JPH11255839A - Heat responsive polymer derivative having both low limit critical temperature and high limit critical temperature - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymer derivative useful for separation, purification, fixation, etc., of a material which shows difficulty in temperature selection such as an enzyme by making a polymer include a monomer component having a low limit critical temperature and a monomer component having a high limit critical temperature. SOLUTION: A polymer is obtained by copolymerization of at least one monomer component having a low limit critical temperature preferably selected from monomers represented by formulae I-IV and at least one monomer component having a high limit critical temperature preferably selected from monomers represented by formula V (wherein R<1> is H or CH3 ; R<5> is an 1-10C alkyl, alkoxy, alkylamono, aryl or heterocyclic group; R<2> -R<3> are each H or R<5> ; R<4> is an 1-10C alkyl or alkylalkoxyl group; R<6> is an 1-10C alkyl, alkoxyl, alkylamino or phenyl group; R<7> is a single bond or an 1-4C alkylene group; R<8> -R<10> are each R<1> ; X and X' are each O, S, Se or Te). A hydrophilic or hydrophobic monomer, if necessary, is included as a copolymerzing component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolymer derivative which can be used as a drug delivery system (DDS), various separating agents, catheters, artificial muscles and the like and is suitable as an excellent stimulus-responsive polymer.

[0002]

2. Description of the Related Art In recent years, stimuli-responsive polymers have been used in drug delivery systems (DDS), various separating agents, catheters,
It is widely applied to artificial muscles, chemo valves, etc., and its importance is rapidly increasing. For example, JP-A-8-103653
In the publication, a stimuli-responsive polymer is described that swells or shrinks in an aqueous solution by changing its higher-order structure due to heat, pH, electric potential, light, etc., and has an upper critical temperature (UCST) for water. Or, as a polymer having a lower critical temperature (LCST) and swelling and shrinking in response to a temperature change, acrylamide or methacrylamide such as poly-N-isopropylacrylamide, N, N-diethylacrylamide, and N-isopropylmethacrylamide And vinyl-ethers such as vinyl methyl ether.

[0003]

However, polymer compounds known to swell and shrink in response to these temperature changes are described as having an upper critical temperature (UCST) or a lower critical temperature (LCST). However, in practice, all have a lower critical temperature (LCST), that is, the polymer reversibly agglomerates between polymers at or above that temperature, insolubilizes in water, and dissolves in water below that temperature. Had. For example, poly-N-isopropylacrylamide (PNIPAM) currently used in DDS and the like
Has a lower critical temperature of 32 ° C. in an aqueous solution, and when a polymer is gelled, it swells and shrinks reversibly at that temperature due to heat.

[0004] Since a polymer compound having a lower critical temperature (LCST) shrinks at a certain temperature or higher, it is desired to shrink at a low temperature (preferably at a body temperature or lower) when applied to a DDS or a separating agent. There was a request.

On the other hand, if a thermoresponsive polymer material having a lower critical temperature (LCST) and an upper critical temperature (UCST) simultaneously can be obtained, the above adjustment can be easily performed, and particularly in a field where fine adjustment is required. Since the application range of the thermoresponsive polymer material has been greatly expanded, its appearance has been expected.

[0006] An object of the present invention is to solve the above-mentioned problems, and a lower critical temperature (LCST) and an upper critical temperature (UCS).
An object of the present invention is to provide a thermoresponsive polymer having T) at the same time.

[0007]

The inventors of the present invention have made intensive efforts to solve the above-mentioned problems, and as a result, have found that the lower critical temperature (LCS)
Surprisingly, by preparing a copolymer derivative containing a monomer component having T) and a monomer component having an upper critical temperature (UCST), a thermoresponsive polymer having a lower critical temperature and an upper critical temperature simultaneously Is found to be obtained.

Further, in the present invention, the following general formulas (1) to (4) are used as monomer components having a lower critical temperature (LCST).
It is preferable that the monomer is represented by

[0009]

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[In the formulas (1) to (4), R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ each independently represent a hydrogen atom, a linear or branched C 1-10 carbon atom. Or a cyclic alkyl group, alkoxyl group or alkylamino group, aryl group or heterocyclic group, which may be halogenated. R ⁴ is a straight-chain having 1 to 10 carbon atoms, branched or cyclic, an alkyl group or an alkyl alkoxylated group, it may be respectively halogenated. R ⁵ represents a linear C1-10, branched or cyclic alkyl group, an alkoxyl group or an alkylamino group, an aryl group or a heterocyclic group, or may be respectively halogenated. n represents 4 or 5. ]

Further, the monomer component having the upper critical temperature (UCST) is preferably a monomer represented by the following general formula (5).

[0012]

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[In the formula (5), R ⁶ represents 1 to 10 carbon atoms.
A linear, branched or cyclic alkyl group, alkoxyl group, alkylamino group or phenyl group, which may be halogenated. R ⁷ represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms which may be halogenated. R ⁸ , R ⁹ and R ¹⁰
Each independently represents a hydrogen atom or a methyl group. X and X 'each independently represent an oxygen atom, a sulfur atom, a selenium atom or a tellurium atom. ]

Further, in the present invention, a hydrophilic or hydrophobic monomer can be further contained as a third component as a copolymerization component. Thereby, the transition point can be adjusted.

The monomer component represented by the general formula (5) exhibits strong hydrogen bonding represented by a peptide bond and reversible ketoenol tautomerism. As shown in the following reaction formula A, the monomer component is subjected to ketoenol switching. , The upper critical temperature (UCST).

[0016]

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That is, such that they are enolized and hydrated at a high temperature, converted into keto bodies at a low temperature and aggregated by hydrogen bonding,
By designing the molecular orbital calculation method using a computer, a monomer component exhibiting the upper critical temperature (UCST) can be obtained. More specifically, it is desirable that the site having the peptide bond synthesizes a monomer component in which the keto form is thermodynamically stable.

The thermoresponsive copolymer derivative of the present invention comprises:
It can be effectively applied to separation, immobilization, calibration, control, etc. of various substances. In particular, since it has both an upper critical temperature (UCST) and a lower critical temperature (LCST) at the same time, separation / purification, immobilization, calibration, and calibration of substances (eg, proteins such as bioproducts, enzymes, and antibodies) that are particularly difficult to select temperatures It can be effectively used for control, chemo valve, etc.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail. According to the present invention, as described above, the lower critical temperature (LCS
By copolymerizing at least one of the monomer components having T) and at least one of the monomer components having the upper critical temperature (UCST) into a polymer derivative, a lower critical temperature (LCST) and an upper critical temperature (UCST) are obtained. ) Can be obtained at the same time.

In the present invention, as the monomer component having the lower critical temperature (LCST), the above-mentioned general formulas (1) to (4)
Can be preferably used.

In the general formulas (1) to (4), each substituent is particularly preferably as follows. That is, R ¹ is preferably a hydrogen atom or a methyl group, and R ² and R ³ are each preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group, R ⁴ is preferably a methyl group, and R ⁵ is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group.

More specifically, the monomer component represented by the general formula (1) may be N-methylacrylamide, N-ethylacrylamide, N-cyclopropylacrylamide,
Isopropyl acrylamide, Nn-propyl acrylamide, N-tert-butyl acrylamide, N-sec-butyl acrylamide, Nn-butyl acrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, N-cyclopropyl methacrylamide, N-isopropyl methacryl Amide, Nn-propyl methacrylamide, N-tert-butyl methacrylamide, N-sec-butyl methacrylamide,
Nn-butyl methacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylmethacrylamide, N-methyl-N-ethylacrylamide, N-methyl-N -Isopropylacrylamide, N-methyl-Nn-propylacrylamide, N-methyl-N-ethylmethacrylamide, N-methyl-N-
Isopropyl methacrylamide, N-methyl-Nn-propyl methacrylamide, N, N-diisopropyl acrylamide, N, N-di-n-propyl acrylamide, N, N-diisopropyl methacrylamide, N, N-di-n-propyl methacryl Amides and the like.

More specifically, the monomer component represented by the general formula (2) includes, for example, methyl vinyl ether and methoxyethyl vinyl ether.

More specifically, the monomer component represented by the general formula (3) includes N-vinylacetamide, N-vinylpropionamide, N-vinylbutyrylamide, N-vinylisobutyrylamide and the like. .

More specifically, the monomer component represented by the general formula (3) may be N-acetylacrylamide, N-fluoroacetylacrylamide, N-propionylacrylamide, N-butanoylacrylamide, N-pentanoylacrylamide, -Hexanoylacrylamide, N-isobutanoylacrylamide, N-benzoylacrylamide, N- (3-fluorobenzoyl) acrylamide, N-
(2,3-difluorobenzoyl) acrylamide, N-pyridylcarbonylacrylamide, N-pyrimidylcarbonylacrylamide, N-acetylmethacrylamide, N-fluoroacetylmethacrylamide, N-propionylmethacrylamide, N-butanoylmethacrylamide, N-pentanoyl methacrylamide, N-hexanoyl methacrylamide, N-isobutanoyl methacrylamide, N-benzoyl methacrylamide, N- (3-fluorobenzoyl) methacrylamide, N- (2,3-difluorobenzoyl) methacryl Amide, N-pyridylcarbonyl methacrylamide, N-pyrimidylcarbonyl methacrylamide, N-acroyl-
N'-methylurea, N-acroyl-N'-ethylurea, N
-Acroyl-N'-fluoromethylurea, N-Acroyl
-N'-difluoromethylurea, N-acroyl-N'-trifluoromethylurea, N-methacryloyl-N'-methylurea, N-methacryloyl-N'-ethylurea, N-methacryloyl-N'-fluoromethylurea, N -Methacryloyl-N'-
Difluoromethylurea, N-methacryloyl-N'-trifluoromethylurea,

Methyl N-acroylcarbamate, ethyl N-acroylcarbamate, N-acroylcarbamate
-n-butyl, N-isopropyl carbylcarbamate, N
-N-butyl acroylcarbamate, isobutyl N-acroylcarbamate, t-butyl N-acroylcarbamate, fluoromethyl N-acroylcarbamate, difluoromethyl N-acroylcarbamate, N-acrobutyl Trifluoromethyl ylcarbamate, -2,2,2-trifluoroethyl N-acroylcarbamate, methyl N-methacryloylcarbamate, ethyl N-methacryloylcarbamate, n-butyl N-methacryloylcarbamate , N-isopropyl N-methacryloylcarbamate, -n-butyl N-methacryloylcarbamate, isobutyl N-methacryloylcarbamate, t-butyl N-methacryloylcarbamate, fluoromethyl N-methacryloylcarbamate, N- Difluoromethyl methacryloylcarbamate, trifluoromethyl N-methacryloylcarbamate, N-methacryloyl And 2,2,2-trifluoroethyl carbamate and the like.

On the other hand, as the monomer component having the upper critical temperature (UCST), a monomer containing a substituent component represented by the following general formula (6) can be preferably used.

[0028]

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In the formula (6), R ⁶ , X and X ′ are as defined in the above formula (5).

The monomer component of the formula (5) (for the sake of simplicity, the case where X and X 'are oxygen atoms) will be described below.
As shown in the following reaction formula B, it is reversibly converted into a keto form and an enol form.

[0031]

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In general, a compound having an amide bond has a self-aggregating action due to a strong hydrogen bond in an aqueous solution, and a polyamide existing as a keto body in an aqueous solution is insoluble in water. However, it is presumed that the keto form is converted to an enol form by a change in heat, and the self-aggregation action is cleaved to become a water-soluble compound.

The monomer component represented by the general formula (5) will be described more specifically. In the formula (5), R ⁶ is preferably a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms,
Alkoxyl group, alkylamino group or phenyl group, more preferably methyl group, ethyl group, propyl group,
It is an isopropyl group, a phenyl group, a methoxy group, an ethoxy group, a propoxyl group, an isopropoxyl group, a methylamino group or an ethylamino group, and particularly preferably a methyl group, an ethoxy group or a methylamino group. Further, these groups may be substituted with a halogen atom, for example, a fluorine atom, a bromine atom, a chlorine atom, an iodine atom and the like. Particularly preferred substituents are a fluorine atom and a chlorine atom.

R ⁷ is preferably a single bond or a group having 1 to 2 carbon atoms.
Is a linear or branched alkylene group or a halogenated alkylene group, particularly preferably a single bond. Preferred substituents are a fluorine atom and a chlorine atom. X and X 'are each preferably an oxygen atom or a sulfur atom.

Examples of the monomer represented by the formula (5) include N-acetylacrylamide, N-fluoroacetylacrylamide, N-propionylacrylamide, N-butanoylacrylamide, N-pentanoylacrylamide, N-hexanoylacrylamide, N
-Isobutanoylacrylamide, N-benzoylacrylamide, N- (3-fluorobenzoyl) acrylamide, N- (2,3-difluorobenzoyl) acrylamide, N-pyridylcarbonylacrylamide, N
-Pyrimidylcarbonylacrylamide, N-acetylmethacrylamide, N-fluoroacetylmethacrylamide, N-propionylmethacrylamide, N-butanoylmethacrylamide, N-pentanoylmethacrylamide, N-hexanoylmethacrylamide, N-iso Butanoyl methacrylamide, N-benzoyl methacrylamide, N- (3-fluorobenzoyl) methacrylamide, N- (2,3-difluorobenzoyl) methacrylamide, N-pyridylcarbonyl methacrylamide,
N-pyrimidylcarbonyl methacrylamide,

N-Acroyl-N'-methylurea, N
-Acroyl-N'-ethylurea, N-acroyl-
N'-fluoromethylurea, N-acroyl-N'-
Difluoromethylurea, N-acroyl-N'-trifluoromethylurea, N-methacryloyl-N'-methylurea, N-methacryloyl-N'-ethylurea, N
-Methacryloyl-N'-fluoromethylurea, N-methacryloyl-N'-difluoromethylurea, N-methacryloyl-N'-trifluoromethylurea,

N-methyl acroylcarbamate, N-
Ethyl acroylcarbamate, n-propyl N-acroylcarbamate, isopropyl N-acroylcarbamate, n-butyl N-acroylcarbamate, N
-Isobutyl acroylcarbamate, t-butyl N-acroylcarbamate, fluoromethyl N-acroylcarbamate, difluoromethyl N-acroylcarbamate, trifluoromethyl N-acroylcarbamate, N-acroyl Carbamic acid-2.2.2-trifluoroethyl, N-methyl methacryloylcarbamate, N-
Ethyl methacryloylcarbamate, n-propyl N-methacryloylcarbamate, isopropyl N-methacryloylcarbamate, n-butyl N-methacryloylcarbamate, isobutyl N-methacryloylcarbamate, N-
T-butyl methacryloylcarbamate, fluoromethyl N-methacryloylcarbamate, difluoromethyl N-methacryloylcarbamate, trifluoromethyl N-methacryloylcarbamate, N.2.2-trifluoro-2-methacryloylcarbamate Ethyl and the like.

In the present invention, the composition ratio of the monomer component having the lower critical temperature to the monomer component having the upper critical temperature is not particularly limited, and is appropriately selected according to the purpose. Generally, the monomer component having the lower critical temperature: the monomer component having the upper critical temperature is 2: 1 to 1: 5 (weight ratio).
Is preferable.

The molecular weight of the polymer derivative of the present invention is not particularly limited.
Almost independent of its molecular weight. Normal 10 ² to 10 about ^6, preferably from 10 ³ to 10 about ^5.

Further, in the present invention, in addition to a monomer component having a lower critical temperature and a monomer component having an upper critical temperature, a copolymer is further copolymerized with a hydrophilic or hydrophobic monomer so that the lower critical temperature can be varied in various temperature ranges. A thermoresponsive polymer having a temperature and an upper critical temperature can be obtained.

The hydrophilic monomer and the hydrophobic monomer are not particularly limited, and may be various ones. Examples of the hydrophilic monomer include acrylamide, allylamine, hydroxyethyl (meth) acrylate, glycerin mono (meth) Examples of hydrophobic monomers such as acrylates include (meth) acrylates, vinyl chloride,
Examples include vinylidene chloride and styrene.

Further, the switching range (transition temperature range) is preferably as narrow as possible. According to the present invention, a thermoresponsive polymer having a practical switching range of 10 ° C. or less can be obtained.

Furthermore, the novel stimuli-responsive polymer derivative of the present invention can be used for separation, immobilization, calibration,
Effective for control, etc., for example, drug delivery system (DDS), various separating agents, catheters, artificial muscles,
It can be effectively applied to chemo valves and the like.

[0044]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 [Synthesis of copolymer of N-acetylacrylamide and N-isopropylacrylamide and its physical properties]

N-acetylacrylamide: 1.0 g and N-isopropylacrylamide: 200 mg in a three-necked flask
Was added and dissolved in 5 ml of ethanol. AIBN:
5 mg was further added and stirred at 70 ° C. for 4 hours. The precipitated polymer was washed with ethanol and dried sufficiently under reduced pressure to obtain 780 mg of a copolymer (weight average molecular weight: about 7000). 25 mg of the obtained copolymer was added to 5 ml of a 15% aqueous ethanol solution.
And the upper critical temperature (UCST) was measured.
Met. In this same sample, the lower critical temperature (LCS
It was 83 ° C when T) was measured. The upper critical temperature (U
CST) and lower critical temperature (LCST) were determined using the transmittance of visible light.

Comparative Example 1 [Synthesis and Physical Properties of Poly-N-isopropylacrylamide (PNIPAM)] In a nitrogen gas atmosphere, 1.0 g of N-isopropylacrylamide and 5 mg of AIBN were dissolved in 5 ml of ethylene glycol dimethyl ether and charged in a flask. ° C
For 3 hours. The obtained reaction solution was reprecipitated with a mixed solvent of cyclohexane / ethyl acetate = 10/1 to obtain 0.6 g of a white solid. Dissolve 50 mg of this polymer in 5 ml of distilled water,
The lower critical temperature (LCST) was measured to be about 30 ° C.
This aqueous solution was allowed to stand at 1 ° C. for 1 week, but no polymer deposition was confirmed. In this polymer, the upper critical temperature (UCS
T) does not exist.

[0048]

According to the present invention, the upper critical temperature (UCST)
And a thermo-responsive polymer having a lower critical temperature (LCST). Separation / purification, immobilization, calibration, control, etc. of substances (for example, proteins such as bioproducts, enzymes and antibodies) for which temperature selection is particularly difficult. Alternatively, it can be effectively used for a chemo valve or the like.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 220/54 C08F 220/54 220/56 220/56 220/58 220/58 226/02 226/02 230/00 230/00 (72) Inventor Kazunori Kataoka 2641 Yamazaki, Noda City, Chiba Prefecture, Tokyo University of Science (72) Inventor Katsuhiko Ueno 1-1-1 Higashi, Tsukuba City, Ibaraki Pref.

Claims (4)

[Claims] 1. A thermoresponsive material having a lower critical temperature and an upper critical temperature simultaneously, comprising at least one monomer component having a lower critical temperature and at least one monomer component having an upper critical temperature. Copolymer derivatives. 2. The method according to claim 1, wherein the monomer component having the lower critical temperature is at least one monomer component selected from monomers represented by the following general formulas (1) to (4). The thermoresponsive copolymeric polymer derivative according to the above. Embedded image [In the formulas (1) to (4), R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ each independently represent a hydrogen atom, a linear, branched or cyclic C 1-10 carbon atom. , An alkyl group, an alkoxyl group or an alkylamino group, an aryl group or a heterocyclic group, each of which may be halogenated. R ⁴ is a straight-chain having 1 to 10 carbon atoms, branched or cyclic, an alkyl group or an alkyl alkoxylated group, it may be respectively halogenated. R ⁵ is a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms,
It represents an alkoxyl group, an alkylamino group, an aryl group or a heterocyclic group, each of which may be halogenated. n represents 4 or 5. ] 3. The thermoresponsive copolymer according to claim 1, wherein the monomer component having the upper limit critical temperature is at least one monomer component represented by the following general formula (5). Polymer derivatives. Embedded image [In the formula (5), R ⁶ represents a linear, branched or cyclic, optionally halogenated alkyl group, alkoxyl group, alkylamino group or phenyl group having 1 to 10 carbon atoms. R ⁷ represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms which may be halogenated. R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a methyl group. X and X 'each independently represent an oxygen atom, a sulfur atom, a selenium atom or a tellurium atom. ] 4. The thermally responsive copolymerized polymer derivative according to claim 1, further comprising a hydrophilic or hydrophobic monomer as a copolymerization component.