JP2019143083A - Polymer, method for producing polymer, drug conjugate, and micelle - Google Patents

Abstract

To provide a polymer, a method for producing the same, and a drug conjugate containing the polymer.SOLUTION: The polymer has a repeating unit represented by general formula (I-1), a repeating unit represented by general formula (I-2), and a repeating unit represented by general formula (II) (Lrepresents a divalent aromatic hydrocarbon group; Lrepresents a divalent aliphatic hydrocarbon group; and X represents OR, SRor NRR).SELECTED DRAWING: None

Description

  The present invention relates to a polymer, a method for producing the polymer, a drug complex, and a micelle.

A polymer containing an aldehyde group or a ketone group (hereinafter sometimes referred to as “aldehyde / ketone-containing polymer”) is a physiologically active molecule having a functional group such as an amino group, an imino group, or a hydrazide group. Can be used to bond by formation.
The aldehyde group-containing polymer can also be used for core crosslinking of cationic polypeptides. For this reason, aldehyde / ketone-containing polymers have attracted attention, particularly in the pharmaceutical field, as carriers for drug delivery.
As a method of introducing an aldehyde into a polymer, a method of obtaining an aldehyde-introduced polymer by RAFT polymerization of 4-vinylbenzaldehyde is known (for example, see Non-Patent Documents 1 to 4).

Synthesis of Aldehyde functionalized and degradable block copolymer and their bioconjugation.Jian-bing Huang, Zhong-peng Xiao, Hui Liang, Jiang Lu Acta Polymerica SInica, 2015, issue 4, 459-465 Synthesis of Functional Core, Star Polymers via RAFT Polymerization for Drug Delivery Applications Jinna Liu, Hien Duong, Michael R. Whittaker, Thomas P. Davis, Cyrille Boyer Macromolecular Rapid Communications, Volume 33, Issue 9 Pages 760-766 A Well-Defined Novel Aldehyde-Functionalized Glycopolymer: Synthesis, Micelle Formation, and Its Protein Immobilization Nai-Yu Xiao, An-Long Li, Hui Liang, and Jiang Lu, Macromolecules, 2008, 41, 2374-2380. Well-defined polymers with activated ester and protected aldehyde side chains for bio-functionalization, Jungyeon Hwang, Ronald C. Li, Heather D. Maynard, Journal of Controlled Release 122 (2007) 279-286

However, since the methods of Non-Patent Documents 1 to 4 can introduce only aromatic aldehydes, there is a problem that aliphatic aldehydes, aromatic aldehydes, aliphatic ketones and aromatic ketones cannot be selectively introduced. It was. In addition, the methods of Non-Patent Documents 1 to 4 have only a homopolymer because of RAFT polymerization, and there is a problem that the reaction process becomes complicated when other functional groups are introduced.
In Non-Patent Document 4, acetal group-introduced methacrylate is used. However, since it is bonded to the base polymer via an ester bond, it is dissociated at physiological pH (pH 7.4), which is inappropriate for drug delivery.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a novel polymer, a method for producing the same, and a drug complex containing the polymer.

In order to solve the above problems, the present invention employs the following configuration.
(1) Repeating unit (I-1) represented by the following general formula (I-1),
The repeating unit (I-2) represented by the following general formula (I-2), and the repeating unit (II) represented by the following general formula (II)
A polymer characterized by having

[Wherein, m represents 1 or 2. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]

(2) A method for producing a polymer,
The polymer (P1) having a repeating unit (II ′) represented by the following general formula (II ′), the compound (1a-1) represented by the following general formula (1a-1), and the following general formula (1a) -2) is reacted with the compound (1a-2) represented by the following general formula (I'-1), the repeating unit (I'-1) represented by the following general formula (I'-2) A step (1) of obtaining a polymer (P2) having a repeating unit (I′-2) represented by formula (I) and the repeating unit (II ′);
The polymer (P2) is hydrolyzed under neutral or weakly acidic conditions, and the repeating unit (I-1) represented by the following general formula (I-1) or the following general formula (I-2) A step (2) of obtaining a polymer having a repeating unit (I-2) represented by formula (II-1) and a repeating unit (II-1) represented by the following general formula (II-1):
A process for producing a polymer, comprising:

[Wherein, m represents 1 or 2. R ² represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Ra ¹¹ and Ra ¹² each independently represent a methyl group or an ethyl group, or Ra ¹¹ and Ra ¹² are bonded to each other to represent an ethylene group or a propylene group. Ra ¹³ and Ra ¹⁴ each independently represent a methyl group or an ethyl group, or Ra ¹³ and Ra ¹⁴ are bonded to each other to represent an ethylene group or a propylene group. R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]

(3) A polymer (P1) having a repeating unit (II ′) represented by the following general formula (II ′), a compound (1a-1) represented by the following general formula (1a-1), and the following general formula The compound (1a-2) represented by the formula (1a-2) is reacted to give a repeating unit (I′-1) represented by the following general formula (I′-1), the following general formula (I ′ -2) to obtain a polymer (P2) having the repeating unit (I'-2) represented by formula (I'-2) and the repeating unit (II ');
The polymer (P2) is subjected to at least one treatment selected from the group consisting of hydrolysis under alkaline conditions, transesterification, aminolysis, and hydrolysis under alkaline conditions and amide coupling. '-1), a step (2a) for obtaining a polymer (P3) having the repeating unit (I'-2) and the repeating unit (II) represented by the following general formula (II):
The polymer (P3) is hydrolyzed under neutral or weakly acidic conditions, and the repeating unit (I-1) represented by the following general formula (I-1) or the following general formula (I-2) A step (2b) of obtaining a polymer having the repeating unit (I-2) represented above and the repeating unit (II);
A process for producing a polymer comprising

[Wherein, m represents 1 or 2. R ² represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Ra ¹¹ and Ra ¹² each independently represent a methyl group or an ethyl group, or Ra ¹¹ and Ra ¹² are bonded to each other to represent an ethylene group or a propylene group. Ra ¹³ and Ra ¹⁴ each independently represent a methyl group or an ethyl group, or Ra ¹³ and Ra ¹⁴ are bonded to each other to represent an ethylene group or a propylene group. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]

(4) A drug complex comprising the polymer according to (1) and at least one drug bonded to the polymer.

(5) Repeating unit (IA-1) represented by the following general formula (IA-1),
The repeating unit (IA-2) represented by the following general formula (IA-2), and the repeating unit (II) represented by the following general formula (II)
The drug conjugate according to the above (4), which contains a polymer having

[Wherein, m represents 1 or 2. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. BM represents an active molecule. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]

(6) A micelle containing the drug complex of (5).

  According to the present invention, a novel polymer in which an aliphatic aldehyde and / or an aliphatic ketone and an aromatic aldehyde and / or an aromatic ketone are selectively introduced, a production method thereof, and a drug is bonded to the polymer. Drug conjugates can be provided.

FIG. 1 is a synthesis scheme of an aromatic aldehyde group-containing polymer and an aliphatic aldehyde group-containing polymer according to an embodiment of the present invention. FIG. 2 is a ¹ H-NMR spectrum of a polymer according to one embodiment of the present invention. FIG. 3 is a ¹ H-NMR spectrum of a polymer according to one embodiment of the present invention. FIG. 4 is a ¹ H-NMR spectrum of a polymer according to one embodiment of the present invention. FIG. 5 is a ¹ H-NMR spectrum of a polymer according to one embodiment of the present invention. FIG. 6 shows the analysis results of the micelle size and polydispersion index (PDI) of the drug conjugate according to one embodiment of the present invention. FIG. 7 is an analysis result of the micelle size and polydispersion index (PDI) of the drug conjugate according to one embodiment of the present invention. FIG. 8 shows the analysis results of the micelle size and polydispersion index (PDI) of the drug conjugate according to one embodiment of the present invention. FIG. 9 shows the analysis results of the micelle size and polydispersion index (PDI) of the drug conjugate according to one embodiment of the present invention. FIG. 10 is a graph showing a pH sensitive drug release profile of a drug conjugate according to a reference example. FIG. 11 is a graph showing a pH-sensitive drug release profile of a drug complex according to a reference example. FIG. 12 is a graph showing a pH sensitive drug release profile of a drug conjugate according to one embodiment of the present invention. FIG. 13 is a graph showing changes in body weight of a mouse over time when a drug conjugate according to one embodiment of the present invention is administered to the mouse. FIG. 14 shows the results of an in vivo anti-tumor test of a drug conjugate according to one embodiment of the present invention. FIG. 15 shows the results of an in vivo antitumor test of a drug conjugate according to one embodiment of the present invention. FIG. 16 is a graph showing the time course of survival rate when a drug conjugate according to one embodiment of the present invention is administered to mice. FIG. 17 is an MRI image of the mouse brain when the drug conjugate according to one embodiment of the present invention is administered to the mouse. FIG. 18 is an MRI image of the mouse brain when the drug conjugate according to one embodiment of the present invention is administered to the mouse.

<Polymer>
The polymer of this embodiment includes a repeating unit (I-1) represented by the following general formula (I-1), a repeating unit (I-2) represented by the following general formula (I-2), and the following general formula. It has a repeating unit (II) represented by (II).

[Wherein, m represents 1 or 2. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]

In the general formulas (I-1), (I-2) and (II), m is 1 or 2, and 1 is preferable.
In the general formula (I-1), L ¹¹ represents a divalent aromatic hydrocarbon group.
Examples of the divalent aromatic hydrocarbon group for L ¹¹ include a phenylene group and a benzylene group.
The divalent aromatic hydrocarbon group for L ¹¹ may have a substituent. Examples of the substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a nitro group, and a halide.
Among these, as L ¹¹ , a benzylene group is preferable.

In the general formula (I-2), L ¹² represents a divalent aliphatic hydrocarbon group. Examples of the divalent aliphatic hydrocarbon group for L ¹² include an ethylene group, a propylene group, a butylene group, and a pentylene group. The divalent aliphatic hydrocarbon group for L may have a substituent.
Examples of the substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, and a halide.
Among them, as the L ^12, a methylene group, an ethylene group or a propylene group is preferable, and a methylene group or an ethylene group is more preferable.

In the general formulas (I-1) and (I-2), R ¹¹ and R ¹² each independently represent a hydrogen atom, an aliphatic hydrocarbon group, or an aromatic hydrocarbon group.
Examples of the aliphatic hydrocarbon group for R ¹¹ and R ¹² include an ethyl group, a propyl group, a butyl group, and a pentyl group. The aliphatic hydrocarbon group for R ¹¹ and R ¹² may have a substituent. Examples of the substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a tert-pentyl group, a cyclohexyl group, and a trihalomethyl group. .
Examples of the aromatic hydrocarbon group of R ¹¹ and R ¹² include phenyl group, benzyl group, pyridyl group, naphthyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, xylyl group, methylphenyl group, nitrophenyl group, chlorophenyl Group, fluorophenyl group, iodophenyl group, bromophenyl group and the like.
Among these, as R ^11, preferably a hydrogen atom or an aliphatic hydrocarbon group, more preferably a hydrogen atom or a methyl group, a hydrogen atom more preferred.
R ¹² is preferably a hydrogen atom or an aliphatic hydrocarbon group, more preferably an aliphatic hydrocarbon group, and still more preferably a methyl group.

In the general formula (II), X represents OR ^x , SR ^x or NR ^x1 R ^x2 .
In the general formula (II), R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Examples of the aliphatic hydrocarbon group for R ^x include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, tert-pentyl group, cyclohexyl group, and trifluoro group. A methyl group etc. are mentioned.
The aromatic hydrocarbon group for R ^x includes phenyl, benzyl, pyridyl, naphthyl, hydroxyphenyl, methoxyphenyl, ethoxyphenyl, xylyl, methylphenyl, nitrophenyl, chlorophenyl, fluoro, Examples include an orophenyl group, an iodophenyl group, and a bromophenyl group.
R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
Examples of the aliphatic hydrocarbon group represented by R ^x1 and R ^x2 include methyl group, ethyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, tert-pentyl group, cyclohexyl group, and trihalomethyl. Group.
Examples of the aromatic hydrocarbon group represented by R ^x1 and R ^x2 include phenyl group, benzyl group, pyridyl group, naphthyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, xylyl group, methylphenyl group, humanlophenyl group, and chlorophenyl. Group, fluorophenyl group, iodophenyl group, bromophenyl group and the like.
Among them, X is preferably OR ^{x and} more preferably OH (hydroxy group).

The polymer of the present embodiment has a repeating unit other than the repeating units (I-1), (I-2) and (II) (hereinafter sometimes referred to as “repeating unit (III)”). May be.
The repeating unit (III) is preferably a hydrophilic repeating unit. For example, a repeating unit derived from polyethylene glycol, a repeating unit derived from poly (ethylethylene phosphate), a repeating unit derived from polyvinyl alcohol, polyvinyl Examples thereof include a repeating unit derived from pyrrolidone, a repeating unit derived from poly (oxazoline), and a repeating unit derived from poly (N- (2-hydroxypropyl) methacrylamide) (PHPMA). Among them, the repeating unit (III) is preferably a repeating unit derived from polyethylene glycol.

In the present embodiment, the content of the repeating units (I-1), (I-2), (II) and (III) is not particularly limited.
The total content of the repeating unit (I-1) and the repeating unit (I-2) is preferably from 5 to 100 mol%, preferably from 10 to 80 mol based on the total (100 mol%) of all repeating units constituting the polymer. % Is more preferable, and 20-50 mol% is still more preferable.
The content of the repeating unit (II) is preferably from 0 to 80 mol%, more preferably from 10 to 60 mol%, more preferably from 20 to 40 mol%, based on the total (100 mol%) of all repeating units constituting the polymer. Further preferred.
The content of the repeating unit (III) is preferably from 0 to 95 mol%, more preferably from 20 to 90 mol%, more preferably from 50 to 80 mol%, based on the total (100 mol%) of all repeating units constituting the polymer. Further preferred.

The ratio (molar ratio) between the repeating unit (I-1) and the repeating unit (I-2) can be adjusted as appropriate according to the type of the drug bound to the polymer, but the repeating unit (I-1) / repeating unit ( I-2) = 1/99 to 99/1 is preferable, 5/95 to 95/5 is more preferable, and 10/90 to 90/10 is still more preferable.
When the ratio between the repeating unit (I-1) and the repeating unit (I-2) is within the above range, toxicity can be alleviated when the drug conjugate is obtained by binding the drug to the polymer according to this embodiment. As well as adequate control of the maximum tolerated dose (MTD).
For example, when a more toxic drug is bonded to the repeating unit (I-1) and a less toxic drug is bonded to the repeating unit (I-2), the repeating unit (I-1) and the repeating unit ( By adjusting the ratio with I-2) within the above range, a synergistic therapeutic effect can be obtained.

  The molecular weight of the polymer of this embodiment is preferably from 2,000 to 1,000,000 D, more preferably from 5,000 to 100,000 D, and even more preferably from 10,000 to 40,000 D.

<Polymer production method (1)>
The polymer production method of the present embodiment (hereinafter sometimes referred to as “production method (1)”) includes a polymer (P1) having a repeating unit (II ′) represented by the following general formula (II ′): A compound (1a-1) represented by the following general formula (1a-1) is reacted with a compound (1a-2) represented by the following general formula (1a-2) to give the following general formula (I ′ -1) a repeating unit (I′-1), a repeating unit (I′-2) represented by the following general formula (I′-2), and a polymer (P2) having the repeating unit (II ′) And the repeating unit (I-1) represented by the following general formula (I-1) by hydrolyzing the polymer (P2) under neutral or weakly acidic conditions: The repeating unit (I-2) represented by the following general formula (I-2) and the repeating unit represented by the following general formula (II-1) And (2) obtaining a polymer having a returning unit (II-1).

[Wherein, m represents 1 or 2. R ² represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Ra ¹¹ and Ra ¹² each independently represent a methyl group or an ethyl group, or Ra ¹¹ and Ra ¹² are bonded to each other to represent an ethylene group or a propylene group. Ra ¹³ and Ra ¹⁴ each independently represent a methyl group or an ethyl group, or Ra ¹³ and Ra ¹⁴ are bonded to each other to represent an ethylene group or a propylene group. R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]

In the formulas (I′-1), (I′-2), (II ′), (I-1), (I-2) and (II-1), m, L ¹¹ , L ¹² , R ¹¹ , R ¹² and R ^x are the same as m, L ¹¹ , L ¹² , R ¹¹ , R ¹² and R ^{x in the} general formulas (I-1), (I-2) and (II).
In the general formulas (1a-1) and (I′-1), Ra ¹¹ and Ra ¹² each independently represent a methyl group or an ethyl group, or Ra ¹¹ and Ra ¹² are bonded to each other to form an ethylene group or propylene. Represents a group. When Ra ¹¹ and Ra ¹² are bonded to each other to represent an ethylene group or a propylene group, the compound (1a-1) becomes a cyclic acetal or a cyclic ketal.
In the general formulas (1a-2) and (I′-2), Ra ¹³ and Ra ¹⁴ each independently represent a methyl group or an ethyl group, or Ra ¹³ and Ra ¹⁴ are bonded to each other to form an ethylene group or propylene. Represents a group. When Ra ¹³ and Ra ¹⁴ are bonded to each other to represent an ethylene group or a propylene group, the compound (1a-2) becomes a cyclic acetal or a cyclic ketal.

(Process (1))
Step (1) of production method (1) is an aminolysis reaction of polymer (P1), compound (1a-1) and compound (1a-2). By the step (1), the acetal structure or ketal structure of the compound (1a-1) and the compound (1a-2) is introduced into the side chain of the polymer (P1).
The amount of compound (1a-1) and compound (1a-2) in step (1) is not particularly limited, but compound (1a-1) is a volume ratio of compound (1a-1) and compound (1a-2). / Compound (1a-2) = 10/90 to 90/10 is preferable, 15/85 to 80/20 is more preferable, and 20/80 to 60/40 is still more preferable.
The reaction temperature in the step (1) is not particularly limited as long as the acetal structure or the ketal structure of the compound (1a-1) and the compound (1a-2) is introduced into the side chain of the polymer (P1). It is 4 degreeC-100 degreeC, and room temperature-45 degreeC is preferable.
The reaction time in the step (1) is not particularly limited as long as the acetal structure or the ketal structure of the compound (1a-1) and the compound (1a-2) is introduced into the side chain of the polymer (P1). Although it can be selected depending on the time and the type and amount of compound (1a), it is usually 4 hours to 5 days.
In step (1), compound (1a-2) can also be reacted after reacting reactive polymer (P1) with compound (1a-1). In this case, the reaction temperature is usually 4 ° C to 100 ° C, preferably room temperature to 45 ° C. The reaction time is preferably in the range of 4 hours to 5 days in total for all reactions.

(Process (2))
In the step (2) of the production method (1), the polymer (P2) is hydrolyzed under neutral or weakly acidic conditions, and the repeating units (I′-1) and (I′-2) of the polymer (P2) are obtained. ) Or a ketal structure is converted to a ketone.
Hydrolysis is not particularly limited as long as the acetal structure of the repeating units (I′-1) and (I′-2) of the polymer (P2) can be converted into an aldehyde or a ketal structure into a ketone. For example, (i) a method of treating with 0.1N hydrochloric acid for 30 to 90 minutes, (ii) a method of treating in the presence of acetone and indium (III) trifluoromethanesulfonate (catalyst), and (iii) in water at 30 ° C. A method using a catalytic amount of sodium tetrakis (3,5-trifluoromethylphenyl) borate, (iv) a method using 1-5 mol% Er (OTf) ₃ in wet nitromethane at room temperature, (v) almost in the middle Known methods such as a method using a catalytic amount of cerium (III) triflate in wet nitromethane at room temperature under neutral pH conditions.

<Polymer production method (2)>
The polymer production method of the present embodiment (hereinafter sometimes referred to as “production method (2)”) includes a polymer (P1) having a repeating unit (II ′) represented by the following general formula (II ′): A compound (1a-1) represented by the following general formula (1a-1) is reacted with a compound (1a-2) represented by the following general formula (1a-2) to give the following general formula (I ′ -1) a repeating unit (I′-1), a repeating unit (I′-2) represented by the following general formula (I′-2), and a polymer (P2) having the repeating unit (II ′) And at least one treatment selected from the group consisting of hydrolysis under alkaline conditions, transesterification, aminolysis, hydrolysis under alkaline conditions, and amide coupling. And the repeating unit (I′-1) A step (2a) of obtaining the polymer (P3) having the repeating unit (I′-2) and the repeating unit (II) represented by the following general formula (II), and the polymer (P3) under neutral conditions or Hydrolysis under mildly acidic conditions, repeating unit (I-1) represented by the following general formula (I-1), repeating unit (I-2) represented by the following general formula (I-2) and And (2b) obtaining a polymer having the repeating unit (II).

[Wherein, m represents 1 or 2. R ² represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Ra ¹¹ and Ra ¹² each independently represent a methyl group or an ethyl group, or Ra ¹¹ and Ra ¹² are bonded to each other to represent an ethylene group or a propylene group. Ra ¹³ and Ra ¹⁴ each independently represent a methyl group or an ethyl group, or Ra ¹³ and Ra ¹⁴ are bonded to each other to represent an ethylene group or a propylene group. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]

In the general formulas (I′-1), (I′-2), (II ′), (I-1), (I-2) and (II), m, L ¹¹ , L ¹² , X, R ^x , R ^x1 and R ^x2 are the same as m, L, X, R ^x , R ^x1 and R ^{x2 in the} general formulas (I) and (II).
In the general formulas (1a-1), (1a-2), (I′-1) and (I′-2), R ¹¹ , R ¹² , Ra ¹¹ , Ra ¹² , Ra ¹³ and Ra ¹⁴ are as described above. It is the same.

(Process (1))
Step (1) of production method (2) is the same as step (1) of production method (1).

(Process (2a))
In the step (2a) of the production method (2), the polymer (P2) is subjected to a predetermined treatment so that the repeating units (I′-1) and (I′-2) are protected with an acetal structure, A desired functional group can be introduced into the side chain of the repeating unit (II ′).
Hydrolysis under alkaline conditions is, for example, a method of treating in a mixture of 0.5N NaOH solution and DMSO (volume ratio: 50/50) at room temperature for 30 minutes, or treating with triethylamine in DMSO at room temperature for 1 hour. And a method of treating with diisopropylethylamine in DMSO for 1 hour at room temperature. Carboxylic acid residues obtained by hydrolysis under alkaline conditions attract protons in the core of micelles described later, facilitate hydrolysis of hydrazone bonds, and allow release of biomaterials under low pH conditions.
Aminolysis can introduce an amino functional group by cleaving the ester with, for example, ethylenediamine or diaminopropane. By introducing an amino group, it can be combined with a fluorescent dye. Moreover, it can also attach | subject to the diagnostic imaging agent which has another carboxylic acid group, and well-known amino coupling. Since the acetal structure and the ketal structure are stable under such amino group introduction conditions, the acetal structure and the ketal structure can be used for the polyfunctional nanocarrier design of the polymer.
For hydrolysis and amide coupling under alkaline conditions, for example, after the ester residue is treated by hydrolysis under alkaline conditions, the resulting carboxylic acid is subjected to transesterification or amide coupling using a known coupling agent. be able to. With appropriate structural motifs with hydroxy / amine functional groups, the hydrophilic / hydrophobic balance of the polymer can be made desirable, contributing to self-assembly in polar or non-polar solvents.

(Process (2b))
In step (2b) of production method (2), polymer (P3) is hydrolyzed under mildly acidic conditions, and the acetal structure of repeating units (I′-1) and (I′-2) of polymer (P3) is converted. Convert to aldehyde. Hydrolysis conditions are the same as in step (2) of production method (1).

<Drug complex>
The drug complex of the present embodiment contains the polymer and at least one drug bonded to the polymer.
The drug is not particularly limited, and a drug having a desired activity can be bound. In the present specification, the drug may be referred to as an “active molecule”. Here, the active molecule refers to a molecule having some physiological or chemical activity. The type of physiological activity or chemical activity possessed by the active molecule is not particularly limited, and the physiological activity possessed by a compound known as an active ingredient of a pharmaceutical or the chemical or physiological possessed by a diagnostic agent administered and used in the body May include activity. Examples of the drug (active molecule) include, but are not limited to, an anticancer agent, a signal transduction inhibitor, an antimetabolite, an analgesic, an anti-inflammatory agent, a contrast agent, and the like. Examples of anticancer agents include vinca alkaloids such as vinblastine, COX-2 selective non-steroidal anti-inflammatory agents such as OSU-03012, BET bromodomain inhibitors such as (+)-JQ1, and staurosporine analogues such as K252A And demethylating agents such as hydralazine, alkylating agents such as bendamustine and chlorambucil, fasinel transferase inhibitors such as AZD39, non-steroidal anti-inflammatory agents such as flurbiprofen, and the like. By using a drug complex with the polymer, side effects can be expected to be reduced even with drugs such as anticancer drugs whose dose is limited by side effects. Therefore, such a drug is a preferred example of a drug that is conjugated to the polymer. Examples of such drugs include vinca alkaloid compounds such as vinblastine.
Among these, as the drug, vinca alkaloids such as vinblastine, staurosporine analogs such as K252A, and BET bromodomain inhibitors such as (+)-JQ1 are preferable.

  When the polymer has a nitrogen atom-containing group capable of forming an aldehyde group and a Schiff base (hereinafter sometimes referred to as “Schiff base-forming group”), the drug and the drug are bonded. It can be carried out by reacting a group with an aldehyde group contained in the repeating unit (I) of the polymer. Examples of such a Schiff base include an amino group, an imino group, and a hydrazide group. Also. When the drug does not have a Schiff base forming group, the Schiff base forming group may be introduced into the drug. The introduction of the Schiff base forming group can be performed by a known method.

  For example, since vinblastine has no Schiff base-forming group, it can be bound to the polymer by introducing a hydrazide group into desacetylvinblastine hydrazide (DAVBNH). In addition, a Schiff base-forming group can be introduced by a similar method for staurosporine analogs such as K252A and BET bromodomain inhibitor (+)-JQ1.

  The drug conjugate of the present embodiment includes a repeating unit (IA-1) represented by the following general formula (IA-1), a repeating unit (IA-2) represented by the following general formula (IA-2), and the following A polymer having the repeating unit (II) represented by the general formula (II) is preferable.

[Wherein, m represents 1 or 2. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. BM represents an active molecule. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]

In the general formulas (IA-1), (IA-2) and (II), m, L ¹¹ , L ¹² , R ¹¹ , R ¹² , X, R ^x , R ^x1 and R ^x2 are represented by the general formula ( It is the same as m, L ¹¹ , L ¹² , R ¹¹ , R ¹² , X, R ^x , R ^x1 and R ^{x2 in} I-1), (I-2) and (II).
In the general formulas (IA-1) and (IA-2), BM represents an active molecule. Examples of the active molecule include the compounds exemplified in the drug.

According to the drug complex of this embodiment, various drugs can be carried on a polymer by being carried on a polymer. In the polymer, the amount of aldehyde group or ketone group to be introduced can be controlled, and the amount of drug bonded to the aldehyde group or ketone group can also be controlled. Therefore, the drug dosage can be controlled appropriately.
In the polymer, the aldehyde group or ketone group to be introduced can be selected from an aromatic aldehyde group, an aliphatic aldehyde group, an aromatic ketone group, and an aliphatic ketone group.
A Schiff base of an aromatic aldehyde group or an aromatic ketone group is more stable than a Schiff base of an aliphatic aldehyde group or an aliphatic ketone group, so that when an aromatic aldehyde group is introduced, the drug is held more stably. Is done. Therefore, the sustained release of the drug can be controlled by selecting the type of aldehyde group or ketone group to be introduced according to the disease state or the type of drug. Furthermore, in the drug conjugate of the present embodiment, since the drug is stably maintained and the toxicity is alleviated while the drug is held in the polymer, side effects can be reduced and the therapeutic effect can be enhanced.

The drug complex can be administered to a living body as it is, but may be formulated by appropriately mixing with other components by a known technique. Accordingly, the present invention also provides a pharmaceutical composition comprising the drug conjugate. When the drug complex is formulated, the dosage form is not particularly limited, and emulsions, emulsions, liquids, gels, capsules, ointments, patches, patches, granules, tablets, contrast agents, etc. It can be. The drug complex may be in the form of a micelle. The micelle containing the drug complex can be prepared by a known method. For example, the drug conjugate is dissolved or suspended in a lipophilic or hydrophilic solvent, and the solution or suspension is dropped into a hydrophilic or lipophilic solvent and stirred to contain the drug conjugate. Micelles can be prepared.
The pharmaceutical composition containing the drug conjugate may optionally contain other components of the drug conjugate. As other components, components generally used in the pharmaceutical field can be used without particular limitation. For example, the pharmaceutical composition may be obtained by dissolving or suspending the drug complex in a pharmaceutically acceptable carrier. As the pharmaceutically acceptable carrier, those commonly used in the pharmaceutical field can be used without particular limitation. For example, water, physiological saline, phosphate buffer, DMSO, dimethylacetamide, ethanol, glycerol, mineral An oil etc. can be mentioned. Other components include, in addition, solvents, solubilizers, suspending agents, tonicity agents, buffers, pH adjusting agents, excipients, stabilizers, antioxidants, osmotic pressure adjusting agents, Preservatives, colorants, fragrances and the like can be mentioned.

The administration route of the pharmaceutical composition is not particularly limited, and can be administered by an oral or parenteral route. The parenteral route includes all routes other than oral administration such as intravenous, intramuscular, subcutaneous, intranasal, intradermal, ophthalmic, intracerebral, intrarectal, intravaginal, intraperitoneal, etc. To do. Administration may be local administration or systemic administration.
The pharmaceutical composition can be administered in a single dose or in multiple doses, and the administration period and interval are the type of drug, the type and condition of the disease, the administration route, the age, weight and sex of the administration subject. It can be appropriately selected depending on the above.
The dosage of the pharmaceutical composition can be appropriately selected depending on the administration period and interval, the type of drug, the type and condition of the disease, the administration route, the age, weight and sex of the administration subject. The dosage of the pharmaceutical composition can be a therapeutically effective amount, for example, about 0.01 to 1000 mg per kg of body weight per time.

In addition, the drug conjugate of this embodiment exhibits pH sensitive drug release characteristics, particularly when in the form of micelles. In particular, considering the environment in vivo, drug release in the surrounding environment of acidified cancer (pH 6.6) and endosome (pH 5) after being taken into the cytoplasm is an aliphatic aldehyde group or an aliphatic ketone. Drug conjugates with introduced groups are excellent.
Therefore, when a highly toxic drug such as vinblastine is used, a drug complex into which an aromatic aldehyde group or an aromatic ketone group with a slow drug release at pH 5 to 6.6 is introduced is preferable. On the other hand, when a relatively low toxicity drug such as K252a or JQ-1 is used, a drug complex into which an aliphatic aldehyde group or an aliphatic ketone group with a fast drug release at pH 5 to 6.6 is introduced is preferable.
In the drug conjugate of this embodiment, an aromatic aldehyde group or an aromatic ketone group is introduced into the repeating unit (IA-1), and an aliphatic aldehyde group or an aliphatic ketone group is introduced into the repeating unit (IA-2). Has been introduced. Therefore, the drug conjugate of the present embodiment can alleviate drug toxicity and appropriately control the maximum tolerated dose (MTD).
Moreover, the drug complex of this embodiment can design the release profile of a drug with high precision and control the therapeutic efficacy by the combined use of the repeating unit (IA-1) and the repeating unit (IA-2).

  In addition, when the drug conjugate of the present embodiment is in the form of micelles, side effects can be reduced because the drug is stably maintained and toxicity is reduced while the drug is held in the polymer. Therefore, the micelle of the drug complex of this embodiment has a maximum tolerated dose (MTD) that is longer than that of the drug alone.

  The present invention will be described based on examples. However, the embodiment of the present invention is not limited to the description of these examples.

Synthesis Example 1 Synthesis of methoxy-poly (ethylene glycol) -b-poly (β-benzyl-aspartamide) α-methoxy-ω-amino β-initiated by the terminal primary amino group of poly (ethylene glycol) -Benzylaspartic acid By ring-opening polymerization of N-carboxaldehyde, methoxy-poly (ethylene glycol) -b-poly (β-benzyl-aspartamide) (MeO-PEG-PBLA; PEG molecular weight = 12 kDa; degree of polymerization of PBLA = 40 ) A copolymer was synthesized. The ω-amine group was blocked by acetylation to obtain a PEG-PBLA polymer.

Example 1 Synthesis of Polymer 1 PEG-PBLA polymer (300 mg) was dissolved in DMF (3 mL), and 3,3-dimethoxybutan-1-amine (120 μL) and {[4- (dimethoxymethyl) phenyl] methanamine } (60 μL) was added. The reaction was stirred at 40 ° C. for 48 hours, HCl solution (300 μL, 0.1N) was added and stirred for 1 hour.
Polymer 1 was recovered by dialyzing against water and freeze-drying the polymer.
The reaction scheme is shown in FIG. Also, Figure 2 shows the ¹ H-NMR analysis results of the resulting polymer 1. It was confirmed that 31 aliphatic ketone units and 4 aromatic aldehyde units were introduced into polymer 1.

[Example 2] Synthesis of polymer 2 PEG-PBLA polymer (100 mg) was dissolved in DMF (1 mL), and 3,3-dimethoxybutan-1-amine (75 μL) and {[4- (dimethoxymethyl) phenyl] methanamine were dissolved. } (25 μL) was added. The reaction was stirred at 40 ° C. for 48 hours, HCl solution (100 μL, 0.1N) was added and stirred for 1 hour.
Polymer 1 was recovered by dialyzing against water and freeze-drying the polymer.
The reaction scheme is shown in FIG. Moreover, the ¹ H-NMR analysis result of the obtained polymer 1 is shown in FIG. It was confirmed that 31 aliphatic ketone units and 6 aromatic aldehyde units were introduced into polymer 1.

[Example 3] Synthesis of polymer 3 PEG-PBLA polymer (100 mg) was dissolved in DMF (1 mL), and 3,3-dimethoxybutan-1-amine (50 μL) and {[4- (dimethoxymethyl) phenyl] methanamine were dissolved. } (50 μL) was added. The reaction was stirred at 40 ° C. for 40 hours, HCl solution (100 μL, 0.1 N) was added and stirred for 1 hour.
Polymer 1 was recovered by dialyzing against water and freeze-drying the polymer.
The reaction scheme is shown in FIG. Also, Figure 4 shows the ¹ H-NMR analysis results of the resulting polymer 1. It was confirmed that 21 aliphatic ketone units and 9 aromatic aldehyde units were introduced into polymer 1.

Example 4 Synthesis of Polymer 4 PEG-PBLA polymer (100 mg) was dissolved in DMF (3 mL), and 3,3-dimethoxybutan-1-amine (50 μL) was added. The reaction was stirred at 40 ° C. for 16 hours and {[4- (dimethoxymethyl) phenyl] methanamine} (50 μL) was added. The reaction was stirred at 40 ° C. for 24 hours, HCl solution (100 μL, 0.1 N) was added and stirred for 1 hour.
Polymer 1 was recovered by dialyzing against water and freeze-drying the polymer.
The reaction scheme is shown in FIG. Moreover, the ¹ H-NMR analysis result of the obtained polymer 1 is shown in FIG. It was confirmed that 9 aliphatic ketone units and 19 aromatic aldehyde units were introduced into polymer 1.

Reference Example 1 Synthesis of Reference Polymer 1 PEG-PBLA polymer (220 mg, 0.011 mmol) was dissolved in DMF (2 mL), and {[4- (dimethoxymethyl) phenyl] methanamine} (100 μL, 0.58 mmol) was dissolved. Added. The reaction was stirred at 40 ° C. for 4 days, HCl solution (0.1 N 100 μL) was added and stirred for 30 minutes.
The reference polymer 1 was recovered by dialysis with water and freeze-drying the polymer.

Reference Example 2 Synthesis of Reference Polymer 2 PEG-PBLA polymer (318 mg, 0.016 mmol) was dissolved in DMF (3 mL), and 3,3-dimethoxybutane (200 μL) was added to the resulting solution. The reaction was stirred at 40 ° C. for 72 hours, HCl solution (100 μL, 0.1 N) was added and stirred for 1 hour. The reference polymer 2 was recovered by dialysis with water and freeze-drying the polymer.

[Example 5] Preparation of drug conjugate 1 15 mg of a polymer mixture obtained by mixing a compound having a hydrazide group introduced into vinblastine (DAVBNH: manufactured by DSK BioPharmacia, the same shall apply hereinafter) and polymer 1 in a ratio of 2: 1. Was dissolved in DMSO (1 mL). The reaction mixture was stirred at 40 ° C. for 3 days. Thereafter, the reaction mixture was dialyzed to exchange the solvent with dimethylacetamide (DMAc). This solvent exchange produced a clear DMAc solution.
The obtained DMAc solution was added dropwise to water with stirring at a ratio of 1 to 10 water by volume to prepare micelles. This solution was dialyzed against water to remove the organic solvent. The resulting solution was concentrated by ultrafiltration using a 100 kDa MWCO filter membrane to obtain Drug Complex 1.

[Example 6] Preparation of drug conjugate 2 Drug conjugate 2 was obtained in the same manner as in Example 5 except that polymer 2 was used instead of polymer 1.

[Example 7] Preparation of drug conjugate 3 Drug conjugate 3 was obtained in the same manner as in Example 5 except that polymer 3 was used instead of polymer 1.

[Example 8] Preparation of drug conjugate 4 Drug conjugate 4 was obtained in the same manner as in Example 5 except that polymer 4 was used instead of polymer 1.

[Reference Example 3] Preparation of Reference Drug Complex 1 Reference drug complex 1 was obtained in the same manner as in Example 5 except that Reference Polymer 1 was used instead of Polymer 1.

[Reference Example 4] Preparation of Reference Drug Complex 2 Reference drug complex 2 was obtained in the same manner as in Example 5 except that Reference Polymer 2 was used instead of Polymer 1.

<Measurement of micelle size and PDI>
For drug conjugates 1-4, micelle size and polydispersity index (PDI) were determined by dynamic light scattering (DLS) techniques.
The measurement was performed using a green laser (532 nm) as an incident beam and a Zetasizer nano ZS (Malvern instruments, UK) at a detection angle of 173 ° and a temperature condition of 25 ° C. The result of the micelle size of the drug conjugates 1 to 4 is shown in FIGS. In addition, description of each index in FIGS.

  As shown in the results of FIGS. 6 to 9, the repeating unit (I-1) (aromatic aldehyde group / aromatic ketone group introduction unit) and the repeating unit (I-2) (aliphatic aldehyde group / aliphatic ketone group). It was confirmed that the micelle size can be adjusted by adjusting the content ratio with the introduction unit).

<Evaluation of pH sensitive release>
Reference drug complex 1 of Reference Example 3, Reference drug complex 2 of Reference Example 4 and Drug complex 1 of Example 5 were each diluted with 975 μL of phosphate buffer at different pH and cultured at 37 ° C. for 48 hours. Drug release from the drug complex at a given time was measured by reverse phase chromatography (RPLC). The conditions for HPLC analysis are as follows.
HPLC (Tosoh TSKgel ODS-80Tm C18 column 4.6 × 150 mm)
Solvent: 1: 1 mixture of 20 mM phosphate buffer (pH 2.5) and methanol Uniform solvent flow rate: 0.6 mL / min UV detection: wavelength 220 nm

The results of evaluation of pH sensitive release are shown in FIGS. FIG. 10 is a graph showing the pH sensitive drug release profile of Reference Drug Complex 1. FIG. 11 is a graph showing the pH sensitive drug release profile of Reference Drug Complex 2. FIG. 12 is a graph showing the pH sensitive drug release profile of Drug Complex 1.
From the results shown in FIG. 10, it can be confirmed that the reference drug complex 1 into which only the aromatic aldehyde group is introduced has a slow drug release at pH 5 or higher.
From the results shown in FIG. 11, it is confirmed that the reference drug complex 2 into which only the aliphatic ketone group is introduced is excellent in drug release at pH 5 or higher. Considering the environment in vivo, drug release in the environment surrounding acidified cancer (pH 6.6) and endosome (pH 5) after being taken into the cytoplasm is important.
From the results shown in FIG. 12, it was confirmed that the drug complex 1 of Example 5 to which the present invention was applied released a pH sensitive drug. Moreover, it is confirmed that the drug complex 1 is excellent in drug release at pH 5 or higher.
From the above results, the repeating unit (I-1) (aromatic aldehyde group / aromatic ketone group introduction unit) and the repeating unit (I-2) (aliphatic aldehyde group / aliphatic ketone group introduction unit) are used in combination. Thus, it was confirmed that the pH sensitive drug release profile can be adjusted.

<Evaluation of Maximum Tolerated Dose (MTD) of Drug Complex>
The drug was administered to mice (BALB / c Nude, female, 6 weeks old) 4 times every 4 days (0 days, 3 days, 6 days, 9 days) and the maximum tolerated dose (MTD) was evaluated. The administration groups were as follows, and the number of individuals in each group was 3. The results are shown in FIG.
Administration group 1: Drug complex 1 (Example 5) 8 mg / kg
Administration group 2: Drug complex 2 (Example 6) 8 mg / kg
Administration group 3: Drug complex 3 (Example 7) 8 mg / kg

  As shown in FIG. 13, repeating unit (I-1) (aromatic aldehyde group / aromatic ketone group introduction unit) and repeating unit (I-2) (aliphatic aldehyde group / aliphatic ketone group introduction unit) It was confirmed that the maximum tolerated dose (MTD) can be adjusted by adjusting the ratio of. In particular, it was confirmed that the toxicity of the drug conjugate can be suppressed by increasing the content ratio of the repeating unit (I-1).

<Cytotoxicity test of drug conjugate against brain tumor cells>
The in vitro cytotoxicity of vinblastine sulfate, reference drug conjugate 1, reference drug conjugate 2 and drug conjugate 1 was evaluated against U87MG and U3731 using cell-counting kit-8.
U87MG or U3731 cells (3000 cells / well) were cultured in DMEM medium containing 10% FBS using 96-well plates. Thereafter, U87MG cells or U3731 cells were exposed to different doses of vinblastine sulfate or drug conjugates. Cell viability at 48 and 72 hours after exposure was determined by measuring the formazan absorbance at 450 nm, 450 nm. The results are shown in Table 2.

[Evaluation of orthotopic model of brain tumor]
U87MG-Luc2 (1.0 × 10 5 cells in 2 μL) was transplanted intracranial 1.0 mm anterior and 2.0 mm of bregma, and 3.0 mm deep on the brain surface of Balb / c nude mice. Transplanted.
Tumors were allowed to grow for 6 days and anti-tumor activity assays were initiated in 5 groups of BALB / c nude mice (n = 9).
The administration groups were as follows.
Administration group 1: PBS as control
Administration group 2: DAVBNH 2 mg / kg (MTD)
Administration group 3: Reference drug complex 1 (Reference example 3) 16 mg / kg (safety tolerance dose)
Administration group 4: Reference drug complex 2 (Reference example 4) 2 mg / kg
Administration group 5: Drug complex 1 (Example 5) 4 mg / kg
The treatment schedule was as follows.
First phase: set to 4 injections at 2 day intervals (0, 3, 6, and 9 days).
Second phase: injection once a week until the mouse dies.
In vivo imaging was performed using IVIS spectra (Xenogen Corporation), and D-luciferin potassium salt solution was used as a substrate for luciferase.
In addition, for the administration groups 1 to 5, MRI was taken on the 28th day after the start of treatment. For administration groups 4 and 5, MRI on the 50th day after the start of treatment was also taken. BioSpec1T (manufactured by Bruker) was used for MRI imaging.

14 and 15 are graphs showing tumor growth curves in each administration group in the evaluation of the brain tumor orthotopic model.
FIG. 16 is a graph showing the time course of survival rate in the evaluation of the brain tumor orthotopic model.
From the results shown in FIGS. 14 to 16, it was confirmed that the drug complex 1 of Example 5 significantly reduced the brain tumor by tail vein injection and significantly prolonged the survival in the brain tumor orthotopic transplantation model. In particular, in the administration group 5 using the drug complex 1, it was confirmed that about 80% of the mice survived even after 70 days from the start of treatment.

FIG. 17 is an MRI image of the brain of a mouse on the 28th day after the start of treatment in each administration group for evaluation of a brain tumor orthotopic model.
As shown in FIG. 17, in the administration group 1 (PBS as a control), it was confirmed that most mice had a large tumor (white portion of the MRI image).
In administration group 2 (DAVBNH), it was confirmed that about 50% of mice had large tumors.
In administration group 3 (reference drug complex 1, reference example 3), it was confirmed that about 20% of mice had large tumors.
In administration group 4 (reference drug conjugate 2, reference example 4) and administration group 5 (drug conjugate 1, example 5), it was confirmed that the brain tumors of all mice were reduced.

FIG. 18 is an MRI image of the brain of a mouse 50 days after the start of treatment in administration groups 4 and 5 for evaluation of an orthotopic brain tumor model.
In administration group 1 (PBS as a control), most mice died 50 days after the start of treatment. In addition, in the administration group 2 (DAVBNH) and the administration group 3 (reference drug complex 1, reference example 3), only a few mice survived on the 50th day after the start of treatment.
In administration group 4 (reference drug complex 2, reference example 4), about 90% of mice survived on the 50th day after the start of treatment, but it was confirmed that most mice had large tumors. .
On the other hand, in the administration group 5 (drug complex 1, Example 5), it was confirmed that all mice survived on the 50th day after the start of treatment, and only about 20% of mice had large tumors. It was.

Claims (6)

Repeating unit (I-1) represented by the following general formula (I-1),
The repeating unit (I-2) represented by the following general formula (I-2), and the repeating unit (II) represented by the following general formula (II)
A polymer characterized by having
[Wherein, m represents 1 or 2. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ] The polymer (P1) having a repeating unit (II ′) represented by the following general formula (II ′), the compound (1a-1) represented by the following general formula (1a-1), and the following general formula (1a) -2) is reacted with the compound (1a-2) represented by the following general formula (I'-1), the repeating unit (I'-1) represented by the following general formula (I'-2) A step (1) of obtaining a polymer (P2) having a repeating unit (I′-2) represented by formula (I) and the repeating unit (II ′);
The polymer (P2) is hydrolyzed under neutral or weakly acidic conditions, and the repeating unit (I-1) represented by the following general formula (I-1) or the following general formula (I-2) A step (2) of obtaining a polymer having a repeating unit (I-2) represented by formula (II-1) and a repeating unit (II-1) represented by the following general formula (II-1):
A process for producing a polymer, comprising:
[Wherein, m represents 1 or 2. R ² represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Ra ¹¹ and Ra ¹² each independently represent a methyl group or an ethyl group, or Ra ¹¹ and Ra ¹² are bonded to each other to represent an ethylene group or a propylene group. Ra ¹³ and Ra ¹⁴ each independently represent a methyl group or an ethyl group, or Ra ¹³ and Ra ¹⁴ are bonded to each other to represent an ethylene group or a propylene group. R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ] The polymer (P1) having a repeating unit (II ′) represented by the following general formula (II ′), the compound (1a-1) represented by the following general formula (1a-1), and the following general formula (1a) -2) is reacted with the compound (1a-2) represented by the following general formula (I'-1), the repeating unit (I'-1) represented by the following general formula (I'-2) A step (1) of obtaining a polymer (P2) having a repeating unit (I′-2) represented by formula (I) and the repeating unit (II ′);
The polymer (P2) is subjected to at least one treatment selected from the group consisting of hydrolysis under alkaline conditions, transesterification, aminolysis, and hydrolysis under alkaline conditions and amide coupling. '-1), a step (2a) for obtaining a polymer (P3) having the repeating unit (I'-2) and the repeating unit (II) represented by the following general formula (II):
The polymer (P3) is hydrolyzed under neutral or weakly acidic conditions, and the repeating unit (I-1) represented by the following general formula (I-1) or the following general formula (I-2) A step (2b) of obtaining a polymer having the repeating unit (I-2) represented above and the repeating unit (II);
A process for producing a polymer comprising
[Wherein, m represents 1 or 2. R ² represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Ra ¹¹ and Ra ¹² each independently represent a methyl group or an ethyl group, or Ra ¹¹ and Ra ¹² are bonded to each other to represent an ethylene group or a propylene group. Ra ¹³ and Ra ¹⁴ each independently represent a methyl group or an ethyl group, or Ra ¹³ and Ra ¹⁴ are bonded to each other to represent an ethylene group or a propylene group. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ] A drug complex comprising the polymer according to claim 1 and at least one drug bound to the polymer. A repeating unit (IA-1) represented by the following general formula (IA-1);
The repeating unit (IA-2) represented by the following general formula (IA-2), and the repeating unit (II) represented by the following general formula (II)
The drug conjugate according to claim 4, comprising a polymer having
[Wherein, m represents 1 or 2. L ¹¹ represents a divalent aromatic hydrocarbon group. L ¹² represents a divalent aliphatic hydrocarbon group. R ¹¹ and R ¹² each independently represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. BM represents an active molecule. X represents OR ^x , SR ^x or NR ^x1 R ^x2 . R ^x represents a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. R ^x1 and R ^x2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ]   A micelle containing the drug complex according to claim 5.