METHOD FOR REMOVING LIPOPROTEINS USING AN ADSORBENT

Abstract: An adsorbent for lipoproteins which is a water-insoluble matrix having, on at least a part of the surface thereof, a group of the formula -NR¹R² wherein R¹ is hydrogen, methyl group or ethyl group; R² is an atomic group having an aromatic ring satisfying that the value of log P, in which P is a distribution coefficient in a water - octanol system, of a compound of the formula R²H is from 0 to 3.2 and an ap­ paratus for removing lipoproteins using the above adsorbent. The lipoprotein adsorbent has such advantages as a low cost, a good stability and a sufficient adsorption selectivity for adsorbing LDL and VLDL in a fluid containing lipoproteins.

Description: The present invention relates to a method for removing lipoproteins in blood and the like, more specifically for selectively adsorbing lipoproteins containing apo-B-protein, i.e. low density lipoprotein (hereinafter referred to as "LDL") and very low density lipoprotein (hereinafter referred to as "VLDL"). It has been known that lipoproteins present in blood, especially LDL and VLDL, contain a large amount of cholesterol and cause arteriosclerosis. On the other hand, it has been known that high density lipoprotein (hereinafter referred to as "HDL") is a factor which delays causing arteriosclesrosis. As a method for removing LDL and VLDL from body fluid such as blood, there has been employed methods using a membrane and using an adsorbent. In the above method using a membrane, a fair amount of HDL are removed as well as LDL and VLDL. Thus it does not satisfy the desired selectivity of lipoprotein. Further, since some plasma proteins are removed at the same time, it is necessary to supply plasma proteins. With regard to methods using an adsorbent, there are, for instance, a method using an adsorbent wherein an antibody is immobilized, so-called immunoadsorbent, and a method using an adsorbent based on the principle of the affinity chromatography, wherein a compound having an affinity for LDL and VLDL (such compound is hereinafter referred to as "ligand") is immobilized. Though the method using an immunoadsorbent provides an almost sufficient selectivity, there are many problems such as difficulty for obtaining the antibody, a high price of the antibody, poor stability of the adsorbent when preserving. In the method based on the principle of affinity chromatography, heparin, dextran sulfate and the like are typically used as a ligand. The adsorbent immobilized with the above ligand has a good selectivity and the ligand employed is not too expensive. However, many of them are difficult to sterilize and it is required to lower the cost for using ligands in large quantities. There is also an adsorbent, which has an organic compound such as phenylglycidyl ether as a ligand, adsorbing lipoproteins by hydrophobic interaciton between phenyl group and the hydrophobic part on the surface of a lipoprotein. As the above adsorbent, there is commercially available Phenyl-Sepharose CL-4B (made by Pharmacia Fine Chemicals AB). While this adsorbent is inexpensive, it has a serious problem in selectivity as it adsorbs not only LDL and VLDL but also large amount of HDL. The object of the present invention is to provide a method using a low-cost and stable adsorbent which can selectively remove LDL and VLDL from the body fluid. EP-A-0 110 409 discloses adsorbents comprising a porous hard gel on which a sulfated polysaccharide as a ligand is immobilized for the removal of VLDL, LDL and the like from body fluids. EP-A-0 143 369 discloses adsorbents comprising a surface and, linked with the surface, at least one member selected from a silanol group and a synthetic polyanion member at least one member selected from a silanol group and a synthetic polyanion member having a molecular weight of 600 or more for adsorbing low density lipoproteins. The present invention relates to the use of an adsorbent for lipoproteins which is a water-insoluble matrix having, on at least a part of the surface thereof, a group of the formula: _NR¹R² wherein R¹ is hydrogen, methyl group or ethyl group; and R² is an atomic group having an aromatic ring and satisfying the condition that the value of log P, in which P is a distribution coefficient in a water-octanol system, of a compound of the formula R²H is from 0 to 3.2. The apparatus for removing lipoproteins comprises a container having a fluid inlet and a fluid outlet, filters which are provided at both the inlet and outler through which a fluid and components included in the fluid can pass while an adsorbent, which is the above mentioned water-insoluble matrix cannot pass, and an adsorbent which is packed in the container. Fig. 1 is a graph showning a relation between a flow rate and a pressure drop ΔP obtained in Reference Example. Fig. 2 is a schematic longitudinal sectional view of an example of apparatus for removing lipoproteins. US-A-4 321 363 discloses protein adsorbents having as ligands aniline derivatives attached to the surface of agarose for adsorption of urokinase and purification thereof. EP-A-0 154 315 discloses a silica gel having a benzylamine derivative as a ligand for affinity matrixes. As a result of making a study of various water-insoluble matrices having various atomic groups prepared with paying attention to the hydrophobic and electrostatic interaction, which are the most important interactions among physico-chemical interaction between proteins and ligands, it has now been found that the water-insoluble matrix having, on the surface, a group of the formula: _NR¹R² wherein R¹ is hydrogen, methyl group or ethyl group; and R² is an atomic group havig an aromatic ring and satisfying that the value of log P, wherein P is a distribution coefficient in a water-octanol system, of a compound of the formula R²H is from 0 to 3.2 adsorbs LDL and VLDL but hardly adsorbs any HDL. As a result of comparing the adsorbent, wherein R¹ of _NR¹R² is hydrogen atom and R² is phenyl group, of the present invention with the adsorbent having _O_ instead of _NR¹_ in the above adsorbent, it has been found that the latter adsorbs not only both LDL and VLDL but also a lot of HDL at the same time as against that the former adsorbs LDL and VLDL, hardly any HDL. Consequently, nitrogen atom is supposed to be concerning the selectivity of adsorption between the LD- and VLD-lipoproteins and the HD-lipoprotein and also is an important constituent atom in a group of this adsorbent. On the other hand, it is important that _R², which exists in the group _NR¹R² of the adsorbent of the present invention, has aromatic rings. The reason is based on the fact that as a result of comparing two adsorbents with each other, provided both adsorbents have a group _NR¹R² wherein both of R¹ are hydrogen atom; R² is phenyl group and butyl group respectively, the value of log P of a compound of the formula R²H in the above two cases are almost the same, the latter is much inferior to the former in the capacity for adsorbing LDL. This is why an aromatic ring is supposed to be concerned with affinity for LDL. The typical examples of the preferable aromatic ring to be included in the atomic group R² of _NR¹R² existing in the adsorbent of the present invention, are benzene, pyridine, pyrimidine, triazine, pyrrol, imidazol, furan, thiophene, a condensed ring of them and the like. However, the present invention is not limited thereto. The logarithm of a distribution coefficient in water-octanol system, i.e. log P, is a hydrophobic parameter of a compound. The distribution coefficient P is obtained according to the following typical method. First of all, a compound is dissolved in octanol (or water) and an equal volume of water (or an octanol) is added thereto. After shaking for 30 minutes by Griffin flask shaker (made by Griffin and Jorge Ltd.), it is centrifuged for from 1 to 2 hours at 2000 rpm. Then concentrations of the compound in both octanol and water layers can be measured by various methods such as spectroscopic method and GLC and P is obtained according to the following formula: P = Coct/Cw Coct: a concentration of a compound in the octanol layer Cw: a concentration of a compound in the water layer The hydrophobic property of the atomic group _R² of the group _NR¹R² existing in the adsorbent of the present invention, plays an important role in a bond between the adsorbent and lipoprotein. In case that the value of log P of R²H is less than 0, a hydrophobic interaction with lipoproteins is so weak that a capacity for adsorption of lipoproteins is low. On the contrary, in case that the value of log P is more than 3.2, there is a problem in point of selectivity because not only LDL but also HDL and any other proteins are adsorbed. Therefore, the value of log P of a compound of the formula R²H wherein R² is an atomic group in the adsorbent of the present invention is from 0 to 3.2, preferably from 0.8 to 2.7. The typical examples of the compound of R²H satisfying that the value of log P of a compound of the formula R²H is from 0 to 3.2, are, in case that an aromatic ring is a benzene ring, benzene, toluene, xylene, ethylbenzene, phenol, benzyl alcohol, phenethyl alcohol, benzaldehyde, anisole, phenetole, benzoic acid, phenyl acetate, phenoxy acetate, methyl benzoic acid, aniline, nitrobenzene, chlorobenzene, dinitrobenzene, nitrobenzaldehyde, nitroanisole, nitrotoluene, benzamide, acetophenone, ethylphenol, ethoxyphenol, acetanilide, phenylacetamide, methylbenzyl alcohol and so on. The atomic group R² may include other aromatic rings satisfying that the value of log P of R²H is from 0 to 3.2. The adsorbent, which is characterized by being a water-insoluble matrix and having, on at least a part of the surface of the matrix, the group _NR¹R² wherein R¹ is hydrogen atom, methyl group or ethyl group; R² is an atomic group having an aromatic ring and satisfying that the value of log P, in which P is a distribution coefficient in a water-octanol system, of a compound of the formula R²H is from 0 to 3.2 can be prepared as described below. Both are applicable to the present invention. (1) The adsorbent is obtained by introducing the group _NR¹R² into a water-insoluble carrier. (2) The adsorbent is obtained by introducing the group _NR¹R² into a water-soluble high molecular compound, and then subjecting them a treatment such as cross-linking to give a water insoluble matrix. The water-insoluble carrier used for the adsorbent in the above process (1) can be an inorganic carrier, an organic carrier consisting of synthetic high molecular compound or polysaccharide, and a complex carrier consisting of orgamic carrier and/or inorgamic carrier. It is preferable that the carrier has hydrophilic property from the point of the environment of lipoproteins existing in body fluid and have little adsorption for the materials except the object materials, so-called non-specific adsorption. Typical examples of the above water-insoluble carrier are a water-insoluble carrier consisting of polysaccharides such as cross-linked agarose, cross-linked dextran, cross-linked cellulose, crystalline cellulose, cross-linked chitin and cross-linked chitosan, a water-insoluble carrier consisting of synthetic high molecular compound such as cross-linked polyvinylalcohol, crosslinked polyacrylate and cross-linked polyamide, inorganic carriers such as glass beads and silica gel, organic-inorganic complex carrier which the surface of inorganic carrier are coated with polysaccharides or high molecular compound, organic-organic complex carrier which the surface of organic carrier consisting of synthetic high molecular compound are coated with polysaccharides and the like. Typical examples of water-soluble high molecular compound used for preparation of the adsorbent in the above process (2) are polysaccharides such as dextran and starch, high molecular compound such as polyvinyl alcohol and saponificating product of ethylenevinyl acetate copolymer having a small content of ethylene. During the process for preparation of bothe adsorbents of the above process (1) and (2), the group _NR¹R² is introduced into a water-insoluble carrier or a water-soluble high molecular compound. It is preferable that the group _NR¹R² is immobilized onto a water-insoluble carrier or a water-soluble high molecular compound by a covalent bond because of a small possibility of release of ligands. Therefore, it is more preferable that ther are some functional groups, which are available for immobilizing reaction, on a water-insoluble carrier or a water-soluble high molecular compound used for the adsorbent used in the present invention. Typical examples of the above functional groups are amino group, carboxyl group, hydroxyl group, thiol group, aldehyde group, halogen group, acid anhydride group, amide group, ester group, epoxy group, silanol group and the like. The nitrogen atom existing in the group _NR¹R² in the adsorbent used in the present invention, which is supposed to be concerned with the selectivity of adsorption between the LD- and VLD-lipoproteins and the HD-lipoprotein, can be derived from either a water-insoluble carrier, a water-soluble high molecular compound or a ligand. In other words, there are some methods to introduce a group _NR¹R² into either a water-insoluble carrier or a water-soluble carrier; one is that the group _NR¹R² is a group derived from a compound of the formula HNR¹R², wherein R¹ and R² are as defined above, and immobilized to a water insoluble carrier via amino group of the compound and another is that the group _NHR¹R² is combined with the carrier by reacting a water-insoluble carrier having a group of the formula _NHR¹, wherein R¹ is as defined above, with a compound of the formula R²X, wherein R² is as defined above and X is a functional group capable of reacting with amino group or a part of the functional group. Both of them are available for the present invention. The term "a carrier having amino group" in the above is a carrier consisting of a material originally having amino group such as chitin and chitosan, or a carrier at first prepared by introducing amino group into a carrier originally having no amino group by being activated with cyanogen bromide, epichlorohydrine, 1,4-butanediol diglycidyl ether and the like and then being reacted with the compound of either H₂NR¹ or HNR¹R³ wherein R³ is an atomic group having a functional group capable of binding to a carrier. When the group _NR¹R² is introduced into a water-insoluble carrier or a water-soluble high molecular compound, in case of combining the compound HNR¹R² with the carrier, aniline, aniline derivative, a mixture of aniline and aniline derivative, benzylamine, benzylamine derivative and a mixture of benzylamine and benzylamine derivative are particularly useful as a compound of HNR¹R². Examples of aniline derivative are N-monoalkylanilines such as N-methylaniline and N-ethylaniline; aromatic alkyl-substituted anilines such as o-toluidine, m-toluidine, p-toluidine, 2,3-xylidine and 2,4-xylidine; aromatic alkoxysubstituted-anilines such as o-aminoanisole, m-aminoanisole, 2-aminophenetole, 3-aminophenetole and 4-aminophenetole; anilines having one or more substituent group consisting of one or more kinds of substituent groups on the aromatic ring, for instance, o-chloroaniline, m-chloroaniline, p-chloroaniline, o-nitroaniline, m-nitroaniline, p-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline, 3,5-dinitroaniline, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-ethyl aminobenzoate, m-ethyl aminobenzoate, p-ethyl aminobenzoate, p-aminobenzensulfonamide, o-aminophenol, m-aminophenol, p-aminophenol, o-aminophenethyl alcohol, p-aminophenethyl alcohol, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2-amino-4-nitroanisole, 2-amino-4-nitrotoluene and the like. The adsorbent is employed in order to remove LDL and VLDL from blood, serum, plasma, a diluted solution of blood, serum or plasma and a solution containing various lipoproteins, for instance, a solution which has been subjected to a pretreatment such as removal of blood cells, serum proteins. Typically, the adsorbent is used as a adsorbent for treating patients of hyperlipemia or a adsorbent for analyzing various lipoproteins. The adsorbent can be used for therapy in various ways. For the most simple example, the adsorbent can be used as follows: i.e. patient's blood is introduced outside of his body so as to be put into a blood bag and then mixed with the adsorbent to rmove LDL and VLDL, followed by removing the adsorbent through filter. Consequently, the blood treated in this way is returned back to the patient himself. Though this method does not need an intricate apparatus, there are some defects such as a small amount of a treated blood at one time, a lot of time of therapy and a complicated operation. For another method, a column packed with the adsorbent is incorporated into an extracorporeal circulation circuit, and then removal of LDL and VLDL by adsorption is taken by on-line system. There are two treatment methods. One is that whole blood is directly perfused and another is that only plasma separated from the blood is passed through the column. Both the adsorbent and the apparatus for removing lipoproteins can be used in any of the above-mentioned methods. The apparatus for removing lipoproteins comprises a container having a fluid inlet and a fluid outlet, filters through which a fluid and components included in the fluid can pass while the adsorbent packed in cannot pass and which are provided at both the above inlet and outlet and, the adsorbent of the present invention is packed in the above container. A schematic longitudinal sectional view of the example of the apparatus for removing lipoprotains is shown in Figure 2. In Figure 2, 1 and 2 are a fluid inlet and a fluid outlet respectively, 3 is the adsorbent used in present invention, 4 and 5 are filters or mesh which the fluid and components thereof can pass through while the adsorbent can not pass through, and 6 is a column. The filter 4 of the fluid inlet side may be omitted. It is preferable that the adsorbent has a sufficient mechanical strength, i.e. hard adsorbent, so as to prevent compaction of the adsorbent during filling a column with the adsorbent, incorporating the column into an extracorporeal circulation circuit, and treating patients with it by on-line system. The structure of the adsorbent can be porous or non-porous. Especially, it is preferable that the specific surface area is large, that is to say, the adsorbent has a porous structure, particularly a whole porous structure, in order to get a high capacity for adsorbing LDL per unit volume of the adsorbent. The term "hard" in the present invention means, as shown in the Reference Example herein below, that the relation between a pressure drop and a flow rate determined by passing an aqueous fluid through a cylindrical columm uniformly filled with the water-insoluble matrix keeps a linear relationship until the pressure drop is increased to 0.3 kg/cm², which is the minimum required mechanical strength of the adsorbent for incorporating the column into an extracorporeal circulation circuit. The term "porous structure" means that the volume of the pore of the adsorbent is not less than 20% and a specific surface area of it is not less than 3 m²/g. Otherwise, the adsorbent capacity becomes too small. Typical examples of the above mentioned carrier are porous cellulose gel, porous chitosan gel, vinyl porous carrier such as styrene-divinylbenzene copolymer, cross-linked acrylate, cross-linked polyvinyl alcohol, inorganic porous carrier such as glass, silica, alumina. In case that the adsorbent has a porous structure, it is important that there is such a pore size as LDL and VLDL, which have not less than 1 × 10⁶ of molecular weight, can easily enter in it. It means that the molecular weight of the exclusion limit measured with globular proteins is not less than 1 × 10⁶. The molecular weight of the exclusion limit under 1 × 10⁶ has so small capacity of adsorption that it is not suitable for practical use. On the other hand, the molecular weight of the exclusion limit over 1 × 10⁸ is not suitable for practical use neither because the mechanical strength is weakened and the amount of solid contained in the adsorbent is too small to get the sufficient capacity for the adsorption. Therefore, the preferable molecular weight of the exclusion limit of an adsorbent for the present invention is from 10⁶ to 10⁸. More preferably, the exclusion limit is 3 × 10⁶ to 7 × 10⁷ from the points of rather free permeation of proteins to be adsorbed, the strength of the adsorbent and the adsorbent capacity. The term "the molecular weight of the exclusion limit" means, for instance, as described in the literature such as "Jikken Kosoku Ekitai Chromatography (Experimental High Speed Liquid Chromatography)", Hiroyuki Hatano and Toshihiko Hanai, published by Kabushiki Kaisha Kagaku Dojin, the minimum molecular weight of the molecule which cannot permeate into a pore, i.e. which is excluded, in a gel permeation chromatography. The shape of the adsorbent can be optionally selected from shape such as particle, fiber, sheet and hollow fiber. The present invention is more specifically described and explained by the following Reference Example, Examples and Comparative Examples. It is to be understood that the present invention is not limited to the Reference Example, Examples and Comparative Examples. Reference Example A relation between a flow rate and a pressure drop was determined by passing water by means of a peristatic pump through cylindrical glass columns equipped at both ends with filters having a pore size of 15 µm (inner diameter: 9 mm, column length: 150 mm), in which an agarose gel (Biogel A5m made by Biorad Co., particle size: 50 to 100 mesh) and hard gels made of a polymer (Toyopearl HW 6S made by Toyo Soda Manufacturing Co., Ltd., particle size: 50 to 100 µm, and Cellulofine GC-700 made by Chisso Corporation, particle size: 4S to 105 µm) were packed respectively. The results are shown in Fig. 1. As shown in Fig. 1, an increase of a flow rate is nearly proportional to that of a pressure drop in case of hard gels made of a polymer, whereas in case of an agarose gel, consolidation occurrs and a flow rate does not increase even if a pressure drop increases. Example 1 Twenty mℓ of n-heptane, 6 mℓ of a 20% by weight aqueous solution of sodium hydroxide and 2 drops (50 µℓ) of Tween 20 (made by Kao Atlas Kabushiki Kaisha) were added to 20 mℓ of a porous cellulose gel (CK gel A-3 made by Chisso Corporation, exclusion limit of globular protains: 5 × 10⁷, particle size: 63 to 125 µm). After stirring for 2 hours at 40°C, there was added 6 mℓ of epichlorohydrin. Further, after the stirring was continued for 2 hours a 40°C and then washed with water, an epoxy-activated gel was obtained. To 10 mℓ of the obtained epoxide epoxy-activated gel, 10 mℓ of a 30% by volume aqueous solution of dioxane wherein 300 mg of aniline was dissolved was added. After 4 hours reaction by allowing it to stand at 40°, the resultant gel was filetered and washed with a 15% by bolume aqueous solution of dioxan, water, a 2 M aqueous solution of sodium chloride and water in turn to obtain an aniline-immobilized gel. One mℓ of the obtained aniline-immobilized gel was put into a test tube, and thereto 4 mℓ of human serum was added. After shaking for 2 hours at 37°C, the concentrations of LDL, VLDL and HDL-cholesterol in the supernatant liquid were measured. The result is shown in Table 1. Example 2 There was suspended 20 mℓ of a cross-linked agarose gel (Sepharose CL-6B made by Pharmacia Fine Chemicals AB, exclusion limit: 4 × 10⁶, particle size: 45 to 165 µm) to 20 mℓ of water. And there was added 10 mℓ of a 2 M aqueous solution of sodium hydroxide and adjusted at 40°C. Then thereto 4 mℓ of epichlorohydrin was added. After stirring for 2 hours at 40°C and then washing with water, an epoxy-activated gel was obtained. To 10 mℓ of the obtained epoxy-activated gel, 10 mℓ of a 30% by volume aqueous solution of dioxane wherein 300 mg of aniline was dissolved was added. After 4 days reaction by allowing it to stand at room temperature, the resultant gel was filtered and washed with a 15% by volume aqueous solution of dioxan, water, a 2 M aqueous solution of sodium chloride and water in turn to obtain an aniline-immobilized gel. One mℓ of the obtained aniline-immobilized gel was put into a test tube, and thereto 4 mℓ of human serum was added. After shaking for 2 hours at 37°C the concentrations of LDL, VLDL and HDL-cholesterol in the supernatant liquid were measured. The result is shown in Table 1. Example 3 There was added 10 mℓ of water, 5.4 mℓ of a 2 M aqueous solution of sodium hydroxide and 1.9 mℓ of epichlorohydrin to 10 mℓ of a porous cellulose gel (CK gel A-3 made by Chisso Corporation, exclusion limit of globular protains: 5 × 10⁷, particle size: 63 to 125 µm). After completion of the reaction under stirring for 2 hours at 40°C, the resultant gel was filtered and washed with water to obtain an epoxy-activated gel. To 10 mℓ of the obtained epoxy-activated gel, 8 mℓ of water and 137 mg of benzylamine were added. After mixing well, the mixture was allowed to stand for 6 days at 50°C. After completion of the reaction, the resultant gel was filtered and then washed with water to obtain a benzylamine-immobilized gel. One mℓ of the obtained benzylamine-immobilized gel was put into a test tube, and thereto 4 mℓ of human serum was added. After shaking for 2 hours at 37°C, the concentrations of β-lipoprotain and HDL-cholesterol in the supernatant liquid were measured. The result is shown in Table 2. Example 4 The procedures of Example 3 were repeated except that 120 mg of aniline was used instead of 137 mg of benzylamine in Example 3 to obtain an aniline-immobilized gel and examine the absorption of the obtained aniline-immobilized gel. The result is shown in Table 2. Example 5 There was added 10 mℓ of water and 0.5 mℓ of a 30% aqueous ammonium solution to 10 mℓ of epoxy-activated CK gel A-3 obtained by the same procedures as in Example 3. After mixing well, the mixture was allowed to stand for 2 days at 40°C. After completion of the reaction, the resultant gel was filtered and then washed with water to obtain an aminated gel (hereinafter referred to as N-gel). 10 mℓ of the obtained N-gel was washed with 50 mℓ of dioxane, 50 mℓ of a 10% by volume triethylamine dioxane solution and 100 mℓ of dioxane in turn on a glass filter. Then the gel was transferred to a reaction vessel, and thereto 25 mℓ of dioxan wherein 90 mg of benzoic acid was dissolved. 2 mℓ of dioxan wherein 100 mg of dicyclohexyl carbodiimide was dissolved was added under stirring. After the stirring was continued for 3 hours, there was further added 2 mℓ of dioxan wherein 100 mg of dicyclohexyl carbodiimide was dissolved was added. After completion of the reaction under stirring for 3 hours, the resultant gel was filtered and then washed with 100 mℓ of dioxan, 100 mℓ of methanol, 100 mℓ of dioxan and 500 mℓ of water in turn to obtain a benzoic acid-immobilized N-gel. One mℓ of the obtained benzoid acid-immobilized gel was put into a test tube, and thereto 4 mℓ of human serum was added. After shaking for 2 hours at 37°C, the concentrations of β-lipoprotein and HDL-cholesterol in the supernatant liquid were measured. The result is shown in Table 2. Example 6 The procedures of Example 5 were repeated except that 123 mg of p-nitrobenzoic acid was used instead of 90 mg of benzoic acid to give a p-nitrobenzoic acid-immobilized N-cellulose gel and examine the absorption of the obtained p-nitrobenzoic acid-immobilized N-cellulose gel. The result is shown in Table 2. Example 7 The procedures of Example 3 were repeated except that 155 mg of phenethylamine was used instead of 137 g of benzylamine and that 10 mℓ of a 30% by volume aqueous solution of dioxan was used instead of 10 mℓ of water to obtain a phenethylamine-immobilized gel and examine the adsorption of the obtained phenethylamine-immobilized gel. The result is shown in Table 2. Example 8 The procedures of Example 3 were repeated except that p-aminobenzenesulfonamide was used instead of benzylamine to otain a p-aminobenzensulfonamide immobilized gel and examine the adsorption of the obtained p-aminobenzensulfonamide-immobilized gel. The result is shown in Table 2. Comparative Example 1 One mℓ of Phenyl-Sepharose CL-4B (made by Pharmacia Fine Chemicals AB) was put into a test tube, and thereto 4 mℓ of human serum was added. After shaking for 2 hours at 37°C, the concentrations of LDL, VLDL and HDL-cholesterol in the supernatant liquid were measured. The result is shown in Table 1. Comparative Example 2 One mℓ of Ringer's solution (made by Otsuka Seiyaku Kabushiki Kaisha) was put into a test tube, and thereto 4 mℓ of human serum was added. After shaking for 2 hours at 37°C, the concentrations of LDL, VLDL and HDL-cholesterol in the supernatant liquid were measured. The result is shown in Table 1. Comparative Exammple 3 The procedures of Example 3 were repeated except that 94 mg of n-butylamine was used instead of 137 g of benzylamine to obtain a n-butylamine-immobilized gel and examine the adsorption of the obtained n-butylamine-immobilized gel. The result is shown in Table 2. Comparative Example 4 The procedures of Example 7 were repeated except that 173 mg of γ-phenylpropylamine was used instead of 155 g phenethylamine to obtain a γ-phenyl propylamine-immobilized gel and examine the adsorption of the obtained γ-phenylpropylamine-immobilized gel. The result is shown in Table 2. Comparative Example 5 One mℓ of Ringer's solution (made by Otsuka Seiyaku Kabushiki Kaisha) was put into a test tube, and thereto 4 mℓ of human serum was added. After shaking for 2 hours at 37°C, the concentration of β-lipoprotein and HDL-cholesterol in the supernatant liquid were measured. The result is shown in Table 2. As shown in Table 1 and 2, the adsorbent in the present invention adsorbs both LDL and VLDL, while HLD-cholesterol is hardly adsorbed. In addition to the ingredients used in the Examples, other ingredients can be used in the Examples as set forth in the specification to obtain substantially the same results.

Claims: 1. Method for the removal of low density lipoproteins and very low density lipoproteins from body fluids using an adsorbent, which is a water-insoluble matrix having, on at least a part of the surface thereof, a group of the formula: _NR¹R² wherein R¹ is hydrogen atom, methyl group or ethyl group; and R² is an atomic group having an aromatic ring and satisfying the condition that the value of log P, in which P is a distribution coefficient in a water-octanol system, of a compound of the formula R²H is from 0 to 3.2. 2. Method of claim 1, wherein said group _NR¹R² is a group derived from a compound of the formula HNR¹R², wherein R¹ and R² are as defined above, and immobilized to a water-insoluble matrix via amino group of said compound. 3. Method of claim 1, wherein said group _NHR¹R² is introduced to said matrix by reacting a water-insoluble matrix having a group of the formula _NHR¹, wherein R¹ is as defined above, with a compound of the formula R²X, wherein R² is as defined above and X is a functional group capable of reacting with amino group or a part of the functional group. 4. Method of claim 1, wherein said water-insoluble matrix is a hydrophilic matrix. 5. Method of claim 1, wherein said water-insoluble matrix has a porous structure. 6. Method of claim 2, wherein the compound of the formula HNR¹R² is aniline, an aniline derivative, or a mixture thereof. 7. Method of claim 2, wherein the compound of the formula HNR¹R² is benzylamine, a benzylamine derivative, or a mixture thereof. 8. Method of claim 5, wherein said water-insoluble matrix has a molecular weight of the exclusion limit measured with a globular protein of from 1 × 10⁶ to 1 × 10⁸.

Inventors: FURUYOSHI, SHIGEO, TANI, NOBUTAKA
Applicants: KANEGAFUCHI KAGAKU KOGYO KABUSHIKI KAISHA
Application year: 1987
Main classification: B01D15
IPC codes: A61M1, B01D15, G01N30, B01J20