JPH0588150B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for sterilizing an adsorbent. More specifically, the present invention relates to a method for sterilizing an adsorbent for extracorporeal circulation therapy having a sulfate ester group. [Prior art] For the purpose of selectively removing harmful components from body fluids, adsorbents in which substances with specific affinity for harmful components (so-called ligands) are immobilized on water-insoluble carriers have been used for extracorporeal circulation therapy. Attempts are being made to use it. Although sterilization is essential for use in treatment, chemical sterilization is inappropriate due to safety issues and handling during use, and high-pressure steam sterilization is preferred. However, when these adsorbents are sterilized with high-pressure steam, the deactivation or desorption of the ligand occurs, and in fact, no adsorbent for extracorporeal circulation treatment that has been sterilized with high-pressure steam has been realized. In particular, adsorbents having sulfate ester groups are known to be susceptible to decomposition such as desulfation during high-pressure steam sterilization. [Problems to be solved by the invention] When an adsorbent for extracorporeal circulation therapy having a sulfate ester group is sterilized under severe conditions such as 121°C for 20 minutes, the sulfate ester group and the fixed sulfate ester group-containing compound are removed. Since it may be hydrolyzed and removed, a problem arises in that its ability to remove harmful components from the blood is not sufficient. The present invention has been made in order to solve the problems that occur when steam sterilization is performed as described above. [Means for Solving the Problems] The present invention provides an adsorbent for extracorporeal circulation therapy having a sulfate ester group (excluding an adsorbent for extracorporeal circulation therapy in which a sulfated polysaccharide is immobilized on a water-insoluble carrier).
The present invention relates to a method for sterilizing an adsorbent, which is characterized in that the adsorbent is sterilized in an aqueous solvent whose pH is controlled to 5 to 9. [Example] The adsorbent having a sulfate ester group in the present invention is (1) an adsorbent formed by immobilizing a sulfate ester group-containing compound (excluding sulfated polysaccharides) on a water-insoluble carrier; (2) (3) An adsorbent obtained by directly converting a hydroxyl group-containing water-insoluble carrier into a sulfuric acid ester, and (3) an adsorbent obtained by converting a hydroxyl group-containing water-soluble polymer into a sulfuric acid ester and making it water-insoluble through crosslinking or other treatments. , but not limited to these. The sulfate ester group-containing compounds used in the adsorbent (1) above include sulfate esters of hydroxyl group-containing compounds such as alcohols, sugars, and glycols (however,
(excluding sulfated polysaccharides), but compounds having a sulfate ester group and a functional group that can be used for immobilization on a water-insoluble carrier are preferred. Such compounds include partially sulfated alcohols, especially sulfated sugars (excluding sulfated polysaccharides), which contain both sulfate groups and functional groups necessary for immobilization, and have high bioactivity. It is particularly preferred because of its compatibility and activity. Examples of the water-insoluble carrier for immobilizing the sulfate group-containing compound in the adsorbent (1) include agarose, dextran, and soft gels such as polyacrylamide, which are carriers normally used for affinity chromatography, and porous gels. Examples include, but are not limited to, solid glass, inorganic porous bodies such as porous silica, polymer gels made of synthetic polymers, and porous cellulose gels. The hydroxyl group-containing water-insoluble carrier used in the adsorbent (2) above includes gels made of polysaccharides such as agarose and dextran, which are also used in the adsorbent (1), and polymer gels made of synthetic polymer compounds. Formulas such as cross-linked polyvinyl alcohol, saponified ethylene-vinyl acetate copolymer, and cross-linked compounds thereof, etc.

A polymer compound having a unit represented by [Formula] in at least a part of the molecule,
Formulas such as polyhydroxy methacrylate, copolymers containing hydroxy methacrylate, etc.

A polymer compound having a unit represented by the formula, a polyunsaturated compound containing a hydroxyl group such as pentaerythritol dimethacrylate or glycerin dimethacrylate, or a compound having an oxirane ring such as epichlorohydrin or butanediol diglycidyl ether is used as a crosslinking agent. Examples include gels made of polymer compounds into which hydroxyl groups have been introduced, porous cellulose gels, etc., but are not limited to these. Among the water-insoluble carriers used in the adsorbents (1) and (2) above, hard gels are preferred because they provide a sufficient flow rate of body fluids and are less likely to cause clogging, and porous cellulose gels are particularly preferred (i). ) Due to its relatively high mechanical strength and toughness, it is less likely to be destroyed or produce fine powder due to operations such as stirring, and when packed in a column, it will not become compacted even if body fluids are flowed at a high flow rate. Because it does not clog, it can be flowed at a high flow rate, and the pore structure is not easily changed by high-pressure steam sterilization. There are many hydroxyl groups that can be used to bind group-containing compounds or convert to sulfate ester groups, and there is little nonspecific adsorption. (iii) Even with large pore volume, it has relatively high strength, so it is inferior to soft gels. (iv) It is highly safe compared to synthetic polymer gels. By directly converting porous cellulose gel into sulfuric acid ester, an adsorbent that can selectively adsorb and remove harmful components at a high flow rate can be obtained. Regarding the adsorbent using porous cellulose gel, please refer to Japanese Patent Application No. 58-68116 and Japanese Patent Application No. 59.
-231012 It is described in detail in each specification. Next, typical examples of hydroxyl group-containing water-soluble polymers used in the adsorbent (3) above include polyvinyl alcohol, polymers obtained by saponifying ethylene-vinyl acetate copolymers with low ethylene content, etc. Examples include, but are not limited to. In the present invention, the adsorbent (1) above is produced by fixing a sulfate group-containing compound to a water-insoluble carrier, and various known methods can be used for the fixing method. That is, physical methods, ionic bonding methods, covalent bonding methods, etc. can be mentioned. Since it is important that the immobilized sulfate group-containing compound is difficult to detach, a strong covalent bonding method is preferable, and even if other methods are used, it is preferable to prevent detachment. Furthermore, a spacer may be introduced between the water-insoluble carrier and the sulfuric acid ester group-containing compound, if necessary. As the sulfuric acid esterification method in the adsorbent production process of (2) and (3) above, various known methods using chlorosulfonic acid, sulfuric acid, etc. can be used. In the adsorbent production step (3) above, various known methods can be used to crosslink the sulfuric acid esterified hydroxyl group-containing water-soluble polymer compound, such as a method using a crosslinking agent, a method using irradiation with ultraviolet rays, β-rays, etc. can be used. In the present invention, the adsorbent for extracorporeal circulation therapy produced in this way is sterilized by steam sterilization in an aqueous solvent controlled at pH 5 to 9, usually at 121°C for about 20 minutes, and then used. be done. If the pH during steam sterilization is less than 5, the adsorption activity of the steam sterilized adsorbent will be significantly reduced, and the desorption due to hydrolysis of sulfate ester groups and fixed sulfate ester group-containing compounds will become significant. do. In addition, even if the pH exceeds 9, the same phenomenon occurs as when the pH is less than 5, and in both cases, the adsorbent performance deteriorates. There are no particular limitations on the method of controlling the PH of the aqueous solvent used in steam sterilization, and while automatically measuring changes in PH during steam sterilization,
Adjustments may be made and buffers may be used. Adjusting the pH using a buffer solution allows for stable pH adjustment without the need for special equipment, and also prevents activity reduction due to pH changes during storage of sterilized extracorporeal circulation treatment adsorbents, and the ability to reduce the activity of sulfuric acid, which is a ligand. This is preferable because it also suppresses the elimination of ester group-containing compounds and sulfate ester groups. Buffers used in the preparation of buffer solutions include, for example, citric acid, phosphoric acid, acetic acid, boric acid, tartaric acid, carbonic acid, maleic acid, glycine, etc., or their sodium salts, potassium salts, calcium salts, etc. Safe ones are preferred, and these may be used alone or in combination of two or more. When a buffer is used to adjust the pH of an aqueous solvent, there is no particular limit to the concentration of the buffer, and it can be used as long as it functions as a buffer, but it is easy to wash before using it as an adsorbent for extracorporeal circulation therapy. For reasons such as 0.001 to 10% (weight%, the same applies hereinafter)
is preferable, and 0.01 to 2% is more preferable. The adsorbent for extracorporeal circulation therapy manufactured in this way and sterilized according to the present invention is packed with the adsorbent in a column equipped with a filter, mesh, etc. at the inlet and outlet that allow body fluid components to pass through but not the adsorbent. However, the column can be incorporated into an extracorporeal circulation circuit and used without limitation in applications such as extracorporeal circulation therapy in which blood, plasma, etc. are passed through the column. Next, the method of the present invention will be explained based on examples. Production example 1 As a porous cellulose gel, CK gel A-3 (exclusion limit molecular weight 50000000, particle size 45 to 105 μm, Chitsuso
Co., Ltd.) was taken and dried by critical point drying in ethanol. The dried gel was suspended in 10 ml of well-dehydrated pyridine and cooled on ice. 2 ml of chlorosulfonic acid was added dropwise to this while stirring, and stirring was continued for 10 minutes after the addition was completed. After the reaction was completed, the gel was neutralized with 20% caustic soda, filtered, and washed with pyridine and then water to introduce 0.05 mmol/ml of sulfuric acid residue onto the surface.
CK gel A-3 (hereinafter referred to as A) was obtained. Production Example 2 The method described in the Examples of JP-A No. 58-12656, that is, 100 g of vinyl acetate, 24.1 g of triallylisocyanurate, 124 g of ethyl acetate,
124g heptane, polyvinyl acetate (degree of polymerization 500)
A homogeneous liquid mixture consisting of 3.1 g and 3.1 g of 2,2'-azobisisobutyronitrile, 1% by weight of polyvinyl alcohol, 0.05% by weight of sodium dihydrogen phosphate dihydrate, and 3.1 g of 2,2'-azobisisobutyronitrile, and 0.05% by weight of sodium phosphate dihydrogen phosphate dodecahydrate. After 400 ml of water containing 1.5% by weight of the substance dissolved in it was put into a flask and stirred thoroughly, the mixture was heated at 56.5℃ for 18 hours.
Suspension polymerization was carried out by heating and stirring at 75°C for 5 hours.
A granular copolymer was obtained. After filtration, water washing, and ascent extraction, the copolymer was subjected to an ester conversion reaction at 40°C for 18 hours in a solvent consisting of 46.5 g of caustic soda and 2 methanol. Mainly composed of vinyl alcohol units. Porous water-insoluble hard gel (exclusion limit molecular weight approximately 1.8 million,
10 ml of the sample (average particle size: 150 μm) was taken and dried by critical point drying method in acetone. Thoroughly dehydrate the resulting dry gel with 10 ml of N,N-dimethylformamide.
Suspended in the solution, cooled on ice, and added chlorsulfonic acid 1
ml was added dropwise while stirring, and stirring was continued for 10 minutes after the dropwise addition was completed. After the reaction was completed, the gel was neutralized with a 10% caustic soda aqueous solution, filtered, and thoroughly washed with water to form a porous water-insoluble hard gel with 0.8 mmol/ml of sulfuric acid residue introduced onto the surface (hereinafter referred to as B). I got it. Examples 1-2 and Comparative Examples 1-2 10 g (wet weight) of the gel (adsorbent) shown in Table 1 obtained in Production Examples 1-2 was placed in a hard glass flask, and 10 ml of the aqueous solvent shown in Table 1 was added. and 121℃
High-pressure steam sterilization was performed for 40 minutes. of aqueous solvent before and after sterilization for each adsorbent.
PH and ligand amount were measured. The results are shown in Table 1.

[Table] [Effects of the Invention] According to the method of the present invention, an adsorbent for extracorporeal circulation therapy can be steam sterilized at 121°C for 40 minutes, which is stricter than the usual condition of 121°C for 20 minutes. , a good quality adsorbent for circulation therapy with less desorption of the ligand can be obtained.

Claims (1)

[Scope of Claims] 1. When performing steam sterilization on an adsorbent for extracorporeal circulation therapy having a sulfate ester group (excluding an adsorbent for extracorporeal circulation therapy consisting of a sulfated polysaccharide immobilized on a water-insoluble carrier), A method for sterilizing an adsorbent, characterized by sterilizing it in an aqueous solvent controlled at pH 5 to 9. 2. The sterilization method according to claim 1, wherein the PH-controlled aqueous solvent is a buffer solution. 3 The buffer solution is citric acid, phosphoric acid, acetic acid, boric acid,
The sterilization method according to claim 2, which is a buffer solution using at least one of tartaric acid, carbonic acid, maleic acid, glycine, or salts thereof.