JP7741629B2 - Advanced glycation end products adsorbent - Google Patents

Description

The present invention relates to an advanced glycation end product (ADSP) adsorbent that can efficiently remove advanced glycation end products (ADSPs), which are the cause of many diseases, including diabetic complications.

Sugars are essential nutrients for life. However, they modify lysine and arginine residues in proteins in vivo, forming cross-links that alter the three-dimensional structure of proteins and affect their activity and physical properties. Advanced glycation end-products (AGEs) are the final products formed when various glucose metabolic products bind to proteins and undergo multiple reactions, including oxidation, dehydration, and condensation. Known glucose metabolic products that bind to proteins to form AGEs include glyoxazole, glycolaldehyde, Amadori compounds, 3-deoxyglucosone, methylglyoxazole, glyceraldehyde, and Haynes compounds.
Among the AGEs produced in the body, glyceraldehyde-derived AGEs are particularly toxic and are involved in the onset and progression of a variety of diseases, including diabetic complications, arteriosclerosis, osteoporosis, ossification of the posterior longitudinal ligament, muscle atrophy, rheumatoid arthritis, age-related macular degeneration, cataracts, non-alcoholic steatohepatitis, insulin resistance, periodontal disease, Alzheimer's disease, skin diseases, and skin aging.

AGEs in the body can be reduced by limiting the intake of foods that are likely to produce AGEs, but for patients for whom this is not sufficient, a treatment has been proposed in which blood is removed from the body, the AGEs in the blood are removed, and the blood is then returned to the patient's body.

Various adsorbents have been proposed for use in removing AGEs by extracorporeal blood circulation. For example, Patent Document 1 teaches that peptides with specific amino acid sequences have affinity for AGEs, and that these peptides immobilized on water-insoluble carriers can be used as AGE adsorbents.
Furthermore, Patent Document 2 teaches that a peptide having the entire or partial amino acid sequence of RAGE (Receptor to AGE), a receptor to which a type of AGE binds and causes the onset of diabetic complications, immobilized on a water-insoluble carrier can be used as an AGE adsorbent for extracorporeal blood circulation.
However, since these adsorbents are peptides, special care must be taken in distribution and storage, and they are not easy to use.

Furthermore, Patent Document 3 teaches that a specific hydrophilic methacrylate-containing copolymer adsorbs AGEs and can be used as a packing material for hemodialysis columns to remove AGEs.
Furthermore, Patent Document 4 teaches that alkylamino compounds having an aromatic ring have affinity for AGEs and low-density lipoproteins, and that such alkylamino compounds bound to organic polymer supports can be used as adsorbents for removing AGEs and low-density lipoproteins.
These adsorbents are easy to handle because they do not contain peptides or proteins that are easily denatured, but their adsorption efficiency for AGEs in blood is not sufficient for practical use.

JP 2006-63024 A International Publication No. 2001/18060 International Publication No. 2007/037554 Patent Publication No. 2013-17536

The objective of the present invention is to provide an AGE adsorbent that can efficiently adsorb AGEs and is easy to handle.

In order to solve the above problems, the present inventors have conducted extensive research and have obtained the following findings.
(1) A complex containing (A) a substrate and (B) a polymer with acidic groups efficiently adsorbs AGEs.
(2) When the complex contains (A) a base material and (B) a polymer having acidic groups, as well as (C) polyvalent metal ions, it efficiently adsorbs phosphorus in addition to AGEs.

The present invention has been completed based on the above findings, and provides the following [1] to [14].
[1] An advanced glycation end product adsorbent comprising (A) a substrate and (B) a complex containing a polymer having an acidic group.
[2] The adsorbent according to [1], wherein the composite is porous.
[3] The adsorbent according to [1] or [2], wherein the substrate (A) is a water-insoluble polymer.
[4] The adsorbent according to any one of [1] to [3], wherein the polymer having an acidic group (B) is a water-soluble polymer.
[5] The adsorbent according to any one of [1] to [4], wherein the complex further contains (C) a polyvalent metal ion.
[6] The adsorbent according to [5], wherein the polyvalent metal concentration is 1 to 30% by weight based on the total dry weight of the complex.
[7] The adsorbent according to [5] or [6], which further adsorbs phosphorus.
[8] A column for adsorbing advanced saccharification end products, packed with the adsorbent according to any one of [1] to [4].
[9] A column for adsorbing advanced saccharification end products and phosphorus, packed with the adsorbent according to claim 5 or 6.
[10] An adsorbent for advanced glycation end products, comprising a complex obtained by a method including a step of contacting a solution or suspension containing (A) a substrate and (B) a polymer having an acidic group with a solution containing a poor solvent for the substrate.
[11] The adsorbent according to [10], wherein the content of the (A) substrate in the solution or suspension containing the (A) substrate and the (B) polymer having an acidic group is 1 to 50 parts by weight per 1 part by weight of the (B) polymer having an acidic group, on a dry weight basis.
[12] A method for producing an adsorbent for advanced glycation end products, comprising a step of contacting a solution or suspension containing (A) a substrate and (B) a polymer having an acidic group with (C) a poor solvent for the substrate containing a salt of a polyvalent metal ion.
[13] The production method according to [12], wherein the content of the (A) substrate in the solution or suspension containing the (A) substrate and the (B) polymer having an acidic group is 1 to 50 parts by weight per 1 part by weight of the (B) polymer having an acidic group, in terms of dry weight.
[14] A method for producing a sample or material from which advanced glycation end products have been removed or reduced, comprising a step of contacting the adsorbent according to any one of [1] to [4] with a sample or material from which advanced glycation end products are to be adsorbed or removed.

The adsorbent of the present invention is a composite containing (A) a base material and (B) a polymer having acidic groups, and therefore efficiently adsorbs AGEs. Therefore, it can be suitably used, for example, for the adsorption and removal of AGEs during extracorporeal blood circulation, where the patient's blood is returned to the same patient. It can also be used to remove AGEs from foods, cosmetics, and pharmaceuticals such as blood products.
Among various diseases caused by AGEs, patients with diabetic renal failure, which is one of the diabetic complications, may undergo dialysis treatment. The adsorbent of the present invention is useful for removing AGEs when used in combination with dialysis in patients with diabetic renal failure.

Furthermore, when the adsorbent of the present invention contains (C) a polyvalent metal ion in addition to (A) a base material and (B) a polymer having an acidic group, it efficiently adsorbs phosphorus in addition to AGEs.
Phosphorus is an essential component of living organisms, a major intracellular ion, and is involved in energy metabolism, so blood phosphorus concentrations must be maintained within an appropriate range. However, when phosphorus excretion from the kidneys decreases due to renal failure or other reasons, the blood phosphorus concentration becomes abnormally high, resulting in hyperphosphatemia. Hyperphosphatemia weakens bones and causes calcification of soft tissues, leading to stroke and myocardial infarction.
Among the various diseases caused by AGEs, patients with diabetic renal failure, a diabetic complication, are prone to hyperphosphatemia because they are unable to excrete phosphorus sufficiently under current dialysis conditions. Therefore, when the adsorbent of the present invention contains (C) polyvalent metal ions and thereby efficiently adsorbs phosphorus in addition to AGEs, it is useful, for example, for simultaneously removing AGEs and phosphorus when used in combination with dialysis in patients with diabetic renal failure.

When the adsorbent of the present invention contains polyvalent metal ions, the polyvalent metal ions bond with phosphorus-containing anions, such as phosphate ions, reducing the number of bonds with the acidic groups of the polymer, making them more susceptible to release from the polymer. However, in reality, salts of polyvalent metal ions and anions are difficult to release from the complex. While not bound by this theory, it is believed that this is because the metal ions are polyvalent ions, so they bond with anions while remaining partially bonded to the acidic groups of the polymer, or because the complex between the base material and the polymer with acidic groups encapsulates or embeds the polyvalent metal salts released from the acidic groups, preventing them from releasing from the complex. In this way, the generated polyvalent metal salts are retained in the complex, preventing the elution of unwanted components from the adsorbent after phosphorus adsorption. Therefore, the adsorbent of the present invention is suitable for adsorption and removal by extracorporeal blood circulation, where the patient's blood is returned to the same patient. Furthermore, when used in the treatment of food, cosmetics, and pharmaceuticals, there is no risk of toxicity due to the inclusion of polyvalent metals in these products.

Furthermore, when the adsorbent of the present invention contains polyvalent metal ions, even if the acidic groups of the polymer become free due to binding between anions in the sample to be adsorbed and the polyvalent metal, the polymer is believed to form a complex in which it is tightly entangled with the base material, and the polymer does not detach from the complex. Therefore, the amount of unnecessary components in the sample to be adsorbed is not increased. In particular, with samples intended for human use, such as extracorporeally circulated blood, food, cosmetics, and pharmaceuticals, it is important to avoid the inclusion of unnecessary components in the sample to be adsorbed after treatment. Therefore, the adsorbent of the present invention is suitable for use in the removal of AGEs and phosphorus from extracorporeally circulated blood, and for the removal of AGEs and phosphorus from food, cosmetics, and pharmaceuticals.

Because the adsorbent of the present invention is not a peptide or protein, it does not require special care to prevent denaturation during distribution or storage, and is easy to handle.

1 is a graph showing the adsorption rate of carboxymethyllysine by the adsorbent of the present invention.

The present invention will be described in detail below.
The AGE adsorbent of the present invention is an adsorbent comprising (A) a substrate and (B) a complex containing a polymer having acidic groups.

(1) Complex
(A) Substrate A polymer can be used as the substrate. The substrate may be any material that is water-insoluble when it forms a complex with a polymer having an acidic group or when it forms a complex with a polymer having an acidic group and a polyvalent metal ion. Specifically, the substrate may be any material that forms a water-insoluble complex within a temperature range suitable for the intended use, preferably at temperatures of 25 to 45°C. If the complex is water-insoluble at temperatures of 25 to 45°C, which are temperatures around body temperature, it can be suitably used as an adsorbent for extracorporeal blood circulation.
Among these, it is preferable that the substrate itself is a water-insoluble polymer, since this makes it easier to render the composite water-insoluble. In the present invention, the water-insoluble polymer also includes polymers that become water-insoluble by adjusting conditions such as temperature, pH, ionic strength, and solvent. For example, starch forms a hydrogel containing water when heated in water and then cooled, and becomes water-insoluble, and such polymers are also included in the water-insoluble polymer of the present invention. In addition, in the present invention, poorly water-soluble polymers are also included in the water-insoluble polymer.

Examples of the substrate include synthetic polymers such as acrylate polymers (polymethyl methacrylate (PMMA), poly(2-methoxyethyl acrylate), polytetrahydrofurfuryl acrylate, etc.), vinyl polymers such as polymethyl vinyl ether, ethylene-vinyl alcohol copolymer, polyacrylonitrile (PAN), polyvinyl alcohol (PVA), ethylene-vinyl acetate copolymer (EVA), polystyrene, and polyethylene; sulfonyl group-containing polymers such as polysulfone, polyethersulfone, and polyarylethersulfone; polycarbonate; polypropylene; cellulose derivatives such as cellulose acetate; polylactide (PLA); polyglycolide (PGA); polycaprolactone (PCL); polyethylene oxide-poly(butylene terephthalate) copolymer; and polyethylene glycol.
Furthermore, examples of natural polymers include glucans (starch, cellulose, curdlan, pullulan, glycogen, etc.), chitosan, chitin, agarose or agar, gelatin, collagen, lignin, etc. Starch contains linear amylose and branched amylopectin.
These are water-insoluble polymers that are biocompatible or highly biocompatible.
In addition, it is desirable to increase the hydrophilicity of highly hydrophobic polymers such as polysulfone by mixing them with a hydrophilizing agent such as polyvinylpyrrolidone (PVP) to improve their affinity with the sample to be adsorbed to AGEs.
Among these, synthetic polymers are preferred in terms of uniformity of polymer composition, and polymethyl methacrylate (PMMA), polysulfone, and polyethersulfone, which have a proven clinical track record of being used in extracorporeal blood circulation applications, are more preferred.
One or more types of substrates can be used.

(B) Polymer Having Acidic Groups The polymer having acidic groups can electrostatically support polyvalent metal ions in the complex.
The position and number of the acidic groups are not particularly limited. The polymer may be a polymer of a single monomer or a copolymer of multiple types of monomers. A polymer containing many monomers having acidic groups as its constituent components will have many acidic groups throughout the molecule.
Furthermore, the polymer having an acidic group may be either a water-soluble polymer or a water-insoluble polymer, but is preferably a water-soluble polymer because it has a high affinity for water and is therefore more likely to adsorb AGEs in blood or food.

Examples of the acidic group include a carboxyl group, a sulfo group, and a phosphate group.
Examples of polymers having carboxyl groups include synthetic polymers such as acrylic polymers such as polyacrylic acid (PAA), cellulosic polymers such as carboxymethyl cellulose (CMC) and carboxyethyl cellulose, carboxymethyl dextran, and carboxyvinyl polymers, and natural polymers such as pectin, alginic acid, and hyaluronic acid.
Examples of polymers having sulfo groups include synthetic polymers such as polyethylene sulfonic acid (polyvinyl sulfonic acid), polystyrene sulfonic acid, polymethacrylic acid, poly(2-(meth)acrylamido-2-methylpropane-sulfonic acid), poly(3-(meth)allyloxy-2-hydroxypropanesulfonic acid), poly(2-methyl-1,3-butadiene-1-sulfonic acid), poly(2-hydroxy-3-acrylamidopropanesulfonic acid), and dextran sulfate; and natural polymers such as carrageenan, keratan sulfate, chondroitin sulfate, fucoidan, and heparan sulfate.
Furthermore, examples of polymers having both a carboxyl group and a sulfo group include synthetic polymers such as acrylic acid/ethylene sulfonic acid copolymer, methacrylic acid/styrene sulfonic acid copolymer, acrylic acid/vinyl sulfate copolymer, acrylic acid/styrene sulfonic acid copolymer, methacrylic acid/ethylene sulfonic acid copolymer, and methacrylic acid/vinyl sulfate copolymer.
Furthermore, derivatives in which a carboxyl group, a sulfo group, and/or a phosphate group is introduced into a general-purpose polymer such as an acrylic polymer can also be used.
In addition, commercially available cation exchange resins can also be used.
Among these, synthetic polymers are preferred in terms of uniformity of polymer composition, and polyacrylic acid is more preferred in terms of cost and stable supply of raw materials.

The weight-average molecular weight of the polymer having acidic groups is preferably 1,000 or more, more preferably 2,000 or more, and even more preferably 5,000 or more; and preferably 5,000,000 or less, more preferably 2,000,000 or less, and even more preferably 1,000,000 or less. If the molecular weight is too low, the degree of molecular entanglement with the substrate may decrease, resulting in leaching. On the other hand, if the molecular weight is too high, the viscosity of the solution or suspension containing the polymer having acidic groups used for composite molding may increase, making molding difficult. However, such problems do not occur within the above range. In the present invention, the weight-average molecular weight of the polymer having acidic groups is determined by dissolving the target substance in a solvent and analyzing it by gel permeation chromatography (GPC).
Examples of the mass average molecular weight of the polymer having an acidic group include 1,000 to 5,000,000, 1,000 to 2,000,000, 1,000 to 1,000,000, 2,000 to 5,000,000, 2,000 to 2,000,000, 2,000 to 1,000,000, 5,000 to 5,000,000, 5,000 to 2,000,000, and 5,000 to 1,000,000.
The polymer having an acidic group can be used alone or in combination of two or more.

As a combination of a base material and a polymer having an acidic group, a combination of polymers that are compatible in a solution containing both of these components, which serves as a stock solution when producing the composite, is preferred, because this increases the degree of entanglement between the molecules of the base material and the polymer having an acidic group in the composite.
For example, a combination of at least one substrate selected from the group consisting of acrylate polymers, glucans, and sulfonyl group-containing polymers and at least one polymer having an acidic group selected from the group consisting of polymers having carboxyl groups (particularly, acrylate polymers having carboxyl groups, cellulose polymers having carboxyl groups, and natural polymers having carboxyl groups) can be mentioned.
Preferred examples include a combination of an acrylate polymer and a polymer having a carboxyl group (especially an acrylate polymer having a carboxyl group), a combination of a glucan and a polymer having a carboxyl group (especially an acrylate polymer, cellulose polymer, or natural polymer having a carboxyl group), and a combination of a sulfonyl group-containing polymer and a polymer having a carboxyl group (especially an acrylate polymer having a carboxyl group).
Particularly preferred are combinations of polymethyl methacrylate (PMMA) and polyacrylic acid (PAA), combinations of starch and polyacrylic acid (PAA), combinations of starch and carboxymethyl cellulose (CMC), combinations of starch and alginic acid, combinations of polyethersulfone (PES) and polyacrylic acid (PAA), and combinations of polysulfone (PSU) and polyacrylic acid (PAA).

Manufacturing method of the composite: A solution or suspension containing a substrate and a polymer having acidic groups (hereinafter sometimes referred to as "adsorbent stock solution") is brought into contact with a poor solvent for the substrate, whereby the adsorbent stock solution solidifies to obtain a composite containing the substrate and a polymer having acidic groups.

The solvent for dissolving or suspending the substrate and the polymer having an acidic group may be any solvent capable of dissolving or suspending a mixture of the substrate and the polymer having an acidic group, and examples thereof include water, a hydrophilic solvent, a polar solvent, and a hydrophobic solvent. From the viewpoint of formability, the solvent is preferably capable of dissolving both the substrate and the polymer having an acidic group. Furthermore, the solvent may be one that is not soluble at room temperature but dissolves when heated.
Examples of hydrophilic or polar solvents include lower alcohols such as methanol, ethanol, isopropyl alcohol, and butanol; glycols such as ethylene glycol and propylene glycol; ketones such as acetone and methyl ethyl ketone; alkyl ethers such as diethyl ether, tetrahydrofuran, and dimethoxyethane; dimethyl sulfoxide; dimethylacetamide; dimethylformamide; N-methylpyrrolidone; acetonitrile; and dioxane.
Examples of hydrophobic solvents include aromatic compounds such as benzene, toluene, and xylene; aliphatic hydrocarbon compounds such as hexane and cyclohexane; acetate esters such as methyl acetate and ethyl acetate; and halogenated hydrocarbon compounds such as chloroform and dichloromethane.
Among these, water, hydrophilic solvents, and/or polar solvents are preferred because they can be easily removed with water in a subsequent washing step, and among these, water, lower alcohols, dimethyl sulfoxide, dimethylacetamide, etc. are preferred because they have a proven track record of being used in the production of existing materials used in extracorporeal blood circulation applications, such as as a stock solvent for hollow fiber membranes for dialyzers. Furthermore, when the base material or the polymer having an acidic group is a natural polymer, the solvent is preferably water.
One or more solvents can be used.

The ratio of the base material to the polymer having acidic groups is preferably 1 part by weight or more (particularly more than 1 part by weight) of the base material per 1 part by weight of the polymer having acidic groups, on a dry weight basis, and can also be 2 parts by weight or more, 5 parts by weight or more, 10 parts by weight or more, or 30 parts by weight or more. Within this range, the complex can be formed into a specific shape, such as a particle or thread, and the complex can maintain its shape without disintegrating during use of the adsorbent. Furthermore, the polymer having acidic groups can be prevented from detaching from the complex and contaminating the sample to be adsorbed during use of the adsorbent.
The ratio of the base material to the polymer having an acidic group is preferably 50 parts by weight or less, more preferably 40 parts by weight or less, even more preferably 30 parts by weight or less, and even more preferably 20 parts by weight or less, of the base material per 1 part by weight of the polymer having an acidic group, on a dry weight basis. It can also be 10 parts by weight or less. If the base material contains polyvalent metal ions, the amount of the polyvalent metal ions supported will be sufficient, resulting in practically sufficient phosphorus adsorption capacity.
The ratio of the base material to the polymer having an acidic group to be used is, for example, 1 to 50 parts by weight (particularly, more than 1 part by weight and not more than 50 parts by weight), 1 to 40 parts by weight (particularly, more than 1 part by weight and not more than 40 parts by weight), 1 to 30 parts by weight (particularly, more than 1 part by weight and not more than 30 parts by weight), 1 to 20 parts by weight (particularly, more than 1 part by weight and not more than 20 parts by weight), or 1 to 10 parts by weight (particularly, more than 1 part by weight and not more than 1 part by weight) of the base material relative to 1 part by weight of the polymer having an acidic group. Parts by weight of the hydroxybenzoate may be 10 parts by weight or less), 2 parts by weight to 50 parts by weight, 2 parts by weight to 40 parts by weight, 2 parts by weight to 30 parts by weight, 2 parts by weight to 20 parts by weight, 2 parts by weight to 10 parts by weight, 5 parts by weight to 50 parts by weight, 5 parts by weight to 40 parts by weight, 5 parts by weight to 30 parts by weight, 5 parts by weight to 20 parts by weight, 5 parts by weight to 10 parts by weight, 10 parts by weight to 50 parts by weight, 10 parts by weight to 40 parts by weight, 10 parts by weight to 30 parts by weight, 10 parts by weight to 20 parts by weight, 30 parts by weight to 50 parts by weight, and 30 parts by weight to 40 parts by weight.

The concentration of the substrate in the adsorbent stock solution is preferably 2.5 wt% or more, more preferably 3 wt% or more, and even more preferably 5 wt% or more, based on the total amount of the adsorbent stock solution. It is also preferably 50 wt% or less, more preferably 30 wt% or less, and even more preferably 20 wt% or less. Within this range, contact between the adsorbent stock solution and the poor solvent for the substrate allows the composite to be formed into a shape suitable for the adsorbent, such as particles or threads. Depending on the type of substrate, a gel-like composite may be obtained, but within the above concentration range, a gel mass can be formed in the poor solvent for the substrate.
Examples of the substrate concentration relative to the total amount of the adsorbent stock solution include 2.5% by weight to 50% by weight, 2.5% by weight to 30% by weight, 2.5% by weight to 20% by weight, 3% by weight to 50% by weight, 3% by weight to 30% by weight, 3% by weight to 20% by weight, 5% by weight to 50% by weight, 5% by weight to 30% by weight, and 5% by weight to 20% by weight.

The concentration of the polymer having acidic groups in the adsorbent stock solution is preferably 0.3 wt% or more, more preferably 0.5 wt% or more, more preferably 1 wt% or more, and even more preferably 2 wt% or more, based on the total amount of the adsorbent stock solution. It is also preferably 15 wt% or less, more preferably 10 wt% or less, and even more preferably 5 wt% or less. Within this range, contact between the adsorbent stock solution and the poor solvent for the substrate allows the composite to be formed into a shape suitable for the adsorbent, such as particles or threads. Depending on the type of substrate, a gel-like composite may be obtained, but within the above concentration range, a gel mass can be formed in the poor solvent for the substrate.
Examples of the concentration of the polymer having acidic groups relative to the total amount of the adsorbent stock solution include 0.3 wt% to 15 wt%, 0.3 wt% to 10 wt%, 0.3 wt% to 5 wt%, 0.5 wt% to 15 wt%, 0.5 wt% to 10 wt%, 0.5 wt% to 5 wt%, 1 wt% to 15 wt%, 1 wt% to 10 wt%, 1 wt% to 5 wt%, 2 wt% to 15 wt%, 2 wt% to 10 wt%, and 2 wt% to 5 wt%.

The adsorbent stock solution is discharged in the form of droplets into a poor solvent for the substrate, and the adsorbent stock solution solidifies upon contact with the poor solvent, yielding particles containing a complex of the substrate and a polymer having an acidic group.
Alternatively, particles containing a composite of a substrate and a polymer having an acidic group can be obtained by dissolving or melting a substrate and a polymer having an acidic group in a solvent by heating, and then cooling the polymer solution dropwise. In order to eject the adsorbent stock solution in the form of droplets into the poor solvent for the substrate, for example, the adsorbent stock solution may be dropped into the poor solvent for the substrate in the form of droplets, or a nozzle having holes containing the adsorbent stock solution may be rotated in the poor solvent for the substrate to scatter the adsorbent stock solution in the form of droplets.
The adsorbent stock solution can be prepared by heating it to about 50 to 80°C as needed. The particle size of the particles produced can be controlled by adjusting the discharge port diameter of the adsorbent stock solution, the polymer concentration of the adsorbent stock solution, the temperature, the viscosity, etc.

Furthermore, by adjusting the viscosity of the adsorbent stock solution and discharging the adsorbent stock solution into a poor solvent for the substrate in the form of a thread, a thread containing a composite of the substrate and a polymer having an acidic group can be obtained. For example, a thread-like composite can be obtained by allowing the adsorbent stock solution to flow down into the poor solvent for the substrate, or by rotating a nozzle with holes containing the adsorbent stock solution in the poor solvent for the substrate to continuously discharge the adsorbent stock solution. A hollow fiber can be obtained by using an orifice with a ring-shaped discharge port.
In this case, a fibrous composite can be obtained by adjusting the polymer concentration, temperature, viscosity, etc. of the adsorbent stock solution, by intermittently discharging the adsorbent stock solution, or by cutting the threads.
The thread-like or fibrous composite can be used by processing it into any desired shape such as a film, a column (columnar block), etc. The molding can be carried out, for example, by a papermaking process.

In either case, the resulting composite can be washed with water to remove any remaining solvent or other unwanted components. The composite can be used in a wet state or after drying.

Depending on the type of base material and the polymer containing acidic groups, the resulting complex may become gel-like. For example, when using natural polymers such as starch, agarose, agar, gelatin, or collagen as the base material, the adsorbent stock solution is heated to approximately 80-100°C and then cooled to approximately 0-30°C, causing the adsorbent stock solution to gel or a gel containing the complex to precipitate. The gel containing the complex can then be washed with water to remove any unnecessary components, such as the solvent, remaining in the complex. The complex can also be used in a wet state or after drying.

(C) Polyvalent Metal Ions The complex in the adsorbent of the present invention may further contain polyvalent metal ions.
Examples of polyvalent metal ions include alkaline earth metal ions (calcium ion (Ca ²⁺ ), strontium ion (Sr ²⁺ ), barium ion (Ba ²⁺ )), iron group element ions (iron ion (Fe ²⁺ , Fe ³⁺ ), cobalt ion (Co ²⁺ ), nickel ion (Ni ²⁺ )), magnesium group element ions (magnesium ion (Mg ²⁺ ), zinc ion (Zn ²⁺ ), beryllium ion (Be ²⁺ )), tin group element ions (titanium ion (Ti ⁴⁺ ), zirconium ion (Zr ³⁺ , Zr ⁴⁺ ), tin ion (Sn ²⁺ , Sn ⁴⁺ , Sn ⁶⁺ ), hafnium ion (Hf ⁴⁺ )), aluminum group element ions (aluminum ion (Al ³⁺ ), gallium ion (Ga ³⁺ ), indium ion (In ³⁺ )), and rare earth element ions (yttrium ion (Y ^{3+ ))} . ), lanthanum ion (La ³⁺ ), cerium ion (Ce ³⁺ , Ce ⁴⁺ ), praseodymium ion (Pr ³⁺ ), neodymium ion (Nd ³⁺ ), samarium ion (Sm ³⁺ ), europium ion (Eu ³⁺ )), copper group element ions (copper ion (Cu ²⁺ ), gold ion (Au ³⁺ )), platinum group element ions (platinum ion (Pt ²⁺ , Pt ⁴⁺ )), manganese group element ions (manganese ion (Mn ²⁺ ), rhenium ion (Re ⁴⁺ , Re ⁷⁺ )), earth element ions (niobium ion (Nb ²⁺ , Nb ³⁺ , Nb ⁴⁺ , Nb ⁵⁺ ), tantalum ions (Ta ²⁺ , Ta ³⁺ , Ta ⁴⁺ , Ta ⁵⁺ )), chromium group element ions (molybdenum ion (Mo ⁴⁺ )), lanthanide ions (thorium ion (Th ⁴⁺ )), etc.
Among these, trivalent or higher (e.g., trivalent to hexavalent), especially trivalent, polyvalent metal ions are preferred because they are advantageous for forming crosslinks with polymers having acidic groups and have a high bonding strength with phosphate ions. Among these, Fe ³⁺ , Al ³⁺ , and La ³⁺ are more preferred, and Fe ³⁺ , which is abundant in blood and has low toxicity, is even more preferred. When the polyvalent metal ion is Fe ³⁺ , the adsorbent can be suitably used for extracorporeal blood circulation applications. Note that the adsorbent of the present invention can be used for extracorporeal blood circulation applications, even if it is a polyvalent metal ion other than Fe ³⁺ , as long as it has low toxicity. Furthermore, among divalent polyvalent metal ions, Ca ²⁺ is preferred because it can provide high phosphorus adsorption capacity.
One or more types of polyvalent metal ions can be used.

In order to obtain the effects of the present invention, the combination of the substrate and/or the polymer having an acidic group with the polyvalent metal ion is not particularly important. However, for example, an example of a combination of a substrate, a polymer having an acidic group, and a polyvalent metal ion is a combination of at least one substrate selected from the group consisting of acrylate polymers, glucans, and sulfonyl group-containing polymers, at least one polymer having an acidic group selected from the group consisting of polymers having a carboxyl group (particularly, acrylate polymers having a carboxyl group, cellulose polymers having a carboxyl group, and natural polymers having a carboxyl group), and at least one polyvalent metal ion selected from the group consisting of alkaline earth metal ions, iron group element ions, and rare earth element ions.
Among these, there can be mentioned a combination of an acrylate polymer, a polymer having a carboxyl group (particularly, an acrylate polymer having a carboxyl group), and an iron group element ion (particularly, iron ion); a combination of a glucan, a polymer having a carboxyl group (particularly, an acrylate polymer, cellulose polymer, or natural polymer having a carboxyl group), and an alkaline earth metal ion (particularly, calcium ion), an iron group element ion (particularly, iron ion), or a rare earth element ion (particularly, lanthanum ion); and a combination of a sulfonyl group-containing polymer, a polymer having a carboxyl group (particularly, an acrylate polymer having a carboxyl group), and an iron group element ion (particularly, iron ion).
Among these, there may be mentioned a combination of polymethyl methacrylate (PMMA), polyacrylic acid (PAA), and iron ions, a combination of starch, polyacrylic acid (PAA), and iron ions, a combination of starch, carboxymethyl cellulose (CMC), and iron ions, a combination of starch, alginic acid, and calcium ions, iron ions, or lanthanum ions, a combination of starch, carboxymethyl cellulose (CMC), and calcium ions, iron ions, or lanthanum ions, a combination of polyethersulfone (PES), polyacrylic acid (PAA), and iron ions, and a combination of polysulfone (PSU), polyacrylic acid (PAA), and iron ions.

Method for producing a composite containing polyvalent metal ions By contacting a solution or suspension (adsorbent stock solution) containing a substrate and a polymer having acidic groups with an aqueous solution of a polyvalent metal salt (especially an aqueous solution), a cation exchange reaction occurs between the counter ions and polyvalent metal ions in the acidic groups of the polymer having acidic groups, and the polymer having acidic groups electrostatically bonded to the polyvalent metal ions is composited with the substrate, thereby forming a composite of the substrate, the polymer having acidic groups, and the polyvalent metal ions.
The aqueous solution of the polyvalent metal salt is a poor solvent for the substrate.

The polyvalent metal salt may be any water-soluble salt, and examples thereof include halides (fluorides, chlorides, bromides, iodides), sulfates, nitrates, perchlorates, acetates, sulfides, hydroxides, and borides.
Specifically, calcium fluoride, calcium chloride, calcium bromide, calcium iodide, calcium nitrate, calcium chlorate, calcium perchlorate, calcium permanganate; strontium nitrate, strontium chloride, strontium bromide; barium acetate, barium chloride, barium bromide, barium chlorate, barium perchlorate, barium cyanide; iron chloride (ferrous chloride, ferric chloride), iron bromide (ferrous bromide, ferric bromide), iron nitrate (ferrous nitrate, ferric nitrate), iron sulfate (ferrous sulfate, ferric sulfate), iron sulfide (ferric sulfide), iron perchlorate (ferric perchlorate); cobalt chloride, cobalt bromide, cobalt nitrate, cobalt sulfate, cobalt chlorate, cobalt perchlorate; nickel chloride, Nickel chloride, nickel chlorate, nickel perchlorate; magnesium acetate, magnesium thiosulfate, magnesium fluoride, magnesium chloride, magnesium bromide, magnesium iodide, magnesium hydride, magnesium diboride, magnesium sulfate, magnesium nitrate, magnesium phosphate, magnesium chlorate, magnesium perchlorate; zinc chloride, zinc sulfide, zinc sulfate, zinc chlorate; beryllium chloride, beryllium perchlorate, beryllium sulfate; titanium chloride; zirconium sulfate, zirconium chloride; tin sulfide, tin fluoride, tin chloride, tin bromide; hafnium fluoride, hafnium chloride; aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum perchlorate; indium bromide Gallium chloride, gallium sulfate, gallium nitrate; Yttrium chloride, yttrium bromide, yttrium nitrate, yttrium orthovanadate, yttrium dioxide sulfide; Lanthanum chloride, lanthanum acetate, lanthanum nitrate, lanthanum bromate, lanthanum nitrate, lanthanum selenate, lanthanum bromate; Cerium hydroxide, cerium fluoride, cerium chloride, cerium bromide, cerium iodide, cerium sulfate, cerium nitrate, cerium perchlorate, cerium sulfide, cerium oxalate, cerium acetate; Praseodymium chloride, praseodymium nitrate, praseodymium sulfate, praseodymium bromate; Neodymium nitrate, neodymium hydroxide, neodymium sulfate, neodymium fluoride, neodymium chloride, neodymium bromide, neodymium iodide, bromine Examples of the organic solvent include neodymium acetate, neodymium boride, neodymium acetate, samarium chloride, samarium sulfide, europium chloride, europium sulfide, europium oxychloride, europium sulfate, europium nitrate, europium acetate, copper sulfide, copper nitrate, copper chloride, copper bromide, copper sulfate, copper chlorate, gold fluoride, gold chloride, gold bromide, gold iodide, gold hydroxide, tetrachloroauric acid, platinum chloride, manganese chloride, manganese bromide, manganese sulfate, manganese nitrate, perrhenic acid, ammonium perrhenate, rhenium sulfide, niobium fluoride, niobium chloride, niobium bromide, niobium iodide, niobium sulfide, tantalum sulfide, tantalum fluoride, tantalum chloride, tantalum bromide, tantalum iodide, molybdenum sulfide, and thorium nitrate.

The concentration of the polyvalent metal salt in the aqueous solution of the polyvalent metal salt is preferably 1% by weight or more, more preferably 5% by weight or more, and even more preferably 10% by weight or more, based on the total amount of the aqueous solution. Within this range, polyvalent metal ions can be sufficiently bonded to the acidic groups of the acidic group-containing polymer.
Furthermore, the concentration of the polyvalent metal salt in the aqueous solution of polyvalent metal salt is preferably 50% by weight or less, more preferably 20% by weight or less, and even more preferably 15% by weight or less, based on the total amount of the aqueous solution. If the concentration of the polyvalent metal salt in the aqueous solution of polyvalent metal salt is extremely high, the adsorbent stock solution may not sink into the aqueous solution of polyvalent metal salt, and a composite with the intended shape may not be formed, or the polyvalent metal ions may not be sufficiently impregnated into the interior of the composite. However, if the concentration is within this range, the polyvalent metal ions can be sufficiently impregnated into the interior of the composite.
Examples of the concentration of the polyvalent metal salt in the aqueous solution of the polyvalent metal salt include 1% by weight to 50% by weight, 1% by weight to 20% by weight, 1% by weight to 15% by weight, 5% by weight to 50% by weight, 5% by weight to 20% by weight, 5% by weight to 15% by weight, 10% by weight to 50% by weight, 10% by weight to 20% by weight, and 10% by weight to 15% by weight.

The aqueous solution is typically an aqueous solution, but may also be a mixture of water and a hydrophilic or polar solvent.
Examples of hydrophilic or polar solvents include lower alcohols such as methanol, ethanol, isopropyl alcohol, and butanol; glycols such as ethylene glycol and propylene glycol; ketones such as acetone and methyl ethyl ketone; alkyl ethers such as diethyl ether, tetrahydrofuran, and dimethoxyethane; dimethyl sulfoxide; dimethylacetamide; dimethylformamide; N-methylpyrrolidone; acetonitrile; and dioxane.
One or more hydrophilic or polar solvents can be used.
In the case of a mixture of water and a hydrophilic or polar solvent, the water content is preferably 80% by volume or more.

As described above, by discharging the adsorbent stock solution in the form of droplets into a poor solvent for the substrate, the adsorbent stock solution solidifies upon contact with the poor solvent, resulting in a composite of the substrate and a polymer having acidic groups. By immersing this composite of the substrate and the polymer having acidic groups in an aqueous solution of a polyvalent metal salt, particles containing a composite of the substrate, the polymer having acidic groups, and polyvalent metal ions are obtained. Alternatively, by discharging the adsorbent stock solution in the form of droplets into a poor solvent for the substrate containing the polyvalent metal salt, for example, an aqueous solution of the polyvalent metal salt, coagulation and the addition of polyvalent metal ions can proceed in parallel, allowing particles containing a composite of the substrate, the polymer having acidic groups, and polyvalent metal ions to be efficiently obtained.
As mentioned above, particles containing a composite of a substrate and a polymer having acidic groups can also be obtained by dissolving or melting a substrate and a polymer having acidic groups in a solvent by heating, and then cooling the resulting polymer solution dropwise. In this case, particles containing a composite of a substrate, a polymer having acidic groups, and a polyvalent metal ion can also be obtained by immersing this composite in an aqueous solution of a polyvalent metal salt, or by discharging the adsorbent stock solution in the form of droplets into the aqueous solution of a polyvalent metal salt.
The adsorbent stock solution can be prepared by heating it to about 50 to 80°C as needed. The particle size of the particles produced can be controlled by adjusting the discharge port diameter of the adsorbent stock solution, the polymer concentration of the adsorbent stock solution, the temperature, the viscosity, etc.

Furthermore, by adjusting the viscosity of the adsorbent stock solution and discharging the adsorbent stock solution in the form of a thread into an aqueous solution of a polyvalent metal salt, a thread containing a complex of the substrate, a polymer having acidic groups, and a polyvalent metal ion can be obtained. Alternatively, by discharging the viscosity-adjusted adsorbent stock solution in the form of a thread into a poor solvent solution of the substrate, allowing it to solidify, and then immersing the resultant in an aqueous solution of a polyvalent metal salt, a thread containing a complex of the substrate, a polymer having acidic groups, and a polyvalent metal ion can also be obtained.
In this case, a fibrous composite can be obtained by adjusting the polymer concentration, temperature, viscosity, etc. of the adsorbent stock solution, by intermittently discharging the adsorbent stock solution, or by cutting the threads.
The thread-like or fibrous composite can be used by processing it into any desired shape such as a film, a column (columnar block), etc. The molding can be carried out, for example, by a papermaking process.

In either case, the resulting composite can be washed with water to remove any remaining solvent or other unwanted components. The composite can be used in a wet state or after drying.

Furthermore, as mentioned above, depending on the types of the base material and the polymer having acidic groups, the resulting composite may be in a gel state. If this gel is immersed in an aqueous solution of a polyvalent metal salt, the gel is impregnated with polyvalent metal ions, and a gel-like composite of the base material, the polymer having acidic groups, and the polyvalent metal ions is obtained.
The gel containing the complex may be washed with water to remove unnecessary components such as the solvent remaining in the complex. The complex may be used in a wet state or after drying.

Characteristics of the Complex : When the complex is granular, it can be formed into various shapes, including spherical, prolate spheroidal (ellipsoidal), cylindrical, and irregular. The average particle size is preferably 100 μm or greater, more preferably 500 μm or greater, and even more preferably 1 mm or greater. Because particles within this range are significantly larger than blood cells (diameter: 2 μm to 20 μm), they can be used to remove AGEs not only from plasma but also from whole blood. When whole blood is passed through a column packed with an adsorbent containing the complex, a filter with a mesh size smaller than the particle size of the adsorbent is installed to prevent the adsorbent from leaking from the column. However, if the complex particles are sufficiently larger than the blood cells, a filter with a mesh size larger than the blood cells can be used, allowing the blood cells to pass through the filter without clogging and preventing the adsorbent from leaking from the column.
The particle size is preferably an average particle diameter of 1 cm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. Within this range, the contact area with the sample to be adsorbed is large, resulting in good adsorption efficiency.
When the complex is in a granular form, the average particle size may be, for example, 100 μm to 1 cm, 100 μm to 5 mm, 100 μm to 3 mm, 500 μm to 1 cm, 500 μm to 5 mm, 500 μm to 3 mm, 1 mm to 1 cm, 1 mm to 5 mm, or 1 mm to 3 mm.
In the present invention, the average particle size is a value measured by a sieving method.

When the complex is fibrous, the average fiber diameter is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 200 μm or more, and is preferably 1 mm or less, more preferably 500 μm or less, and even more preferably 300 μm or less. Since this range is sufficiently larger than the diameter of blood cells, it can also be used to remove AGEs from whole blood. Furthermore, the contact area with the sample to be adsorbed is sufficient, resulting in good adsorption efficiency.
When the composite is in a fibrous form, the average fiber diameter may be 50 μm to 1 mm, 50 to 500 μm, 50 μm to 300 μm, 100 μm to 1 mm, 100 μm to 500 μm, 100 μm to 300 μm, 200 μm to 1 mm, 200 to 500 μm, or 200 μm to 300 μm.
The average fiber length should be between 500 μm and 10 cm. This range makes it easy to pack into a column and to further mold the fibers. The average aspect ratio should be between 10 and 10,000. "Average aspect ratio" refers to the ratio of the average fiber length to the average fiber diameter (average fiber length/average fiber diameter).
In the present invention, the average fiber diameter, average fiber length, and average aspect ratio are values calculated from the results of measuring the dimensions of at least 20 randomly selected fibers using an electron microscope, optical microscope, or the like depending on the size of the fibers.

When the composite is in a filamentous form, if the fiber diameter (or outer diameter in the case of hollow fibers) is too small, it may increase the pressure loss in the column or the fibers themselves may pass through the filter. On the other hand, if it is too large, the contact area with the sample to be adsorbed decreases, resulting in poor removal efficiency. Therefore, the fiber diameter is preferably 30 μm or more, more preferably 50 μm or more, and even more preferably 70 μm or more, and is preferably 1 mm or less, more preferably 500 μm or less, and even more preferably 300 μm or less.
When the complex is in the form of a thread, the thread diameter may be, for example, 30 μm to 1 mm, 30 μm to 500 μm, 30 μm to 300 μm, 50 μm to 1 mm, 50 μm to 500 μm, 50 μm to 300 μm, 70 μm to 1 mm, 70 μm to 500 μm, or 70 μm to 300 μm.
Furthermore, when the composite is in the form of a hollow fiber, the inner diameter is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 120 μm or more, and is preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 180 μm or less. Within this range, when the sample to be adsorbed is whole blood, blood cells do not clog the fiber lumen when the sample is passed through the lumen. Furthermore, the contact area between the fiber lumen surface and the sample, including the sample to be adsorbed, is sufficient, resulting in good adsorption efficiency.
When the composite is in the form of a hollow fiber, the inner diameter may be 50 μm to 250 μm, 50 μm to 200 μm, 50 μm to 180 μm, 100 μm to 250 μm, 100 μm to 200 μm, 100 μm to 180 μm, 120 μm to 250 μm, 120 μm to 200 μm, or 120 μm to 180 μm.

Preferably the composite is porous.
Porous composite particles can be produced, for example, by the following method: A stock solution of an adsorbent, prepared by dissolving a substrate and a polymer having acidic groups in a mixed solution of a good solvent and a poor solvent for the substrate, is discharged in the form of droplets into a solution containing a poor solvent for the substrate, and non-solvent-induced phase separation is allowed to proceed and solidification is carried out, thereby obtaining porous particles made of the substrate and the polymer having acidic groups.
Furthermore, when a composite containing polyvalent metal ions is to be obtained, the porous particles can be immersed in an aqueous solution of a polyvalent metal salt to obtain porous particles containing a composite of a substrate, a polymer having acidic groups, and polyvalent metal ions. Furthermore, by dissolving the substrate and a polymer having acidic groups in a mixed solution of a good solvent and a poor solvent for the substrate, and then discharging the resulting adsorbent stock solution in the form of droplets into a poor solvent for the substrate in which a polyvalent metal salt has been dissolved, phase separation and the incorporation of polyvalent metal ions can be carried out in parallel, thereby efficiently obtaining porous particles containing a composite of a substrate, a polymer having acidic groups, and polyvalent metal ions.

Alternatively, porous particles consisting of the base material and a polymer having acidic groups can be obtained by dropping an adsorbent stock solution in which the base material has been dissolved at high temperature and cooling it to cause thermally induced phase separation and solidification.
In addition, when a complex containing a polyvalent metal ion is to be obtained, porous particles containing a complex of a substrate, a polymer having an acidic group, and a polyvalent metal ion can be obtained by immersing porous particles in an aqueous solution of a polyvalent metal salt. Alternatively, porous particles containing a complex of a substrate, a polymer having an acidic group, and a polyvalent metal ion can also be obtained by dissolving a substrate in an aqueous solution of a polyvalent metal salt at high temperature and discharging the resulting adsorbent stock solution in the form of droplets.

However, if starch, gelatin, or the like is used as the base material and water or a hydrophilic solvent containing water is used as the solvent for dissolving or suspending the base material and the polymer with acidic groups, a gel-like composite is obtained, but this gel is not porous.

If the composite is porous, the average pore radius measured using a differential scanning calorimeter (DSC) should be 0.5 nm or more, preferably 1.5 nm or more, and preferably 2 nm or more, and 200 nm or less, preferably 40 nm or less, and 25 nm or less. This range allows for efficient adsorption of AGEs. If the pore diameter is too large, the contact area between the adsorbent and the sample to be adsorbed decreases, resulting in low adsorption efficiency. On the other hand, if the pore diameter is too small, the sample to be adsorbed cannot penetrate into the pores, preventing effective use of the inner pore surface, resulting in low adsorption efficiency.
Examples of the average pore radius measured using DSC include 0.5 nm to 200 nm, 0.5 nm to 40 nm, 0.5 nm to 25 nm, 1.5 nm to 200 nm, 1.5 nm to 40 nm, 1.5 nm to 25 nm, 2 nm to 200 nm, 2 nm to 40 nm, and 2 nm to 25 nm.
Furthermore, the pore specific surface area measured using a differential scanning calorimeter (DSC) is preferably 10 m ² /g or more, more preferably 20 m ² /g or more, and even more preferably 50 m ² /g or more, and is preferably 1000 ^{m 2} /g or less, more preferably 800 ^{m 2} /g or less, and even more preferably 500 m ² /g or less. By increasing the pore specific surface area, adsorption performance can be improved. On the other hand, if the pore specific surface area is extremely large, the mechanical strength of the adsorbent will be insufficient. Within this range, the contact area with the sample to be adsorbed is sufficient, resulting in good adsorption efficiency and sufficient mechanical strength.
Examples of the pore specific surface area measured using DSC include 10 m ² /g to 1000 ^{m 2} /g, 10 m ² /g to 800 ^{m 2} /g, 10 m ² /g to 500 m ² /g, 20 m 2 /g to 1000 m ² /g, 20 m ² /g to 800 ^{m 2 /} g, 20 m ^{2 /g to 500 m 2 /} g, 50 m ² /g to 1000 m ² /g, 50 m ² /g to 800 ^{m 2} /g, and 50 m ² /g to 500 m ² /g.

When the composite contains polyvalent metal ions, the polyvalent metal concentration in the resulting composite is preferably 1 wt% or more, more preferably 2 wt% or more, and even more preferably 5 wt% or more, based on the total amount (dry weight) of the composite. This range ensures sufficient adsorption efficiency for practical use. Furthermore, if the polyvalent metal concentration is extremely high, there is a possibility of leakage of the polyvalent metal or the degree of cross-linking may become too high, making the composite brittle. From these viewpoints, the polyvalent metal concentration in the composite is preferably 30 wt% or less, more preferably 20 wt% or less, and even more preferably 10 wt% or less, based on the total amount (dry weight) of the composite.
Examples of the polyvalent metal concentration relative to the total amount (dry weight) of the complex include 1 wt % to 30 wt %, 1 wt % to 20 wt %, 1 wt % to 10 wt %, 2 wt % to 30 wt %, 2 wt % to 20 wt %, 2 wt % to 10 wt %, 5 wt % to 30 wt %, 5 wt % to 20 wt %, and 5 wt % to 10 wt %.
When the polyvalent metal is iron, the polyvalent metal concentration in the composite is a value measured by the method described in the Examples section. When the polyvalent metal is other than iron, the measurement is performed in accordance with this method using an inductively coupled plasma (ICP) optical emission spectrometer.

(2) Adsorbent The adsorbent of the present invention may consist of the above-mentioned complex, or may consist of the above-mentioned complex and other components, such as adsorbents for other AGEs and adsorbents for other substances (cytokines such as IL-6, IL-8, and TNF-α, blood components such as LDL, VLDL, phosphorus, and β2-microglobulin, heavy metals, etc.).
When the adsorbent is composed of the above-described composite and other components, its shape can be, similar to the composite described above, granular, fibrous, thread-like, membrane-like, columnar, etc. Furthermore, the physical properties of the entire adsorbent, such as the average particle size, average fiber diameter, average fiber length, aspect ratio, outer diameter and inner diameter of the thread, average pore radius, pore specific surface area, and polyvalent metal content, can also be similar to those of the composite described above.

The adsorbent of the present invention can be used to adsorb AGEs in blood, or to adsorb AGEs and phosphorus in blood, during blood processing, in which blood taken from a human is returned to the same human after processing. For example, in a hemodialysis circuit, the adsorbent of the present invention can be placed in series or parallel with a hemodialyzer. The adsorbent of the present invention is suitable for adsorption on blood (including whole blood, serum, plasma, etc.). It can also be used to adsorb AGEs and phosphorus in foods, cosmetics, and pharmaceuticals such as blood products.

Since it is generally desirable to remove AGEs, the adsorbent of the present invention can also be considered as a material for removing AGEs. Therefore, in the present invention, the sample to which AGEs are adsorbed includes a material to which AGEs are removed.
Furthermore, when the complex contains polyvalent metal ions, it can also adsorb phosphorus, and since it is usually desirable to remove phosphorus, the adsorbent of the present invention can also be considered a material for removing AGEs and phosphorus. Therefore, in the present invention, the sample to which AGEs and phosphorus are to be adsorbed includes the material to which AGEs and phosphorus are to be removed.

The adsorbent of the present invention can typically be packed into a column container and used as a column. A column packed with the adsorbent of the present invention can be used as a column for adsorbing or removing AGEs. When the complex contains a polyvalent metal ion, it can be used as a column for adsorbing or removing AGEs and phosphorus.

Furthermore, if the dialysate material (usually formed in a hollow fiber shape) of a hemodialyzer is made from the adsorbent of the present invention, the hemodialyzer will have the ability to adsorb AGEs, or AGEs and phosphorus.

As mentioned above, AGEs is a general term for end products formed when various metabolic products of glucose bind to proteins and then undergo further reactions such as oxidation, dehydration, and condensation. AGEs whose structures have been elucidated include carboxymethyllysine, carboxyethyllysine, carboxymethylarginine, pentosidine, crosslin, fluorolink, imidazolone, argpyrimidine, pyrropyridine, and pyraline. However, in the present invention, AGEs are not limited to these and include all end products formed in vivo by the binding of sugars and proteins.

The adsorbent of the present invention can achieve an adsorption rate of 10% or more, preferably 30% or more, and more preferably 60% or more of AGEs in a blood sample, regardless of the presence or absence of polyvalent metal ions in the complex. The upper limit of the adsorption rate of AGEs in a blood sample is 100%.
Furthermore, when the complex contains a polyvalent metal ion, the adsorbent of the present invention can have an adsorption rate of phosphorus in a blood sample of 10% or more, preferably 50% or more, and more preferably 80% or more, with the upper limit of the adsorption rate of phosphorus in a blood sample being 100%.

When using the adsorbent and adsorption column of the present invention as medical devices, etc., it is preferable to sterilize or disinfect them before use. Various methods can be used for sterilization or disinfection. Examples include high-pressure steam sterilization, gamma ray sterilization, electron beam sterilization, ethylene oxide gas sterilization, and ultraviolet sterilization. Of these methods, high-pressure steam sterilization, gamma ray sterilization, electron beam sterilization, and ethylene oxide gas sterilization are preferred due to their high sterilization efficiency.

(3) Adsorption Method By bringing the adsorbent of the present invention into contact with a sample to which AGEs (or AGEs and phosphorus) are to be adsorbed or a material to which AGEs (or AGEs and phosphorus) are to be removed, the AGEs (or AGEs and phosphorus) in the sample to which AGEs are to be adsorbed or the material to which AGEs are to be removed are adsorbed onto the adsorbent.
Therefore, the present invention provides a method for adsorbing AGEs (or AGEs and phosphorus), a method for removing AGEs (or AGEs and phosphorus), or a method for producing a sample or material from which AGEs (or AGEs and phosphorus) have been removed or reduced, which comprises a step of contacting the adsorbent of the present invention with a sample or material from which AGEs (or AGEs and phosphorus) are to be adsorbed or removed.

The adsorbent of the present invention can be contacted with a sample to be adsorbed or removed of AGEs (or AGEs and phosphorus) using a batch method. The batch method can be performed by leaving the material to stand, or by stirring or shaking. The contact time should be 1 to 24 hours, preferably 3 to 5 hours. The temperature during contact varies depending on the type of sample to be adsorbed or material to be removed, but should be 10°C to 50°C, preferably 25°C to 45°C.

Contact between the adsorbent of the present invention and the sample to be adsorbed or the material to be removed can also be achieved by a flow separation method, i.e., by passing the sample to be adsorbed or the material to be removed through the adsorbent of the present invention. Examples of such methods include filling a column with the adsorbent of the present invention and passing the sample to be adsorbed or the material to be removed through the column, passing the sample to be adsorbed or the material to be removed through the adsorbent of the present invention formed into a filter, or passing the sample to be adsorbed or the material to be removed through the adsorbent of the present invention formed into a pillar. Examples of filters include membrane filters, hollow fiber membranes, and tubular membranes. Pillars can be used in monolith chromatography as continuous porous bodies with minute pores. Alternatively, the adsorbent of the present invention can be placed on filter paper and the sample to be adsorbed or the material to be removed passed through it.

The method of the present invention can further include a step of separating the sample or material to be adsorbed or removed from which AGEs (or AGEs and phosphorus) have been removed or reduced after contact with the adsorbent, from the adsorbent that has adsorbed AGEs (or AGEs and phosphorus). Separation can be performed by filtration, centrifugation, or the like. That is, the method of the present invention can further include a step of recovering the sample or material from which AGEs (or AGEs and phosphorus) have been removed or reduced from a mixture of the adsorbent of the present invention and the sample or material to be adsorbed or removed from which AGEs (or AGEs and phosphorus) have been removed.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

(1) Test method
Measurement of moisture content of adsorbent After production, the adsorbent was stored immersed in water without being dried, and used as a measurement sample. The adsorbent was removed from the water, and the water adhering to the surface of the adsorbent in the wet state was wiped off with a cloth, and then the weight was measured and this was taken as the weight in the wet state Ww (g).
This adsorbent in a water-containing state was dried under reduced pressure and then reweighed, and this was taken as the weight in a dry state Wd (g).
The moisture content of the adsorbent was calculated using the following formula.

Moisture content of adsorbent (%) = [(Ww(g) - Wd(g))/Ww(g)] x 100

Measurement of AGE adsorption rate Commercially available FBS (Biowest, Colombia) was used.
FBS was added at a ratio of 10 g to 0.5 g of hydrated adsorbent (equivalent to dry weight), and the mixture was stirred with a magnetic stirrer at room temperature for 4 hours. The supernatant was then collected and used as post-adsorption FBS. The FBS without adsorbent was used as pre-adsorption FBS, and the concentrations of carboxymethyllysine (CML), a type of AGE, were measured for both samples using a CircuLex CML/N ^ε -(Carboxymethyl)lysine ELISA Kit (MBL).
The carboxymethyllysine concentration in FBS before adsorption was defined as Cs (μg/mL), and the carboxymethyllysine concentration in FBS after adsorption was defined as Ce (μg/mL). The adsorption rate of carboxymethyllysine in FBS was calculated using Cs (μg/mL), Ce (μg/mL), the weight of the added hydrated phosphate adsorbent Ww (g), the water content u (%) of the phosphate adsorbent, and the weight of FBS added F (g) using the following formula, which corrects for the decrease in carboxymethyllysine concentration due to dilution by the water contained in the phosphate adsorbent.

Adsorption rate of carboxymethyllysine in FBS (%) = [[Cs (μg/mL) - {1 + Ww (g) × (u (%)/100)/F (g)} × Ce (μg/mL)]/Cs (μg/mL)] × 100

Measurement of phosphorus content in FBS
An aqueous solution containing 12 g/L of hexaammonium heptamolybdate tetrahydrate, 0.48 g/L of bis[(+)-tartrate]diantimony(III) dipotassium trihydrate, and 294 g/L of sulfuric acid was prepared as an ammonium molybdate solution.
An aqueous solution containing 72 g/L of L(+)-ascorbic acid was prepared as an ascorbic acid solution.
Immediately before measuring the phosphorus concentration, an ammonium molybdate solution and an ascorbic acid solution were mixed in a volume ratio of 5:1 to prepare a color reagent.
0.8 mL of color reagent was added to 10 mL of the FBS sample to be measured or an FBS sample diluted with water for injection at a specified ratio, and the mixture was stirred for at least 30 seconds using a vortex mixer, then allowed to stand for at least 15 minutes, and the absorbance at 880 nm was measured. This absorbance was used as an index of the phosphorus content in FBS.

Measurement of phosphorus adsorption rate Commercially available FBS (manufactured in Colombia, phosphorus concentration 9.3 mg/dL (3.1 mM), Biowest) was used.
FBS was added at a ratio of 10 g to 0.5 g of hydrated adsorbent (dry weight equivalent). The mixture was stirred for 4 hours at room temperature using a magnetic stirrer, and the supernatant was collected and used as post-adsorption FBS. The FBS without adsorbent was used as pre-adsorption FBS. The pre-adsorption FBS and post-adsorption FBS samples were each diluted 100-fold with water for injection. The absorbance at 880 nm of these diluted solutions was measured using the method described above for measuring the phosphorus content in FBS. The absorbance of pre-adsorption FBS was defined as As, and the absorbance of post-adsorption FBS as Ae. The phosphorus adsorption rate in FBS was calculated using the following formula, corrected for the decrease in phosphorus concentration due to dilution by the water content of the phosphorus adsorbent: As, Ae, the weight of the added hydrated phosphorus adsorbent (Ww) (g), the water content of the phosphorus adsorbent (u) (%), and the weight of added FBS (F) (g).

Phosphorus adsorption rate in FBS (%) = [[As - {1 + Ww(g) × (u(%)/100)/F(g)} × Ae]/As] × 100

(2) Production of adsorbent and evaluation of adsorption performance
Example 1
An adsorbent stock solution was prepared by adding 2.0 g of methyl methacrylate polymer (PMMA, Fujifilm Wako Pure Chemical Corporation) and 0.5 g of polyacrylic acid 250,000 (PAA, Fujifilm Wako Pure Chemical Corporation) to 13.8 g of DMSO and dissolving the mixture in a hot water bath at 80°C while stirring with a magnetic stirrer. This adsorbent stock solution was drawn up with a dropper and immediately added dropwise to 50 mL of water. The resulting particles were then allowed to stand for approximately 24 hours to produce particles. The particles were then collected by filtration, followed by three cycles of washing (dispersion in water) and filtration. Small particles were then removed using a 2 mm sieve, and any deformed or fused particles were visually removed to obtain particles composed of PMMA and PAA.

Example 2
An adsorbent stock solution was prepared by adding 2.0 g of methyl methacrylate polymer (PMMA, Fujifilm Wako Pure Chemical Corporation) and 0.5 g of polyacrylic acid 250,000 (PAA, Fujifilm Wako Pure Chemical Corporation) to 28.7 g of dimethyl sulfoxide (DMSO) and dissolving the mixture in an 80°C water bath while stirring with a magnetic stirrer. This adsorbent stock solution was then drawn up with a dropper and immediately added dropwise to 100 mL of a 10 wt% aqueous solution of ferric chloride (ferric chloride hexahydrate, Fujifilm Wako Pure Chemical Corporation). The mixture was then allowed to stand for approximately 24 hours to produce particles. The particles were then collected by filtration, followed by repeated washing (dispersion in water) and filtration until the color of the wash solution disappeared. After that, small particle diameter components were removed using a sieve with 2 mm openings, and then deformed particles and fused particles were removed by visual inspection to obtain particles consisting of PMMA, PAA, and iron ions.

Comparative Example 1
An adsorbent stock solution was prepared by adding 2.0 g of methyl methacrylate polymer (PMMA, Fujifilm Wako Pure Chemical Industries, Ltd.) to 11.3 g of dimethyl sulfoxide (DMSO) and dissolving the mixture in a magnetic stirrer while heating in an 80°C water bath. This adsorbent stock solution was then drawn up with a dropper and immediately dropped into water. The resulting particles were then allowed to stand for approximately 24 hours to produce particles. The particles were then collected by filtration, and the process of dispersing in water, washing, and collecting by filtration was repeated three times. Small particle sizes were then removed using a 2 mm sieve, and any deformed or fused particles were visually removed to obtain particles composed of PMMA.

The adsorption rates of carboxymethyllysine and phosphorus in FBS were measured when the adsorbents of Examples 1 and 2 and Comparative Example 1 were used, respectively. The results are shown in FIG.
As shown in Figure 1, the adsorbent of Example 1, which was made of PMMA and PAA, adsorbed AGEs (CML) at a high adsorption rate of 70%. The adsorbent of Example 2, which was made of PMMA, PAA, and iron ions, adsorbed AGEs (CML) at 69%, similar to the adsorbent of Example 1, and also adsorbed phosphorus at an extremely high adsorption rate of 95%. In contrast, the particles of Comparative Example 1, which were made of PMMA, did not adsorb either AGEs (CML) or phosphorus at all.

The adsorbent of the present invention efficiently adsorbs AGEs and can therefore be suitably used to remove AGEs from blood circulated outside the body, making it useful for improving diseases caused by AGEs, such as diabetic complications. When the adsorbent of the present invention contains polyvalent metal ions, it also adsorbs phosphorus, making it useful for treating the blood of patients who require a reduction in both phosphorus and AGEs, such as patients with renal failure, a diabetic complication. The adsorbent of the present invention can also be used to remove AGEs and phosphorus from foods, cosmetics, blood products, and the like.

Claims (12)

An advanced glycation end product adsorbent comprising: (A) at least one substrate selected from the group consisting of polymethyl methacrylate, poly(2-methoxyethyl acrylate), polytetrahydrofurfuryl acrylate, polymethyl vinyl ether, ethylene-vinyl alcohol copolymer, polyacrylonitrile, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polystyrene, polyethylene, polysulfone, polyethersulfone, polyarylethersulfone, polycarbonate, polypropylene, cellulose acetate, polylactide, polyglycolide, polycaprolactone, polyethylene oxide-poly(butylene terephthalate) copolymer, and polyethylene glycol; and (B) a composite containing a carboxyl-containing acrylic water-soluble polymer having a mass-average molecular weight of 1,000 to 1,000,000. The adsorbent material of claim 1, wherein the composite is porous. The adsorbent according to claim 1 or 2, wherein (A) the substrate is a water-insoluble polymer. The adsorbent according to any one of claims 1 to 3, wherein (B) the polymer having an acidic group is a water-soluble polymer. The adsorbent according to any one of claims 1 to 4, wherein the complex further contains (C) a polyvalent metal ion. The adsorbent according to claim 5, wherein the polyvalent metal concentration is 1 to 30% by weight based on the total dry weight of the complex. The adsorbent according to claim 5 or 6, further intended for adsorbing phosphorus. A column for adsorbing advanced saccharification end products, packed with the adsorbent described in any one of claims 1 to 4. A column for adsorbing advanced glycation end products and phosphorus, packed with the adsorbent described in claim 5 or 6. A method for producing an adsorbent for advanced glycation end products, comprising the steps of contacting a solution or suspension containing (A) at least one substrate selected from the group consisting of polymethyl methacrylate, poly(2-methoxyethyl acrylate), polytetrahydrofurfuryl acrylate, polymethyl vinyl ether, ethylene-vinyl alcohol copolymer, polyacrylonitrile, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polystyrene, polyethylene, polysulfone, polyethersulfone, polyarylethersulfone, polycarbonate, polypropylene, cellulose acetate, polylactide, polyglycolide, polycaprolactone, polyethylene oxide-poly(butylene terephthalate) copolymer, and polyethylene glycol, and (B) a carboxyl-containing water-soluble acrylic polymer having a mass-average molecular weight of 1,000 to 1,000,000, with (C) a poor solvent for the substrate containing a salt of a polyvalent metal ion. The production method according to claim 10, wherein the content of the (A) substrate in the solution or suspension containing the (A) substrate and the (B) polymer having an acidic group is 1 to 50 parts by weight per 1 part by weight of the ( B ) polymer having an acidic group, in terms of dry weight. A method for producing a sample or material from which advanced glycation end products have been removed or reduced, comprising the step of contacting the adsorbent according to any one of claims 1 to 4 with a sample or material from which advanced glycation end products are to be adsorbed or removed.