JPS5827559A - Low density lipoprotein adsorbent - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

Hypercholesterolemia, especially familial hypercholesterolemia, is caused by a genetic defect in the low-density 18° riboprotein receptor in cell membranes, resulting in a high level of cholesterol in the blood, which causes arteriosclerosis due to deposition of cholesterol in blood vessel walls. It is a disease with a high rate of death due to myocardial infarction and angina pectoris. Therefore, it is necessary to remove cholesterol and low-density lipoproteins 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.

The adsorption method has the advantage of not requiring fluid replacement if it can selectively remove cholesterol or low-density lipoproteins.
jat++ et al., Cl1n, Chiru, A.
cta 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 also adsorbed blood coagulation factors at the same time.

As a result of intensive research into these circumstances, the present inventors found that a porous material having a specific functional group on its surface and a specific average pore diameter was able to absorb low-density lipoproteins in plasma (and therefore cholesterol). ) was found to selectively decrease
The present invention has now been completed. That is, the present invention has a sulfonic acid group on the surface and an average pore diameter of 700 to 200.
This is a low-density lipoprotein adsorbent characterized by being a porous material within the range of 0A.

The surface of the adsorbent of the present invention has sulfonic acid groups (-80sH,
-80g-) is required.

Here, the surface refers to the entire surface including the outer surface and the inner surface of the pores of the adsorbent. Low-density riboproteins are selectively adsorbed to adsorbents with sulfonic acid groups, but it is not clear why the selectivity is not as high for carboxyl groups, silanol groups, etc.; It is thought that a specific binding site exists. The concentration of sulfonic acid groups is preferably in the range of 5 to 100 μmol/f.

When the concentration is lower than 5μmad/f, there is a tendency that the effect is not sufficient, and when the concentration is lower than 5μmad/f,
When the concentration exceeds 17'ff, the effect tends to be saturated and even if the concentration is increased, a correspondingly high effect cannot be obtained.

Examples of methods for introducing sulfonic acid groups include a method of introducing them through chemical bonding using a silane coupling agent, and a method of coating the material with a polymer containing a sulfonic acid group. There is a method of introducing amino groups onto the surface of the carrier by stirring 5-aminopropyltriethoxysilane, reacting with glutaraldehyde in an acidic solution, and then reacting with taurine in a basic solution. Introduction of sulfonic acid groups by polymer coating can be carried out by coating with a polymer having sulfonic acid groups (for example, a polymer containing styrene sulfonic acid as a copolymer component of styrene sulfonic acid). As the coating method 7f, a method can be used in which a monomer is coated with a solution containing a polymerization initiator, if necessary, and then polymerized by heating polymerization or the like.

Porous glass, porous silica, porous alumina, porous silica-alumina, etc. can be used as the carrier to introduce the sulfonic acid group, but porous glass has high physical strength and is preferably used.

Since low-density riboprotein is a globular protein with a molecular weight of several million, the average pore diameter of the adsorbent needs to be 700A or more, and more preferably 900λ or more. Low-density lipoproteins are adsorbed to pores of 700 μm or less, and other proteins such as r-globulin are also adsorbed, which is not preferable. Therefore, cation exchange resins with a very small average pore diameter (801 or less), such as cation exchange resins with sulfonic acid groups, are unsuitable because low-density lipoproteins cannot enter the pores and are hardly adsorbed. . If the average pore diameter exceeds 2000 A, it is not preferable because the physical strength decreases and fine pieces are likely to occur. More preferably, the average pore diameter is 1600λ or less.

In order to selectively adsorb proteins, it is preferable that the pore size distribution of the adsorbent is narrow, and when the average pore diameter is D, the diameter of pores 11 is within the range of 0.8D to 1.2D. It is preferable that the volume ratio accounts for 80% or more of the total pore volume.

In addition, the pore volume of the adsorbent is 1. i 0.5 cc/f ~
It is preferably within the range of 2.0 cc/f. 0
．． If it is less than 5 cc/f, the protein adsorption capacity will be low and it will not be suitable for the purpose of the present invention. 2. If it exceeds Occ/f, the skeleton becomes brittle and minute fragments are likely to occur.

Since the adsorbent used in the present invention is brought into contact with body fluids such as blood or plasma, the particle diameter is 0.1-51.
It is preferably within the range of 111, and 0.2W1 to 2
It is more preferable to fall within the range (2). Particle size is 0.1.
If the size is smaller, the pressure drop in the adsorbent layer will increase, causing problems such as hemolysis. If the particle size is larger than 5 m, the voids between the particles will become large and the adsorption performance will deteriorate, 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.

These adsorbents may be used as they are, but their surfaces may be coated with a hydrophilic polymer to improve their affinity with blood. As a method for coating with a hydrophilic polymer, a method is preferred in which the porous body is immersed in a hydrophilic polymer solution and then the solvent is removed. According to this method,
Since the hydrophilic polymer hardly penetrates into the pores of the porous body, there is almost no possibility that the sulfonic acid groups on the inner surface of the pores will be covered with the hydrophilic polymer and the functionality will deteriorate. In addition, as the hydrophilic polymer, a polymer containing a crosslinking component is preferable,
It is more preferable to heat and crosslink after the coating treatment. Examples of the hydrophilic polymer include acrylic ester polymers, methacrylic ester polymers, acrylamide polymers, polyvinyl alcohol polymers, polyvinylpyrrolidone yalulose nitrate, and gelatin.

It is used by filling. 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 column having a filter having a mesh size of 80 to 180 mesh is preferable, but columns having other shapes having substantially the same function can be used for this purpose. The material of the column is glass and polyethylene.

Polypropylene, polycarbonate, polystyrene, polymethyl methacrylate, etc. can be used, but polypropylene, polycarbonate, etc., which can be sterilized by autoclaving, are preferable. The filter may be made of any physiologically inert and strong material, but one made of polyester is particularly preferred.

The column packed with the adsorbent of the present invention is normally used after being sterilized, such as autoclave sterilization, ri! Sterilization is preferred.

The entire surface of the adsorbent of the present invention can be directly fused, but it may also be brought into contact with plasma sludge that has been separated in advance using a plasma separator or the like.

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

Examples 1-4. Comparative Examples 1 to 5 Porous glass with an average pore diameter of 720λ (k720λ,
Percentage of pore volume with pore diameter between 0.8D and 1.2D9
9%, pore volume 3.95 cc/f, particle size 0.2 m~o,
Comparative Example 1 was prepared using Comparative Example 1. It was heated with 5-aminopropyltriethoxysilane in toluene to introduce an amino group, and then heated with glutaraldehyde in 1N hydrochloric acid at room temperature.
React for 2 hours, then taurine and 1N hydroxide l-I
55.1 by reacting for 12 hours at room temperature in a Jium aqueous solution.
A porous glass introduced with μmol/f of sulfonic acid groups was used as Example 1.

Porous glass with an average pore diameter of 1060λ (n=1060
^, The proportion of pore volume with a pore diameter of 0.8D to 1.2D is 81%, the pore volume is 0.92cc/p, the particle size is 0.2cm to
0.5m) was designated as Comparative Example 2, and Example 2 was obtained by introducing 54.5 μmol/f of sulfonic acid groups into this in the same manner as in Example 1. Following Comparative Example 2, an amino group was introduced in the same manner as in Example 1, and then a carboxyl group was introduced by reacting with fluoric anhydride in dioxane at room temperature for 6 hours. used as. Example 3 (n = 15001, pore diameter 0.8D ~
1.90% of pore volume in 2D, pore volume 1-0
The particle size was 0.2-0.5111) at 5 cc/liter. Porous glass with an average pore diameter of 1400X (n=1400
The proportion of pore volume with a pore diameter of 0.8D to 1.2D is 88%, the pore volume is 90.94cc/f, and the particle size is 0.2D.
wm ~ 0.5 m) by the same method as in Example 1).
Example 4 was prepared by introducing a sulfonic acid group of 6.8 μmail/f. In addition, a porous glass with an average pore diameter of 560 and a sulfonic acid group introduced in the same manner as in Example 1 (D, 560A, a pore diameter of 0.8D to 1
．． Percentage of pore volume in 2D: 91%, pore volume: 0.76
cc/f, particle size 0.21ml~0.51121+, sulfonic acid group concentration 71.5μmog/? ) was used as Comparative Example 4. Following Examples 1 to 4 and Comparative Examples 1 to 4, 22 of each were filled into a polypropylene cuff (with a 180-mesh polyester filter on both ends), and 20 rabbit plasma were purchased. 1 was circulated at 57°C for 3 hours. The total protein concentration before and after circulation was determined by the biuret method, and the cholesterol concentration was determined by the ortho-phthalaldehyde method, and the removal rate was calculated. (Removal rate (%) - (1 - post-circulation concentration / pre-circulation concentration) x 100), cholesprol rarely exists alone in the blood, and most of it exists bound to low-density riboproteins. There is. Therefore, since the removal rate of cholesterol and the removal rate of low-density lipoprotein are considered to be substantially equal, the concentration of cholesterol was analyzed.

As shown in Table 1, the decrease in total protein due to the adsorbent of the example is small, and the cholesterol content is around 70%.
3, the cholesterol removal rate was low. In Comparative Example 4, in which the average pore diameter was smaller than 700 A, the removal rate of cholesterol was high, but the removal rate of total protein was also high, resulting in low selectivity.

Chapter 1 Table Patent applicant Rishi Co., Ltd. Representative Patent Attorney Ken Honda

Claims (1)

[Claims] 1. Has a sulfonic acid group on the surface and has an average pore diameter of 7.
A low-density IJ, tF protein adsorbent characterized by being a porous material having a porosity within the range of 00A to 200OA. 2. The low-density lipoprotein adsorbent according to claim 1, having an average pore diameter within the range of 900A to 1/+OOA. 5. The pore volume of the porous body is 0.3 cc/f or more; 2.
0 cc/1? A low-density lipoprotein adsorbent according to any one of claims 1 and 2 below. 4. The particle diameter of the porous body is 0.1. The low-density lipoprotein adsorbent according to any one of claims 1 to 3, which falls within the range of . 5. In the porous body, the proportion of the volume of pores having a pore diameter in the range of 0.8D to 1.2D, where D is the average pore diameter, accounts for 80% or more of the total pore volume. The low-density lipoprotein adsorbent according to any one of claims 1 to 4, which is a porous body.