and solvents. Radical polymerization is less susceptible to these impurities, so the operation is simple and
Further, since it can be applied to various monomers and various polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization can be used, it is widely used both at the laboratory level and industrially. Among them, solution polymerization, which has good copolymerizability of vinyl monomers, such as (meth) acrylic acid derivative, is preferably used.

The copolymer used in the coating material of the present invention is insoluble in water. The water solubility / water insolubility in the present invention was evaluated as follows. A filter manufactured by coating a filter substrate with an evaluation sample by the method described below,
When immersed in pure water at 60 ° C. for 20 minutes, the coated sample is water-soluble if the elution amount is 30 wt% or more and water-insoluble if it is less than 5 wt%.

The method for coating the evaluation sample on the filter substrate is, for example, as follows. The evaluation sample is 90 to 200 mg (hereinafter, the coating amount is mg / m 2 with respect to the total surface area per 1 g of the filter substrate).
The concentration of the coating solution is adjusted so as to be coated within the range (expressed in units of ² ). The coating solution had an average fiber diameter of 1 to 3 μm and a basis weight of 20 to 100 g / m ² ,
A non-woven fabric made of polyethylene terephthalate fiber having a thickness of 0.15 to 0.30 mm is soaked for 2 to 3 minutes, and then the excess coating solution is removed, and the solution is left at room temperature for one day or 40 days.
Dry in a vacuum dryer at ℃ for about 3 hours until a constant weight is obtained.

In the present invention, the weight of the evaluation sample coated on the filter substrate (hereinafter, simply referred to as the coating amount) is specifically measured as follows. The diameter of the non-woven fabric coated by the above-mentioned method is optionally 25
It is cut out into a circular shape of mm and the weight of this filter is weighed with an electronic balance. Then, the weighed filter is immersed in about 20 to 50 mL of a good solvent for the evaluation sample, and shaken in a constant temperature bath at 60 ° C. for 1 to 2 hours. After the immersion treatment, the filter taken out is dried in a vacuum dryer at 60 ° C. for about 3 hours until the weight becomes constant. In addition, it is confirmed by NMR measurement that no evaluation sample remains on the substrate by this treatment.
The dried filter is weighed with the electronic balance described above, and (1)
The coat amount of the evaluation sample is calculated according to the formula. Coat amount (mg / m ² ) = (weight of filter before immersion treatment−weight of dried filter after immersion treatment) / (weight of dried filter after immersion treatment) × (total surface area per 1 g of the filter substrate) ... (1)

In the present invention, the elution amount of the evaluation sample is specifically measured as follows. A non-woven fabric coated by the method described above is arbitrarily cut into a circular shape having a diameter of 25 mm, and the weight of this filter is weighed with an electronic balance. Weigh the filter with pure water at 60 ° C about 50-100
Immerse in mL for 20 minutes. The test time of 20 minutes assumes the time of contact with blood when actually filtering blood with a leukocyte removal filter. After the immersion treatment, the filter taken out was placed in a vacuum dryer at 60 ° C for 3 hours.
Let it dry for about an hour until it reaches a constant weight. In addition, it is confirmed by NMR measurement that no evaluation sample remains on the substrate by this treatment. The filter after drying is weighed by the electronic balance described above, and the weight change rate calculated by the equation (2) is the elution amount (wt%) of the evaluation sample. Elution amount of the evaluation sample (wt%) = (filter weight before immersion in pure water-weight of filter after immersion in pure water) / (weight of filter before immersion in pure water-weight of filter base material before coating) ... (2) If the elution amount calculated according to the equation (2) is 30 wt% or more, it is water-soluble, and if it is less than 5 wt%, it is water-insoluble.

In the case of producing a leukocyte selective removal filter using the coating material according to the present invention, the filter base material is preferably a fibrous material such as a non-woven fabric or a porous body having communicating pores. It is known that the physical structure of the filter substrate greatly contributes to the capture of leukocytes, and the selection of the filter substrate is also important in order to further improve the leukocyte capture performance.

That is, when a fibrous material such as a non-woven fabric is used as the filter substrate, the average fiber diameter is 0.3.
μm or more and 3.0 μm or less, more preferably 1.0 μm
As described above, it is 2.0 μm or less. Average fiber diameter is 0.3 μm
If it is less than the above range, it may cause clogging of blood cells and increase in pressure loss, which is not preferable. On the other hand, if the average fiber diameter exceeds 3.0 μm, the leukocyte capturing performance may be deteriorated, which is not preferable.

When a porous material having communicating pores is used as a filter substrate, the average pore diameter is 1 μm or more, 30
μm or less, preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 10 μm or less. If the average pore diameter is less than 1 μm, pressure loss increases when filtering whole blood and the like, which is likely to be impractical such as clogging of blood cells and filtration taking a long time. The average pore size is 30
When it exceeds μm, the frequency of contact between the porous body and the white blood cells decreases, and the white blood cell trapping performance may decrease.

In the case of producing a leukocyte selective removal filter using the coating material according to the present invention, the method for coating the coating material of the present invention on the filter substrate is to dissolve the coating material in a suitable good solvent capable of dissolving the coating material. After the filter base material is dipped in the coating material solution, excess solution is removed from the filter base material by an operation such as squeezing, and then dried at room temperature or hot air.
Further, for the purpose of preventing the coating material from falling off from the filter base material, heat can be applied to the coated filter to enhance the adhesiveness between the filter base material and the coating material.

When a leukocyte selective removal filter is produced using the coating material according to the present invention, the good solvent capable of dissolving the coating material is not particularly limited as long as it can dissolve the coating material, but it is available. Alcohols are preferred because of their ease, ease of handling, and low boiling point. If a solvent having a low boiling point is used as the solvent for the coating material, drying after coating becomes easy.

When a leukocyte selective removal filter is produced using the coating material of the present invention, the coating amount of the coating material is preferably 90 mg / m ² or more and 300 mg / m ² or less. When the coating amount is less than 90 mg / m ² ,
Platelet passage rate is reduced, while the coat amount is 300
When it exceeds mg / m ² , the leukocyte capturing performance is deteriorated.
When a leukocyte selective removal filter is manufactured using the coating material according to the present invention, the packing density when the filter coated with the coating material is filled in a container is 0.1 g.
/ Cm ³ or more and 0.3 g / cm ³ or less is preferable. If the packing density is less than 0.1 g / cm ³ , the leukocyte trapping performance may decrease, while if the packing density exceeds 0.3 g / cm ³ , blood cells may become clogged and pressure loss may increase. It is not preferable because it may cause

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 N, N-dimethylacrylamide (hereinafter abbreviated as DMAA; molecular weight: 99) as a nonionic water-soluble monomer forming a water-soluble unit, and a basic group-containing monomer forming a basic group-containing unit N, N '
-These terpolymers are prepared by using dimethylaminoethyl methacrylate (hereinafter abbreviated as DM; molecular weight: 157) and 2-hydroxypropyl methacrylate (hereinafter abbreviated as HPMA) as a monomer forming a water-insoluble unit. It was synthesized in this way.

49.6 g of DMAA was placed in a 1 L separable flask equipped with a stirrer, a reflux condenser connected with a nitrogen introducing tube at the top, a temperature sensor and a tube for dropping an initiator.
(0.50 mol), DM 4.72 g (30.0 mmo
1) and 67.7 g (0.47 mol) of HPMA, 240 mL of ethanol was added, and the system temperature was adjusted to 6 while stirring the flask inside at 100 rpm under a nitrogen stream.
The temperature was raised to 0 ° C. 0.82 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (hereinafter abbreviated as V-65) as an initiator was added to 45 mL of ethanol to prepare an initiator solution, which was stored in a syringe. The syringe pump was adjusted so that the initiator solution was dropped into the flask over 4 hours, and radical polymerization was carried out by continuously dropping it while blowing nitrogen into the flask. After polymerizing for another 2 hours, 170 mL of ethanol was added to the polymerization solution and poured into excess n-hexane to precipitate and collect the polymer.
The obtained polymer was redissolved in ethanol, precipitated with n-hexane, and then washed with water for purification.

The water solubility / insolubility of the polymer was measured according to the above-mentioned method for measuring the amount of dissolution, and the amount of dissolution was 1 w.
It was less than t% and was therefore insoluble in water. Composition analysis
^When calculated from the integrated value of ¹ H-NMR measurement, the composition ratio (wt%) in the polymer was DMAA / DM / HPMA.
= 37.0 / 4.4 / 58.6, and thus the content of basic nitrogen atoms was 0.4 wt%. The weight average molecular weight is determined by gel permeation chromatography (hereinafter abbreviated as GPC) to be a standard polymethyl methacrylate (hereinafter abbreviated as PMMA) converted molecular weight of 5.
It was 6 × 10 ⁵ . This polymer is named DM3.

A homopolymer of DMAA was synthesized by the same polymerization method as above. The water solubility / insolubility of the homopolymer was measured by

The amount of elution was 80
It was more than wt% and was therefore water-soluble. Also, HP
A homopolymer of MA was synthesized by the same polymerization method as above. When the water solubility / insolubility of the homopolymer was measured according to the above-described elution amount measurement method, the elution amount was 2 wt.
% Or less and thus was insoluble in water.

Next, the obtained DM3 was coated on a filter substrate by the method shown below. 10 g of DM3 was dissolved in 190 g of ethanol to prepare a 5 wt% coating solution. A non-woven fabric (40 g) made of polyethylene terephthalate fibers having an average fiber diameter of 1.2 μm was added to the coating solution.
/ M ² areal weight, thickness 0.20 mm, width 150 mm) was continuously dipped, and then passed through by being sandwiched by nip rolls to remove an excess coating solution. The coated nonwoven fabric was dried overnight at room temperature in a drying chamber equipped with an exhaust duct, and then collected.

Coated nonwoven produced in this way
Cut a piece of cloth into a circular shape with a diameter of 20 mm, part 3
Fill 2 pieces into a filter holder (filling density 0.2 g /
cm ³)did. For this column, use the
Fresh whole blood was collected at a constant flow rate of 0.
Flowed at 74 mL / min and collected 13.3 mL. Hi
Fresh whole blood is anticoagulant against 100 mL of collected blood
Filtered CPD solution (trisodium citrate
Hydrate 26.3 g, citric acid monohydrate 3.27 g, glu
23.2 g of course, and sodium dihydrogen phosphate dihydrate
2.51 g of the Japanese product was dissolved in 1 L of distilled water for injection, and the pore size was
Add 14 mL of solution filtered with 0.2 μm filter)
By mixing and storing at 20 ° C for 3 hours.
It was

A certain amount of blood was collected from the blood before filtration and the collected liquid after filtering the blood, and the leukocyte concentration was measured by the LeucoCOUN reagent system for residual leukocyte measurement.
T ^™ kit, flow cytometer FACSCalib
ur and analysis software CELL Quest (above,
It was measured using a BD Bioscience (USA). In addition, the platelet concentration can be calculated using the automatic blood cell counter MAX A /
It measured using L-Retic (BECKMAN COULTER, USA).

Using the white blood cell concentration and the platelet concentration before and after filtration obtained as described above, the leukocyte removal ability (hereinafter abbreviated as white removal ability) is calculated by the following equations (3) and (4).
And the platelet loss rate were calculated respectively. Leukocyte removal capacity (-Log) = -Log (white blood cell concentration in collected solution after filtration / leukocyte concentration in blood before filtration) (3) Platelet loss rate (%) = {1- (collected solution after filtration Platelet concentration in blood / platelet concentration in blood before filtration) × 100 ... (4) Further, the selectivity index shown in the following formula (5) is introduced. Selectivity index = {white blood cell removing ability (−Log) / platelet loss rate (%)} × 100 (5) The selectivity index represented by the formula (5) is used when the platelet loss rate becomes low. Since it shows a large value, it can be considered that leukocytes are selectively removed. Hemofiltration experiments using this filter were carried out three times, and the average values of the leukocyte-removing ability (-Log), platelet loss rate (%), and selectivity index are shown in Table 1.

[0043]

Comparative Example 1 DM as a monomer forming a basic group-containing unit, and 2-hydroxyethyl methacrylate (hereinafter referred to as HEM) as a monomer forming a water-insoluble unit.
Abbreviated as A. A copolymer (hereinafter abbreviated as HM3) by the same polymerization method as in Example 1 using a molecular weight of 130).
1%: HEMA / DM = 97/3) was synthesized. The water solubility / insolubility of this copolymer was measured according to the above-described elution amount measuring method. As a result, the elution amount was 3 wt% or less, and thus it was water insoluble. Composition analysis ¹ H-NMR
When calculated from the integral value of the measurement, the composition ratio (wt%) in the polymer was HEMA / DM = 96.4 / 3.6, and thus the content of basic nitrogen atoms was 0.3 wt%. Further, the weight average molecular weight as a PMMA-converted molecular weight was 8.7 × 10 ⁵ by GPC measurement. This polymer is named HM3. Further, a HEMA homopolymer was polymerized by the same polymerization method as in Example 1. When the water solubility / insolubility of the homopolymer was measured according to the above-described method for measuring the amount of elution, the amount of elution was 2 wt% or less, and thus it was water-insoluble. Hemofiltration experiments were performed 3 times using the filter produced in the same manner as in Example 1 except that the coating material was HM3, and the leukocyte removal ability (-Lo
g), platelet loss rate (%) and selectivity index,
The average value of each is shown in Table 1.

[0044]

Comparative Example 2 A copolymer was synthesized by the same polymerization method as in Example 1 using DMAA as a monomer forming a water-soluble unit and HPMA as a monomer forming a water-insoluble unit. The weight of monomers used was 49.6 g (0.50 mol) DMAA and HPM, respectively.
It was A72.1g (0.50mol). After the polymerization, the water-solubility / insolubility of the polymer purified by the same method as in Example 1 was measured by the above-described elution amount measurement method. As a result, the elution amount was 1 wt% or less, and thus it was water-insoluble. When the composition analysis was calculated from the integrated value of ¹ H-NMR measurement, the composition ratio (wt%) in the polymer was found to be DMAA.
/HPMA=39.7/60.3, and thus the content of basic nitrogen atoms was 0 wt%. Further, the weight average molecular weight as a PMMA-equivalent molecular weight was 6. by GPC measurement.
It was 3 × 10 ⁵ . This polymer is designated as DM0. Three hemofiltration experiments were carried out using the filter produced in the same manner as in Example 1 except that the coating material was DM0.
The average values of leukocyte-removing ability (-Log), platelet loss rate (%) and selectivity index are shown in Table 1.

[0045]

Comparative Example 3 By the same polymerization method as in Example 1, DMAA was used as a monomer forming a water-soluble unit, DM was used as a monomer forming a basic group-containing unit, and HPMA was used as a monomer forming a water-insoluble unit. A copolymer was synthesized. The weight of the monomers used was 49.6 g (0.50 mol) of DMAA and DM15.
7 g (0.10 mol) and HPMA 57.6 g
(0.40 mol). After the polymerization, the water-solubility / insolubility of the polymer purified by the same method as in Example 1 was measured by the above-described elution amount measurement method. As a result, the elution amount was 1 wt% or less, and thus it was water-insoluble. When the composition analysis was calculated from the integrated value of ¹ H-NMR measurement, the composition ratio (wt%) in the polymer was found to be DMAA / DM / HP.
MA = 33.8 / 54.1 / 12.1, therefore the content of basic nitrogen atoms was 1.1 wt%. Also, G
According to PC measurement, the weight average molecular weight as a PMMA-equivalent molecular weight was 4.5 × 10 ⁵ . This polymer is DM1
Name it 0. Hemofiltration experiments were conducted 3 times using the filter produced in the same manner as in Example 1 except that the coating material was DM10, and leukocyte removal ability (-Log), platelet loss rate (%), and selectivity index were respectively determined. The average value of is shown in Table 1.

[0046]

[Table 1] From the results of Examples and Comparative Examples in Table 1, the coating material of Comparative Example 1 having no unit derived from a water-soluble monomer has a large platelet loss rate in the recovered liquid after hemofiltration, and does not selectively remove leukocytes. I haven't been. In addition, the coating material of Comparative Example 2, which does not have a unit derived from the basic group-containing monomer, that is, has no positive charge, is inferior in leukocyte removal performance. However, when the content of the unit derived from the basic group-containing monomer is large like the coating material of Comparative Example 3, that is, when the amount of positive charges is too large, the leukocyte removal performance is improved and the platelet loss rate is also increased. It has become large, and white blood cells have not been selectively removed. The water-insoluble copolymer of the present invention, a water-soluble unit derived from a water-soluble monomer, a basic group-containing unit derived from a basic group-containing monomer, and a water-insoluble unit,
When the coating material having a basic nitrogen atom content of 0.1 to 1.0 wt% is used as the coating material for the leukocyte selective removal filter, the leukocyte removal performance is high,
It can be seen that the platelet loss is suppressed to a low level and the selectivity index that can be regarded as indicating the selective removal of white blood cells is large.

[0047]

When a coating material of the present invention is coated on at least the surface of a base material in the production of a leukocyte selective removal filter, only leukocytes are extracted from a blood cell suspension containing both leukocytes and platelets typified by whole blood. It is possible to provide a leukocyte selective removal filter capable of selectively and efficiently removing, and particularly recovering platelets at a high passage rate, and the coating material of the present invention is very useful in the production of blood products. Further, since the coating material of the present invention allows platelets, which are easily adhered among blood cell components, to pass through without adhering, it is also useful as a material having high compatibility with blood, for example, in applications such as extracorporeal circulation and catheters. .

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takao Nishimura             1-3-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa               Asahi Kasei Corporation F-term (reference) 4C077 AA12 BB03 CC01 EE01 LL02                       LL11 MM02 NN02 PP19                 4D019 AA03 BA11 BA13 BB03 BB10                       BC05 CB06

Claims (3)

[Claims] 1. A water-insoluble copolymer comprising a water-soluble unit derived from a nonionic water-soluble monomer, a basic group-containing unit derived from a basic group-containing monomer, and a water-insoluble unit, and having a basic nitrogen atom. Atom content is 0.1
A coating material characterized by being 1.0 wt%. 2. The nonionic water-soluble monomer has a molecular weight of 4
The coating material according to claim 1, wherein the basic group-containing monomer has a molecular weight of 00 or less and 500 or less. 3. A leukocyte selective removal filter coated with the coating material according to claim 1.