JPH01189346A - Adsorbent for beta2-microglobulin - Google Patents

Abstract

PURPOSE:To obtain a selective adsorbent for beta2-microglobulin by constituting the adsorbent of a specified granular copolymer having a mean particle size, surface area, pore volume, mean pore size, each being regulated to within each specified range. CONSTITUTION:A granular copolymer consisting of a polyvinyl aliphatic monomer and/or a polyvinyl aromatic monomer, with a monovinyl aliphatic monomer, or a granular copolymer consisting of a polyvinyl aliphatic monomer and a polyvinyl aromatic monomer is produced by, pref. a suspension polymn. process. Obtd. granular copolymer is an adsorbent for beta2-microglobulin, having 25-2500mu means particle size, >=100m<2>/g surface area, >=1.6cc/g pore volume, 100-7500Angstrom mean pore size, wherein a percentage of the pore volume of pores having 100-1000Angstrom pore size amounts to 40-60% basing on the total pore volume, and a percentage of pore volume of pores having 1000-7500Angstrom pore size amounts to 60-40% basing on the total pore volume.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to β2-microglobulin (β2-m1cr).

)<Iobulin, β2MG) This also relates to adsorbents, and more specifically to particulate copolymers having specific porous properties.

[Conventional technology]

With the advancement of technologies such as hemodialysis, blood electrification therapy has been established to some extent to remove toxic or pathogenic substances from the blood, from low-molecular to high-molecular substances, depending on the purpose. As a method for removing the pathogenic substance, hemodialysis, hemofiltration, or a combination thereof is used.

Adsorbents that can adsorb and purify pathogenic substances in blood have also been developed. These adsorbents include activated carbon, anion exchange resin, styrene-divinylbenzene copolymer,
Other copolymers are known.

However, although low-molecular-weight solutes that permeate through membranes can be removed by hemodialysis, proteins with relatively low molecular weights cannot be removed by dialysis alone, and they gradually accumulate in the patient's body, making the patient's condition different from that of a healthy person. was.

In general, when using an adsorbent to remove pathogenic substances from blood, it is necessary to selectively and reliably adsorb these pathogenic substances, which are trace amounts but cannot be removed at all by conventional blood purification methods.

Recent studies have shown that β2-microglobulin (βJG
) has been found to be the causative agent of amyloidosis, which frequently occurs during long-term dialysis, and the development of methods for removing this substance has come to occupy an important therapeutic position.

However, the removal effect of β2MG is not sufficient by ordinary hemodialysis, hemofiltration, hemodiafiltration, hemoadsorption using activated carbon, etc.

Furthermore, no research has been reported to date on selectively and efficiently adsorbing β2MG in blood purification.

[Problem to be solved by the invention]

An object of the present invention is to provide a porous particulate copolymer that selectively and efficiently adsorbs β,-microglobulin (β2MG) present in blood.

[Means to solve the problem]

A copolymer made of a monovinyl monomer crosslinked with a polyvinyl monomer maintains a three-dimensional structure and is therefore stabilized, so it has sufficient strength as an adsorbent. However, this copolymer
The adsorption characteristics may vary depending on the type and structure of the material.

Therefore, the present inventors conducted research on adsorbents that specifically adsorb the aforementioned β2MG, based on crosslinked copolymers consisting of polyvinyl monomers, monovinyl monomers, etc.
This led to the present invention.

That is, the present invention provides a polyvinyl aliphatic monomer and/or
or a granular copolymer composed of several thousand polyvinyl aromatic monomers and several thousand monovinyl fat monomers, or a granular copolymer composed of a polyvinyl aliphatic monomer and several thousand polyvinyl aromatic monomers; Average particle size is 25~
2500μ1 surface area is 100+a2/g or more, pore volume is 1.6cc/g or more, and the average pore diameter is 100-7
distributed between 500 and 1000 to 75, of which the pore volume between 100 and 1000 accounts for 40 to 60%.
The β2-microglobulin adsorbent is characterized by having a pore volume of 60 to 40%.

As mentioned above, β2MG could not be removed by conventional hemodialysis, hemofiltration, hemofiltration dialysis, etc., nor could it be sufficiently removed by conventional adsorbents known for blood/liquid immersion. Adsorbents solve this problem.

That is, the adsorbent of the present invention has the property of selectively adsorbing and removing β2MG, which is not removed during conventional blood purification, but not adsorbing and removing proteins such as albumin.

The β2-microglobulin referred to in the present invention is β2-microglobulin that is normally measured by enzyme immunoassay or the like in clinical tests, and more specifically has the following physical property values.

Sedimentation constant 1.65 Partial specific volume 0.72-0.73 m1/g Molecular weight 11000-1200G Nitrogen content
16-17% The β2-microglobulin targeted by the present invention is
Microglobulin itself, complexes of other proteins,
and a partially mutated amino acid sequence of β2-microglobulin.

As for the shape of the copolymer, a spherical nine-grain shape is more preferable than a membrane-like, hollow-like, or thread-like form. This is because, when packed in a column of the same volume, nine spherical particles have a larger area in contact with blood and are more efficient in removing β2-microglobulin.

If the copolymer is in particulate form, the particle size is 25 to 25
00μ gives preferable results as the copolymer of the present invention. If the particle size is less than 25μ, the gaps between the particles during filling will be small, and when used for whole blood purification, platelets etc. will adhere and easily clog; if the particle size exceeds 2500μ,
Although platelets and the like are difficult to adhere to, the outer surface area that comes into contact with blood becomes small, which reduces the efficiency of removing β2-microglobulin, which is not preferable.

Further, a copolymer of the present invention having a particle size of 50 to 2,000 .mu.m gives more preferable results, and a particle size of 250 to 1,500 .mu.m gives particularly preferable results.

The surface structure and internal structure of the copolymer are particularly limited in order to improve adsorption performance. Because the substantial surface area that comes into contact with β2-microglobulin can be increased,
A porous structure is required.

Here, the surface area of the copolymer having a porous structure is a value measured by the BET method using nitrogen gas, +o
om2/g or more is preferable, and it is preferable that the average pore diameter of the pores calculated from the mercury pressure curve obtained by the Mercury Techniques method is in the range of 100 to 7,500 pores. The pore volume at this time is 1. It is preferable that it is δcc/g or more.

The larger the surface area, the better the adsorption efficiency of β2-microglobulin, but it must be within the range of mechanical strength that can maintain the pore size and maintain a porous structure. Surface area was preferred. If the surface area is less than 100 m27g, the adsorbent's ability will be insufficient.

Moreover, if the pore size is less than 100 pores, adsorption of β2-microglobulin becomes extremely poor. In other words, as the pore size decreases, the surface area of the porous material itself tends to increase, but since β2-microglobulin cannot diffuse into the pores of the porous material, there is a substantial increase in the adsorption potential of β2-microglobulin. The surface area becomes extremely small, and β2
- Poor adsorption of microglobulin. On the other hand, if the hole diameter is 75
If it exceeds 00°, β2-microglobulin will diffuse into the pores, but the surface area of the porous material will become smaller, resulting in poor adsorption efficiency of β2-microglobulin.

On the other hand, when the pore size is distributed in the range of 100 to 7,500 pores, β2-microglobulin can easily diffuse into the pores, and the effective surface area on which β2-microglobulin can be adsorbed is large enough. , specific and efficient adsorption of β2-microglobulin becomes possible. therefore,
It is preferable that the surface area is 100o+2/g or more and the pore size ranges from 100 to 7,500 pores.

What matters here is the pore volume and its distribution in relation to the pore size distribution, and it has been found that these are the most important factors for adsorption of β2-microglobulin. Pore volume is 0.5 cc/g or more, more preferably 1. o
cc/g or more, more preferably +6 cc/g or more. In this case, the pore diameter ranges from 100 to 1000 pores, and the pore volume (percentage of pore volume) is 30% to 60%, 10
Pore capacity from 00 to 7,500 pores is 70% to 40
%, more preferably each from 40% to
60% and a range of 60% to 40%.

The copolymer which is the adsorbent of the present invention will be explained. The copolymer of the polyvinyl aliphatic monomer and/or polyvinyl aromatic monomer and monovinyl aliphatic monomer or the copolymer of the polyvinyl aromatic monomer and polyvinyl aliphatic monomer of the present invention can be produced by emulsion polymerization,
It is manufactured by a known polymerization method such as a bulk polymerization method or a suspension polymerization method, but it is preferably manufactured by a suspension polymerization method. This is because by this method, bead-like granules having a uniform particle size can be obtained, and further, by adjusting the stirring speed and the like, particles having a desired particle size can be obtained. Beaded copolymers are advantageous in processing operations such as batch processing and column processing. It is preferable to carry out the polymerization in the presence of a pore-forming agent that does not affect the composition of the copolymer produced in the polymerization system but imparts physical properties, such as pore volume, to the copolymer. Various types of pore-forming agents can be mentioned. For example, an organic liquid (precipitant) that acts as a solvent on the monomer mixture and is substantially insoluble or poorly soluble in water and does not swell the resulting copolymer; An organic liquid (swelling agent) that is insoluble or poorly soluble in water and that swells the resulting copolymer, an organic solvent that allows the above-mentioned swelling agent and precipitant to coexist, the above-mentioned swelling agent, and a uniform liquid phase with this swelling agent. Examples include organic liquids made of monovinyl linear polymers that can form It is of course possible to use other known pore-forming agents without limitation. Suspension polymerization may be carried out without adding these pore-forming agents.

Next, the composition of the adsorbent of the present invention will be explained.

Polyvinyl aliphatic compounds include ethylene glycol dimethacrylate, ethylene glycol diacrylate, trimethylolpropane trimethacrylate, diethylene glycol divinyl ether, allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, diallyl adipate, tetra and trimethacrylate. Examples of polyvinyl aromatic compounds include divinylbenzene, divinyltoluene, trivinylbenzene, divinylchlorobenzene,
Examples include divinyltoluene, divinylnaphthalene, divinylxylene, divinylethylbenzene, diallyl fumarate, and the like. On the other hand, as a monovinyl aliphatic compound,
Methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, ethylhexyl acrylate, hydroxyethyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, ethylhexyl methacrylate, hydroxyethyl methacrylate , glycidyl methacrylate, acrylonitrile, metalrylonitrile, and the like. The proportions of these copolymers are arbitrarily selected.

Examples of the pore-forming agent that imparts porosity to the crosslinked copolymer produced include the following.

First, there may be mentioned an organic liquid that acts as a solvent for the monomer mixture, is substantially insoluble or slightly soluble in water, and does not swell or damage the resulting copolymer. This is commonly called a precipitant. These precipitants include aliphatic hydrocarbons, cycloaliphatic hydrocarbons, and alcohols thereof, and specific examples include butane, hexane, heptane,
Dodecane, isooctane, cyclohexane, cyclopentane, amyl alcohol, hexanol, decanol,
Dodecanol, cyclohexanol, etc. It is important that these precipitants are present in an amount sufficient to impart a phase separation effect to the copolymer, and preferably 20 to 70% (by weight) of the total amount of the gold monomer and precipitant.

Next, mention may be made of organic liquids (swelling agents) that can act as a solvent on the mixture and swell the resulting copolymer.

In order to form more preferable pores, when using this organic liquid, a monovinyl linear polymer capable of forming a homogeneous liquid phase together with the monomer mixture and the above-mentioned swelling agent is allowed to coexist. Examples of the swelling agent include aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene, and aliphatic hydrocarbons such as carbon tetrachloride, tetrachlorethylene, trichlorethylene, dichloroethylene, and methylene chloride. Examples of monovinyl linear polymers include polystyrene, polymethylstyrene, polyethylstyrene, polyvinyl acetate, polyisobutylene,
Examples include poly(meth)acrylic acid ester. When these polymers are used in practice, it is necessary to select them so that they mix with the monomers and organic liquids used to form a homogeneous liquid phase. The amount of swelling agent used is preferably in the range of 50 to 150% (volume/weight) based on monomer, while the monovinyl linear polymer is most preferably used in a range of 5 to 30% (volume/weight) based on monomer.

In addition, when using other organic liquids, there is a method in which the above-mentioned precipitating agent and swelling agent are used in a suspension polymerization system at the same time. Specific examples of the precipitant and swelling agent used are those mentioned above. The amount of precipitant and swelling agent used is
It is at least 20% (by weight) based on the monomer mixture, and its usage ratio is from 25 to 0.3.

Further examples include inert polymeric pore-forming agents that are soluble in the monomer mixture, insoluble in the resulting copolymer, and soluble in water. Typical pore-forming agents include poly(vinyl methyl ether), poly(vinyl ethyl ether), poly(ethylene oxide), copolymers and block copolymers of ethylene oxide and propylene oxide, and the like.

The above are listed as typical pore-forming agents,
It is of course possible to use other known pore-forming agents without being limited thereto.

In addition to the pore-forming agent as described above, the monomer mixture may
For example, in the case of an aqueous medium, styrene-maleic anhydride copolymer is Ammonium salt of the combination, carboxymethyl cellulose,
Polymerization is carried out by adding monomers into a suspending medium containing carboxycellosolve, bentonite, polyvinyl alcohol, sodium poly(meth)acrylate, bentonite, poly(diallylmethylammonium chloride), and the like. It goes without saying that additives exhibiting specific effects, such as gelatin, silicic acid, magnesium, phosphoric acid, sodium chloride, and soda carbonate, may be added to this polymerization system depending on the purpose of use.

In accelerating the polymerization of the present invention, suitable catalysts that provide free radicals to act as polymerization initiators, such as benzoyl peroxide, tertiary butyl hydroxy peroxide,
Cumene peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, tertiary butyl perphthalate, di-tert-
Butyl peroxide, caproyl peroxide, etc.
Furthermore, azo catalysts such as azoisobutyronitrile, azoisobutyramide, 2.2°-azobis(2,4-dimethylmaleronitrile), azobis(α-dimethylvaleronitrile), and azobis(α-methylbutydnitrile) are also available. Available for use. A combination of two or more of these can also be used as a catalyst. The amount of catalyst used is from 0.01 to IO% by weight, based on the mixture. This polymerization reaction only needs to be at or above the decomposition temperature of the polymerization initiator,
Usually, the temperature is 50 to 90°C under normal pressure.

This type of copolymer produced by such a suspension polymerization method has a uniform particle size, and a desired particle size can be obtained by adjusting the stirring speed and the like. Moreover, a copolymer with excellent strength can be obtained.

The crosslinked copolymer thus obtained is subjected to known operations such as extraction treatment, heat treatment, steam treatment, and water washing in order to remove unreacted monomers and pore-forming agents from the copolymer.

The thus obtained adsorbent of the present invention is useful as a blood purification adsorbent, particularly as a selective adsorbent for β2-microglobulin, and exhibits extremely excellent adsorption ability, as shown in the following examples.

The adsorbent of the present invention may be used alone, or may be mixed or layered with other adsorbents such as the above-mentioned activated carbon.

The adsorption method can be applied to known direct blood perfusion methods, plasma perfusion methods, etc., and can be used effectively, safely, and reliably to adsorb and remove ff1M β2-microglobulin from body fluids.

〔Example〕

The present invention will be explained in more detail by showing Examples and Comparative Examples below.

Example 1 A homogeneous mixed solution consisting of 240 g of industrial divinylbenzene (purity 81%), 60 g of methyl methacrylate, 367 g of methyl isobutyl carbinol as a precipitant and 3 g of lauroyl peroxide was mixed with poly(diallyldimethylammonium chloride) in 80 Osfi of water. ) 23 g of dispersant, 2.5 g of gelatin, 2.5 g of boric acid and 20
% aqueous sodium hydroxide solution was added to the well-stirred aqueous phase. This mixed solution was stirred and polymerized at 80° C. for about 6 hours. The inert solvent is then removed by steam distillation.
It was collected. The obtained copolymer was washed with water and dried in a blow dryer at 110°C for 5 hours to obtain 291 g of a white opaque copolymer.
I got it.

The porosity properties of this copolymer, such as average particle diameter, surface area, pore volume, pore capacity relative to pore diameter, and adsorption properties according to the following test methods are summarized in Table 1 along with other examples and comparative examples. Indicated.

Test method The obtained adsorbent (copolymer) in a plastic tube
and test serum (pooled serum from uremic patients) were mixed at a volume ratio of 1:6, then shaken at 37°C for 1 hour, and β2-microglobulin and albumin in the serum before and after shaking were quantified.

The RIA method was used to quantify β2-microglobulin, and the BCG method was used to quantify albumin.

Example 2 A homogeneous mixed solution consisting of 210 g of industrial divinylbenzene (purity 81%), 90 g of methyl methacrylate, 367 g of methyl isobutyl carbinol as a precipitant, and 3 g of lauroyl peroxide was polymerized and dried in the same manner as in Example 1. .

The yield of the obtained copolymer was 290 g.

Example 3 A homogeneous mixed solution consisting of 180 g of industrial divinylbenzene (purity 81%), 120 g of methyl methacrylate, 367 g of methyl isobutyl carbinol as a precipitant, and 3 g of lauroyl peroxide was polymerized and dried in the same manner as in Example 1. .

The yield of the obtained copolymer was 291 g.

Example 4 An example of a homogeneous mixed solution consisting of 150 g of industrial divinylhenzen (purity 81%), 150 g of methyl methacrylate, 367 g of methyl isobutyl carbinol as a precipitant, and 3 g of lauroyl peroxide! It was polymerized and dried in the same manner as above.

The yield of the obtained copolymer was 284 g.

Example 5 A homogeneous mixed solution consisting of 240 g of industrial divinylbenzene (purity 81%), 60 g of methyl methacrylate, 300 g of methyl isobutyl carbinol as a precipitant, and 3 g of lauroyl peroxide was polymerized and dried in the same manner as in Example 1. .

The yield of the obtained copolymer was 290 g.

Example 6 A homogeneous mixed solution consisting of 240 g of industrial divinylbenzene (purity 81%), 60 g of methyl methacrylate, 200 g of methyl isobutyl carbinol as a pore forming agent, 200 g of toluene (swelling agent) and 3 g of lauroyl peroxide was prepared as an example. Polymerization and drying were carried out in the same manner as in 1.

The yield of the obtained copolymer was 286 g.

Comparative Example 1 240 g of industrial divinylbenzene (purity 81%), 60 g of methyl methacrylate, 450 g of methyl isobutyl carbinol as a precipitant, and 3 lauroyl peroxide.
A homogeneous mixed solution consisting of g was polymerized and dried in the same manner as in Example 1.

The yield of the obtained copolymer was 274 g.

Comparative Example 2 A homogeneous mixed solution consisting of 240 g of industrial divinylbenzene (purity 81%), 60 g of methyl methacrylate, 367 g of methyl isobutyl carbinol as a precipitant, and 3 g of α,α'-azobis-isobutyronitrile was prepared in Example 1. It was polymerized and dried in the same manner as above.

The yield of the obtained copolymer was 285 g.

Comparative Example 3 A homogeneous mixed solution consisting of 240 g of methyl methacrylate, 60 g of industrial divinylbenzene (purity 81%), 450 g of methyl isobutyl carbinol as a precipitant, and 3 g of lauroyl peroxide was polymerized and dried in the same manner as in Example 1. .

The yield of the obtained copolymer was 285 g.

(Effects of the Invention) The adsorbent of the present invention is characterized by selectively adsorbing β2-microglobulin and not adsorbing proteins such as albumin.

Therefore, in blood purification, it can be used in combination with hemodialysis, hemofiltration, hemodiafiltration, blood adsorption and removal methods using activated carbon, etc., and it can also be used in adsorption tubes for direct blood perfusion methods, plasma laminar flow methods, etc. be.

Claims (1)

[Claims] A granular copolymer consisting of a polyvinyl aliphatic monomer and/or a polyvinyl aromatic monomer and a monovinyl aliphatic monomer, or a granular copolymer consisting of a polyvinyl aliphatic monomer and a polyvinyl aromatic monomer; The average particle size is 25 to 2500 μ, the surface area is 100 m^2/g or more, the pore volume is 1.6 cc/g or more, and the average pore size is between 100 and 7500 Å, of which 100 to 1000 Å is fine. Pore capacity is 4
A β_2-microglobulin adsorbent characterized by having a pore volume of 0 to 60% and a pore volume of 1000 to 7500 Å occupying 60 to 40%.