JP2016190921A - Temperature-responsive biodegradable polymer composition and production method thereof - Google Patents

Abstract

The present invention relates to a biodegradable polymer composition that exhibits a sol-gel transition in response to temperature, and that can maintain a gel state for a long period of time under humid conditions such as in the body. The purpose is to provide. SOLUTION: (1) ABA type triblock copolymer having reactive functional groups at both ends, and (2) a compound capable of reacting with the AB type triblock copolymer. Or a temperature-responsive biodegradable polymer composition containing a salt thereof, wherein the A block comprises poly (ε-caprolactone-co-glycolic acid) and the B block comprises polyethylene glycol chains. Responsive biodegradable polymer composition. [Selection] Figure 2

Description

  The present invention relates to a biodegradable polymer composition having temperature responsiveness and a method for producing the same.

  The temperature-responsive polymer is a general term for polymers that change physical properties such as solubility in response to temperature changes. Among these, polymers that exhibit a sol-gel phase transition phenomenon in response to an external temperature change in a solution state are known. Particularly in the medical field such as drug carriers, it has biocompatibility and biodegradability, and is in a solution (sol) state at room temperature, but when injected into a living body, the hydrogel is in situ in response to body temperature. The development of a temperature-responsive injectable polymer (hereinafter also referred to as “IP”) has been attracting attention.

  As such temperature-responsive IP, poly (lactic acid) (PLA) and polyglycolic acid (PGA) copolymer (hereinafter sometimes referred to as “PLGA”), polyethylene glycol (PEG) (Hereinafter referred to as “PLGA-b-PEG-b-PLGA” or simply “PLGA-PEG-PLGA”); poly (ε-caprolactone) (PCL) and polyglycolic acid (PGA) ) Copolymer (hereinafter also referred to as “PCGA”) and polyethylene glycol (PEG) and a triblock copolymer (hereinafter referred to as “PCGA-b-PEG-b-PCGA”, simply “PCGA-PEG-”). PCGA ”) and the like have been reported (see Non-Patent Documents 1 to 3).

  In addition, a two-component mixed IP composition is known in which a covalent bond is generated by a chemical reaction by mixing. As such a two-component mixed IP composition, for example, a composition in which a polyether compound having a succinimide ester group at a terminal and a polyether compound having an amino group at a terminal has been reported (Non-Patent Document). 4).

Macromol. Rapid Commun., 2001, 22, p. 587. Macromolecular Research, 2013, 21, p.207-215. Polym. J., 2014, 46, p.632-635. Macromolecules, 2008, 41, p.5379.

  However, the temperature-responsive IP consisting of the above-mentioned PLGA-b-PEG-b-PLGA and PCGA-b-PEG-b-PCGA is gelled by body temperature in vivo, but in a humid environment, particularly due to body fluids, etc. It is diluted and it is considered difficult to maintain the gel state for a long time.

  In addition, since the two-component IP composition is allowed to gel in a mixed state, it must be injected into a living body immediately after mixing and is not easy to handle. Conceivable. Moreover, if gelation occurs at a stage in a syringe, catheter or the like before being injected into the living body, there is a concern that the injection cannot be performed. In particular, it is considered that the method of spraying with a spray or the like cannot be sprayed on the target site as desired.

  The present invention has been made in view of the above-described demands, and is a biodegradable polymer composition that exhibits a sol-gel transition in response to temperature, and can maintain a gel state for a long period of time under wet conditions. An object is to provide a degradable polymer composition.

  As a result of intensive studies to achieve the above object, the present inventors have obtained a compound capable of reacting with the triblock copolymer with respect to the triblock copolymer having a reactive functional group at both ends. The present inventors have found that the polymer composition contained can achieve the above object, and have completed the present invention.

That is, this invention is providing the biodegradable polymer composition which has the following temperature responsiveness, and its manufacturing method.
Item 1.
(1) ABA type triblock copolymer having reactive functional groups at both ends, and
(2) A temperature-responsive biodegradable polymer composition containing a compound or a salt thereof capable of reacting with the ABA type triblock copolymer,
The A block comprises poly (ε-caprolactone-co-glycolic acid);
A temperature-responsive biodegradable polymer composition, wherein the B block comprises a polyethylene glycol chain.
Item 2.
Item 2. The temperature response according to Item 1, wherein the content of the compound (2) or a salt thereof is 0.25 to 20 parts by mass with respect to 100 parts by mass of the (1) A-B-A type triblock copolymer. Biodegradable polymer composition.
Item 3.
The A block constitutes 20 to 75% by mass of the (1) ABA type triblock copolymer,
Item 3. The temperature-responsive biodegradable polymer composition according to Item 1 or 2, wherein the B block constitutes 25 to 80% by mass of the (1) ABA type triblock copolymer.
Item 4.
The temperature-responsive biodegradable polymer composition according to any one of Items 1 to 3, further comprising (3) a temperature-responsive polymer other than the ABA type triblock copolymer.
Item 5.
Item 5. The temperature-responsive biodegradable polymer composition according to any one of Items 1 to 4, wherein the reactive functional group is a succinimide ester group.
Item 6.
Item 6. The temperature-responsive biodegradable polymer composition according to any one of Items 1 to 5, wherein the compound (2) or a salt thereof is a polyamine compound or a salt thereof.
Item 7.
The method for producing a temperature-responsive biodegradable polymer composition according to any one of Items 1 to 6,
(i) a step of producing an ABA type triblock copolymer by polymerizing ε-caprolactone and glycolide in the presence of polyethylene glycol or an aliphatic diol;
(ii) a step of forming a reactive functional group at both ends of the ABA type triblock copolymer obtained in the step (i), and
(iii) (1) A-B-A type triblock copolymer obtained in the step (ii) and (2) a compound capable of reacting with the A-B-A type triblock copolymer or a salt thereof The manufacturing method of a biodegradable polymer composition including the process of mixing these in order.
Item 8.
Item 8. The method for producing a biodegradable polymer composition according to Item 7, wherein in the step (iii), a temperature-responsive polymer other than the (1) ABA type triblock copolymer is further mixed.
Item 9.
The temperature-responsive biodegradable polymer composition according to any one of Items 1 to 6, further comprising (4) water.
Item 10.
Item 10. A gel comprising the temperature-responsive biodegradable polymer composition according to Item 9.

  The biodegradable polymer composition of the present invention is an aqueous solution (sol) at room temperature and exhibits a sol-gel transition in response to temperature. In particular, the biodegradable polymer composition of the present invention can maintain a gel state for a long time even under wet conditions such as in the body.

FIG. 1 is a photograph showing the sol state of the biodegradable polymer composition of Example 1 immediately after mixing in Test Example 1. FIG. 2 is a photograph showing that the biodegradable polymer composition of Example 1 was in a gel state after being heated to 37 ° C. FIG. 3 is a photograph showing that the gel state was maintained even when the biodegradable polymer composition of Example 1 was heated and held at 37 ° C. for 15 minutes and then lowered to 4 ° C.

1. Temperature-responsive biodegradable polymer composition The temperature-responsive biodegradable polymer composition of the present invention (hereinafter sometimes referred to as "temperature-responsive polymer composition" or "polymer composition") is An ABA type triblock copolymer having a reactive functional group (hereinafter referred to as “(1) ABA type triblock copolymer”, “(1) triblock copolymer” or “ (Sometimes referred to as “first component”), and (2) a compound or a salt thereof that can react with the ABA type triblock copolymer (hereinafter referred to as “(2) compound”, “(2) reaction”) (1) the A block of the ABA type triblock copolymer is poly (ε-caprolactone-co-glycolic acid) And (1) the B block of the triblock copolymer contains a polyethylene glycol chain.

  The temperature-responsive biodegradable polymer composition of the present invention exhibits a sol-gel transition in response to temperature. In particular, it has a feature that it can be gelled at a temperature between room temperature and body temperature. Therefore, it is possible to provide an excellent in situ gelation system, eliminate the need for surgical treatment, and form an implant with minimal invasiveness by injection. Since physiologically (pharmacologically) active substances and the like are stably encapsulated and can be sustainedly released in the body, an injectable (injectable) drug delivery system can be provided. Furthermore, it can be used as a scaffold for injectable tissue repair and organ regeneration, and also as a cell delivery system for transplanting cells into a defect site of in vivo tissues by injection administration by encapsulating suitable living cells. Further, it can be used as a vascular embolization substance or the like that intentionally stops blood flow by being injected into a blood vessel, and in this case, it can be used by including a drug, a contrast agent, or the like. Furthermore, a gel-like film can be formed by applying or spraying onto a surface where adhesion may occur during a surgical operation, and can be used as an adhesion preventing material.

The temperature-responsive biodegradable polymer composition of the present invention comprises (1) the A-B-A type triblock copolymer, and (2) a compound capable of reacting with the triblock copolymer or a salt thereof. If it does, it will not specifically limit. For example,
(I) a polymer composition comprising only (1) a triblock copolymer and (2) a reactive compound;
(II) A polymer composition containing (I) and (3) a temperature-responsive polymer other than the triblock copolymer (hereinafter also referred to as “(3) other temperature-responsive polymer”). ;
(III) (1) a triblock copolymer, (2) a polymer composition containing a reactive compound and water;
(IV) A polymer composition containing (III) and (3) another temperature-responsive polymer;
(V) The polymer composition further containing a drug, a dye or a contrast agent in (I) above;
(VI) A polymer composition further containing a drug, a dye or a contrast agent in (II) above;
(VII) a polymer composition further containing a drug, a dye or a contrast agent in (III);
(VIII) The polymer composition further containing a drug, a dye or a contrast agent in (IV) above;
Etc. In the present specification, the expression “containing” or “including” includes the concepts “containing”, “including”, “consisting essentially only”, and “consisting only”.

  In the following description, unless otherwise specified, the polymer composition of the present invention is described as being solid, but the polymer composition of the present invention is not limited to a solid. That is, the polymer composition of the present invention includes both liquid and solid forms.

1-1. (1) Triblock copolymer having reactive functional groups at both ends The polymer composition of the present invention is (1) an ABA type triblock copolymer having reactive functional groups at both ends. Containing.

  (1) The A-B-A type triblock copolymer is biodegradable, the A block includes poly (ε-caprolactone-co-glycolic acid) (PCGA), and the B block is polyethylene glycol. It contains a (PEG) chain and has a reactive functional group (Fc) at both ends.

  The reactive functional group (Fc) is not particularly limited, and examples thereof include a group capable of condensation reaction and a group capable of addition reaction.

  Examples of the group capable of condensation reaction include groups capable of condensation reaction with succinimide ester groups such as amino groups; succinimide ester groups, nitrophenyl ester groups, 1,2,3,4,5-pentafluorophenyl ester groups, 4 -Active ester groups capable of condensation reaction with amino groups such as chlorophenyl ester groups; Groups capable of forming Schiff base bonds with amino groups such as aldehydes; Groups capable of forming Schiff base bonds with aldehyde groups such as amino groups; A group capable of undergoing a condensation reaction with a cysteine residue; a group capable of reacting with a thioester group such as a cysteine residue; a group capable of reacting with a diol group such as a phenylboronic acid group; a group capable of reacting with a phenylboronic acid group such as a diol group Etc. Among these, a succinimide ester group and an amino group are preferable, and a succinimide ester group is more preferable.

  Examples of the group capable of addition reaction include a group capable of thiol-ene click reaction; a group capable of Diels-Alder reaction; a group capable of click reaction; and a group capable of non-catalytic click reaction.

  The reactive functional group is preferably a group capable of a condensation reaction, more preferably a succinimide ester group and an amino group, and particularly preferably a succinimide ester group.

  (1) The A-B-A type triblock copolymer further includes a linker part (hereinafter sometimes referred to as “link”) between the A block and the reactive functional group (Fc). Can do. The linker is not particularly limited, and examples thereof include succinic acid or a derivative thereof (for example, succinic anhydride, dialkyl ester such as dimethyl succinate), ethylene diisocyanate, ethylene glycol, ethylenediamine, piperazine, glycine and the like. Examples include groups formed (derived) from amino acids and oligomers thereof, and combinations thereof.

(1) Various physical properties of ABA type triblock copolymer used in the present invention; for example, (1) Mass ratio of PCGA block (A block) and PEG block (B block) to triblock copolymer ;
Each weight average molecular weight of PCGA block and PEG block;
(1) The number average molecular weight (Mn) of the triblock copolymer and the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn);
Molar ratio of ε-caprolactone to glycolic acid in PCGA;
Each physical property such as each degree of polymerization of ε-caprolactone and glycolic acid is not particularly limited.

A preferred example of each of the above physical properties is as follows:
The mass ratio of PCGA block and PEG block is such that PCGA block constitutes 20 to 75% by mass of (1) triblock copolymer, and PEG block constitutes 25 to 80% by mass of (1) triblock copolymer. It is preferable to configure.

The weight average molecular weight of the PCGA block is preferably 0.8 k to 2.0 k (800 to 2000),
The weight average molecular weight of the PEG block is preferably 0.8 k to 2.0 k (800 to 2000),
(1) The number average molecular weight (Mn) of the triblock copolymer is preferably 2.4 k to 6.0 k (2400 to 6000),
(1) The ratio of the weight average molecular weight to the number average molecular weight of the triblock copolymer (Mw / Mn) is preferably 1.0 to 1.8,
The molar ratio of ε-caprolactone and glycolic acid in PCGA is preferably ε-caprolactone (CL): glycolic acid (GA) = 3.0: 1 to 5.0: 1 (molar ratio),
The polymerization degree of ε-caprolactone is preferably 5 to 20,
The degree of polymerization of glycolic acid is preferably 1-5.

In addition, each said molar ratio, a polymerization degree, and mass ratio can be measured using well-known methods, such as < ¹ > H-NMR. The number average molecular weight and the weight average molecular weight can be measured using, for example, GPC (Gel Permeation Chromatography) in addition to the ¹ H-NMR.

  As the (1) ABA type triblock copolymer used in the present invention, the following formula (A):

And is also referred to as Fc-PCGA-b-PEG-b-PCGA-Fc (where Fc means a reactive functional group and b means a block). The x, y, and z in the above formula (A) are not limited as long as they can satisfy the above-described physical properties. Among these, for example, x is preferably a number from 15 to 50, more preferably a number from 20 to 45. y is preferably a number of 5 to 20, more preferably a number of 7 to 15. z is preferably a number of 1 to 5, and more preferably a number of 1 to 3. Further, two ys described in the formula (A) may be the same number or different numbers. The same applies to the two z described in the formula (A). In addition, x, y, and z represent the average number of each unit in a polymer, and are calculated | required from < ¹ > H-NMR and GPC. In the PCGA block indicated by [] in the formula (A), the arrangement of the ε-caprolactone unit and the glycolic acid unit is not regular and is not limited to the order of the arrangement of the formula (A). Y and z represent the average number of each of the ε-caprolactone units and glycolic acid units contained in one PCGA block.

  The Fc-PCGA-b-PEG-b-PCGA-Fc may have a linker site between the Fc group and the PCGA group. Such a compound can be represented by the following general formula (A ′).

In the above formula A ′, x, y and z are the same as described above, and Fc ′ is the same group as the reactive functional group. Moreover, there is no restriction | limiting in particular as link, For example, a dicarboxylic acid unit, a diol unit, a monopeptide unit, an oligopeptide unit etc. are mentioned. Examples of the dicarboxylic acid include alkylene dicarboxylic acids, and the alkylene is not particularly limited, and examples thereof include linear or branched alkylene groups having 1 to 6 carbon atoms such as methylene, ethylene, propylene, and butylene. Etc. The link may further have a substituent. There is no restriction | limiting in particular as this substituent, For example, halogen atoms, such as a fluorine atom and a chlorine atom, etc. are mentioned.

  Among these, the (1) ABA type triblock copolymer is preferably a triblock copolymer represented by the following general formula (A-1).

(Wherein, x, y, z and Fc ′ are the same as described above.)
More preferably, it is a triblock copolymer represented by the following general formula (A-2)

(Wherein x, y and z are the same as above).

  (1) The ABA type triblock copolymer has a gel transition temperature between room temperature and around the body temperature. Specifically, (1) When a triblock copolymer is dissolved in a medium containing water, such as water or phosphate buffered saline (PBS), it is in a sol state near room temperature and warms to near body temperature. Then, it changes to a gel state. (1) The A-B-A type triblock copolymer itself is solid at room temperature and in the absence of solvent, but for example, (1) 25 wt% solution of A-B-A type triblock copolymer is The sol-gel transition temperature is 40 ° C. Furthermore, the sol-gel transition temperature was adjusted by mixing the solution and a 25 wt% solution of a temperature-responsive polymer other than (3) ABA type triblock copolymer described later at a ratio of 1: 1. It can be lowered to about 33 ° C. That is, in the present invention, the mixing ratio of (1) ABA type triblock copolymer and (3) temperature responsive polymer other than ABA type triblock copolymer is appropriately adjusted. Thus, the sol-gel transition temperature can be changed.

  The (1) triblock copolymer may be used alone or in combination of two or more.

  The content of (1) A-B-A type triblock copolymer in the temperature-responsive biodegradable polymer composition of the present invention is usually about 5 to 30% by mass, preferably about 10 to 25% by mass. is there.

  An example of the production method (polymerization method) of the triblock copolymer will be described later.

1-2. (2) Compound or salt thereof capable of reacting with A-B-A type triblock copolymer The polymer composition of the present invention is (A) A-B-A type having reactive functional groups at both ends. Along with the triblock copolymer, (2) a compound capable of reacting with the ABA type triblock copolymer or a salt thereof is contained. Thereby, the polymer composition of this invention can maintain a gel state for a long period of time in wet conditions, such as a body, hold | maintaining the sol-gel transition property which responds to temperature. The reason for these effects is that when (1) the triblock copolymer and (2) the reactive compound are mixed, (1) the reactive functional group in the triblock copolymer and (2) It is presumed that the reason is that a reactive group in the reactive compound forms a covalent bond and maintains a gel state.

  The reactive compound (2) is not particularly limited, and examples thereof include compounds capable of condensation reaction and compounds capable of addition reaction. (2) The reactive compound may be a salt. There is no restriction | limiting in particular as this salt, For example, hydrogen halide (hydrogen chloride, hydrogen bromide, hydrogen iodide, etc.), organic acid (acetic acid, formic acid, etc.), etc. are mentioned.

  Examples of the compound capable of condensation reaction include an amino group-containing compound capable of reacting with a succinimide ester group; a succinimide ester group-containing compound, a nitrophenyl ester group-containing compound, and a 1,2,3,4,5-pentafluorophenyl ester group. Compounds having active ester groups capable of reacting with amino groups, such as compounds containing 4-chlorophenyl ester groups; compounds having groups capable of forming Schiff base bonds with amino groups such as aldehydes; thioester groups capable of reacting cysteine residues A compound containing a cysteine residue capable of reacting with a thioester group; a compound containing a phenylboronic acid group capable of undergoing a condensation reaction with a diol group; and a compound containing a diol group capable of reacting with a phenylboronic acid.

  Examples of the compound capable of addition reaction include a compound having a group capable of thiol-ene click reaction; a compound having a group capable of Diels-Alder reaction; a compound having a group capable of click reaction; and a group capable of non-catalytic click reaction. Compounds and the like.

  Among them, as the reactive compound (2), a compound having a group capable of condensation reaction or a salt thereof is preferable, and an amino group-containing compound or a salt thereof is more preferable.

The amino group-containing compound or a salt thereof is not particularly limited, and examples thereof include polylysine, 4-arm-PEG-NH ₂ (four branched polyethylene glycol having a terminal primary amino group), PEI (polyethyleneimine). ), Polyamine compounds such as BSA (bovine serum albumin), Cationic Gelatine (cationic gelatin), or salts thereof. (2) As the reactive compound, a commercially available product can be used, and when there is no commercially available product, it can be produced according to a known production method. For example, 4-arm-PEG-NH ₂ is prepared according to the production method described in JP-A-2013-227543 and 4-arm-PEG (manufactured by NOF Corporation) and an aminating agent (for example, ammonia). Can be made to react.

  The number average molecular weight (Mn) of the polyamine compound is not particularly limited, and is usually 200 to 100,000, preferably 500 to 10,000, more preferably 1,000 to 6,000.

  (2) A reactive compound may be used individually by 1 type, or may be used in combination of 2 or more type.

  (2) The content of the reactive compound is not particularly limited, for example, (1) 0.01 to 50 parts by mass is preferable with respect to 100 parts by mass of ABA type triblock copolymer, and 0.025 to 10 Part by mass is more preferable.

1-3. Temperature-responsive polymer other than the triblock copolymer The temperature-responsive polymer composition of the present invention further comprises (3) a temperature-responsive polymer other than the ABA type triblock copolymer (hereinafter referred to as “( 3) Other temperature-responsive polymer ") may also be contained.

  The (3) other temperature-responsive polymer is not particularly limited as long as it is a known temperature-responsive polymer. For example, polylactic acid; polyglycolic acid; polycaprolactone; lactic acid-glycolic acid copolymer; PCGA-b -PEG-b-PCGA; PLGA-b-PEG-b-PLGA; Pluronic (also called poloxamer. PEG-b-PPG-b-PEG, where PPG means polypropylene glycol. "Pluronic" means BASF Registered trademark)).

  Among these, (3) other temperature-responsive polymers include PCGA-b-PEG-b-PCGA, PLGA-b-PEG-, which have a similar structure to the above-mentioned (1) ABA type triblock copolymer. Triblock copolymers such as b-PLGA are preferred, and PCGA-b-PEG-b-PCGA is more preferred.

  (3) When PCGA-b-PEG-b-PCGA is used as another temperature-responsive polymer, each physical property of the PCGA-b-PEG-b-PCGA; for example, a PCGA block (A block for a triblock copolymer) ) And PEG block (B block) mass ratio; weight average molecular weight of each of PCGA block and PEG block; number average molecular weight (Mn) of triblock copolymer and ratio of weight average molecular weight to the number average molecular weight (Mw / Mn) ); Physical properties such as molar ratio of ε-caprolactone and glycolic acid in PCGA; degree of polymerization of ε-caprolactone and glycolic acid; and the like are not particularly limited. Weight ratio of PCGA block and PEG block, weight average molecular weight of PCGA block, weight average molecular weight of PEG block, number average molecular weight of triblock copolymer (Mn), weight average molecular weight relative to number average molecular weight of triblock copolymer The ratio (Mw / Mn), the molar ratio of ε-caprolactone to glycolic acid in PCGA, the polymerization degree of ε-caprolactone, and the polymerization degree of glycolic acid are described in (1-1) AB- The physical properties are the same as those of the A-type triblock copolymer.

  Examples of (3) other temperature-responsive polymers used in the present invention include, for example, the following general formula (B):

The compound represented by these is mentioned.

In the above formula (B), x, y and z are values that can satisfy the above-mentioned physical properties, for example, x is preferably a number of 15 to 50, more preferably a number of 20 to 45. . y is preferably a number of 5 to 20, more preferably a number of 10 to 15. z is preferably a number of 1 to 5, and more preferably a number of 1 to 3. Further, two ys described in the formula (B) may be the same number or different numbers. The same applies to the two z described in the formula (B). In addition, x, y, and z represent the average number of each unit in a polymer, and are calculated | required from < ¹ > H-NMR and GPC. In the PCGA block indicated by [] in the formula (B), the arrangement of the ε-caprolactone unit and the glycolic acid unit is not regular and is not limited to the order of the arrangement of the formula (B). Y and z represent the average number of each of the ε-caprolactone units and glycolic acid units contained in one PCGA block.

  The (3) other temperature-responsive polymer may be used alone or in combination of two. When two types are used in combination, the ratio is not particularly limited.

  In the polymer composition of the present invention, (3) other temperature-responsive polymers may not be contained, but when (3) other temperature-responsive polymers are contained, the content is not particularly limited. Among them, as the content of (3) other temperature-responsive polymer, (1) 1 to 400 parts by weight is preferable with respect to 100 parts by weight of ABA type triblock copolymer, 50 to 200 parts by weight Is more preferable. In the present invention, (3) by adding another temperature-responsive polymer to the polymer composition of the present invention, the gelation temperature of the composition can be adjusted to an optimum one, and (1) A-B- The amount of the A-type triblock copolymer used can be suppressed, and the gel maintenance period after gelation and the period until hydrolysis can be adjusted.

1-4. Other Components Furthermore, the polymer composition of the present invention can be used as a pharmaceutical composition, a sustained drug release device, etc., if necessary, by mixing known drugs, dyes, contrast agents and the like.

2. Method for producing temperature-responsive biodegradable polymer composition
The method for producing the temperature-responsive decomposable polymer composition of the present invention is not particularly limited. For example, the following steps (i), (ii) and (iii):
(i) a step of producing an ABA type triblock copolymer by polymerizing ε-caprolactone and glycolide in the presence of polyethylene glycol (PEG) or an aliphatic diol;
(ii) a step of forming reactive functional groups at both ends of the ABA type triblock copolymer obtained in the step (i), and
(iii) (1) ABA type triblock copolymer ((1) triblock copolymer) obtained in the step (ii) and the ABA type triblock copolymer A step of mixing a reactive compound ((2) a reactive compound),
Are included in order.

  According to the production method, the temperature-responsive biodegradable polymer composition containing the above-mentioned (1) ABA type triblock copolymer and (2) a reactive compound can be suitably produced. .

Process (i)
Step (i) in the production method of the present invention is a step of producing an ABA triblock copolymer by polymerizing ε-caprolactone and glycolide in the presence of PEG or an aliphatic diol.

The polymerization method is not particularly limited. For example, in the case of the triblock copolymer of the above formula (B), PEG is a polymer initiator in the presence of a catalyst such as Sn (Oct) ₂ (tin octylate). Can be produced by polymerizing ε-caprolactone and glycolide. There is no restriction | limiting in particular in the usage-amount of a catalyst, Preferably it is 0.1-10 mass parts with respect to 100 mass parts of mixtures of (epsilon) -caprolactone and glycolide.

  The aliphatic diol is not particularly limited, and examples thereof include linear alkylene diols having 1 to 6 carbon atoms such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and 1,4-butanediol. Is mentioned.

The amount of each raw material of ε-caprolactone, glycolide, PEG, and aliphatic diol used is not particularly limited, and may be appropriately adjusted so as to satisfy, for example, preferable physical properties of the above-described triblock copolymer. Note that ε-caprolactone, glycolide, PEG, aliphatic diol, and Sn (Oct) ₂ may be dried.

  The reaction in step (i) may be performed without a solvent, or a solvent may be used.

  The reaction temperature in step (i) is usually 50 to 200 ° C, preferably 100 to 180 ° C, more preferably 120 to 170 ° C.

  The reaction time in step (i) is usually 1 to 72 hours, preferably 6 to 48 hours, and more preferably 10 to 24 hours.

  Step (i) may be performed in a closed container. There is no restriction | limiting in particular as the container, A stainless steel airtight container, a pressure-resistant specification glass airtight container, etc. are mentioned.

  Step (i) may be performed in an atmosphere of an inert gas such as nitrogen or argon. The reaction pressure is not particularly limited, and the reaction may be performed at normal pressure or may be performed under pressure.

  After completion of the polymerization, a white powder triblock copolymer can be obtained by reprecipitation using a good solvent and a poor solvent and further drying the precipitate. As the good solvent, for example, chloroform can be used, and as the poor solvent, for example, diethyl ether can be used.

Step (ii)
Step (ii) in the production method of the present invention is a step of capping both ends of the ABA triblock copolymer obtained in step (i) (end cap).

  By the step (ii), (1) an ABA type triblock copolymer ((1) triblock copolymer) having reactive functional groups at both ends can be produced.

  There is no restriction | limiting in particular as a method of forming this reactive functional group. For example, the step (ii-1) of reacting the ABA triblock copolymer obtained in step (i) with a compound that forms a linker site, and the linker site obtained in the step (ii-1) A step (ii-2) of reacting the ABA type triblock copolymer having a compound that forms a reactive functional group.

When the reactive functional group is, for example, a succinimide ester group, the ABA-type triblock copolymer obtained in step (i) is reacted with succinic anhydride to form carboxyl groups (COOH) at both ends. Step (ii-1) for obtaining an ABA type triblock copolymer having a group), and an ABA type triblock copolymer having COOH groups at both ends obtained in the step (ii-1) and N-hydroxy It can be produced through a step (ii-2) in which an succinimide is reacted in the presence of a condensing agent to produce an ABA type triblock copolymer having succinimide ester groups at both ends.
Step (ii-1)
Examples of the compound that forms the linker site include compounds that form units such as dicarboxylic acids, diols, monopeptides, oligopeptides, and the like. For example, as a compound which forms a dicarboxylic acid unit, a C1-C6 alkylene dicarboxylic acid etc. are mentioned, for example.

  There is no restriction | limiting in particular as the usage-amount of the compound which forms this linker part, For example, it is 10-500 mass parts with respect to 100 mass parts of ABA type | mold triblock copolymer obtained by process (i).

  The reaction of the step (ii-1) can be performed in a solvent. Examples of the solvent include hydrocarbon solvents such as toluene and xylene; chlorine solvents such as methylene chloride and chloroform; water; mixed solvents thereof.

  The amount of the solvent used is usually 10 parts by mass or more, preferably 20 to 500 parts by mass, more preferably 40 to 100 parts by mass with respect to 100 parts by mass of the triblock copolymer obtained in step (i). 100 parts by mass.

  The reaction temperature in step (ii-1) is usually 100 to 200 ° C, preferably 100 to 150 ° C, more preferably 120 to 150 ° C.

  The reaction time in the step (ii-1) is usually 5 to 72 hours, preferably 12 to 48 hours, and more preferably 20 to 30 hours.

  Step (ii-1) may be performed in a sealed container. There is no restriction | limiting in particular as the container, A stainless steel airtight container, a pressure-resistant specification glass airtight container, etc. are mentioned.

  Step (ii-1) may be performed in an atmosphere of an inert gas such as nitrogen or argon. The reaction pressure is not particularly limited, and the reaction may be performed at normal pressure or may be performed under pressure.

  After completion of the reaction, a purification step may be performed, or the next reaction may be performed as it is. When performing the purification step, the unreacted raw material compound and the like are removed from the resulting reaction mixture by a conventional separation method such as distillation, filtration, and centrifugation, and an ABA type triblock co-polymer having linker sites at both ends. The coalescence can be taken out.

Process (ii-2)
Examples of the compound that forms a reactive functional group include N-hydroxysuccinimide and paranitrophenol. Among these, N-hydroxysuccinimide is preferable.

  The amount of the compound that forms the reactive functional group is not particularly limited. For example, with respect to 100 parts by mass of the ABA type triblock copolymer having a linker site obtained in step (ii-1). 2 to 40 parts by mass.

  The reaction of step (ii-2) can be carried out in a solvent. Examples of the solvent include chlorinated solvents such as methylene chloride and chloroform; hydrocarbon solvents such as toluene and xylene; polar organic solvents such as N, N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO); water; These mixed solvents are exemplified.

  The amount of the solvent used is usually 50 parts by mass or more, preferably 100 to 2000 parts by mass with respect to 100 parts by mass of the triblock copolymer having linker sites at both ends obtained in (ii-1). More preferably, it is 200 to 1000 parts by mass.

  As the condensing agent, a known condensing agent can be used, and examples thereof include dicyclohexylcarbodiimide (DCC), 1- [3- (dimethylamino) propyl] -3-ethylcarbodiimide (EDC) and the like. The amount of the condensing agent to be used is not particularly limited, and is usually 0.1 to 10 parts by mass with respect to 100 parts by mass of the ABA type triblock copolymer having a linker moiety obtained in step (ii-1). It is.

  In the reaction of step (ii-2), a reaction accelerator can be added as necessary. Examples of the reaction accelerator include dimethylaminopyridine (DMAP). When the reaction accelerator is used, the amount used is not particularly limited, and for example, with respect to 100 parts by mass of the ABA triblock copolymer having a linker site obtained in step (ii-1), Usually 0.1 to 10 parts by mass.

  Regarding the reaction temperature in step (ii-2), the reaction temperature for about 2 hours at the beginning of the reaction is usually 0 to 30 ° C., more preferably 0 to 5 ° C. It is 20 degreeC, More preferably, it is 20-30 degreeC.

  The reaction time in the step (ii-2) is usually 5 to 48 hours including the first 2 hours, more preferably 8 to 24 hours.

  Step (ii-2) may be performed in a sealed container. There is no restriction | limiting in particular as the container, A stainless steel airtight container, a pressure-resistant specification glass airtight container, etc. are mentioned.

  Step (ii-2) may be performed in an atmosphere of an inert gas such as nitrogen or argon.

  The reaction pressure is not particularly limited, and the reaction may be performed at normal pressure or may be performed under pressure.

  After completion of the reaction, a purification step may be performed or used as it is. When performing the purification step, unreacted raw material compounds and the like can be removed from the resulting reaction mixture by a conventional separation method such as distillation, filtration, and centrifugation, and (1) the triblock copolymer can be taken out. .

Step (iii)
Step (iii) in the production method of the present invention is a step of mixing (1) a triblock copolymer and (2) a reactive compound. Further, in step (iii) in the production method of the present invention, (1) the triblock copolymer and (2) the reactive compound as well as (3) another temperature-responsive polymer are mixed as necessary. can do.

  The amount of the reactive compound (2) used is not particularly limited, and is, for example, 0.1 to 100 parts by mass, preferably 0.2 to 50 parts by mass with respect to 100 parts by mass of the (1) triblock copolymer. More preferably, it is 0.25 to 20 parts by mass.

  Among the polymer compositions of the present invention, (3) in the case of a temperature-responsive polymer composition containing another temperature-responsive polymer, the amount of the reactive compound (2) used is not particularly limited. (1) It is 0.01-100 mass parts with respect to 100 mass parts of a triblock copolymer, Preferably it is 0.01-20 mass parts, More preferably, it is 0.025-10 mass parts.

  The amount of the (3) other temperature-responsive polymer used is not particularly limited, and is, for example, 0 to 400 parts by weight, preferably 50 to 100 parts by weight per 100 parts by weight of the triblock copolymer. 200 parts by mass.

  There is no limitation in particular as a solvent, For example, water, the medium containing water, acetone, etc. are mentioned. Among these, a medium containing water is preferable. As the medium containing water, the above-mentioned medium containing water (that is, physiological saline, phosphate buffered saline, phosphate buffer without salt, etc.) can be used. The amount of the solvent used is preferably such that (1) the triblock copolymer is about 6 to 25% by mass.

  The mixing method is not particularly limited as long as the above components can be mixed uniformly. For example, (1) a method of mixing a solution containing a triblock copolymer and (2) a solution in which a reactive compound is dissolved or dispersed in a solvent; (1) a solution containing a triblock copolymer does not contain a solvent Examples thereof include a method in which a solid or oily (2) reactive compound is added and mixed.

  Furthermore, (3) a mixing method in the case of a temperature-responsive polymer composition containing another temperature-responsive polymer includes (1) a triblock copolymer, (2) a reactive compound, and (3) another temperature. There is no particular limitation as long as the responsive polymer can be uniformly mixed. For example, (1) a triblock copolymer and (3) another temperature-responsive polymer are separately dissolved or dispersed in a solvent and then combined, and then (2) a reactive compound A solution prepared by dissolving or dispersing a solid (1) triblock copolymer and a solvent-free solid or oily (3) other temperature-responsive polymer in a solvent. The other component is added to the solution and mixed, and then (2) a method of mixing the reactive compound, and the like.

  There is no limitation in particular as a solvent, For example, water, the medium containing water, acetone, etc. are mentioned. Among these, a medium containing water is preferable. As the medium containing water, the above-mentioned medium containing water (that is, physiological saline, phosphate buffered saline, phosphate buffer without salt, etc.) can be used. It is preferable to use the solvent so that the amount of the (1) triblock copolymer is about 5 to 30% by mass.

  In the case of a temperature-responsive polymer composition containing (3) another temperature-responsive polymer, the amount of the solvent used is such that (1) the triblock copolymer is about 5 to 30% by mass. Is preferably used.

  In the step (iii), an acidic solution (for example, hydrochloric acid) or an alkaline solution (for example, an aqueous sodium hydroxide solution) can be added as necessary to adjust the pH appropriately.

  In addition, (1) when the ABA type triblock copolymer is difficult to dissolve or disperse, it is gelled by heating the solution or dispersion, and then the operation of returning to room temperature is repeated, It can be dissolved or dispersed.

3. Properties and Applications of Temperature Responsive Polymer Composition As described above, the polymer composition of the present invention has good biocompatibility, biodegradability, and temperature responsiveness, and can maintain a gel state for a long period of time.

  Here, the temperature-responsive sol-gel transition is a property in which a solution of a compound (or polymer composition) generally shows a transition from a sol (solution) state to a gel (solid) state at the gelation temperature. Say. Specifically, it refers to the property that when an aqueous solution of a compound (or polymer composition) is heated to a temperature equal to or higher than the gelation temperature, it becomes a gel state, and when cooled to a temperature lower than that, it dissolves again and returns to a transparent sol state. .

  The aqueous solution of the polymer composition of the present invention has a gelation temperature in the range of about 10 to 50 ° C., and the gelation temperature can be easily adjusted in such a range, and its application range is extremely wide. In particular, it can be mixed with a drug and used as a medical material.

  For example, in an aqueous solution of a polymer composition having a gelation temperature in the range of 25 to 35 ° C, the gelation temperature must exist between room temperature (for example, about 10 to 20 ° C) and body temperature (about 35 to 40 ° C). Thus, it can be administered into the body by injection in a solution (sol) state, and a hydrogel can be formed in the body. When such a polymer composition is mixed with a drug, it is in a solution state near room temperature and is easy to handle at the time of injection. On the other hand, it becomes an insoluble gel state near body temperature. It is possible to suppress the early diffusion of the drug and improve the retention of the drug at the administration site. Therefore, it can be suitably used as a biodegradable polymer material in an injectable preparation, particularly a long-lasting injectable preparation.

  Examples of the administration form include subcutaneous injection and intramuscular injection.

  The blending amount of the polymer composition in the pharmaceutical composition can be appropriately selected depending on the type of drug used and the like. For example, it may be about 60-99.9% by mass with respect to the total mass of the pharmaceutical composition.

  The drug used in the pharmaceutical composition is not particularly limited, but has physiologically active peptides, proteins, nucleic acids, other antibiotics, antitumor agents, antipyretic agents, analgesics, antiphlogistics, antitussive expectorants, Sedative, muscle relaxant, antiepileptic agent, antiulcer agent, antidepressant agent, antiallergic agent, cardiotonic agent, arrhythmia agent, vasodilator, antihypertensive diuretic agent, antidiabetic agent, anticoagulant, hemostatic agent, anti Tuberculosis agents, hormone agents, narcotic antagonists and the like.

  The amount of the drug in the pharmaceutical composition of the present invention can be appropriately selected depending on the type of drug. In particular, in the case of a sustained injection, the amount of the drug is determined by the type of drug, the period of sustained release, and the like. For example, when the drug is a peptide, in order to obtain a sustained-release preparation of about 1 week to about 1 month, it is usually contained in an amount of about 10% to 50% by mass relative to the total mass of the pharmaceutical composition.

  Moreover, since the polymer composition of the present invention has temperature responsiveness, biodegradability, and safety to living bodies, it can be used as a tissue adhesion preventing material after surgery. Adhesion can be prevented by covering visceral tissue after surgery by application or spraying and isolating it from other living tissue for a certain period of time.

  Furthermore, the polymer composition of the present invention can be applied as a scaffold for regenerative medicine, a cell culture substrate, and the like. As the scaffold, cells, the polymer composition of the present invention, a culture solution, and the like are mixed in a sol state at a low temperature, and the mixture is gelled into a predetermined shape at a high temperature to be used as a scaffold. As a cell culture substrate, a fibrous or porous substrate having a predetermined three-dimensional shape is impregnated with a liquid mixture containing cells, the polymer composition of the present invention and a culture solution, and gelled at a predetermined temperature. It is also possible to retain regenerative cells in the substrate. As the fibrous or porous substrate, materials having high biocompatibility such as collagen and hydroxyapatite can be used, which is particularly effective for regeneration of cartilage tissue and bone tissue. Furthermore, it is possible to provide a system for transplanting cells into damaged tissue (cell delivery).

  The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples.

[Production Example 1]
Synthesis of triblock copolymer (B1)
Only PEG (1,000) (Polyethylene glycol (1,000), manufactured by Wako Pure Chemical Industries, Ltd.) was dried under reduced pressure in a 140 ° C. oil bath for 3 hours, and then ε-caprolactone (produced by Wako Pure Chemical Industries, Ltd.), glycolide (Polysciences) And Sn (Oct) ₂ (manufactured by Wako Pure Chemical Industries, Ltd.) were added and further dried for 6 hours. Next, polymerization was carried out in a 160 ° C. oil bath for 12 hours. After completion of the reaction, reprecipitation was performed using chloroform as a good solvent and diethyl ether as a poor solvent to obtain a white precipitate. After drying the precipitate, a white powder of PCGA-b-PEG-b-PCGA triblock copolymer (structural formula (B) shown in chemical formula 6 to be described later. Hereinafter, also referred to as “CP-OH”). Obtained. The physical properties of the triblock copolymer (B1) are shown in Table 1 below.

[Production Example 2]
Synthesis of triblock copolymer (B2)
A white powder of PCGA-b-PEG-b- was prepared in the same manner as in Production Example 1, except that PEG (1,540) (Polyethylene glycol (1,540), manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of PEG (1,000). A PCGA triblock copolymer (B2) was obtained. The physical properties of the triblock copolymer (B2) are shown in Table 1 below.

a) Measured by ¹ H-NMR (solvent: CDCl ₃ ).
b) GPC (eluent: DMF, standard: PEG, measured by Tosoh GPC-8020 series system from TOSOH) c) Degree of polymerization of ε-caprolactone.
d) Degree of polymerization of glycolide.

[Production Example 3]
(1) Synthesis of triblock copolymers having reactive functional groups at both ends

Process (i)
19.86 g of CP-OH (B2) obtained in Production Example 2, 3.87 g of succinic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.01 L of toluene were placed in a 0.1 L flask and refluxed at 130 ° C. for 24 hours. Reacted. Thereafter, toluene was distilled off by an evaporator, chloroform was added, unreacted succinic anhydride was removed by suction filtration, and PCGA-b-PEG-b-PCGA having a carboxyl group at both ends (the structural formula shown in the above chemical formula 6). (C) 20.63 g of “CP-COOH” was obtained.

Step (ii)
20.63 g of CP-COOH obtained in step (i), 1.78 g of N-hydroxysuccinimide (NHS), 0.47 g of dimethylaminopyridine (DMAP), 1.59 g of dicyclohexylcarbodiimide (DCC) and 0.1 L of methylene chloride in a 0.1 L flask And allowed to react for 2 hours under ice cooling and 24 hours at room temperature. After concentration with an evaporator, dicyclohexylurea (DCUrea) and unreacted NHS are removed by suction filtration, reprecipitation is performed using diethyl ether: methanol = 10: 1 as a poor solvent, and both ends are succinimide esterified (cap) 14.2 g of a white precipitate of PCGA-b-PEG-b-PCGA (structural formula (1a) shown in Chemical Formula 6 above, hereinafter referred to as “CP-OSu”) was obtained (OSu introduction rate: 98% or more) .

[Production Example 4]
CP-OH (1.8k-1.5k-1.8k) (100 mg, 19.4 μmol) obtained in Production Example 2 was put into a sample tube in a powder state, and further phosphate buffered saline (PBS; pH = 7.4) Add 294 μl, soak in a warm bath at 80 ° C. for 5 seconds (gelation), stir with a vortex mixer for 30 seconds and return to room temperature (solation) three times to dissolve and dissolve to 25.5 wt% A mixed polymer aqueous solution (final concentration 25.0 wt%) was obtained (hereinafter, simply referred to as “comparative polymer aqueous solution 1”).

[Production Example 5]
Preparation of polymer aqueous solution (CP-OSu: CP-OH = 1mol: 2mol)
Triblock copolymer (CP-OSu) (50.3 mg, 9.1 μmol, OSu group: 18.2 μmol) obtained in Production Example 3 and CP-OH (50.1 mg, 17.9 μmol) obtained in Production Example 1 Each sample is placed in a solid (powder) state, added with 268 μl of phosphate buffered saline (PBS; pH = 7.4), immersed in a warm bath at 80 ° C. for 5 seconds (gelation), and then vortexed. The operation of stirring for 30 seconds and returning to room temperature (solification) was repeated 3 times to dissolve. 16 μl of 1M NaOH was added to adjust the pH to 7.4 to obtain a 26.1 wt% mixed polymer aqueous solution (final concentration 25.0 wt%) (hereinafter simply referred to as “polymer aqueous solution”).

[Production Example 6]
Preparation of polylysine solution 6.5 mg of polylysine [Poly (L-Lysine) hydrobromide (Sigma Aldrich mol wt 1,000-5,000)] as a polyamine compound was dissolved in 40 μl of PBS (pH = 7.4), and 5 μl of 1M NaOH. And a polylysine solution (pH = 7.4, 0.144 mg / ml) was prepared.

[Production Example 7]
Preparation of Comparative Polylysine Solution Polylysine [(Poly (L-Lysine) hydrobromide (Sigma Aldrich, molecular weight 1,000-5,000)] 32.9 mg as PBS (pH = 7.4) 83 μl as polyamine compound After dissolution, 17 μl of 1M NaOH was added to prepare a polylysine solution (pH = 7.4, 0.329 mg / ml).

[Example 1]
Production of the biodegradable polymer composition of the present invention
Preparation of mixed polymer solution [step (iii)]
284 μl of polymer solution obtained in Production Example 5 (OSu group: 18.2 μmol) and 18.0 μl of polylysine solution obtained in Production Example 6 (Poly (L-Lysine) hydrobromide: 2.51 mg) were mixed. Then, by mixing with a vortex mixer at room temperature for about 10 seconds, a mixed polymer solution 1 (302 μl) containing OSu groups and NH ₂ groups in a ratio of about 1: 1 was prepared (Poly (L-Lysine) hydrogen bromide). Acid salt: 2.51 mg, 0.83 wt%).

[Examples 2 to 6]
Except that the type of the second component (2) reactive compound and the content of the (2) reactive compound in the biodegradable polymer composition were changed as shown in Table 2, the same as in Example 1 Liquid polymer compositions 2 to 6 (Examples 2 to 6) were obtained.

<Second component>
・ Poly-L-lysine hydrobromide (molecular weight: 4,000-15,000) [manufactured by Sigma Aldrich]
・ PEI (Molecular weight: 10,000) [Wako Pure Chemical Industries, Ltd.]
・ BSA (Molecular weight: 66,000) [Wako Pure Chemical Industries, Ltd.]
4-arm PEG-NH ₂ (molecular weight: 5,140) (manufactured according to the method described in JP 2013-227543 A)
4-arm PEG-NH ₂ production
4-arm PEG-OH (trade name: SUNBRIGHT PTE-5000, molecular weight 5,143, manufactured by NOF Corporation) 1.2507 g (243 μmol) was dried at 110 ° C. under reduced pressure for 2 hours. After cooling to room temperature, 4-arm PEG-OH was dissolved in 10 ml of dehydrated methylene chloride, and 1.1 ml (7.8 mmol) of triethylamine (TEA) was added to this solution. While stirring the obtained mixed solution under ice cooling, 300 μl (3.9 mmol) of methanesulfonyl chloride (MeSO ₂ Cl) was slowly added dropwise. After stirring for 2 hours under ice-cooling and then for 10 hours at room temperature, the solvent was removed by an evaporator, and the concentrate was redissolved in 5 ml of chloroform. And it refine | purified by reprecipitation using diethyl ether 100ml as a poor solvent, and the obtained white powder was dried under reduced pressure. The obtained powder was dissolved in 50 ml of aqueous ammonia and stirred at room temperature for 2 days. After stirring, extraction was performed with 50 ml of methylene chloride, the organic layer was recovered, and the solvent was removed with an evaporator. The obtained concentrate was redissolved in methylene chloride and reprecipitated using diethyl ether as a poor solvent. The precipitate was filtered, and the obtained powder was redissolved in 5 ml of chloroform and reprecipitated using 100 ml of diethyl ether as a poor solvent. The precipitate was filtered and the obtained powder was dried to obtain 4-arm PEG-NH ₂ (yield: 0.38 g, yield: 30%).

[Comparative Example 1]
Comparative Example 1 is only the polymer aqueous solution obtained in Production Example 5 above.

[Comparative Example 2]
292 μl (23.6 μmol) of the comparative polymer aqueous solution 1 obtained in Production Example 4 and 7.6 μl of the polylysine solution prepared in Production Example 7 (Poly (L-Lysine): 2.51 mg) were mixed, and the mixture was about vortexed at room temperature. By stirring for 10 seconds, 300 μl of a comparative mixed polymer solution was prepared.

[Test Example 1]
Determination of gelation immediately after mixing The polymer solution containing the first component described in Table 2 and the solution containing the second component were mixed in a sample tube (diameter about 1 cm) and stirred at room temperature for about 10 seconds. It was left at 25 ° C. for 5 minutes, and it was judged by a test tube gradient method whether it was in a sol state or a gel state immediately after mixing.

  Specifically, after elapse of a predetermined time at a predetermined temperature, the sample tube was tilted by about 135 degrees, and “gel” was determined to not flow for about 30 seconds, and “sol” was determined to flow. The results are shown in Table 2 below.

[Test Example 2]
Evaluation of the maintenance period of the gel state in water The mixed polymer aqueous solution of Examples 1 to 6, the solution of Comparative Example 1 and the solution of Comparative Example 2 in a small sample tube (diameter about 1 cm) were each incubated at 37 ° C. for 10 minutes. And gelled. Thereafter, each sample tube was immersed in a large sample tube (diameter: about 3 cm) containing 25 ml of PBS (pH = 7.4, 37 ° C.), and left in a 37 ° C. constant temperature bath. The sample was taken out every predetermined time, and the presence or absence of sol-gel transition of each solution in water was examined by a test tube inclination method.

  Specifically, after elapse of a predetermined time at a predetermined temperature shown in Table 2 below, the sample tube was tilted, and if it did not flow for about 30 seconds, it was judged as “gel”, and if it flowed, it was judged as “sol”.

  Table 2 shows the results after heating at 37 ° C. for 1 minute and the gel state maintenance period (days).

<Evaluation results>
The biodegradable polymer compositions obtained in Examples 1 to 6 are in a sol state only by mixing the first component and the second component at room temperature (25 ° C.). Gelation did not occur even when left at 4 ° C., and the sol remained.

  Therefore, it was found that the biodegradable polymer composition of the present invention does not gel unless the temperature is raised to body temperature.

  In addition, the biodegradable polymer compositions obtained in Examples 1 to 6 were heated at 37 ° C. for 1 minute, and then all gelled and then heated at 37 ° C. in PBS. Maintained for 1 to 30 days.

  On the other hand, the solutions of Comparative Example 1 and Comparative Example 2 gelled immediately after being heated at 37 ° C. for 1 minute, but when heated at 37 ° C. in PBS, the gel state was maintained for less than 24 hours. there were.

[Test Example 3]
Determination of solation due to temperature decrease The mixed polymer aqueous solutions of Examples 1 to 6, the solution of Comparative Example 1 and the solution of Comparative Example 2 were heated to 37 ° C. as in Test Example 2 to be gelled, and predetermined. After a lapse of time, the temperature of each gel was lowered to 4 ° C. After 1 minute, the state of each gel was examined by the test tube gradient method.

  Specifically, the sample tube containing each sample was tilted, and “gel” was judged not to flow for about 30 seconds, and “sol” was judged to flow.

<Evaluation results>
The biodegradable polymer compositions of Examples 1 to 6 maintained the gel state even when the temperature was lowered to 4 ° C. after warming at 37 ° C. for the holding time described in Table 3 (FIG. 3).

  On the other hand, the gels of Comparative Examples 1 and 2 both returned to the sol when the temperature was lowered to 4 ° C. after being held at 37 ° C. for 1 minute or 1 hour.

Claims (8)

(1) ABA type triblock copolymer having reactive functional groups at both ends, and
(2) A temperature-responsive biodegradable polymer composition containing a compound or a salt thereof capable of reacting with the ABA type triblock copolymer,
The A block comprises poly (ε-caprolactone-co-glycolic acid);
A temperature-responsive biodegradable polymer composition, wherein the B block comprises a polyethylene glycol chain. The temperature according to claim 1, wherein the content of the compound (2) or a salt thereof is 0.25 to 20 parts by mass with respect to 100 parts by mass of the (1) A-B-A type triblock copolymer. Responsive biodegradable polymer composition. The A block constitutes 20 to 75% by mass of the (1) ABA type triblock copolymer,
The temperature-responsive biodegradable polymer composition according to claim 1 or 2, wherein the B block constitutes 25 to 80% by mass of the (1) A-B-A type triblock copolymer. The temperature-responsive biodegradable polymer composition according to any one of claims 1 to 3, further comprising (3) a temperature-responsive polymer other than the ABA type triblock copolymer. The temperature-responsive biodegradable polymer composition according to any one of claims 1 to 4, wherein the reactive functional group is a succinimide ester group. The temperature-responsive biodegradable polymer composition according to any one of claims 1 to 5, wherein the compound (2) or a salt thereof is a polyamine compound or a salt thereof. A method for producing the temperature-responsive biodegradable polymer composition according to any one of claims 1 to 6,
(i) a step of producing an ABA type triblock copolymer by polymerizing ε-caprolactone and glycolide in the presence of polyethylene glycol or an aliphatic diol;
(ii) a step of forming a reactive functional group at both ends of the ABA type triblock copolymer obtained in the step (i), and
(iii) The compound or salt thereof capable of reacting with the (1) ABA type triblock copolymer obtained in the step (ii) and the (2) ABA type triblock copolymer. The manufacturing method of a biodegradable polymer composition including the process of mixing these in order. The method for producing a biodegradable polymer composition according to claim 7, wherein in step (iii), a temperature-responsive polymer other than (1) the ABA type triblock copolymer is further mixed.