JPH01242105A - Material for removing endotoxin - Google Patents

Abstract

PURPOSE:To obtain inexpensive material generally usable for removing endotoxin by using a porous body in a specified porous state, consisting of methyl methacrylate polymer contg. methyl methacrylate above a specified proportion, based on monomer fraction to selectively remove endotoxin. CONSTITUTION:A hollow fiber is obtd. for example, by extruding a spinning soln. dissolved methyl methacrylate polymer and methyl methacrylate in a solvent from the outer discharge aperture of an annular spinneret by introducing dry nitrogen gas to the inside thereof to make hollow-fibrous material, and by coagulating and removing the solvent in water. A module is made of the material for removing endotoxin, consisting of the porous body contg. >=50% methyl methacrylate, based on the monomer fraction and having 30-90% equilibrium moisture content in a hydrated state at 20 deg.C. The liq. to be treated is circulated outside of the hollow fiber module. The endotoxin in the liq. to be treated in removed by adsorbing with the hollow-fibrous material for removing endotoxin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an endotoxin removing material for removing endotoxin from a liquid containing endotoxin harmful to living organisms and rendering it harmless.

[Conventional technology] With the advancement of technologies targeting living organisms and biological components, such as bioreactors, cell culture, extracorporeal blood circulation therapy, continuous peritoneal dialysis, and various types of infusion and blood transfusion therapy, these technologies have improved. It is desirable to remove endotoxins that may be contained in the liquids used. Furthermore, endotoxemia, in which endotoxin is mixed into bloodstream, is known, and removal of endotoxin is desired in this case as well.

Endotoxin is chemically a ribopolysaccharide that is a component of the cell surface of Durham-negative bacteria, and its molecular weight is said to be 5 x 103 to 108 because it has various binding states (endotoxin - its structure). and Activity-P, 124, Ishiyaku Publishing Co., Ltd., 1981). In addition, endotoxin is a component harmful to living organisms, and it can impair or modify cell functions and the functions of the entire living tissue, disrupting the equilibrium state of the entire living body, and causing, for example, fever, fatal shock, and complement activation. Endotoxins are sometimes called pyrogens (pyrogens) because exothermic reactions are a typical reaction of endotoxins.

In the various techniques mentioned above that target living organisms and biological components, aseptic handling is strongly required due to the chemical composition and temperature environment suitable for the growth of Durham-negative bacteria.
In reality, this often leads to contamination with Durham-negative bacteria and, as a result, endotoxin contamination. Also, endotoxin is
Although it is derived from bacteria, it is not a living organism, so it cannot be rendered harmless through normal sterilization, and heating to 250°C is required to thermally destroy its chemical structure. Such high-temperature treatment is a condition that defeats the purpose of the technique itself and cannot be applied.

Conventionally, techniques for removing endotoxins that occur frequently and are harmful to living organisms include reverse osmosis membranes, filtration membranes, or ligands that have an affinity for endotoxins, such as histidine (Fermentation Engineering Vol. 65, No. 5, 445).
．． (1987) - have been used to immobilize gel-like substances. However, when using only the former to process blood or protein solutions, it is not possible to properly separate endotoxins from the blood cells or proteins to be used.
In the latter case, when it is desired to process the liquid to be processed by flowing it, a uniform and smooth flow condition cannot be obtained because it is a gel-like material. Furthermore, since the latter is relatively expensive, it cannot be used as a commonly used means for removing endotoxin.

[Problems to be Solved by the Invention] In view of the above-mentioned harmfulness of endotoxin and the status of endotoxin removal methods based on the prior art, the present inventors have developed a method that can be removed more selectively, is less expensive, and is generally available. After extensive research into endotoxin removal materials that can be used, it was discovered that a material with characteristics different from those of the known examples shown above can remove endotoxin by adsorption and/or filtration.

[Means for solving the problem] In other words, the monomer fraction of methyl methacrylate is 50%.
A porous body made of a methyl methacrylate polymer containing the above and having a weight water content of 30 to 90%,
The present inventors have discovered that endotoxins in a liquid to be treated can be suitably removed without impairing the original purpose of the technical field in which this means is to be utilized, and have completed the present invention.
.

Weight moisture content is a measure expressed in percent of the ratio of the weight of water contained in the material to the weight of the material in a water-containing state, and is equivalent to the ratio of the weight of water contained in the material to the weight of the material in a water-containing state. This is a measure that defines the porosity of a material in a state where it has become porosity.

The polymer material used in the material may be a polymer mainly composed of methyl methacrylate, and a polymer having a monomer fraction of methyl methacrylate of 50% or more, more preferably 80% or more.
% or more, and methyl methacrylate homopolymers and various methyl methacrylate copolymers are preferably used.

As the copolymerization component for methyl methacrylate, any component can be used as long as it can maintain the porous structure of the material and can be copolymerized to methyl methacrylate, but methacrylic acid esters other than methyl methacrylate, acrylic acid Vinyl compounds such as ester, methacrylic acid, acrylic acid, acrylamide, sodium methalylsulfonate, sodium allylsulfonate, sodium p-styrenesulfonate, 2-methacryloyloxyethyltrimethylammonium chloride, vinyl acetate, and acrylonitrile are preferably used.

When used as an endotoxin removal material, each of the above-mentioned materials may be used alone, or in combination such as blending or simply coexisting with each other, or supporting the material to make it more effective and stable. It can also be combined with other materials for use.

In order to use the above polymer material as an endotoxin removal material, a specific porous structure is required, and the weight water content of the material is 30 to 90%, more preferably 40 to 80%.
Must be %. In order to form a porous structure using a methyl methacrylate polymer, it is necessary to perform wet/dry molding or wet molding to maintain a state in which a solvent, nonsolvent, water, or other liquid for the polymer is contained within the material. be.

If the water content by weight is less than 30%, it becomes difficult for endotoxin to penetrate into the material, and the removal effect of endotoxin by adsorption is impaired, and if it is more than 90%, it becomes difficult to maintain the shape of the material, which is not preferable. If the porosity of the material is substantially uniform, the weight water content at the surface may be equated with the weight water content of the entire material. When attempting to form a porous body, a non-uniform structure may be obtained; in that case, the water content by weight of the surface layer in contact with the liquid to be treated needs to be 30 to 90%.

The weight water content of the surface layer can be determined by removing only the surface layer and directly measuring the weight water content of that part, or by replacing the water in the material with water-soluble epoxy resin and embedding it, and staining that part with osmium tetroxide. Transmission electron microscopy images obtained by freeze-drying the material or scanning electron microscopy images obtained after freeze-drying the material, and samples with various weight water contents adjusted under slow conditions to make uniform porous bodies. This can be determined by comparing it with an electron microscope image similarly observed.

The endotoxin removing material may be in any form, such as beads, hollow fibers, fibers, or flat membranes, but hollow fibers or flat membranes may not be able to penetrate into the material. This is a particularly preferred form, as it not only allows for the uptake and adsorption of endotoxins, but also allows the same material to be used as a general purpose or dialysis filter, providing a wider range of usage methods.

The effectiveness of this patent will be specifically demonstrated with examples below. In the analysis of endotoxin in the liquid to be treated, a commercially available analysis kit, Pyroday 2li (manufactured by Teikoku Kinki Seiyaku Aji Co., Ltd.) was used.

Example 1 A spinning stock solution in which 12 parts of methyl methacrylate homopolymer polymerized with a Grignard reagent and 60 parts of methyl methacrylate homopolymer obtained by radical polymerization were dissolved in 285 parts of dimethyl sulfoxide was discharged from the outer discharge hole of a circular spinneret. Then, dry nitrogen gas was introduced inside to form hollow fibers. This yarn was coagulated in water at 24° C. and the solvent was removed to obtain hollow fibers with an inner diameter of 200 μm and an outer diameter of 260 μm.

A module with an effective membrane area of 1°0 was created by bundling 8,000 of these hollow fibers, and pure water was filled inside and outside the hollow fibers.
25 was sterilized by irradiating it with GV gamma rays. The methyl methacrylate hollow fiber thus prepared had a nearly uniform porous structure, and its weight moisture content was 62%.

A phosphate buffer (0.05M) prepared using untreated tap water was applied to the outside of the hollow fiber module.

pH7.4, salt 0.7%) 12α at 500ml/mi
Circulate for 3 hours at a flow rate of n, then 100 m1/m from the outside to the inside of the hollow fiber! The mixture was circulated for 2 hours while being filtered with n. The endotoxin analysis values for the outside and inside of the hollow fibers at this time are shown in Table 1.

It has been shown that endotoxin is reduced by circulation alone, and that during this state endotoxin is adsorbed and removed by the hollow fiber material. In addition, when filtration is added, almost no endotoxin is found in the filtrate effluent.
Furthermore, in this case, the starting point of filtering and 90? Considering the mass balance over time, 10.5 μg of endotoxin was removed (2.8 n(]/ml x 12,000 ml).
7.7n(]/ml×3000ml), indicating that during this state endotoxin is removed by adsorption and/or sifiltration.

Example 2 Sodium p-styrene sulfonate with a monomer fraction of 3.5
Methyl methacrylate polymer obtained by solution polymerization containing 1%
5 parts and 15 parts of a methyl methacrylate polymer obtained by solution polymerization containing 2-methacryloyloxyethyltrimethylammonium chloride at a monomer fraction of 3.0%.
A spinning dope dissolved in 50 parts of dimethyl sulfoxide was discharged from the outer discharge hole of the annular spinneret, and a mixed solution consisting of 60 parts of ethylene glycol and 40 parts of dimethyl sulfoxide was injected into the inner side to form hollow fibers. 90℃
By coagulating and removing solvent in water of
µ, obtain a hollow fiber with an outer diameter of 480 µm. This hollow fiber 66
00 fibers were bundled to create a module with an effective membrane area of 1.2Tr12, and pure water was filled inside and outside of the hollow fibers to produce a 25 kg
It was sterilized by irradiating it with gamma rays. The methyl methacrylate hollow fibers prepared in this way had a non-uniform porous structure, and the overall weight water content was 74%, but the weight water content of the inner surface layer of the hollow fibers was approximately 60% based on an electron microscope image. Estimated.

A circulation experiment similar to that in Example 1 was carried out inside this hollow fiber module, but in this example, the flow from the inside of the hollow fiber to the outside was 100 m1/m! The mixture was circulated for 2 hours while being filtered with n. Table 2 shows the endotoxin analysis values for the inside and outside of the hollow fiber at this time.

Only a small amount of endotoxin was observed in the effluent, and when the mass balance between the start of filtration and the 9Q filtration time was calculated, 42.9 μg of endotoxin was removed (6, Ong/ml x 12,000 ml- 9,7n
(1/ml x 3000 ml), adsorption and filtration have been shown to remove endotoxin.

Comparative Example 1 The amount of the two types of polymers was 1.5 times that of Example 1, and 1
Hollow fibers and membrane modules were obtained under the same conditions as in Example 1 except that they were coagulated in water at 1°C.

The methyl methacrylate hollow fibers thus produced had a nearly uniform porous structure and had a weight water content of 27%.

The same experiment as in Example 2 was carried out on this hollow fiber module, but when we calculated the mass balance between the beginning of overfeeding and the time of 9Qi filtration, only 3.3 μg of endotoxin was removed (6.9 nO/ml x 12,000 ml). 26.5
ng/ml×3000ml>, the endotoxin removal ability decreases with a porous structure outside the scope of the claims in this patent.

[Effects of the Invention] (1) Although it is a single material, endotoxin can be removed by adsorption and/or filtration.

(2) It also has filtration and dialysis functions (for other purposes).

(3) It can take a wide range of forms depending on the application.

(4) Materials are inexpensive.

Claims (1)

[Claims] Consists of a methyl methacrylate polymer containing 50% or more of methyl methacrylate as a monomer fraction, and has an equilibrium weight water content of 30 to 90 when kept in a water-containing state at 20°C.
% endotoxin removal material composed of a porous material.