JP2960500B2 - Fatty acid adsorbent - Google Patents

Description

The present invention relates to an adsorbent for selectively adsorbing fatty acids in water. More specifically, the present invention relates to a body fluid purifying adsorbent for selectively adsorbing and removing free fatty acids that are malignant substances from body fluids such as blood, plasma, and serum.

[Problems to be Solved by Conventional Techniques and Inventions] In recent years, various artificial organs have been developed and applied to clinical aspects. Among these artificial organ treatments,
Blood purification methods represented by artificial kidneys used outside the body are the most widespread and effective. The blood purification treatment is to remove waste and harmful substances accumulated in a patient's blood by a physicochemical operation using a membrane or an adsorbent. At present, blood purification therapy that is put into practical use includes hemodialysis using a membrane, hemofiltration, combined use of hemodialysis and dialysis, blood separation, and blood perfusion using an adsorbent. Blood perfusion with an adsorbent is intended to remove harmful substances and the like in blood by adsorbing the adsorbent, thereby reducing their blood concentration and improving the disease state. Generally, the target disease of the blood perfusion method is an intractable disease,
Conventional pharmacotherapy often reaches the limit of its therapeutic effect, and some diseases cannot be saved without such dramatic methods. However, since the adsorbent used for blood perfusion has low selectivity, there is a disadvantage that useful components in the biological fluid are also removed. Therefore, development of an adsorbent that specifically or selectively adsorbs and removes a specific substance in plasma has been desired.

On the other hand, the number of renal failure patients undergoing hemodialysis has been steadily increasing in recent years, and problems arising from dialysis therapy have been raised. In particular, side effects due to the administration of heparin, an anticoagulant, are known, and activation of lipoprotein lipase and hyperfree fatty acidemia accompanying the activation have been reported. Hyperfree fatty acidemia is also associated with suppression of lymphatic function and arrhythmia, and prompt response is required. However, at present, no effective treatment is known at present. In general, free fatty acids are those having 12 to 24 carbon atoms and 0 degrees of unsaturation.
To 5 are fatty acids generally present in biological fluids, and typically include stearic acid, oleic acid, palmitic acid, arachidic acid, linoleic acid and the like.

An object of the present invention is to selectively adsorb free fatty acids without affecting the concentration of other components such as blood, plasma, etc., to have high safety and to be suitable for purification or regeneration of biological fluids such as blood, plasma, etc. The agent is provided.

[Means for Solving the Problem] The present inventors have made intensive studies and found that a specific polymer composition has a selective adsorption ability to fatty acids in water. That is, the present invention provides the following general formula Or (Where Y is a group selected from hydrogen, an alkyl group and a cyano group, X ⁻ is a halogen ion or an atomic group forming an anion, and Z is CH _{2 n} (where n is an integer from 1 to 10), ^{-COOR 3 -, - OCOR 3 -} , - CONHR 3 -, and -NHCOR ³ -
(However, R ³ is CH _{2 m} or -CH ₂ CH ₂ OCH _{2 m} CH
_{2 -, - CH 2 CH (} CH 3) OCH 2 m CH (CH 3) -, ( where, m is an integer of 1 to 10) selected from) group, R ^1,
R ² is the same or different group selected from an alkyl group having 5 or less carbon atoms, a halogenated alkyl group, a hydroxyalkyl group, and a benzyl group; A is two or three long-chain hydrophobic groups;
Or a nonionic monovalent group having one linear hydrophobic group containing a rigid portion in the chain, and B ¹ and B ² are the same or different nonionic monovalent linear hydrophobic groups Represents a group. A fatty acid adsorbent comprising a linear polymer containing 50% by weight or more of the unit represented by the formula (1).

In the present invention, in the general formulas [I] and [II], Y
The alkyl group represented by is not limited with respect to the number of carbon atoms, but those having 1 to 4 carbon atoms are preferably used because of the availability of raw materials. X ^- is a halogen ion represented by fluorine, chlorine, bromine, each ion of iodine, X ^- is the atomic group necessary for forming a stable anion represented by, but known atomic group is used without limitation generally _{^{NO 3 -, ClO 4 -,}} O
_{^{H -, SCN -, CH 3}} COO - and the like are preferably used.

Further, in the general formulas [I] and [II], as the alkyl group having 5 or less carbon atoms represented by R ¹ and R ² , or a halogen-substituted product or a hydroxyl-substituted product thereof, generally known ones are particularly limited. Although it is used without any examples, preferred examples include methyl, ethyl, propyl, butyl, pentyl, chloromethyl, 2,2-dichloroethyl, 2-chloroethyl, and 3-chloro. Propyl group, 2
-Bromoethyl group, hydroxymethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group and the like.

In the general formulas [I] and [II], Z is CH _{2 n} (where n is an integer of 1 to 10, preferably 1 to 4), ^{-COOR 3 -, - OCOR 3 -} , - CONHR 3 -, and -NHCOR ³ -
(However, R ³ is CH _{2 m} or -CH ₂ CH ₂ OCH _{2 m} CH
_{2 -, - CH 2 CH (} CH 3) OCH 2 m CH (CH 3) -, and (where, m is 1 to 10, preferably an integer of 1 to 4),
In the above Z, a nitrogen atom is bonded on the left side and a carbon atom is bonded on the right side. ). The use of these groups facilitates obtaining raw materials and producing polymers.

In the present invention, in the general formula [I], A is a group having two or three long-chain hydrophobic groups or a rigid part in the chain.
It is a nonionic monovalent group having any of the linear hydrophobic groups (hereinafter, abbreviated as a hydrophobic group). The presence of the hydrophobic group improves the selective adsorptivity of the resulting fatty acid adsorbent and increases the stability when used in water.

Among the hydrophobic groups used in the present invention, the long-chain hydrophobic group is preferably a straight-chain alkyl group having 10 to 30 carbon atoms or a halogen-substituted product thereof because of availability of raw materials. Incidentally, the long-chain hydrophobic group referred to in the present invention, in addition to completely linear,
It also includes those having a branch having up to 2 carbon atoms. Preferred specific examples thereof include a lauryl group, a myristyl group, a palmityl group, and a stearyl group.

One embodiment of the hydrophobic group of the present invention is one having two or three long-chain hydrophobic groups. If the number of long-chain hydrophobic groups is one, the resulting adsorbent has insufficient water resistance, and if the number is four or more, it is difficult to obtain raw materials for polymer production.

Further, in another embodiment of the hydrophobic group of the present invention, a nonionic one having one linear hydrophobic group containing a rigid portion in a chain.
In the valency group, the rigid portion includes the following groups.

A divalent group composed of at least two aromatic rings connected directly or through a carbon-carbon multiple bond, a carbon-nitrogen multiple bond, an ester bond, an amide bond, or the like.

Specific examples of such groups include, for example, And other divalent groups.

A divalent group in which two aromatic rings have a plurality of bonds or a single bond between a plurality of atoms, and whose rotation is energetically constrained. A divalent group in which aromatic rings form a condensate and whose condensed rings are stacked between multiple molecules, the rotation of which is sterically constrained to each other. Then And other divalent groups. The number of carbon atoms of the linear hydrophobic group having one linear hydrophobic group containing a rigid portion in the chain is 4 to 30 in view of the water resistance of the obtained adsorbent and the availability of raw materials. Is preferred. Here, the carbon number means a carbon number of a rigid part and a part excluding a bonding part between the rigid part and the linear hydrophobic group. In general, a carbon-carbon bond, an ester bond, or an ether bond is preferably used as the bonding portion between the rigid portion and the linear hydrophobic group. Restricting the number of straight-chain hydrophobic groups containing a rigid portion to one in a chain is extremely difficult if the number is two or more, and the stability of the fatty acid adsorbent may be difficult in molding. This is because many are not desirable.

The hydrophobic group of the present invention is not particularly limited as long as it meets the above, and a known group is used. Typical examples that are generally preferably used are specifically shown below.

However, R ⁴ and R ⁵ are the same or different linear alkyl groups having 12 to 30 carbon atoms or a halogen-substituted product thereof, and D is E
_j CH _{2 k} (where E is Or And j is 0 or 1, and k is a positive integer. )
And h and i are positive integers.

However, R ⁴ , R ⁵ , D and j are the same as above and are 1 or 2.

However, R ⁴ and R ⁵ are the same as above, and k is a positive integer.

R ⁶ -VG- [D] wherein R ⁶ is an alkyl group having 4 to 22 carbon atoms, an alkyloxy group, or an alkyloxycarbonyl group, or a halogen-substituted product thereof; (However, W is -N = CH-, -N = N-, -CH = CH-,-
NO = N-, -CONH-, -COO-, -O-, -CO-, -C
(CH ₃ ) ₂ −, And j is 0 or 1. ) G is, CH _{2 p} or a -OCH _{2 p.} (However, p is a positive integer.) In the above general formulas [A], [B], [C], and [D], k, p
May be a positive integer, but is generally preferably 1 to 16 from the viewpoint of availability of raw materials. In the general formula [A], h and i can be positive integers without any limitation, but are generally preferably 1 to 4 in terms of availability of raw materials. Further, the above general formulas [A], [B],
In [C] and [D], examples of the halogen atom of the halogen-substituted alkyl group represented by R ⁴ and R ⁵ include fluorine, chlorine, bromine, and iodine atoms.

In the general formula [II], B ¹ and B ² are the same or different nonionic monovalent long-chain hydrophobic groups. The presence of the long-chain hydrophobic group in the polymer used in the present invention increases the stability when used in water. The long-chain hydrophobic group was selected from a straight-chain alkyl group having 12 to 30 carbon atoms or a halogen-substituted product thereof, a straight-chain alkylcarboxyalkyl group, or a straight-chain alkyloxycarbonylalkyl group because of availability of raw materials. It is preferably a group. Further, more preferred groups are specifically shown below.

R ⁷ TU _j [E] (where R ⁷ is a linear alkyl group having 12 to 30 carbon atoms or a halogen-substituted product thereof, T is —COO— or —OCO—, and U is CH _{2 q} And j is 0 or 1.) In the general formula [E], if q is a positive integer, it is adopted without any limitation, but from 1 to 5 because of the availability of raw materials.
It is preferred that Furthermore, examples of the halogen atom of the halogen-substituted alkyl group represented by R ⁷ include fluorine, chlorine, bromine, and iodine atoms.

In the polymer constituting the adsorbent of the present invention, units other than the unit represented by the general formula [I] or [II] are not particularly limited as long as they form a linear polymer. III] is preferably used.

(Where P is hydrogen, a halogen atom, a cyano group, an alkyl group, or a carboxyl group; Q is an alkyl group, a carboxyl group, a phenyl group, a naphthyl group, an alkylcarboxyl group, an alkyloxycarbonyl group, an alkylaminocarbonyl group, An aminocarbonyl group, an alkyloxy group, an amino group, an alkylamino group, a trimethylammonioalkyl group and a halogen-substituted or hydroxyl-substituted product thereof.) The carbon number of the unit represented by the general formula [III] is
In consideration of the availability of raw materials, it is preferably 10 or less.

In the polymer constituting the fatty acid adsorbent of the present invention, the weight fraction of the unit represented by the general formula [I] or [II] to the total polymer is preferably 50% by weight or more.
When the unit fraction is less than 50 wt%, the resulting fatty acid adsorbent may have insufficient adsorption capacity,
The stability when used in water may deteriorate. The molecular weight of the polymer used in the fatty acid adsorbent of the present invention is not particularly limited, but the number average molecular weight is preferably 5,000 or more. When the number average molecular weight is 5,000 or less, the obtained fatty acid adsorbent becomes brittle.

As described above, the fatty acid adsorbent of the present invention is a linear polymer (hereinafter abbreviated as a hydrophobic polymer) having a specific amount of the unit represented by the general formula [I] or [II].

The method for producing the hydrophobic polymer is not limited to the above, and any known method may be employed. Generally, the following general formula [IV]
Alternatively, it can be obtained by homopolymerizing a monomer having a structure represented by [V] or copolymerizing two or more monomers.

^{Y, Z, X-, R 1} , R 2, A, for the definition and preferred examples of B ^1, B ² are as stated previously. Further, the monomer represented by the general formula [IV] or [V] can be used as a fatty acid adsorbent even when polymerized alone, but can also be used by copolymerizing the monomer with a copolymerizable vinyl monomer. The hydrophobic polymer can be obtained. As the vinyl monomer copolymerizable with the monomer represented by the general formula [IV] or [V], known monomers can be used without particular limitation. Specific examples of typical compounds generally used preferably include, for example, olefin compounds such as ethylene, propylene and butene; halogen derivatives of olefin compounds such as vinyl chloride and hexafluoropropylene; and aromatic compounds such as styrene and vinylnaphthalene. Vinyl ester compounds such as vinyl acetate; acrylic acid derivatives and methacrylic acid derivatives such as methyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, acrylamide and methacrylamide; unsaturated nitrile compounds such as acrylonitrile; methyl vinyl Vinyl ether compounds such as ethers; and quaternary ammonium compounds such as methylvinylpyridinium iodide and trimethylammonioethyl methacrylate. In addition to the above, vinyl carboxylic acid compounds such as acrylic acid and methacrylic acid; and sulfonic acid compounds such as styrene sulfonic acid and vinyl sulfonic acid can be suitably used.

The polymerization method for producing the above-mentioned hydrophobic polymer may be either ionic polymerization or radical polymerization, but it is desirable to carry out the polymerization in the presence of a radical initiator. As the polymerization operation, generally known operations are not particularly limited, and solution polymerization is preferably used in view of uniformity of the obtained polymer and easy adjustment of the composition ratio of the copolymer. The solvent used in the solution polymerization is not particularly limited as long as the solvent used dissolves the monomer. Generally, water, methanol, ethanol, acetone, benzene, dimethylformamide, dichloromethane, tetrachloromethane, chloroform, tetrahydrofuran, dichloroethane, chlorobenzene and the like are preferably used. The above solvents may be used as a mixture of two or more. The polymerization temperature is preferably from 0 ° C to 150 ° C, more preferably from 40 ° C to 100 ° C. As a method for isolating the hydrophobic polymer, various methods known in the art can be used. In the case of solution polymerization, the reaction mixture is poured into a solvent that does not dissolve the produced polymer. The precipitation method is preferred.

The hydrophobic polymer produced as described above is generally a colorless, white or light yellow solid. In addition, it is hardly soluble in water, but in organic solvents such as cimethylformamide, chloroform, tetrachloromethane, dichloromethane, tetrachloroethane, tetrahydrofuran, etc.
Dissolve at room temperature to 100 ° C. The content of the unit represented by the general formula [I] or [II] in the hydrophobic polymer can be determined by elemental analysis.

The shape when the hydrophobic polymer obtained by the above-mentioned production method is used as an adsorbent is not particularly limited, and can be used in various shapes such as a granular shape, a massive shape, and a film shape.
The molding method for that purpose is not particularly limited, and any method may be used.

The adsorbent of the present invention may be used alone, or may be laminated or mixed with another adsorbent. Activated carbon and cellulose gel can be exemplified as other adsorbents. A wide clinical effect can be expected by combination with other adsorbents or dialysis devices and filtration devices. When used for extracorporeal circulation, the adsorbent volume is suitably about 50 to 600 ml. There are various methods for using the adsorbent of the present invention in extracorporeal circulation. For example, the following methods are available.

1 A method for purifying blood taken out from the body by directly passing through the adsorbent of the present invention 2 Separating blood taken out from the body into a plasma component and a blood cell component using a centrifuge or a membrane-type plasma separator,
Method of passing blood plasma components through the adsorbent of the present invention to purify them, and then returning them to the body together with blood cell components. After passing through the adsorbent of the present invention for purification.

In general, the fatty acid adsorbent of the present invention often exhibits liquid crystallinity as its basic property. The temperature range showing the liquid crystallinity is
It is in the range of 0-200 ° C. Liquid crystallinity is generally confirmed by measurement with a differential scanning calorimeter. In the case of liquid crystal, the amount of heat accompanying the transition from solid to liquid crystal is observed at a certain temperature, and that temperature is called the solid-liquid crystal transition temperature. The fatty acid adsorbent of the present invention can be used at or above this solid-liquid crystal transition temperature, but at or above the transition temperature, the polymer of the present invention softens at or above the transition temperature, and is used at or below the transition temperature in consideration of mechanical strength. Is preferred.

In order to improve the wettability of the fatty acid adsorbent of the present invention with water, it is preferable that the fatty acid adsorbent used is immersed in water having a solid-liquid crystal transition temperature or higher for 1 minute or more. By such an operation, the efficiency of fatty acid adsorption when a biological fluid or the like is passed through the adsorbent is improved.

[Effect] The fatty acid adsorbent of the present invention selectively adsorbs a fatty acid having a long-chain alkyl group. When used as an adsorbent in a blood purification treatment, there is an advantage that the desired free fatty acid is selectively adsorbed without removing other components necessary for the human body, so that there is little adverse effect on the human body. Further, the ability to adsorb fatty acids is extremely large as compared with conventional organic adsorbents such as ion exchange resins and activated carbon. Also,
The fatty acid adsorbent of the present invention has a quaternary ammonium group having a specific structure immobilized in a polymer by a covalent bond. Therefore, the components are hardly eluted, and the life is long. This means that when used as an adsorbent for a biological fluid, that is, when returning a biological fluid once taken out of the body to the body, there is no risk of the adsorbent being mixed into the biological fluid and used for blood purification therapy. Extremely high safety when used as an adsorbent. In view of the above, the industrial value of the fatty acid adsorbent of the present invention is extremely large.

Hereinafter, examples will be described in order to more specifically describe the present invention, but the present invention is not limited to these examples.

In Examples of the present invention, the weight fraction of the unit represented by the general formula [I] or [II] in the hydrophobic polymer is abbreviated as unit fraction.

Production Example 1 5 mmol of the monomers shown in Table 1 and 5 mg of azobisisobutyronitrile were placed in a test tube together with 10 ml of benzene and 10 ml of ethanol. After placing the test tube under a nitrogen atmosphere,
Polymerization was performed at 80 ° C. for 24 hours. The contents were poured into 500 ml of methanol and the resulting precipitate was collected by filtration. Drying under reduced pressure gave a porous white or yellow-white solid as a hydrophobic polymer in the amounts shown in Table 1. The unit fraction of the hydrophobic polymer was determined by elemental analysis. The results are summarized in Table 1.

Production Example 2 Monomer 10 mmol and benzoyl peroxide 7 mg shown in Table 2
Was placed in a test tube with 10 ml of chloroform. After the test tube was placed in a nitrogen atmosphere, the tube was sealed and polymerized at 70 ° C. for 20 hours. The contents were poured into 500 ml of methanol and the resulting precipitate was collected by filtration. By drying under reduced pressure, the solid content as a hydrophobic polymer was obtained in the amount shown in Table 2. The unit fraction of the hydrophobic polymer was determined by elemental analysis. The results are summarized in the second
It is shown in the table.

Production Example 3 Monomer 10 mmol shown below 10 mmol of the monomer shown in Table 3 and 2 mg of azobisisobutyronitrile were put into a test tube together with 10 ml of a benzene-ethanol mixed solvent (1: 1, weight ratio). After the test tube was placed under a nitrogen atmosphere, the tube was sealed and polymerized at 65 ° C. for 30 hours. The contents were poured into 500 ml of methanol and the resulting precipitate was collected by filtration. Drying under reduced pressure gave solids as hydrophobic polymers in the amounts shown in Table 3. The unit fraction of the hydrophobic polymer was determined by elemental analysis. The results are summarized in Table 3.

Production Example 4 3 g of a monomer shown in Table 4 and methyl methacrylate (hereinafter abbreviated as MMA) in an amount shown in Table 4 and azobisisobutyronitrile 3 mg in a benzene-ethanol mixed solvent (1: 1, weight ratio) Placed in a test tube with 10 ml. After the test tube was placed in a nitrogen atmosphere, the tube was sealed and polymerized at 60 ° C. for 30 hours. The contents were poured into 500 ml of methanol and the resulting precipitate was collected by filtration. Drying under reduced pressure gave solids as hydrophobic polymers in the amounts shown in Table 4. The unit fraction of the hydrophobic polymer was determined by elemental analysis. The results are summarized in the fourth
It is shown in the table.

Production Example 5 With 10 mmol of the monomers shown below Ethyl acrylate and the amount shown in Table 5 and azobisisobutyronitrile 2 mg were placed in a test tube together with 10 ml of a benzene-ethanol mixed solvent (1: 1, weight ratio). After the test tube was placed under a nitrogen atmosphere, the tube was sealed and polymerized at 65 ° C. for 30 hours. The contents were poured into 500 ml of methanol and the resulting precipitate was collected by filtration. Drying under reduced pressure gave a solid in the amount shown in Table 5 as a hydrophobic polymer. The unit fraction of the hydrophobic polymer was determined by elemental analysis. The results are summarized in Table 5.

Example 1 Polymer Nos. 1 to 38 obtained in Production Examples 1 to 4 were subjected to 80 ° C.
In water for 1 minute and then dried. This polymer 1.
5 g was dispersed in 10 ml of human serum having a free fatty acid concentration of 2.5 mM / l, and stirred for 10 minutes to perform a free fatty acid adsorption treatment. Thereafter, the polymer was removed by filtration through a glass filter, and the concentration of free fatty acids remaining in the serum was determined. The free fatty acid concentration was determined by using a commercially available reagent for measuring free fatty acids (NEFA C-Test Wako Wako Pure Chemical Industries, Ltd.) to find the difference in concentration described in the instruction manual, and calculating the amount of adsorption.
Table 6 shows the amounts of free fatty acids adsorbed on each polymer. As a comparative polymer, a commercially available ion exchange resin (trade name: Amberlite IRA-410 Organo Corporation)
Table 6 also shows the amount of free fatty acids adsorbed by the same method for the organic adsorbent (trade name: Amberlite XAD-2 Organo Co., Ltd.).

As can be seen from Table 6, the ability of the fatty acid adsorbent of the present invention to adsorb free fatty acids present in biological fluids is extremely high.

Example 2 Using the polymer Nos. 39 to 44 obtained in Production Example 5,
A fatty acid adsorption treatment experiment was performed in the same manner as in Example 1. Table 7 shows the unit fraction of each polymer and the amount of fatty acid adsorbed. If the unit fraction is 50% or less, the adsorptive capacity is reduced, and does not show sufficient adsorptive capacity.

Example 3 Polymer No. 17 obtained in Production Example 2 was placed in water at 80 ° C.
Soak for a minute and then dry. 0.5 g of this polymer was packed in a column shown in FIG. Human serum containing free fatty acids
An adsorption treatment experiment was performed by flowing 10 ml from the top of the column and passing the polymer. The concentration of the component in blood was measured before and after the adsorption by passing through the column.

The quantification of albumin was performed by the bromcresolgrin method (the method described in Clinical Laboratory, Vol. 1, Clinical Chemistry 1984, Medical and Dental Publishing Co., Ltd., p283). The bilirubin concentration was determined by the diazotization method (Je
ndrassik-Grof method: Laboratory Tests, Vol. 1, Clinical Chemistry 1984, Medical and Dental Publishing Co., Ltd. p599). The creatine concentration was measured by the alkaline picric acid method. (Clinical Chemistry Analysis II, 2nd edition, The Japan Society for Analytical Chemistry, Analysis Library 3 1979 Tokyo Chemical Co., Ltd., p. 79) Sodium, potassium, and chloride ions are automatically analyzed by a commercially available electrode method. −03 type electrolyte analyzer (A & T Co., Ltd.). Free fatty acids were measured in the same manner as in Example 1.

The results are shown in Table 8. Adsorption of anionic components other than free fatty acids such as bilirubin and chloride ions hardly occurred, and it was confirmed that only free fatty acids were selectively adsorbed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the structure of a column used when conducting an experiment for adsorbing free fatty acids. 11 ... glass column, 12 ... fatty acid adsorbent, 13 ... glass fiber

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B01J 20/00-20/34 A61M 1/00-1/38

Claims (1)

(57) [Claims] (1) General formula (Where Y is a group selected from hydrogen, an alkyl group, a cyano group, and a halogen atom, X ⁻ is a halogen ion or an anion forming an anion, and Z is CH _{2 n} (where n is an integer from 1 to 10), ^{-COOR 3 -, - OCOR 3 -} , - CONHR 3 -, and -NHCOR ³ -
(However, R ³ is CH _{2 m} or -CH ₂ CH ₂ OCH _{2 m} CH
_{2 -, - CH 2 CH (} CH 3) OCH 2 m CH (CH 3) -, ( where, m is an integer of 1 to 10) selected from) group, R ^1,
R ² is the same or different group selected from an alkyl group having 5 or less carbon atoms, a halogenated alkyl group, a hydroxyalkyl group, and a benzyl group; A is two or three long-chain hydrophobic groups;
Or a nonionic monovalent group having one linear hydrophobic group containing a rigid portion in the chain, and B ¹ and B ² are the same or different nonionic monovalent linear hydrophobic groups Represents a group. A fatty acid adsorbent comprising a linear polymer containing at least 50% by weight of a unit represented by the formula: