JPS59183764A - Adsorbent for purifying blood - 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 for blood purification used for adsorbing and removing toxic substances in blood.

Patients with renal failure or liver failure have a decreased ability to excrete toxic substances from the blood, such as creatinine, uric acid, urea, protein-bound substances, etc., which can lead to accumulation of toxic substances in the blood, which can be life-threatening. You will be threatened. For this reason, toxic substances are removed by dialysis or the use of adsorbents to purify the blood.

However, since dialysis is a purification method using a semipermeable membrane,
It is generally difficult to effectively remove medium to large molecular weight substances and protein-bound substances such as bilirubin. On the other hand, purification methods in which toxic substances are adsorbed and removed by bringing an adsorbent into direct contact with blood can remove various toxic substances from blood by selecting the type of adsorbent. In this case, adsorption of toxic substances in the blood is carried out by liquid phase adsorption.

Generally, in liquid phase adsorption, the diffusion rate of substances is lower than that in gas phase, and the adsorption rate depends on the outer surface area of the adsorbent, so it is desirable to use a powder or particulate adsorbent with a large outer surface area. However, it is difficult to use a particulate adsorbent with a large external surface area because the adsorbent flows into the human body in its original state. Therefore, in order to effectively purify blood using a powder or particulate adsorbent, it is necessary to immobilize the adsorbent by some method. For this reason, a method has been proposed in which a polymeric material and an adsorbent are mixed and immobilized in a spherical or membrane shape. However, in order to maintain its good condition, a large amount of polymeric material is required relative to the amount of adsorbent, and the thickness of the polymeric material on the surface of the adsorbent increases, which reduces the adsorption power. have. In addition, when using granular adsorbents, only the surface needs to be coated, so the thickness of the coating can be made thinner, but because the movement of toxic substances into the interior of the adsorbent is slow, a high adsorption rate is expected. In addition to this, there is also the disadvantage that when blood is poured, there is a large pressure loss in the adsorbent layer.

The present inventors have discovered that an excellent adsorbent free from the above-mentioned drawbacks can be obtained by immobilizing an adsorbent or adsorbent substance on a support having a specific structure, and have thus arrived at the present invention.

That is, the present invention provides an adsorbent for blood purification comprising an adsorbent or an adsorbent substance immobilized on a support, wherein the support has a network structure composed of granular thick parts and linear thin parts. This is an adsorbent for blood purification characterized by the following.

The support used in the present invention has a network structure composed of granular thick parts and linear thin parts. Adsorbents are usually used in layers, but by using a support with this structure, the adsorbents do not come into close contact with each other even if they are stacked, and an appropriate gap is ensured. Therefore, blood flows uniformly throughout the adsorbent, resulting in a high adsorption rate and low pressure loss. Furthermore, the ability to obtain a large external surface area is also advantageous in terms of adsorption rate. An example of such a support is shown in FIGS. 1 and 2. FIG. 1 is an enlarged plan view of the support, and FIG. 2 is an enlarged plan view of the support body.
It is a cross-sectional view when cut along -A. In the figure, ■ is a granular thick part, and 2 is a linear thin part. The thickness of the thick portion is preferably in the range of 40 to 500 μm, and the thickness of the thin portion is preferably in the range of 3 to 30 μm. Further, the porosity of the network structure is preferably in the range of 30 to 80%. If the porosity is less than 30%, the pressure loss will increase, and if it is more than 80%, the amount of adsorbent that can be fixed will decrease. The diameter of the thick part and the width of the thin part are not particularly limited, but the diameter of the thick part is in the range of 50 to 1000μ, and the width of the thin part is in the range of 5 to 500μ.
A range of is appropriate. And the thick part is lO~2004
It is preferable that it exists at a density similar to that of Wd.

Materials for the support include polymeric materials such as polyethylene, polypropylene, nylon, polyester, and cellulose, metals, and ceramics, but polymeric materials are advantageous in terms of ease of handling and manufacturing. be. Further, the support preferably has a tensile strength of 0.2 cm/ffi width or more in practical terms.

The above support can be manufactured by a known method,
For example, the method described in JP-A-54-88977 is convenient. A support produced by such a method has polygonal or circular thick parts scattered about, and thin parts extending radially from the thick parts to connect the thick parts (see FIG. 1).

Examples of the adsorbent or adsorptive substance used in the present invention include activated carbon, organic porous resin, porous alumina, porous silica, and antigens, antibodies, complements, and DNA. These adsorbents or adsorbent substances may be appropriately selected depending on the purpose. The shape of the adsorbent is preferably powder or particulate from the viewpoint of adsorption speed. The preferred average particle size is lO-100μ. A method for immobilizing an adsorbent on a support is to attach a mixed solution or melt of the adsorbent and polymer onto the support by dipping, coating, spraying, etc., and then drying, coagulating, or
An example of this method is to solidify the polymer by cooling or the like. In order to achieve the object of the present invention, the thickness of the adsorbent layer immobilized on the support is preferably thinner than the thickness of the thick portion of the support. Furthermore, it is preferable that the polymer on which the adsorbent is immobilized has a porous structure in order to obtain a high adsorption rate. Porous structures can be obtained by extrusion using known methods, for example by contacting a polymer solution with a non-solvent that is miscible with the solvent but does not dissolve the polymer. Polymers used to immobilize the adsorbent include polyurethane, polysulfone, polystyrene, polyamide, polyethylene, polypropylene, polyvinyl alcohol, hydrophilic methacrylate polymers, hydrophilic acrylate polymers, and the like. Among these, those with excellent blood affinity are preferred.

In addition, adsorbent substances such as antigens, antibodies, complement, and DNA are
Direct immobilization is possible depending on the support, but
-1. The above-mentioned adsorbent and other materials (e.g., synthetic polymers, natural polymers, glass, etc.) are immobilized on powder or fine particles using the same method as the adsorbent immobilization method described above. It's okay.

The adsorbent of the present invention is usually wound into a roll or arranged in multiple layers and stored in a mold having an inlet and an outlet for blood purification. The blood may be whole blood or plasma. Further, when using the product, it is preferable to sterilize it by steam sterilization, gamma ray sterilization, or the like.

The adsorbent for blood purification of the present invention has an adsorbent or an adsorbent substance immobilized on a support having a network structure composed of granular thick-walled parts and linear thin-walled parts. Appropriate gaps are secured even when stacked, and the adsorbents do not come into close contact with each other. Compared to cases where a film or a simple mesh body is used as a support, blood flows uniformly throughout the adsorbent, reducing pressure loss. Has a small advantage. Therefore, toxic substances in the blood can be efficiently removed, making it useful for treating renal failure, liver failure, drug addiction, and various immune diseases.

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited in any way by these examples.

Example Powdered activated carbon (average particle size 10-4011) 100g
was mixed with 500 txt of polyurethane solution (IOW/V% polyurethane in tetrahydrofuran solution) and suspended, and a polyethylene support (thick part thickness: 140 to 160μ, A sample with a thickness of 20011 was created by pouring the thin-walled suspension into the membrane.Next, this membrane was immersed in water to extract tetrahydrofuran into water.
The adsorbent was further immersed in hot water at 80°C to completely extract the solvent. The activated carbon content of the obtained adsorbent is 65%
, and many pores of about 1 to 6 μm were observed in the polyurethane. Approximately 40 m of this adsorbent was wound into a roll and housed in a container having a blood inlet and an outlet to prepare a blood purification column.

The amount of activated carbon contained in the adsorbent stored in the column is approximately 80
It is g.

Add 50 mlymin of dog whole blood to the above blood purification column.
The difference in pressure between the inlet and outlet of the column, that is, the pressure drop, was measured and found to be 15 mHg.

In contrast, in the case of a commercially available blood purification column packed with granular activated carbon, the pressure drop reached 100 MHg. Furthermore, there was almost no difference in the amount of coal dust generated between the two. As described above, the adsorbent of the present invention has a small pressure loss when blood is passed through it, so problems such as hemolysis do not occur, and a large amount of fine powder of the adsorbent is detached and mixed into the blood. Therefore, blood purification can be performed safely.

[Brief explanation of drawings]

FIG. 1 is a plan view of a support used in the present invention, and FIG. 2 is a cross-sectional view taken along line A--A in FIG. 1. 1. Grainy thick part 2, Linear thin part

Claims (1)

[Claims] (1) An adsorbent for blood purification comprising an adsorbent or adsorbent substance immobilized on a support, the support comprising a granular thick part and a linear thin part. Adsorption for blood purification characterized by having a network structure (2) The adsorbent for blood purification according to claim 1, wherein the network structure has a porosity of 30 to 80%. (3) The adsorbent for blood purification according to claim 1 or 2, wherein the thickness of the thick portion is in the range of 40 to 5 μm, and the thickness of the thin portion is in the range of 3 to 30 μm. . (4) The adsorbent for blood purification according to any one of claims 1 to 3, wherein the support is made of a polymeric material. (5) The adsorbent for blood purification according to any one of claims 1 to 4, wherein the support has a tensile strength of 0.21 g/ax width or more.