JP3270592B2 - Block copolymer-anticancer drug complex pharmaceutical preparation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block copolymer-anticancer drug complex pharmaceutical preparation.

[0002]

2. Description of the Related Art Techniques for increasing the solubility of a poorly water-soluble anticancer drug with a surfactant-like substance are known, but they could not be expected to enhance the pharmacological effect.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polymer / anticancer drug composite pharmaceutical preparation which enhances the solubility of a poorly water-soluble anticancer drug and has a high pharmacological effect which cannot be obtained by the anticancer drug. is there.

[0004]

Means for Solving the Problems The present inventors have intensively studied to solve the drawbacks of the conventional hydrophobic anticancer drugs.
As a result, the specific block copolymer-anticancer agent complex,
The present inventors have found that not only the anticancer agent can be made water-soluble but also its pharmacological effect can be dramatically improved, and the present invention has been completed.

That is, the present invention relates to (1) a method in which a carboxyl group which is a side chain of a polymer carboxylic acid moiety of a block copolymer having a hydrophilic polymer structural moiety and a polymer carboxylic acid moiety has a hydrophobic property other than an anticancer agent. A polymer block copolymer having a hydrophilic polymer structure portion obtained by binding a compound and a hydrophobic polymer structure portion to which an anticancer agent is not bound is a micelle having the hydrophilic polymer structure portion as an outer core A block copolymer-anticancer agent complex pharmaceutical preparation comprising a hydrophobic inner core and a water-insoluble anticancer agent, (2) a hydrophilic polymer structural part having a polyethylene glycol structure, (1) the pharmaceutical preparation of the block copolymer-anticancer agent complex according to the above (1), (3) the hydrophobic polymer structural part is a polyamino acid or a salt structure thereof, and the side chain part is aliphatic and / or aromatic. The block copolymer-anticancer agent complex pharmaceutical preparation according to the above (1) or (2), which has a residue, (4) the above (1), (2) or (3), wherein the anticancer agent is an anthracycline anticancer agent (5) The pharmaceutical preparation of a block copolymer-anticancer agent composite according to the above (1), (2) or (3), wherein the anticancer agent is adriamycin, and (6) micelle formation. The functional polymer block copolymer has the following formula (1):
(2) or the above (1) having the structure of a salt thereof,
(4) or (5) the block copolymer-anticancer agent complex pharmaceutical preparation;

[0006]

Embedded image

(Wherein, R ₁ represents a lower alkyl group or hydrogen, R ₂ represents a bonding group, R ₃ represents a methylene group or an ethylene group, Y represents hydrogen or a protecting group, and R represents each independently Represents a hydroxyl group or an aliphatic or aromatic substituent, at least one of Rs represents the substituent, and n represents 5
１，1000, m indicates an integer of 2 to 300, and x indicates an integer of 0 to 300, where x is not larger than m. ) (7) Y is -COR ₄ (R ₄ is a methyl group, the above-described block copolymer (6) which is a lower alkyl group or an aromatic hydrocarbon group such as a phenyl group such as an ethyl group) -
An anticancer drug complex pharmaceutical preparation.

[0008] The pharmaceutical preparation of the present invention is a water-soluble preparation having a high pharmacological effect.

Hereinafter, the present invention will be described in detail.

The structure of the hydrophilic polymer structural portion in the present invention includes, for example, structures of polyethylene glycol, polysaccharide, polyacrylamide, polymethacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, chitosan and the like. There is no particular limitation as long as it has a structure. A particularly preferred structure is a polyethylene glycol structure.

Examples of the hydrophobic polymer structural part include aromatic amines and fatty acids on the side chains of high molecular carboxylic acids such as polyamino acids (polyaspartic acid, polyglutamic acid, etc.), polyacrylic acid, polymethacrylic acid, polymaleic acid and the like. A structure in which residues of a hydrophobic compound such as an aromatic amine, an aromatic alcohol, an aliphatic alcohol, an aromatic thiol, or an aliphatic thiol are bonded, or a salt thereof (eg, an alkali metal salt such as a sodium salt or a potassium salt). . Examples of the hydrophobic compound to be bonded to the side chain (carboxyl group) of the high molecular carboxylic acid include aromatic amines such as aniline, aliphatic amines such as propylamine and stearylamine, aromatic alcohols such as naphthol, lauryl alcohol, and benzyl. Aliphatic alcohols such as alcohols, aromatic thiols such as benzenethiol, and aliphatic thiols such as ethanethiol and phenylmethanethiol, but are not limited thereto. If the part can be made hydrophobic,
Either can be used. These are bonded to the side chain (carboxyl group) of the high molecular carboxylic acid moiety by an ester bond, an amide bond or the like.

The molecular weight of the polymer block copolymer is not particularly limited as long as it is water-soluble.
00 to 100,000, particularly preferably 5000 to 500
00. The ratio of the hydrophilic polymer structural portion to the hydrophobic polymer structural portion in the polymer block copolymer is not particularly limited as long as the water solubility of the pharmaceutical preparation of the present invention is maintained, but is preferably 1: 0.1. To 10 (weight ratio), particularly preferably 1: 0.2 to 5 (weight ratio).

In the above formula (1) or (2), R ₁ represents a lower alkyl group or hydrogen, and a preferable one is a methyl group. Further, R ₂ is not particularly limited and is not necessarily required as long as the water solubility of the block copolymer-anticancer agent composite is not impaired. A methylene group (-CH ₂ -), ethylene group (-CH ₂ CH ₂ -), propylene (-CH
(CH ₃ ) CH ₂ —), trimethylene group (—CH ₂ CH)
₂ CH ₂ —), butylene group (—CH ₂ CH (CH ₃ ) C
Examples thereof include an alkylene group having 1 to 8 carbon atoms, preferably 2 to 4 carbon atoms, such as H _2- ).

Further, n is 5 to 1,000, preferably 15 to 400, m is 2 to 300, preferably 10 to 100, and x is 0 to 300. Preferably it is 0-100.

The anticancer agents to be contained in the hydrophobic core of micelles of the polymer block copolymer include adriamycin, daunomycin, pinorbin, methotrexate,
Examples include, but are not limited to, mitomycin C, etoposide, cisplatin, and derivatives thereof.

The content of the anticancer agent in the block copolymer-anticancer agent conjugate is preferably from 1 to the amount of the block copolymer.
The content is 200% by weight, particularly preferably 2 to 60% by weight. However, as long as the micelle forming ability of the block copolymer-anticancer agent complex is not impaired, there is no problem in containing as much as possible.

The pharmaceutical preparation of the present invention can be produced, for example, as follows.

That is, a compound (for example, polyethylene glycol, polysaccharide, polyacrylamide, polymethacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, chitosan or a derivative thereof) or a terminal thereof which constitutes a hydrophilic polymer structural portion is used. The modified compound is reacted with a polymer compound having a carboxyl group or a carboxyl group protected by a protecting group,
After that, those containing a protecting group are obtained by removing the protecting group, or reacting a compound that constitutes a hydrophilic polymer structural portion or a modified terminal thereof with a monomer of a polymerizable carboxylic acid or a derivative thereof, For those containing a protective group, by removing the protective group, a block copolymer having a hydrophilic polymer structure portion and a polymer carboxylic acid portion is obtained, and a hydrophobic compound is reacted with the block copolymer to obtain a micelle-forming product. It can be obtained by adding an anticancer agent which is hardly soluble in water to the hydrophobic inner core of the polymer block copolymer.

Modification of the terminal of the compound constituting the hydrophilic polymer structural portion can be carried out by a known method. For example, as a method of converting a hydroxyl group to an amino group, a method of reacting ethyleneimine, a method of acrylonitrile After adding Michael or methacrylonitrile, reducing the nitrile group to an amino group, replacing the hydroxyl group with a halogen group, and then reacting with an alcoholamine such as ethanolamine, or directly converting the hydroxyl group to a nitrile group , And a method of converting to an amino group. Further, as a method for converting a hydroxyl group into a carboxyl group, a usual oxidation reaction, condensation reaction, addition reaction, hydrolysis reaction, a reaction combining these, or the like can be adopted. For example, a hydroxyl group can be converted to a carboxyl group by alcoholating a hydroxyl group with metallic sodium, adding a halogenated fatty acid ester such as ethyl bromoacetate, and then hydrolyzing.

The method for removing the protecting group can be a method using an alkali, a method using an acid, or a reduction method. As the alkaline substance used in the alkaline method, ordinary alkaline substances such as sodium hydroxide, sodium hydroxide, hydrazine, and ammonia can be used. As the acidic substance used in the acid method, it is possible to use ordinary acidic substances such as trifluoromethanesulfonic acid, methanesulfonic acid, trifluoroacetic acid, acetic acid, formic acid, hydrofluoric acid, hydrobromic acid, and hydrochloric acid. . In order to prevent a side reaction, anisole, thioanisole, m-cresol, o-cresol and the like can be added. As the reduction method, a general method such as a catalytic reduction method or a catalytic hydrogen transfer reduction method can be used.

When the polymer structural portion (polymer carboxylic acid portion) to which the hydrophobic compound is bound is a polyamino acid structure having an amino group at the terminal, the terminal amino group is modified and reacted with the hydrophobic compound. It can also be done.
Examples of the modification method include a known method using an acid anhydride such as acetic anhydride or an acid halide such as acetyl chloride. Modifications can be made either before or after removal of the protecting group.

A micelle-forming polymer block copolymer can be obtained by reacting a hydrophobic compound with the thus obtained block copolymer having a hydrophilic polymer structure portion and a polymer carboxylic acid portion. The hydrophobic compound binds to the block copolymer by forming an ester bond, an amide bond, or the like. These reactions can be performed according to a known method such as known esterification or amidation. For example, when a hydrophobic compound is bonded to a block copolymer (raw material copolymer) having a hydrophilic polymer structure portion and a polymer carboxylic acid portion by an amide bond, the reaction is carried out in a conventional manner known as a peptide bond formation method. It can be performed according to it. For example, an acid halide method, an acid anhydride method, a coupling method and the like can be used, but a coupling method using a condensing agent is preferable. Examples of the condensing agent include 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC),
-Ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride (EDC.HCl), dicyclohexylcarbodiimide (DCC), carbonyldiimidazole (CDI), 1-ethoxycarbonyl-2-ethoxy-
1,2-dihydroxyquinoline (EEDQ), diphenylphosphoryl azide (DPPA) and the like can be used. The condensing agent is preferably used in a molar amount of 0.5 to 20 times, more preferably 1 to 10 times the molar amount of the hydrophobic compound. At this time, N-hydroxysuccinimide (HO
NSu), 1-hydroxybenzotriazole (HOB)
t), N-hydroxy-5-norbornene-2,3-dicarboxylic acid imide (HONB) and the like may coexist.

The amount of the hydrophobic compound to be used is not particularly limited, but it is usually 1 equivalent of the carboxyl group of the raw material copolymer.
0.1 to 2 mol is used.

The condensation reaction is preferably performed in a solvent. Examples of the solvent include N, N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), dioxane, tetrahydrofuran (THF), water, and a mixed solvent thereof. Various types can be used and are not particularly limited. Although the amount of the solvent used is not particularly limited, it is usually used in an amount of 1 to 500 times the weight of the raw material copolymer.

The condensation reaction is preferably carried out at -10 to 40 ° C, particularly preferably at -5 to 30 ° C. It is sufficient to carry out the reaction for 2 to 48 hours.

For example, in the micelle-forming polymer block copolymer thus obtained, the hydrophobic compound preferably reacts with and binds to 1% or more of the total carboxyl groups of the starting copolymer. In particular, it is preferable to react with and bind to 5% or more of carboxyl groups.

To the polymer block copolymer thus obtained, an anticancer agent which is sparingly soluble in water is added, followed by appropriate treatment to obtain the pharmaceutical preparation of the present invention (block copolymer-anticancer agent complex). ) Is obtained.

As a treatment method, a method in which an anticancer agent or a solution thereof is added to a condensation reaction solution is dialyzed and ultrafiltered to obtain an aqueous solution. Alternatively, the condensation reaction solution may be precipitated with a poor solvent such as isopropyl ether (IPE) and then dissolved in an appropriate solvent, and the anticancer agent or a solution thereof may be added, followed by dialysis and ultrafiltration. Alternatively, after the dialysis and ultrafiltration of the condensation reaction solution, an anticancer agent or a solution thereof may be added, and the dialysis and ultrafiltration may be performed again. As the solvent used when mixing the polymer block copolymer and the anticancer agent, a solvent that dissolves both the polymer block copolymer and the anticancer agent is preferable, and those in which the polymer block copolymer does not form micelles are more preferable. preferable. For example, a mixed solvent of DMF and water is exemplified. Further, when mixing the polymer block copolymer and the anticancer agent, treatment such as ultrasonic irradiation may be performed.

The following is an example of a hydrophilic polymer structural portion derived from a polyethylene glycol derivative and a block copolymer in which an aliphatic amine is bonded to the side chain of polyaspartic acid in which the terminal amino group has been modified with an acetyl group. The synthesis method will be described in detail.

The synthesis of this block copolymer was carried out as shown in the following reaction formula: β-benzyl-L-aspartate-
N-carboxylic anhydride (BLA-NCA) is prepared by using polyethylene glycol (PE) having an alkoxy group such as a methoxy group at one end and a 3-aminopropyl group at the other end.
G-NH ₂₎ (preferably molecular weight 250～20,00
0) as an initiator, ring-opening polymerization in a solvent such as dimethylformamide, dimethylsulfoxide, dioxane, chloroform, tetrahydrofuran, acetonitrile,
Polyethylene glycol-poly (β-benzyl-L-aspartate) block copolymer (PEG-PBLA)
Then, acetic anhydride and a tertiary amine such as triethylamine are added to the polymerization solution to modify the terminal amino group with an acetyl group, thereby obtaining a polyethylene glycol-poly (β-benzyl-L-aspartate) block copolymer N -An acetylated product (PEG-PBLA-Ac) is obtained. This PEG
-Polyethylene glycol-polyaspartic acid block copolymer N-acetylated product (PEG-P (Asp.)-A
Obtain c).

The modification of the terminal amino group is PEG-PB
LA is obtained and then the benzyl ester is hydrolyzed to give PE
After obtaining GP (Asp.), PEG-P (Asp.)-Ac was obtained by adding acetic anhydride and a tertiary amine such as triethylamine to modify the terminal amino group with an acetyl group.
You can also get

[0032]

Embedded image

Thereafter, amines are reacted with the side chain of the polyaspartic acid after hydrolysis to obtain a micelle-forming polymer block copolymer. Aliphatic amines condensed on the side chain of polyaspartic acid include aliphatic alkylamines such as methylamine, alicyclic amines such as cyclohexylamine, unsaturated amines, and aromatic rings such as benzylamine. And the like. However, there is no particular limitation as long as the structure allows the hydrophobic anticancer agent to be sufficiently retained. Particularly preferred is an aliphatic amine having an aromatic ring such as a benzene ring, a naphthalene ring, a benzoquinone ring, and a naphthoquinone ring, and there is no problem in having a substituent other than the substituent capable of bonding to the side chain of polyaspartic acid. .

Thereafter, the polymer block copolymer is mixed with an anticancer agent under a solvent condition in which micelles are not formed. After the mixing, the polymer block copolymer is formed into micelles, and the anticancer agent not contained in the inner core is removed.

The pharmacological activity of the block copolymer-anticancer drug complex pharmaceutical preparation of the present invention is high.
As shown in the figure, it is epoch-makingly high although there is not much difference in dosage from the original adriamycin.

The pharmaceutical preparation of the present invention can be used in various dosage forms generally used, for example, in the form of solid preparations, ointments, liquid preparations and the like. The total amount is about 10 to ²⁰⁰ mg / m ² week after 1 to 3 administrations.

[0037]

Next, the present invention will be described in detail with reference to examples.

Example 1 5.7 g of β-benzyl-L-aspartate-N-carboxylic anhydride (BLA-NCA) are dissolved in 60 mL of N, N′-dimethylformamide (DMF). _3. methoxy group at one terminal polyethylene glycol (PEG-NH ₂ ) having a 3-aminopropyl group at one terminal (molecular weight: 5,100)
0 g was dissolved in DMF (40 mL), and the solution was added to BLA-N.
Add to CA solution. While maintaining the mixed solution at 35 ° C, 40
Polymerized for hours. After confirming that the polymerization reaction was completed by HPLC analysis, 50 mL of acetic anhydride and 2.5 g of pyridine were used.
And react at room temperature for 2 hours. The reaction mixture was added dropwise to 2 L of isopropyl ether (IPE), and the precipitated polymer was collected by suction filtration, washed with IPE, dried in vacuo, and then dried in polyethylene glycol-poly (β-benzyl-).
L-aspartate) block copolymer N-acetylated product (PEG-PBLA-Ac) 8.03 g (yield 99.
4%).

PEG-PBLA-Ac 7.0 g was added to 0.5
The benzyl ester is hydrolyzed at room temperature while suspended in N sodium hydroxide. After the copolymer is dissolved, the pH is acidified with acetic acid and dialyzed in water using a dialysis membrane (fraction molecular weight: 1,000). The solution in the membrane is freeze-dried and polyethylene glycol-polyaspartic acid block copolymer N-acetylated product (PEG-P (Asp.)-Ac)
4.44 g (79% yield) were obtained.

195 mg of PEG-P (Asp.)-Ac
Is dissolved in 0.5 mL of water. A solution prepared by dissolving 25 mg of cyclohexylamine in 5 mL of DMF is added thereto.
To this, 72 μL of EDC and 27 mg of N-hydroxysuccinimide (HONSu) are added and reacted at room temperature for 24 hours. The reaction mixture was added dropwise to 0.2 L of IPE to collect the precipitated polymer, which was washed with IPE and dried under vacuum to obtain 220 mg of a micelle-forming polymer block copolymer.

Micelle-forming high molecular block copolymer 16
0 mg was dissolved in 8 mL of DMF and 2 mL of water, and 160 mg of adriamycin hydrochloride and 40 μL of triethylamine were dissolved.
And mix for 2 hours at room temperature. The mixture is dialyzed overnight using a dialysis membrane (fraction molecular weight = 1,000) in a 0.1 M sodium acetate buffer (pH 4.5) over one night. After dialysis, ADVANTEC UK-10 (fraction molecular weight = 1)
(000) to remove adriamycin and other low molecular substances not contained in the inner core of the micelle-forming polymer block copolymer. The amount of adriamycin contained in the obtained micelle-forming polymer block copolymer-anticancer agent complex was 30 mg, which was 18.8% of the charged amount (by HPLC measurement).

Example 2 PEG-P (Asp.)-Ac390m obtained in Example 1
g in 1 mL of water. There stearylamine 1
Add 08 mg dissolved in 10 mL DMF. To this, 144 μL of EDC and 55 mg of HONSu are added and reacted at room temperature for 24 hours. 0.5 L of IPE
The precipitated polymer was recovered by dropping into a polymer, washed with IPE, and then dried in vacuum to form a micelle-forming polymer block copolymer 4.
27 mg are obtained.

Micelle-forming polymer block copolymer 16
0 mg was dissolved in 8 mL of DMF and 2 mL of water, and 160 mg of adriamycin hydrochloride and 40 μL of triethylamine were dissolved.
And mix for 2 hours at room temperature. The mixture is dialyzed overnight using a dialysis membrane (fraction molecular weight = 1,000) in a 0.1 M sodium acetate buffer (pH 4.5) over one night. After dialysis, ADVANTEC UK-10 (fraction molecular weight = 1)
(000) to remove adriamycin and other low molecular substances which are not contained in the micelle-forming polymer block copolymer. The amount of adriamycin contained in the obtained micelle-forming polymer block copolymer-anticancer agent complex was 51 mg, which was 32.0% of the charged amount (by HPLC measurement).

Application Example 1 A mouse colon cancer Co was subcutaneously subcutaneously on the dorsal side of a CDF1 female mouse.
lon26 cells were transplanted, and the micelle-forming polymer block copolymer-anticancer agent conjugate or adriamycin hydrochloride (ADR) synthesized in Example 1 or 2 was injected every 4 days from the time when the tumor volume reached about 100 mm ^3. It was administered once intravenously (indicated by arrows in the figure) three times in total, and the effect on advanced cancer was examined. Each drug was diluted with physiological saline before use. The drug concentration was an adriamycin equivalent concentration. The antitumor effect of the drug was determined from the number of tumor-erased mice and the tumor growth curve. The results are shown in Table 1 and FIGS.

[0045]

TABLE 1 Anti-cancer activity sample against mouse colon cancer Colon 26 Dose (mg / kg) Tumor -erased mouse Complex of Example 1 (anti-cancer agent) 10 1/3 5 1/3 Complex of Example 2 (anti-cancer agent) 3) Results up to 30 days of 10 1/3 50/3 ADR 100/3 As apparent from FIGS. 1 to 3, when administration of adriamycin, the growth suppression effect of the transplanted tumor was observed, but the tumor shrinkage was observed. Was rarely observed. On the other hand, in the case of the block copolymer-anticancer drug conjugate of the present invention (Examples 1 and 2), the tumor transplanted in one out of three mice 30 days after administration at a dose of 10 mg / kg / day (per administration) Was completely eliminated, and a higher pharmacological effect was observed as compared with adriamycin alone.

[0046]

Industrial Applicability The pharmaceutical preparation of a micelle-forming polymer block copolymer-anticancer agent complex of the present invention is prepared by incorporating an anticancer agent into the micelle core without binding to the polymer.
The present invention can provide an extremely useful pharmaceutical preparation according to the present invention, because the dosage has been reduced and the antitumor activity has been successfully achieved beyond the intrinsic efficacy of the anticancer agent.

[Brief description of the drawings]

FIG. 1 shows a mouse colon cancer Colon 2 when a block copolymer-anticancer drug complex pharmaceutical preparation (Example 1) was administered.
6 is a tumor growth curve of FIG.

FIG. 2: Mouse colon cancer Colon2 when a block copolymer-anticancer drug complex pharmaceutical preparation (Example 2) was administered.
6 is a tumor growth curve of FIG.

FIG. 3 is a tumor amplification curve of mouse colon cancer Colon 26 when adriamycin hydrochloride was administered.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazunori Kataoka 1083-4, Omuro, Kashiwa City, Kashiwa City, Chiba Prefecture, 141-9 (72) Inventor Mitsuo Okano 6-12-12, Kokufudai, Ichikawa City, Chiba Prefecture (72) Invention Inventor Yasuhisa Sakurai 3-17-6 Eifuku, Suginami-ku, Tokyo Inventor Mekumi Machida 36-3 Uenodai, Fukaya City, Saitama Prefecture (72) Inventor Hisao Yumoto 2-1-1-1-803, Shimo, Kita-ku, Tokyo (72) Inventor Kazuya Okamoto 5-7-10 Higashio Higashio, Arakawa-ku, Tokyo -305 (72) Inventor Yoko Mashiba 3-29-11 Shimo, Kita-ku, Tokyo (56) References JP-A-6-107565 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name A61K 9/107 A61K 47/34 CA (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. An amide bond to a carboxyl group which is a side chain of a polymer carboxylic acid moiety of a block copolymer having a polyethylene glycol structure moiety and a polymer carboxylic acid moiety.
Polyethylene glycol moiety and an amide obtainable by coupling hydrophobic compounds other than anti-cancer agents by coupling
A polymer block copolymer having a hydrophobic polymer structural portion to which a hydrophobic compound other than an anticancer agent is bound by bonding ,
A pharmaceutical preparation of a block copolymer-anticancer drug composite, which forms micelles having a polyethylene glycol structural portion as an outer core and contains a water-insoluble anticancer agent in a hydrophobic inner core. Wherein the hydrophobic polymer structure moiety is aliphatic in its side chain polyamino acid or a salt structure and / or block copolymer of claim 1 having an aromatic residue of - anticancer complex pharmaceutical Formulation. 3. The pharmaceutical preparation according to claim 1, wherein the anticancer drug is an anthracycline anticancer drug. 4. The method of claim anti-cancer agent is adriamycin
3. The pharmaceutical preparation of a block copolymer-anticancer agent conjugate according to 1 or 2 . 5. The micelle-forming block copolymer is represented by the following formula (1), 請 with (2) or structure of these salts
The pharmaceutical preparation of the block copolymer-anticancer agent conjugate according to claim 1 . Embedded image (Wherein, R ₁ represents a lower alkyl group or hydrogen, R ₂ represents a bonding group, R ₃ represents a methylene group or an ethylene group, Y represents a hydrogen or a protecting group, and R represents each independently a hydroxyl group. Alternatively, it represents an aliphatic or aromatic substituent,
At least one of the substituents represents the substituent, and n is 5 to 1,00
0, m is an integer of 2 to 300, x is an integer of 0 to 300,
x is not greater than m. )