JPS63267436A - Bilirubin adsorbent - Google Patents

Abstract

PURPOSE:To adsorb bilirubin selectively by treating the surface of porous articles consisting of copolymers of divinylbenzene (DVB) and glycidylmeth acrylate (GMA) with serum protein or hydrophilic synthetic polymer. CONSTITUTION:Precipitant which is monohydric alcohol having carbon atom. number of 5-12 such as n-amyl alcohol is dissolved in a mixture of a monomer mixture of about 35-99wt.% of DVB and about 1-65wt.% of GMA dispersed at a ratio of about 65-180wt.% of the former based on 100wt.% of the latter in a dispersed water phase. Then porous particles obtained by suspending and polymerizing the monomer mixture are immersed in an aqueous solution of hydrophilic synthetic polymer of serum protein such as albumin or polyvinyl alcohol for surface treatment. Bilirubin in the serum can be selectively adsorbed without setting the blood charge out of balance, by permitting said porous particles to come into contact with the serum of a patient suffering from hyperbilirubinemia as in the case of ion exchange membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bilirubin adsorbent that can effectively and selectively adsorb and remove high aIf bilirubin from blood.

[Prior art and its problems] In symptoms such as acute drug poisoning and fulminant hepatitis, the detoxification metabolic function decreases and the bilirubin concentration in the blood increases. Therefore, for emergency treatment of such symptoms, the direct blood perfusion method is effective, in which blood is circulated extracorporeally and brought into direct contact with an adsorbent, and the high concentration of bilirubin in the blood is adsorbed and removed. Adsorbents for this method include activated carbon,
Ion exchange resins, synthetic resin adsorbents, etc. are being studied and some are being used clinically.

However, although activated carbon is excellent in adsorbing low-molecular-weight substances and middle-molecular old substances, it is difficult to adsorb and remove high-molecular weight substances such as protein-bound bilirubin, and is not satisfactory. Furthermore, since bilirubin itself is an ionic substance in the ion exchange resin, although it has a high adsorption capacity, it also adsorbs other ionic substances in the blood, causing problems such as loss of charge balance. Synthetic resin adsorbents that have no charge do not have the same disadvantages as the ion exchange resins mentioned above, but they still have another problem in that they non-selectively adsorb useful substances such as other proteins and enzymes. There is.

[Means for Solving the Problem] In view of the above-mentioned current situation, the present inventors have conducted intensive research to develop an adsorbent that can effectively and selectively adsorb bilirubin. This has led to the completion of the present invention.

That is, the bilirubin adsorbent of the present invention consists of porous particles made of a copolymer of divinylbenzene (hereinafter referred to as DVB) and glycidyl methacrylate (hereinafter referred to as GMA), which are surface-treated with blood protein or a hydrophilic synthetic polymer. It is characterized by its high selective adsorption to lirubin.

Porous particles that can be used in the present invention include DV
A precipitant is added to the monomer mixture of B and GMA, and after suspension polymerization in water, the resulting copolymer particles are treated with an appropriate purification step to remove the precipitant and unreacted supernatant remaining in the particles. By removing -, (q can be obtained.

In the present invention, the precipitant refers to a solvent that is completely compatible with the monomer but has no affinity for the polymer produced by polymerization, and when the monomer is subjected to suspension polymerization in the coexistence of the solvent. Most of them produce extremely fine secondary polymer particles with a diameter of 1 μm or less, which become aggregates to form porous particles generally called macroreticular porous resins.

The above porous particles (7) that can be used in the present invention
) The DVB/GMA (7) copolymerization ratio is preferably in the range of 35 to 99% by weight/1 to 65% by weight, particularly 6
It is preferably in the range of 5 to 95% by weight and 15 to 35% by weight. If the copolymerization ratio of DVB is less than 35% by weight, the porous particles obtained will not have pores suitable for bilirubin adsorption, and the adsorption performance will be significantly reduced.On the other hand, if it exceeds 99% by weight, the particle surface Because it is extremely hydrophobic in nature, it has poor affinity for water, making the subsequent surface treatment process difficult.

In the porous particles, one copolymer component DV
Of course, high-purity VB can be used as B, but industrial DVB (containing ethylvinylbenzene and various other mixtures, D
VB purity is about 5 oz., and when industrial DVB is used, the copolymerization ratio with GMA is preferably within the range of the above copolymerization ratio based on the DVB content.

As a precipitant that can be used to make the DVB/GMA porous particles porous, a monohydric alcohol having 5 to 12 carbon atoms is preferably used.

Monohydric alcohols with less than 5 carbon atoms have a high solubility in water (for example, n-butanol with 4 carbon atoms dissolves 7.79 times in 100 rn!! of water at 30°C);
During suspension polymerization, it dissolves in the dispersion medium aqueous phase, reduces the amount of alcohol in the hexamer phase, and makes it difficult to achieve the desired porosity.
Furthermore, since the solubility in the alcohol DVB/GMA mixed monomer having more than 12 carbon atoms is poor, a uniform porous state may not be obtained or the strength of the particles may be reduced, which is not preferable. Even monohydric alcohols with 5 to 12 carbon atoms have high solubility in water (for example, tert-amyl alcohol dissolves at 149°C in 100rr11 of water).
is eluted into the aqueous phase of the dispersion medium in the same way as monohydric alcohols with less than 5 carbon atoms, and the desired porosity may not be obtained. In addition, it is generally preferred that the solubility in water (dissolution in 100 m of water at 30°C) is 7 or less, preferably 5 or less, particularly preferably 3 or less.

Specific examples of precipitants that can be preferably used in the present invention include n-amyl alcohol, n-octyl alcohol, 4-methyl-2-pentanol, 3,5.5
, -trimethylhexanol, lauryl alcohol,
2-Ethylhexyl alcohol, diisobutyl carbinol In the present invention, the porous particles can be produced by making the above-mentioned precipitating agent exist in the above-mentioned mixed monomer and carrying out suspension polymerization in an aqueous medium, and the amount of the precipitating agent used is , DV
65 to 100 parts by weight of B/GMA mixed sevens
It is preferable to add 180 parts by weight, especially in the range of 80 to 150 parts by weight. If the amount of precipitant is less than 65 parts by weight, it becomes difficult to obtain good porosity, and if it exceeds 180 parts by weight, porosity becomes excessive and the particles may have low particle strength.

Further, the suspension polymerization method itself is not special, and can be carried out by conventionally known methods. The resulting polymer particles are washed using an appropriate purification method, for example, first washed with water and then methanol, and then subjected to Soxhlet extraction with acetone until a constant weight is reached to remove the precipitant remaining in the particles and any unreacted supernatant. By removing -, porous particles S: can be obtained.

The porous particles with TI9 can be used as they are for adsorbing bilirubin, but they also tend to non-selectively adsorb other useful components in blood. The adsorbent of the present invention is surface-treated with protein or hydrophilic synthetic polymer, and thereby exhibits selective adsorption to bilirubin.

Examples of blood proteins that can be used for surface treatment of the porous particles include albumin, gamma-globulin, fibrinogen, etc., and examples of hydrophilic synthetic polymers include polyvinyl alcohol. For surface treatment of porous particles, if the particles are supplied in a dry state, the particles are immersed in ethanol, thoroughly washed with water to make them hydrophilic, and then mixed with a surface treatment solution. , 37
It can be obtained by boiling at ℃ for 3 hours and then filtering. The surface treatment solution is an aqueous solution of blood plasma protein or hydrophilic synthetic polymer, and its concentration is preferably 0.1 to 10% by weight, particularly preferably 0.2 to 7% by weight.

The surface-treated porous particles can selectively adsorb bilirubin in the serum by contacting them with the serum of a patient with hyperlirubinemia.

[Examples] Hereinafter, the present invention will be described in more detail based on Examples.

Example 1 450 ml of ion-exchanged water was placed in a 1 g separable flask equipped with a stirring blade and condenser installed in a water bath.
g of the dispersant [
Polyvinyl alcohol (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., Gohsenol GH-23>6% aqueous solution 17.59 and NaC11
8g was added and dissolved to form an aqueous phase. DV for this
B (Industrial DVB with 55% DVB content>22.59
A mixed solution/liquid obtained by adding a monomer mixture of GMA 7.59, 4-methyl-2-pentanol 303 as a precipitant, and a polymerization initiator (benzoyl peroxide>0.39) was added under stirring. The polymerization reaction was carried out over 7 hours while increasing the external temperature stepwise from 60°C to 90°C.The reaction solution was filtered through a 100-mesh sieve, and 1q of polymer particles were mixed with water first, then with water. Thoroughly wash with methanol and purify with soxhlet extraction until a constant weight is obtained using acetone. Porous particles with a diameter of about 0.15 to 0.4 m are extracted at a concentration of about 90% of the seven-layered sample. Obtained in yield.

After the porous particles obtained above were immersed in ethanol,
Hydrophilization treatment was performed by thoroughly washing with water. Then, 0.59 (dry weight) of porous particles was placed in a 50 d Erlenmeyer flask, and 10 ml of albumin aqueous solution (5 t3/(H”)
After stirring at 37°C for 3 hours, the mixture was separated.

Next, the filtered particles and 1 rni of serum collected from a patient with hyperbilirubinemia were placed in a test tube and an adsorption test was conducted at 37°C for 2 hours. As a result of measuring the components in serum, the total amount of bilirubin before the adsorption test was 12°65 my/d1, but after the test, 85% of it was adsorbed to 1.90 mff/d,
l! decreased to However, total protein ff16.8
8y/d, Q did not change even after the adsorption test, indicating extremely excellent selective adsorption of bilirubin.

Comparative Example 1 Porous particles prepared in the same manner as in Example 1 were coated with an aqueous albumin solution. ! A bilirubin adsorption test similar to that in Example 1 was conducted without further treatment. the result,
98% of total bilirubin was adsorbed, but 98% of total protein was also adsorbed.
2% was adsorbed, and no selective adsorption was observed.

Example 2 Porous particles prepared in the same manner as in Example 1 were surface-treated with an aqueous T-globulin solution (5 tj/d, l! Ta.

1.0i of dimethyl sulfoxide to 15mg of bilirubin,
0.1M sodium carbonate2. OrI! Add 0.134 MIJ-M buffer solution (117,4) to this solution.
Aluminum standard solution (5,59/d,!) prepared using
The pH was adjusted to 7.4 to prepare a high bilirubin value simulating serum. An adsorption test similar to that in Example 1 was conducted using this simulated serum, and as a result, 97% of total bilirubin was adsorbed, but the adsorption rate of albumin was 43%, indicating selective adsorption.

Example 3 Porous particles prepared in the same manner as in Example 1 were surface-treated with 10 rall of fibrinogen aqueous solution (5 g/cH!), and an adsorption test using high bilirubin value simulated serum was conducted in the same manner as in Example 2. . As a result, 98% of total bilirubin was adsorbed, but the albumin adsorption rate was 60%, indicating selective adsorption.

Example 4 Porous particles prepared in the same manner as in Example 1 were added to an aqueous solution (5 g/d) of polyvinyl alcohol (degree of polymerization 1500).
J! As in Example 2, an adsorption test using a serum simulating a high bilirubin value was conducted on the particles surface-treated with >10 rnl. As a result, 98% of total bilirubin was adsorbed, but the albumin adsorption rate was 77%, indicating selective adsorption.

Comparative Example 2 Porous particles prepared in the same manner as in Example 1 were subjected to an adsorption test using the high bilirubin value simulated serum of Example 2 without surface treatment. As a result, 99% of total bilirubin
However, 92% of albumin was also adsorbed, and no selective adsorption was observed.

[Effects of the Invention] The bilirubin adsorbent of the present invention is made of porous particles made of a copolymer of DV-B and GMA that have been surface-treated with blood plasma protein or a hydrophilic synthetic polymer. It is an excellent material that has high selective adsorption properties and can adsorb effectively.

Claims (4)

[Claims] (1) A selectively adsorbent bilirubin adsorbent comprising porous particles made of a copolymer of divinylbenzene and glycidyl methacrylate whose surface is treated with plasma protein or a hydrophilic synthetic polymer. (2) The bilirubin adsorbent according to claim 1, wherein the plasma protein is albumin, γ-globulin, or fibrinogen. (3) The bilirubin adsorbent according to claim 1, wherein the hydrophilic synthetic polymer is polyvinyl alcohol. (4) The bilirubin adsorbent according to claim 1, wherein the plasma protein is albumin.