JPS5826819A - Porous glass adsorbent for low-density lipoprotein particles - Google Patents

Abstract

PURPOSE:To titled adsorbent that is made of a porous glass with a specific average pore size, thus permitting selective removal of low-density lipoprotein containing a large amount of cholesterols from the blood of a hypercholesterolemia patient. CONSTITUTION:The objective absorbent is made of a porous glass is which the average pore size ranges from 700 to 2,000Angstrom , preferably from 900 to 1,600Angstrom , the pore volume ranges from 0.3cc/g to 2.0cc/g and the particle size ranges from 0.1-5mm.. Further, when the average pore diameter is defined as D, the volume percentage of the pores with their diameter ranging from 0.8D to 1.2D is required to exceed 80 based on the total pore volume. In order to effect the selective adsorption of said protein, the pore size distribution of the porous glass is required to be narrow, the particle sizes preferably are in the above range in terms of the problem of hemolysis, since the particles are brought into contact with blood, plasma or other body liquids and the shape of the particles is preferably spherical in order to prevent the blood from coagulating.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adsorbent capable of removing low density riboproteins containing a large amount of cholesterol from the blood of hypercholesterolemic patients.

Hypercholesterolemia, especially familial hypercholesterolemia, is caused by a genetic defect in the cell membrane low-density cell membrane protein Sedator, resulting in high blood cholesterol levels and deposition of cholesterol on blood vessel walls, which can lead to arteriosclerosis. It is a disease with a high rate of death due to myocardial infarction and angina pectoris. Therefore, it is necessary to remove low-density riboproteins that contain large amounts of cholesterol from the blood of these patients.

Conventionally, methods such as plasma exchange have been implemented, but there are problems in that the plasma that needs to be replenished each time is expensive and in short supply.

Adsorption methods have the advantage of not requiring fluid replacement if cholesterol or low-density riboproteins can be selectively removed, but such adsorbents include agarose immobilized with heharin (8, Moorjani et al., Cl1n,
Chim, Acts 77 (1977) 21-
30. ) have been used and reported to be effective. However, there was a problem that the carrier, agarose, was mechanically weak and blood coagulation factors were also attached at the same time. Moreover, when activated carbon, organic porous resin, or ion exchange resin, which has been conventionally used to adsorb and remove waste products and toxic substances in blood, is used, low density riboproteins are hardly adsorbed.

In view of these circumstances, the present inventors have conducted extensive research and have found that porous glass with a specific average pore diameter is able to absorb low-density riboproteins in plasma (therefore, cholesterol-1%/) f:
They have discovered that it can be selectively reduced and have completed the present invention. That is, in the present invention, the average pore diameter is 700 to 20
This is a low-density lipoprotein adsorbent characterized by being made of porous glass (but does not have sulfonic acid groups on the surface) within the range of 0.00 pores. The reason why the adsorbent of the present invention selectively adsorbs low-density riboproteins is not clear, but it is presumed that the Schifnol groups present on the surface of the porous glass have some kind of interaction with the protein.

Since low-density riboprotein is a globular protein with a molecular weight of several hundred blades, the average pore diameter of the porous glass needs to be 700λ or more, and more preferably 900A or more. Low-density riboproteins are difficult to adsorb to pores of 700 Å or less, and pore proteins such as γ-globulin are also adsorbed therein, which is not preferable. Average pore diameter is 2000
If it exceeds Å, the physical strength decreases and fine pieces are likely to be formed, which is not preferable. More preferably, the average pore diameter is 1600 Å or less.

In order to selectively adsorb proteins, it is preferable that the pore size distribution of the porous glass is narrow, and when the average pore diameter is D, the pore diameter is within the range of 0.8D to 1.2D. It is preferable that the volume of the pores accounts for 80 or more of the total pore volume.

In addition, the pore volume of porous glass is 0. scc/Q~2
, 0 QC/9. 0.5
Below cc, /f, the adsorption capacity of the I-i protein is low, making it unsuitable for the purpose of the present invention. If it exceeds 2.0 cc79, the skeleton becomes weak and fine fragments are likely to occur.

Since the porous glass used in the present invention is brought into contact with body fluids such as blood or plasma, the diameter of the particles is 0.1M.
II to 5m, preferably within the range of 0.2aI
It is more preferably in the range of I to 2#. Particle size is 0
．． When it is smaller than 1 m, the pressure loss of the adsorbent layer becomes large.
Problems such as hemolysis occur. If the particle size is larger than 5M, the voids between the particles will become large, resulting in a decrease in adsorption performance, which is not preferable.

Further, since the present adsorbent is brought into contact with blood, it is preferable to have a spherical external shape in order to increase the safety against blood cell components and to prevent blood clots and the like.

Porous glass may be used as it is, but its surface may be coated with a hydrophilic polymer to improve its affinity with blood. As a method of coating with a hydrophilic polymer, after immersing porous glass in a hydrophilic polymer solution,
A method that removes the solvent is preferred. According to this method, the hydrophilic polymer hardly penetrates into the pores of porous glass, but the Schifnol groups present on the inner surface of the pores are covered by the hydrophilic polymer, resulting in a decrease in functionality. There is little to do. Further, as the hydrophilic polymer, a polymer containing a crosslinking component is preferable, and it is more preferable to crosslink it by heating after the coating treatment. Examples of hydrophilic polymers include acrylic ester polymers, methacrylic ester polymers, acrylamide polymers, and polyvinyl alcohol polymers.

Examples include polyvinylpyrrolidone, cellulose nitrate, and gelatin.

The low-density lipoprotein adsorbent made of porous glass of the present invention is usually used by filling a column. The column has a main body having an inlet and an outlet shaped to be easily connected to a blood circuit on both sides of an adsorbent layer, and a space between the adsorbent layer and the inlet and outlet, through which blood, etc. passes, but the adsorbent does not pass through. A filter having a mesh size of 80 to 180 meshes is preferred, but any cuff having substantially the same function can be used for this purpose even if it is shaped like a pond. The material of the column can be glass, polyethylene, polypropylene, polycarbonate, polystyrene, polymethyl methacrylate, etc., but polypropylene, polycarbonate, etc., which can be sterilized by autoclaving, are preferable.The filter should be physiologically inert and strong. However, those made of polyester are particularly preferred.

The adsorbent of the present invention is preferably packed into a column together with water or physiological saline, and the filled column is usually sterilized before use, but it can be sterilized by autoclaving.

R-ray sterilization is preferred.

The adsorbent of the present invention can be brought into contact with whole blood as it is, but it may also be brought into contact with only plasma that has been separated in advance using a plasma separator or the like.

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited to such embodiments.

Examples 1-2. Comparative Example 1 Porous glass with an average pore diameter of 720 (D = 720, the proportion of pore volume with a pore diameter of 0.8D to 1.2D is 99 sec, pore volume 0.95 cc, / g, particle size 0,2
a ~ 0.5M) as Example 1, a porous glass with an average pore diameter of 1060 people (D, = 1060 people, the proportion of the pore volume with a pore diameter of 0.8D ~ 1.2D 81 %.

Pore volume 0.92 cc/f, particle size 0.211M~0
5 cod) was used as Example 2. In addition, porous glass with an average pore diameter of 560 people (D = 560 people, 91% of the pore volume with a pore diameter of 0.8D to 1.2D, pore volume 0.76 cc/9, Particle size 0.2W~0.431
1) was used as Comparative Example 1. A polypropylene column (with a 180-mesh polyester filter on both ends) was filled with 2 f of each of the above-mentioned porous guffs, and 20 w1 of rabbit plasma was circulated at 37° C. for 5 hours. The total protein concentration before and after circulation was quantified by the biuret method and the cholesterol concentration was quantified by the aldehyde method, and the removal rate was calculated (removal rate (%) = (1 - concentration after circulation / concentration before circulation) x 100 ). Cholesterol rarely exists alone in the blood; most of it exists bound to low-density riboproteins. Therefore, since the removal rate of cholesterol and the removal rate of low-density riboprotein are considered to be substantially equal, the concentration of cholesterol was analyzed.

As shown in Table 'jlIJ1, the decrease in total protein by the adsorbent of Example is small and about 50-48% of cholesterol Fi is removed, but in Comparative Example 1 where the average pore diameter is smaller than 70OA, the removal rate of cholesterol is Although it was large, the total protein removal rate was also large and the selectivity was low.

Table 1 Example 5. Comparative Examples 2-5 The same porous glass used in Example 2 was used as Example 6, and the organic porous resin XAD-4 (D=280 people) from Rohm & Eighth.

The proportion of the pore volume with a pore diameter of 0.8 D to 1.2 D is 16%, the pore volume is 0.65 ca/9, and the average particle size is 0.
/iW) was used as Comparative Example 2, and XAD-y (D
= sbo person.

Proportion of pore volume with pore diameter between 0.8D and 1.2D2
2 volumes, pore volume 0.66 cc/Q, average particle size o, a
m) 414 cases 3. ! :L, XAD-8 (D = 36OA
, +l1il pore 1 [proportion of pore volume with diameter between 0.8D and 1.2D22].

Pore volume 0.57 cc/f, average particle size 0.8m! 1
1) was used as Comparative Example 4. In addition, the ion exchange resin Dowex I X 4 (CI
type) was used as Comparative Example 5.

Each of the above porous bodies 19 was packed in a polypropylene column, and human plasma was circulated at 10 d'i at 37°C for 90 minutes, and the total protein removal rate and cholesterol removal rate (i.e., low-density riboprotein removal rate) were determined by the method described above. It was measured. As shown in Table 2, cholesterol is hardly removed when organic porous resins or ion exchange resins are used.

Margin below

Claims (1)

[Scope of Claims] 1. Low-density riboprotein adsorption characterized by being made of porous glass (with no sulfonic acid groups on the surface) having an average pore diameter within the range of 700 to 2000 pores. agent. 2. The low-density riboprotein adsorbent according to claim 1, wherein the average pore diameter is within the range of 900A to 1600A. 5. The pore volume of the porous glass is o, 3cc7q or more, 2
．． 000/f or less, the low-density riboprotein adsorbent according to any one of claims 1 and 2. 4. The low-density lipoprotein adsorbent according to any one of claims 1 to 3, wherein the particle diameter of the porous glass is within the range of 0.1 to 5 dia. 5. The porous glass has pores in which the volume of pores with a pore diameter in the range of 0.8D to 1.2D accounts for 8D or more of the total pore volume, where D is the average pore diameter. The low-density lipoprotein adsorbent according to any one of Claims IJIc 1 to 4, which is a synthetic glass.