JP3176754B2 - Blood component separation membrane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane for separating blood components used in artificial kidneys, plasma separation, plasma fractionation and the like.

[0002]

2. Description of the Related Art In order to separate unnecessary components from blood or to separate blood into desired components, a hollow fiber made of regenerated cellulose, polymethyl methacrylate, cellulose acetate, polyacrylonitrile, polyolefin, polysulfone, or the like is used. Techniques using flat membranes have become widespread.

[0003]

[Problems to be solved by the invention] By the way, such as glass,
When the surface of a material having a large amount of negative charge on the surface comes into contact with blood, the activation of blood coagulation factor XII occurs, and kallikrein is generated from prekallikrein by activated blood coagulation factor XII, and further high molecular weight kininogen is generated by kallikrein. Is limited to kinin (blood kinin:
Bradykinin) is known to be produced. It is also known that this kinin is one of the causative substances of anaphylactic reactions such as lowering of blood pressure, hot flush, conjunctival hyperemia, smooth muscle contraction, and pain, that is, one of anaphylatoxins. However, on the other hand, quantitative information on the production of kinin and the negative charge on the surface of the material has not been sufficiently obtained, and the optimal negative charge on the surface of filter materials that can be used clinically has been studied. Not. Further, there is no clinically known quantitative relationship between the anaphylactic reaction symptoms and the amount of kinin. According to the study of the present inventors, known polyacrylonitrile and cellulose, in the blood component separation membrane mainly containing polymethyl methacrylate and the like,
The negative charge on the surface of the material, which is thought to be derived from groups introduced to enhance the hydrophilicity of blood, is high, causing kinin to rise, and sometimes causing anaphylatoxy often due to kinin rise. found. An object of the present invention is to provide a blood component separation membrane that has excellent blood wettability and does not cause an increase in kinin during blood processing.

[0004]

SUMMARY OF THE INVENTION That is, the present invention relates to a method for shading a surface.
A blood component separation membrane comprising a polymer having a neutral charge, an average pore size of 10 to 1.0 μm, and a water permeability of 3.4 to 8,000 ml / hr / m ² / mmHg, comprising a triiodide complex
Specified by surface negative charge measurement method using ions
Negative charge of 0.01 μeq / g or more and 30 μeq / g
The following is a membrane for separating blood components .

[0005]

In the present invention, the surface of the membrane refers to both surfaces of the membrane and the surface portion of the pore in the membrane wall to which the blood to be treated can substantially contact. In addition, in the case of a film whose surface has been subjected to a treatment such as coating, it refers to an exposed portion that can be substantially contacted with the blood to be treated after the treatment. In the present invention, the negative charge on the surface of the membrane is
It is a charge existing on the surface layer of the film and refers to a charge measured by a method for measuring a charge amount described later. It is the charge that exists between the surface and a depth of 10 ° from the surface, if it is quantitatively indicated.

Definition of Negative Charge Negative charge in the present invention includes carboxyl group, phosphate group, phosphite group, sulfonic group, sulfate group, sulfite group, hyposulfite group, sulfide group, phenol group, hydroxysilyl group. And those derived from acidic groups that are negative at neutral pH such as groups. The above acidic group is only one example, and the present invention is not limited thereto. Among them, a carboxyl group, a sulfonic acid group and a sulfate group have a high charge strength and are particularly important in practical use. This negative charge is derived from the negative group originally possessed by the material of the membrane itself, for example, heat, oxides, acids, chemicals such as alkali solutions, and those generated by hydrolysis due to radiation during the production of the membrane, and negative charges. Includes charges derived from groups introduced into a charged compound by methods such as covalent bonding, grafting, physical adsorption, ionic bonding, embedding, and the like. Furthermore, the negative charge newly generated in the monomer or membrane when the monomer derived from the group introduced as a result of graft polymerization of a monomer having a negative group by radiation grafting or plasma craft, or when a monomer having no negative group is graft-polymerized, Included, and consequently all negative charges present on the membrane surface when the membrane is used. The amount of charge on the surface of the membrane according to the present invention is the same as that at the time of blood treatment, that is, the amount of charge remaining as a result of canceling out all positive and negative charges coexisting on the membrane surface in blood around pH 5 to 9. It is.

Surface negative charge measurement method The negative charge on the surface can be measured by neutralization titration with an acid alkali, reverse titration, redox titration, dye adsorption, measurement by zeta potential, nuclear magnetic resonance spectroscopy, infrared Absorption spectrometry, X-ray photoelectron spectroscopy (ESCA), electron probe microanalysis (EPMA), secondary ion mass spectrometry (SIMS), Auger electron spectroscopy (AES),
Known methods such as X-ray fluorescence analysis can be used. For the measurement,
Either method may be used, but neutralization titration, reverse titration, redox titration, measurement by zeta potential, dye adsorption, etc., have low detection sensitivity and are not always satisfactory in terms of accuracy. Nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, X-ray photoelectric spectroscopy (ESCA), electron probe microanalysis (EPMA), secondary ion mass spectrometry (SIMS), Auger electron spectroscopy (AE
S), X-ray fluorescence analysis and the like are good means, but they are expensive, require expensive equipment, and require a measurement technique, and are not simple methods. Furthermore, it is not necessarily the most suitable method in the sense of measuring the negative charge that works effectively when the porous membrane surface comes into contact with blood, such as paper, cotton, woven fabric, nonwoven fabric, sponge, and porous beads. Therefore, prior to the present invention, iodine and iodide ions are reacted in an organic solvent such as alcohol using negative charge on the surface of the film to be measured as a catalyst to generate triiodide complex ions, and the triiodide is formed. A method for measuring the amount of negative charge on the surface of the porous membrane by measuring the absorbance of the amount of the complex ions was completed. Hereinafter, this measurement method is referred to.

Hereinafter, the present measuring method will be described in more detail. The membrane for measuring the negative charge on the surface is reacted with iodine and an iodide salt in a solvent such as water or alcohol, and the iodide complex ion produced is measured for absorbance at a wavelength of 359 nm. When eluate is present from the membrane, it is desirable to perform a removal operation in advance to remove the influence on the measurement in order to more accurately obtain the negative charge. Separately, a membrane on which a known amount of negative charge such as a carboxyl group is fixed on the surface is prepared, and the same operation is performed to prepare a calibration curve. From this calibration curve, the amount of negative charge on the membrane surface can be determined. In addition, the absorbance at a wavelength of 290 nm,
And 359 nm. As the substance giving the iodide complex ion referred to in the present measurement method, all iodide salts can be used. Preferred examples include potassium iodide, sodium iodide, magnesium iodide, zinc iodide, and iodide. It is an iodide salt that easily dissolves in alcoholic solvents such as manganese iodide, iron (1) iodide, and lithium iodide. In particular, iodide salts such as potassium iodide and sodium iodide are more preferably used than the solubility in alcoholic solvents, the availability, and the ease of storage. Further, as iodine, a trace amount of iodine contained in iodide may be used, or good measurement can be carried out by further adding iodine. When a small amount of negative charge is measured, only a small amount of iodine contained in the iodide salt can be measured favorably. The iodide salt used is not limited to the above salts. The alcoholic solvent referred to in this measurement refers to a mixture of alcohol such as methanol, ethanol, n-propanol, isopropyl alcohol and t-butanol, mixed with water and an organic solvent having no absorption at 359 nm, and further dissolves the film itself. And a solvent that dissolves the iodide salt. The measurement can be performed with any of the above-mentioned alcoholic solvents. As the alcoholic solvent, a solvent having no absorption in the visible and ultraviolet regions between 200 nm and 500 nm can be used. If this wavelength is further limited, it is useful to have no absorption at wavelengths between 250 nm and 450 nm, more particularly between 300 nm and 400 nm. Preferably,
Alcohols having a mixing ratio of water of 50% by weight or less,
More preferably, 100% alcohol is good. In particular, when measuring the surface charge of a nonwoven fabric such as polyester, 100% methanol is cited as the best alcoholic solvent because of the good affinity between the solvent and the membrane and the solubility of the iodide salt. In the present measurement method, the concentration of iodine and iodide ions in the alcoholic solvent is not particularly limited, but needs to be a concentration that dissolves in the alcoholic solvent at the reaction temperature. The absorption around 359 nm indicates absorption in water or an alcoholic solvent of a triiodide complex ion generated from iodine and iodide ion by a surface negative charge acting as a catalyst in an alcoholic solvent. Therefore, the absorption around 359 nm by the triiodide complex ion increases proportionally as the surface negative charge increases. The amount of increase in absorbance over a certain period of time corresponds to the amount of increase in the triiodide complex ion, and this is determined as the surface negative charge of the substance to be measured. As a result, the measurement can be performed if the surface negative charge amount is several μeq / g, and the measurement can be performed even for a minute amount of the negative charge. Furthermore, the amount of triiodide complex ion generated is replaced with ultraviolet absorbance for measurement, so that clear numericalization can be performed, and the difference in negative charge is amplified by replacing the surface negative charge with increased triiodide complex ion. And appear as a large difference in absorbance, thereby enabling highly accurate measurement. In the case where an extract from the membrane is present in the present measurement method, the extract itself may absorb at the measurement wavelength or have a negative charge, which may affect the present measurement method. Therefore, it is preferable to sufficiently remove the solvent in advance or to use a non-solvent for the extract. However, according to the study of the present inventors, in the weight ratio between the alcoholic solution and the measured film under the measurement conditions,
At the temperature used in the measurement, if the absorbance in the ultraviolet absorption region of the eluate in the reaction time for the measurement is 0.1 or less, the influence on the measurement result is small.
The measurement can be suitably performed when the value is 01 or less, most preferably 0.001 or less. In the present measurement method, measurement can be performed on any type of membrane, such as a flat membrane and a hollow fiber, but it is particularly suitable for a membrane having a low specific surface area of 5 m ² / g or less. Generally, the amount of charge on the surface of a substance is usually expressed in terms of the charge density per unit surface area.However, in our study, even if the charge density is low, the larger the surface area of the membrane, the more kinin is generated. Therefore, it is not appropriate in the present invention to simply evaluate the charge density per surface area.

Materials for the Membrane-Type Filtration Material The materials for the membrane in the present invention include polyacrylonitrile, cellulose, cellulose acetate, polysulfone, polyvinyl alcohol (PVA), vinyl alcohol-ethylene copolymer, polystyrene, polyamide polymer, Polyester polymer, cuprammonium regenerated cellulose, polyester such as polyethylene terephthalate, polybutylene terephthalate and polyoxyethylene terephthalate, polyamide such as nylon 6, nylon 6,6, aromatic polyamide, polystyrene and derivatives thereof, polyethylene, polypropylene , Polybutene and other polyolefins, and polymer compounds obtained by polymerizing methacrylic acid ester derivatives such as methyl methacrylate and ethyl methacrylate; methyl acrylate and ethyl acrylate. A polymer compound obtained by polymerizing an acrylate derivative such as a acrylate, a synthetic polymer compound such as polytrifluorochloroethylene, polyvinyl formal, polyurethane, polyvinyl acetal, or polycarbonate. Polymers, copolymers, block polymers and blends of the above-mentioned polymer compounds, including blended and alloyed ones, and regenerated fibers such as cellulose and / or derivatives thereof and synthetic polymer compounds shown above And those containing alloys. In particular, from its film-forming properties, from the sharpness of the pore distribution, a polymer compound obtained by homopolymerizing or copolymerizing a polymer compound containing polyacrylonitrile as a main component, methyl methacrylate, and a methacrylate derivative such as ethyl methacrylate, A polymer compound mainly composed of regenerated fibers such as cellulose and / or a derivative thereof is preferably used.

Surface Modification Method Further, various low molecular weight and high molecular weight compounds are covalently bonded, ion bonded, grafted by radiation or plasma, physically adsorbed, embedded or insolubilized on the material surface, etc. It can also be fixed using any known method. For example, surface modification is performed by a known method such as graft polymerization of a polymer compound or a monomer thereof using radiation, plasma, or the like, or covalent bonding (Japanese Unexamined Patent Publication No.
249063, JP-A-3-502094) is also suitably used in the present invention. Examples of monomers and polymer compounds used for surface modification include methacrylic acid, acrylic acid, 2-methacryloyloxyethyl succinic acid, mono (2-acryloyloxyethyl) acid phosphate, 2-sulfoethyl methacrylate, -Acrylic acid or methacrylic acid derivatives such as methacryloyloxyethyl phthalic acid, p-styrenesulfonic acid, p-
Various styrene derivatives such as vinyl benzoic acid, phenol derivatives such as vinyl phenol, acrylic compounds such as sodium allyl sulfonate, and various vinyl monomers such as acetylene derivatives, trioxane derivatives, etc. A molecular compound, or a monomer having a polymerizable functional group, preferably a vinyl group or an acetylene group, such as 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 1,2-
Neutral monomers such as acrylate and methacrylate derivatives such as dihydroxyethyl methacrylate, methoxytriethylene glycol methacrylate, methoxy nonaethylene glycol methacrylate, methyl methacrylate, ethyl methacrylate, methyl acrylate and ethyl acrylate, and styrene and its derivatives , N, N-diethylaminoethyl methacrylate,
N, N-dimethylaminoethyl methacrylate, N, N
A copolymer with a cationic monomer such as -diethylaminoethyl acrylate or N, N-dimethylaminoethyl acrylate, or a synthetic compound such as a polymer compound or an oligomer obtained as a block polymer. A polymer compound obtained by polymerizing is preferred because of high polymerizability and easy availability. The blood component separation membrane of the present invention is mainly composed of components (impurities) of whole blood or plasma by fractionation (filtration) or dialysis depending on the size of molecules (particles).
It is used for fractionating and separating some or all of contaminants and the like. More specifically, such as hemodialysis and hemofiltration used for removal of low molecular weight plasma components such as electrolytes and urea, creatinine, and low molecular weight proteins in blood of patients with renal failure, extracorporeal circulation treatment, production of plasma preparations, etc. It is used for the purpose of collecting or separating plasma from blood for the purpose, and further separating, for example, albumin and the like from macroglobulin, immune complex and the like.

Average pore diameter, pore diameter, film thickness, hollow fiber inner diameter, hollow fiber outer diameter The average pore diameter of the membrane of the present invention is determined by taking a film of the membrane with a scanning electron microscope and visually dispersing the film on the photographing surface. The hole diameter is determined by randomly measuring at least 1,000 holes. Or,
It is also possible to determine a rough value based on the permeability of a compound of a known size. The average pore diameter at this time varies depending on the application, but is preferably 10 ° or more and 1 µm or less, more preferably 10 ° or more and 0.5 µm or less, and a filtration type dialysis membrane enables good filtration at 15 to 20 °. . Similarly, a scanning electron microscope image is taken, and the pore diameter, film thickness, hollow fiber inner diameter, and hollow fiber outer diameter of the fine pores dispersed on the photographing surface are visually measured. Hole diameter 30 ~ 400mm
At the time of, it becomes a good film. In the hollow fiber, the smaller the inner diameter, the outer diameter, and the film thickness are, the larger the number of pieces in the same volume is preferable in that a large number of membrane areas can be used. , 5-20
0 μm, inner diameter 50-300 μm, outer diameter 100-100
The range is 00 μm.

Total Volume Porosity The total volume porosity of the membrane of the present invention is obtained from the dry weight of the membrane and its specific gravity. Considering the filtration efficiency, the total volume porosity is preferably a high value. Considering the strength, good filtration is achieved at 30 to 75%, and more preferably 40 to 75%, considering the filtration efficiency.

Water Permeability of Hollow Fiber Membrane The water permeability of the present invention is defined by the amount of water permeating from the inside to the outside of the membrane per unit time per fixed membrane area when a certain pressure is applied to the hollow fiber membrane. Depending on the application, various water permeability is required, but a preferable value is 3.4.
8,000 / hr / m ² / mmHg, more preferably 3.4-10,000 / hr / m ² / mmHg. When the water permeability is high, the water permeates well, and it is favorably used for artificial dialysis and the like.

A method for reducing the surface negative charge to 30 μeq / g or less. An example of a method for reducing the surface negative charge to 30 μeq / g or less is a homopolymer containing no negative charge in the raw material polyacrylonitrile-based synthetic polymer material. To give a hollow fiber or flat membrane that can be formed into a film by using the above method. As another example of the method for reducing the surface negative charge to 30 μeq / g or less, amidation by reacting with known primary and secondary amines and compounds having an amino group using a known carbodiimide such as dicyclohexylcarbodiimide. And an esterification reaction such as methyl esterification using diazomethane. Furthermore, a method such as an esterification reaction with a self-hydroxyl group or a negative group embedding by contact with a hydrophobic surface, etc., by performing a vacuum heating dehydration treatment may be used. Furthermore,
It can be carried out by improving the surface by a known grafting method using radiation and plasma. Alternatively, a coating layer of a compound having a hydrophilic partial structure such as a polyethylene glycol chain having no positive and negative functional groups or a hydrophilic compound having a positive functional group is formed on the film surface by coating or the like. Can also be carried out preferably.

Zeta potential Zeta electrons of the flat membrane type material can be measured by a streaming potential measuring device (ZP-10B, manufactured by Shimadzu Corporation). In the hollow fiber, platinum electrodes were attached to both ends of one filament of a material having a length of 14 cm, and KCl (KCl concentration, 10 ⁻³ mol /
l) Apply pressure to the bottle containing the aqueous solution, (0 to 0.
5 kg / cm ³ ), the change in the streaming potential due to the pressure increase is measured, and can be obtained by the first equation. Formula 1 Zeta potential (mV) = 1.44 x ^10-3 x streaming potential x conductivity x pressure The zeta potential is particularly due to the fact that the negative charge inside the hollow fiber causes blood kinin production in the hollow fiber. It is more preferable to measure by the above method than to measure the whole like other filtration materials. Since the amount at the time of measurement is different, the measured value is different from other filtration materials. The zeta potential also serves as a criterion for observing surface charge and hydrophilicity in a certain sense, and the value depends on the hydrophilicity. In a hollow fiber membrane, when the zeta potential is -2 mV or more, blood A safe filter with no rise in kinin. The increase in blood kinin is lower when the zeta potential due to the negative group is higher, so that a better membrane is obtained, preferably at -1 mV or more, and more preferably at -0.5 mV or more and 0 mV or less.

[0016]

The present inventor focused on the relationship between the rise of kinin caused by blood contact with the membrane for separating blood components and the negative charge on the membrane surface, and found that there was a clear positive correlation between the two. It was found that the rise in kinin could be suppressed by reducing the negative charge on the membrane surface. In the case of a membrane having a surface negative charge of 30 μeq / g or more, especially 50 μeq / g or more, citric acid and salts thereof are added in a flask in an amount of 0.1%.
According to an in vitro blood test in which blood is brought into contact with blood containing about 20% by weight, the kinin concentration in the blood increases,
It was found that the concentration was as high as 0 pg / ml or more. Further, even during actual blood component separation treatment using the membrane, the kinin concentration in the treated blood rises to 4000 pg / ml or more, and when kinin of 4000 pg / ml or more enters the body, anaphylactic symptoms such as hot flushing and blood pressure decrease. Was also found. When the negative charge on the membrane surface is 30 μeq / g or less, activation of blood coagulation factor XII in the blood is small,
Therefore, the increase in the concentration of kinin is insignificant,
It was found that it did not rise above 4000 pg / ml. The surface negative charge of the membrane is preferably as low as possible in order to suppress the rise of kinin, and the more preferable surface negative charge of the membrane is 25 μeq / g or less, more preferably 20 μeq / g or less.
μeq / g or less. However, from the viewpoint of practical use of the membrane such as wettability and blood compatibility between blood and the membrane surface, and furthermore, the non-specific adsorption of plasma proteins is low, it is preferable that some negative charge is present on the membrane surface. .01 μeq / g
Or more, more preferably 0.1 μeq / g or more, and more preferably 1 μeq / g or more.
It preferably has a negative charge of at least μeq / g.

The wettability of blood on the membrane The lower the amount of negative charge on the surface, the better the membrane is in terms of kinin production. On the other hand, according to the study of the present inventors, the lower the negative charge on the surface, the more the surface wettability. When wettability is expressed in terms of critical wet surface tension (CWST) due to reduced non-specific adsorption of plasma proteins, increased adhesion of platelets, and difficulty in wetting at the start of use CWST is preferably 40 dyne / cm or more. In particular, it was most preferable when it was 50 dyne / cm or more. Although the wettability is not determined only by the amount of the negative group on the surface, the contribution of a sulfate group or a carboxyl group is highest in a film of polyacrylamide or the like which is usually used. The upper limit of the CWST is preferably higher as the wettability increases, but on the other hand, it is preferably 102 dyne / cm or less, more preferably 90 dyne / cm, since kinin production may increase.
cm or less. However, it is possible to increase the CWST while maintaining a negative group at 30 μeq / g or less, for example, by holding a neutral hydrophilic group on the surface.
CWST can be measured by the method described in Japanese Patent Application No. Hei 3-502094. That is, the surface tension is sequentially 2 to 4
Prepare a series of standard solutions for reagents that differ by dyne / cm. Apply at least 10 drops of at least two standard solutions with continuous surface tension separately to a typical portion of the membrane surface.
Leave for a minute. At this time, there is no problem because the flat membrane can secure a sufficient surface area on which droplets can be placed, but it is difficult to measure with a hollow fiber. Therefore, the hollow fiber is fixed on both sides on a flat plate such as a slide glass with silicon adhesive etc. and arranged without gaps.
Thereafter, the hollow fiber is crushed while being held down by another slide glass or the like, and measurement is performed using an apparently flat membrane. After placing the droplet on it for 10 minutes,
If 9 or more of the 0 drops are wet, it is determined that the drop is wet with the liquid having the surface tension. If only eight or less of the ten drops are wetted, it is determined that they have not been wetted. The test is continued using successively higher or lower surface tension standards until it is confirmed that one of the two standard solutions having a continuous surface tension is dropped and one is wet and the other is not wet. If the above phenomenon is confirmed, the average value of the surface tensions of the two standard solutions used at this time is calculated, and the CW of the film is calculated.
CT value. Although wettability is not determined solely by the amount of negative groups on the surface, the carboxyl groups and sulfate groups normally used contribute the highest, and the CWST also decreases by reducing the amount of carboxyl groups and sulfate groups. I understood. The upper limit of the CWST is preferably higher as the wettability increases, but on the other hand, it is preferably 102 dyne / cm or less, more preferably 90 dyne / cm or less, since kinin production is increased. For example, by holding a neutral hydrophilic group on the surface, the amount of C is maintained while the amount of the negative group is maintained at 30 μeq / g or less.
It is possible to increase WST.

Vessel Shape of Membrane-Type Blood Component Separator The vessel may have a blood inlet and an outlet and / or a blood inlet and an outlet, a dialysate inlet and an outlet, and / or a blood filtrate such as a plasma component. There is no particular limitation as long as it is a container having an outlet, but as an example, a container that can be filled with a known flat membrane in a laminated shape, a columnar shape that can fix only a part of the hollow fiber, a triangular columnar shape, a square columnar shape , Hexagonal column,
Any container shape such as an octagonal prism-shaped container or the like, and a container capable of fixing only the blood inlet and outlet portions with the hollow fiber inner surface open can be used. At this time, the ratio of the cross-sectional area to the length of the container (cross-sectional area / length, S / L) is preferably 2.5 cm or more and 60 cm or less, which is a good S / L.

The preferred length of the blood component separator is not particularly limited.
More than 15cm3 due to its ease of manufacture and blood throughput
5 cm or less is preferable. Accordingly, the effective hollow fiber effective length is 10 to 30 cm.

Priming Amount of Blood Component Separator The priming amount of the blood component separator is preferably 10 to 4 liters depending on its shape, size and use because it takes less time to use and simplifies the operation. preferable.

Usage Shape of Blood Component Separator Any of blood bags, blood circuits, chambers, clamps, roller clamps, drip chambers, needles, drip chambers with mesh, blood pump tubes, etc. before and after the membrane filter of the present invention. A circuit for extracorporeal circulation or a circuit for blood transfusion incorporating one or more can be used. Further, the blood processing can be used by incorporating a pump such as a blood pump, a liquid sending pump or a suction pump in the middle of the circuit. In addition, a head due to the weight of blood can be used favorably.

Use of the blood component separator The filtration material of the model of the present invention is used for blood separation such as hemodialysis, filtration type dialysis, plasma separation, double filtration, concentration of bodily fluids such as ascites, push and pull, etc. A container can be filled and used for hemofiltration.

Method for Measuring Bradykinin Concentration As a method for measuring the bradykinin concentration of a membrane, a membrane having a blood inlet and an outlet is filled with the membrane, blood is allowed to flow, blood is sampled from the outlet side, and the bradykinin concentration is measured. Although it is possible, a large amount of blood is required, and it is difficult to evaluate many membranes at one time. Therefore, in the present invention, the evaluation was performed by the following method. Hereinafter, it is referred to as an in vitro blood test. A membrane having a uniform surface area and a measured surface charge was placed in a 50 ml Erlenmeyer flask made of polycarbonate, and the ACD-A solution was added thereto. % To make the hematocrit 40% or more and 60% or less,
Alternatively, a solution prepared by adding a physiological saline solution containing 11.1% of ACD-A solution to the erythrocyte concentrate to adjust hematocrit is added to 3
After heating to 7 ° C, 5 ml is added and the mixture is left at 37 ° C for 5 minutes. In the study of the present inventors, a liquid prepared from an erythrocyte concentrate was high in bradykinin elevation, was relatively easy to obtain, and was particularly suitable. After exactly 5 minutes, tradiol as a kallikrein degradation inhibitor and a kininase inhibitor,
After adding soybean trypsin inhibitor, protamine sulfate and ethylenediaminetetraacetic acid-2-sodium salt, cooling and centrifuging at 4 ° C. to remove only plasma components and freezing, and then measuring the bradykinin concentration by a known radioimmunoassay method (PEG precipitation method). The amount of bradykinin was determined. At the same time, as a negative control, a polycarbonate in an Erlenmeyer flask without a membrane was subjected to the same in vitro blood test and used as a control. The in vitro blood test of the positive control using a glass Erlenmeyer flask is performed in the same manner as the in vitro blood test except that the material of the Erlenmeyer flask is glass and no membrane is inserted.

Example 1 A hollow fiber was spun from a polyacrylonitrile (PAN) homopolymer having an inner diameter of 250 μm and an outer diameter of 320 μm by dry spinning. The surface negative charge of this hollow fiber was measured. The hollow fiber was sufficiently washed in advance with an 80% aqueous ethanol solution to remove the eluate. After sufficiently drying the hollow fiber, 1 g was weighed and immersed in 50 ml of a methanol solution in which 5% potassium iodide was dissolved. This was reacted under shaking at 30 ° C. for 24 hours. After the reaction, the supernatant was recovered and 359
Absorbance measurements were taken at nm and 290 nm. At this time, a methanol solution in which 5% potassium iodide was dissolved was used as a control (blank). Separately, the absorbance was measured at 359 nm and 290 nm in the same manner as described above using a non-woven fabric comprising polypropylene and polyethylene and immobilized with 0.572 meq / g of methacrylic acid by a radiation grafting method. The negative charge on the surface of this non-woven fabric is EC
It was measured in advance using H-Sepharose 4B (Pharmacia) as a control. From this measured value, determine the calibration curve between the absorbance and the negative charge on the surface,
From this calibration curve, the amount of negative charge on the surface of the specimen was calculated. The negative charge on the surface of the hollow fiber was 23.2 μeq / g.
At this time, the zeta potential was -1.2 mV. The kinin-producing ability of the PAN hollow fiber was measured as follows. Erythrocyte concentrate (hematocrit value 65%) collected using CPD as an anticoagulant and treated was used for ACD-A solution 11.1
The blood was used as a test blood with a hematocrit value of 45% using a physiological saline solution containing 5%. 5 ml of this test blood is added to a polycarbonate Erlenmeyer flask, cut into a length of about 5 mm,
0.05 g was further added and reacted at 37 ° C. for 5 minutes. After the reaction, the blood was collected, and 5,000 U of Tradirol, 2 mg of soybean trypsin inhibitor, 5 mg of protamine sulfate, and 20 mg of sodium ethylenediaminetetraacetate were immediately added and mixed under ice cooling, and mixed at 4 ° C. and 3,000 rpm.
The supernatant was collected by centrifugation for mx 10 minutes. The concentration of bradykinin in this supernatant was determined by polyethylene glycol precipitation using a radioisotope.
g / ml. At this time, in the control which was similarly reacted without adding the PAN hollow fiber, the concentration of bradykinin in the plasma was 65.4 pg / ml, and although the bradykinin concentration increased in the presence of the PAN hollow fiber, it was 10% of the control. It was a slight increase of about twice.

Example 2 A polyacrylonitrile homopolymer having an inner diameter of 250 μm and an outer diameter of 320 μm was used as an example of a plasma filtration apparatus using a dry-formed hollow fiber.
And molded into a hemodialysis machine. At this time, the filling factor was 68.5%, and the effective film area was 1.0 m ² . Hemodialysis using heparin as an anticoagulant was performed using this dialysis apparatus. The blood kinin concentration of the blood collected from the vicinity of the blood outlet was 750 pg / ml.

Comparative Example 1 The raw material polymer was spun into a hollow fiber by dry spinning as an acrylonitrile copolymer to which 0.05% of methacrylic acid was added, without changing the conditions at all. The amount of negative charge on the surface of this PAN hollow fiber was measured by the method of Example 1 and was found to be 198.0 μeq / g. When the bradykinin elevating property was determined by the method of Example 1, the bradykinin concentration in plasma was 12,000 p.
g / ml, and an increase in bradykinin concentration was observed.

COMPARATIVE EXAMPLE 2 The hollow fiber of Comparative Example 1 having an inner diameter of 250 μm and an outer diameter of 320 μm was used as an example of a plasma filtration device, having an inner diameter of 31.6 m.
m, housed in a container having a length of 210 mm, and molded to prepare a hemodialysis apparatus. At this time, the filling factor was 68.5%, and the effective film area was 1.0 m ² . With this dialysis machine,
Hemodialysis using heparin as an anticoagulant revealed that the blood kinin concentration of the blood collected from near the blood outlet was 1%.
It was 1,250 pg / ml.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-7024 (JP, A) JP-A-60-7856 (JP, A) JP-A-2-239871 (JP, A) JP-A-61- 57504 (JP, A) JP-A-6-7429 (JP, A) JP-A-6-7430 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61K 35/14 A61M 1 / 00-1/34

Claims (2)

(57) [Claims] 1. A negatively charged surface having an average pore size of 10 °
１．０1.0 μm, water permeability 3.4 to 8,000 ml / hr
/ M ² / mmHg, a blood component separation membrane comprising a macromolecule, and surface negative charge measurement using triiodide complex ion
The negative charge specified by the method is 0.01 μeq /
A blood component separation membrane having a g of 30 g / g or less and 30 g / g or less. 2. The membrane for separating blood components according to claim 1, wherein the material of the membrane is mainly composed of polyacrylonitrile, cellulose, or polymethyl methacrylate.