Polymer having halogen-containing moiety and pharmaceutical composition using said polymer

Abstract

The present invention provides a polymer represented by formula (I) etc., said polymer being useful as a drug carrier for effectively delivering a drug to a target site. (In the formula, each symbol is as defined in the description.)

Description

[Technical Field]

[0001] The present invention relates to polymers useful as carriers for the effective delivery of drugs to target sites. [Background technology]

[0002] Drugs that are required to exert effective pharmacological effects at target sites, such as nucleic acid drugs, are able to regulate various genes within cells, and are therefore highly anticipated for application to a variety of diseases that have been considered difficult to treat until now, such as cancer and genetic disorders. However, nucleic acid drugs require appropriate delivery technology (DDS technology) to target cells, as the nucleic acid molecules themselves have low stability in the body. For example, a nucleic acid delivery technique has been disclosed in which a block copolymer having a hydrophilic polymer segment and a cationic polymer segment is used to form a complex (polyion complex) between the nucleic acid and the block copolymer via electrostatic interaction (Patent Documents 1 and 2). While these patent documents describe an excellent nucleic acid drug delivery technique, they do not describe a block copolymer containing a polymer segment with a specific structure having an alkyl group (also referred to as a "haloalkyl group") substituted with one or more halogen atoms in the side chain. Non-Patent Documents 1 to 3, which relate to DDS technology, describe block copolymers having haloalkyl groups, but do not describe or suggest the polymers of the present invention having the specific structures represented by the formulae (I) to (IV) below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 096399 [Patent Document 2] International Publication No. 2017 / 086467 [Non-patent literature]

[0004] [Non-Patent Document 1] Angew.Chem.Int.Ed.2016,55,755-759 [Non-patent document 2] Macromol. Biosci.2017,17,1700114 [Non-patent document 3] Mater. Chem. B,2018,6,7230-7238 Summary of the Invention [Problem to be solved by the invention]

[0005] DDS technology for drugs that are required to exert effective pharmacological effects at target organs (target sites) requires three functions: 1) the ability to deliver the drug intensively to the lesion site, 2) the ability to appropriately control drug release from the formulation, and 3) the ability to improve the efficiency of drug uptake into target cells by improving the drug's absorbability through mucous membranes such as the skin and intestinal tract and its permeability through the blood-brain barrier.However, conventional DDS technology has not necessarily been able to satisfactorily improve these functions.The present invention aims to solve these problems in the DDS technical field. [Means for solving the problem]

[0006]

[0005] As a result of extensive research, the present inventors have come up with a polymer segment of a specific structure having a haloalkyl group in the side chain portion, and have found that the above-mentioned problems can be solved by forming a polymer using this polymer alone or in combination with a hydrophilic polymer segment and / or a polycation segment. Furthermore, they have also found that drugs having a haloalkyl group can form a more stable complex with this polymer, and have completed the present invention. Specifically, the present invention is as follows.

[0007] [1] A polymer represented by the following formula (I), (II), (III) or (IV):

[0008] [ka]

[0009] [In each formula, R 1 and R 2 are each independently a hydrogen atom or an optionally substituted C 1-12 represents an alkyl group, R 3 represents the side chain of any amino acid, A represents a single bond or a hydrophilic polymer chain; L 1a and L 1b each independently represents a single bond or a linking group, L 2 is a single bond or L 3 represents L 3 represents a linker represented by formula (V) or (VI),

[0010] [ka]

[0011] (In the formula, m and n each independently represent an integer of 0 to 5, The * on the left represents the bond position to the -NH- group, and The * on the right indicates the bond position to the carbonyl group. B is C 1-20 represents a haloalkyl group, D represents a cation-containing group, an anion-containing group, or a group represented by formula (VII),

[0012] [ka]

[0013] (wherein t represents an integer of 0 to 5, ** represents the position of attachment to the -(CH2)q- group, and G represents O or NH. E represents an NHCOR group, an NHCOOR group, a CONHR group, or a COOR group; R represents an alkyl group having 3 to 20 carbon atoms or a group derived from a lipid; z represents an integer of 2 to 500; x represents an integer equal to or greater than 40% of z; y represents an integer, which may be 0; w represents an integer, which may be 0; zxyw represent integers, which may be 0, zx represents an integer, which may be 0; p, q, and r each independently represent an integer of 1 to 10; s represents an integer of 0 to 10. (However, in formulas (III) and (IV), (i) when A represents a single bond, (ii) m represents an integer of 0 to 2.) [2] The polymer according to the above [1], wherein in formula (I) or (II), the sum of x, y, and w is 95% or more of z.

[0014] [3] The polymer according to [1] or [2] above, wherein A is a hydrophilic polymer chain. [4] The polymer according to the above [1] or [2], wherein A is a single bond.

[0015] [5] B is C 1-20 The polymer according to any one of the above [1] to [4], which is a fluoroalkyl group. [6] B is C in which all hydrogen atoms are replaced with fluorine atoms. 1-20 The polymer according to the above [5], which is an alkyl group.

[0016] [7] A polymer-drug conjugate, in which the polymer according to any one of the above [1] to [6] forms a conjugate with a drug. [8] The polymer-drug conjugate according to [7] above, wherein the drug is a biopolymer. [9] A pharmaceutical comprising the polymer-drug conjugate according to either [7] or [8] above as an active ingredient. [Effects of the Invention]

[0017] The present invention provides a polymer that is useful as a carrier for effectively delivering drugs to target sites. [Brief explanation of the drawings]

[0018] [Figure 1] The results of the evaluation of blood retention in animal experiments described below, when ASO was used as the nucleic acid, are shown below. [Figure 2] The results of the evaluation of blood retention in animal experiments described below, in which HDO was used as the nucleic acid, are shown below. [Figure 3] The results of the evaluation of blood retention in animal experiments described below are shown when HDO modified with haloalkyl groups was used as the nucleic acid. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below with reference to the embodiments. Unless otherwise defined in context, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described below. All publications and patents mentioned herein are incorporated by reference for the purpose of describing and disclosing, for example, the constructs and methodology described in the publications that might be used in connection with the described invention. The polymers used in the present invention may exhibit a degree of polydispersity when obtained as polymerization products, and therefore, when referring to the properties of the polymer (such as molecular weight, degree of polymerization, charge, etc.), unless otherwise specified, the reference is to the average of the entire polydisperse polymerization product. In this specification, in the polymers represented by formulas (I) to (IV), structurally corresponding groups and moieties are defined using the same symbols, such as R1, A, B, x, y, z, etc., but these groups and moieties are independent of each other among the polymers (I) to (IV). Therefore, for example, preferred embodiments of groups and moieties represented by the same symbols may be the same or different for each polymer (e.g., between polymers (I) and (II)).

[0020] I. Polymers represented by formulas (I) to (IV) of the present invention The present invention provides a polymer represented by the following formula (I), (II), (III) or (IV) (sometimes collectively referred to herein as "the polymer of the present invention").

[0021] [ka]

[0022] [In each formula, R 1 and R 2 are each independently a hydrogen atom or an optionally substituted C 1-12 represents an alkyl group, R 3 represents the side chain of any amino acid, A represents a single bond or a hydrophilic polymer chain; L 1a and L 1b each independently represents a single bond or a linking group, L 2 is a single bond or L 3 represents L 3 represents a linker represented by formula (V) or (VI),

[0023] [ka]

[0024] (In the formula, m and n each independently represent an integer of 0 to 5, The * on the left represents the bond position to the -NH- group, and The * on the right indicates the bond position to the carbonyl group. B is C 1-20 represents a haloalkyl group, D represents a cation-containing group, an anion-containing group, or a group represented by formula (VII),

[0025] [ka]

[0026] (wherein t represents an integer of 0 to 5, ** represents the position of attachment to the -(CH2)q- group, and G represents O or NH. E represents an NHCOR group, an NHCOOR group, a CONHR group, or a COOR group; R represents an alkyl group having 3 to 20 carbon atoms or a group derived from a lipid; z represents an integer of 2 to 500; x represents an integer equal to or greater than 40% of z; y represents an integer, which may be 0; w represents an integer, which may be 0; zxyw represent integers, which may be 0, zx represents an integer, which may be 0; p, q, and r each independently represent an integer of 1 to 10; s represents an integer of 0 to 10. (However, in formulas (III) and (IV), (i) when A represents a single bond, (ii) m represents an integer of 0 to 2.)

[0027] In each of the above formulas, the partial structure [...] ZThe portion represented by is a polymer containing a segment having a haloalkyl group as a side chain, and is a structural feature of the polymer of the present invention (hereinafter, this may be referred to as a "haloalkylated segment"). The "haloalkylated segment" is composed of one or more types of structural units, and may be a polymer composed of a single type of structural unit, or a copolymer composed of two or more types of structural units. In the copolymer, the order of polymerization of the structural units constituting the copolymer is not particularly limited and may be any order, and the copolymer may be either a random copolymer or a block copolymer.

[0028] In the polymers of the present invention represented by the above formulas (I) to (IV), such constitutional units are represented by the following partial structural formulas. Polymers of formula (I) (polypeptide structures)

[0029] [ka]

[0030] Polymer of formula (II) (polypeptide structure)

[0031] [ka]

[0032] Polymer of formula (III) (polyethyleneimine structure)

[0033] [ka]

[0034] Polymer of formula (IV) (polyethyleneimine structure)

[0035] [ka]

[0036] In the polymer of the present invention, the structural units represented by the partial structural formulae (Ia), (II-a), (III-a) and (IV-a) are essential. In this specification, each structural unit represented by the partial structural formula above may be referred to as a "monomer" or "monomer (Ia)".

[0037] The definition of each symbol in formulas (I) to (IV) will be explained in detail below.

[0038] (1) a polymer portion containing a haloalkylated segment z represents the total number of monomers constituting each polymer represented by formulae (I) to (IV), and each z independently represents an integer of 2 to 500. x represents the total number of monomers (Ia), (II-a), (III-a), and (IV-a) constituting the "haloalkylated segment" in each polymer represented by formulas (I) to (IV), and each x independently represents an integer that is 40% or more of z.

[0039] For the monomer (Ia) and the monomer (II-a), x is preferably each independently an integer equal to or greater than 50% of z. y represents the total number of monomers (Ib) and (II-b) in each polymer represented by formula (I) and (II), and each independently represents an integer, and may be 0. y may be, for example, an integer of 1 or greater, an integer of 2 or greater, or an integer of 5 or greater. y may also be, for example, an integer of 200 or less, an integer of 100 or less, an integer of 80 or less, an integer of 40 or less, or an integer of 20 or less. w represents the total number of monomers (Ic) and (II-c) in each of the polymers represented by formula (I) and (II), and each independently represents an integer, and may be 0. w may be, for example, an integer of 1 or greater, an integer of 2 or greater, or an integer of 5 or greater. Furthermore, w may be, for example, an integer of 200 or less, an integer of 100 or less, an integer of 80 or less, an integer of 40 or less, or an integer of 20 or less. Here, "x+y+w", which indicates the total number of monomers (Ia) and (Ib), monomers (II-a) and (II-b), and monomers (Ic) and (II-c), is preferably each independently an integer that is 95% or more of z. Furthermore, in each polymer represented by formula (I) and (II), "zxyw" indicating the total number of monomers (Id) and (II-d) respectively independently represents an integer and may be 0.

[0040] For the monomer (III-a) and the monomer (IV-a), x is preferably each independently an integer equal to or greater than 50% of z. Furthermore, in each polymer represented by formula (III) and (IV), "zx" indicating the total number of monomers (III-b) and (IV-b) respectively independently represents an integer and may be 0.

[0041] B is C 1-20 represents a haloalkyl group. The "C 1-20 "Haloalkyl group" means a group in which one or more hydrogen atoms of a linear or branched alkyl group having 1 to 20 carbon atoms are substituted with a halogen atom, and "C 1-20Examples of the "haloalkyl group" include bromomethyl, 2-bromoethyl, 3-bromopropyl, 4-bromobutyl, 5-bromopentyl, 6-bromohexyl, iodomethyl, 2-iodoethyl, 3-iodopropyl, 4-iodobutyl, 5-iodopentyl, 6-iodohexyl, fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl, tribromomethyl, trichloromethyl, trifluoromethyl, difluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluoroisobutyl, perfluoro-sec-butyl, and perfluoro. -tert-butyl, perfluoropentyl, perfluorohexyl, perfluoroisohexyl, perfluoro-1,1-dimethylbutyl, perbromo-2,2-dimethylbutyl, periodo-3,3-dimethylbutyl, perfluoro-2-ethylbutyl, perfluoroheptyl, perfluorooctyl, perfluoro-3-methyloctyl, perfluorononyl, perfluorodecyl, perfluoroundecyl, perfluorododecyl, perbromotridecyl, perfluorotetradecyl, periodopentadecyl, perfluorohexadecyl, perfluoroheptadecyl, perfluorooctadecyl, perfluorononadecyl, and perfluoroicosyl. The above "C 1-20 The "haloalkyl group" may have one or more oxygen atoms forming an ether bond as constituent atoms of its carbon chain at positions where they can be inserted. 1-20 haloalkyl group ("C 1-20 Preferred specific examples of the haloalkoxyalkyl group) include CF3OCF2-, CF3CF2OCF2-, (CF3)2CFOCF2-, CF3OCF2CF2-, CF3CF2OCF2CF2-, CF3CF2OCF2CF2-, CF3CF2OCF2CF2OCF2-, CF3CF2OCF2CF2OCF2-, CF3CF2OCF2CF2OCF2-, CF3CF2OCF2CF2OCF2CH2-, CF3CF2CF2OCF(CF3)-, and CF3CF2CF2OCF(CF3)CF2OCF(CF3)-. Here, "C 1-20The "haloalkyl group" includes a C group in which one or more hydrogen atoms are replaced by a fluorine atom. 1-20 Alkyl groups are preferred, and C 1-20 Alkyl groups are more preferred.

[0042] As described above, D represents a cation-containing group, an anion-containing group, or a group represented by formula (VII).

[0043] [ka]

[0044] (wherein t represents an integer of 0 to 5, ** represents the position of attachment to the -(CH2)q- group, and G represents O or NH.

[0045] Here, the "cation-containing group" represented by D is any suitable group containing a cation, such as a group containing an ammonium cation. While the structural units (monomers (Ib) and (II-b)) having a cation-containing group are not essential for the polymers of the present invention, the inclusion of such monomers results in the formation of polycation segments within the haloalkylated segments, enabling the polymers of the present invention to more effectively form complexes with biopolymers (e.g., siRNA) used as drugs under physiological conditions. Specifically, preferred "cation-containing groups" include groups selected from the group consisting of amino groups, amidine groups, and groups derived from diethylenetriamine and represented by the following (i) to (iv):

[0046] (i) -J-(CH2) l1 -(NH-(CH2) m1 -) n1 -NH2 (ii) -J-(CH2) l2 -N(-(CH2) m2 -NH2)2 (iii) -J-(CH2) l3 -N((-(CH2)m3 -NH2)(-(CH2) m4 -NH-) n2 -H) (iv) -J-(CH2) l4 -N(-(CH2) m5 -N(-(CH2) m6 -NH2)2)2 (In the formula, J represents NH or CONH, and l1 to l4 and m1 to m6 each independently represent an integer of 2 or 3, and more preferably 2. It is preferable that n1 and n2 each independently represent an integer of 1 to 3.) Here, a more preferred "cation-containing group" is a group represented by formula (i).

[0047] The structural units (monomers (Ib) and (II-b)) having the "cation-containing group" may have a thiol group (-SH group) at the end of the side chain, i.e., at the end of the cation-containing group. Thiol groups can react with each other to form a crosslinking reaction via a disulfide bond. This increases the association between the polymers of the present invention, resulting in a polymer capable of forming highly stable micelles. Furthermore, disulfide bonds are easily cleaved in a reducing environment. Therefore, stable micelles can be maintained outside the cell in a non-reducing environment, and the encapsulated substance can be efficiently released inside the cell in a reducing environment. Thus, in one embodiment, D is -NH + =C(=NH)-(CH2) o -SH, and o is an integer of 1 to 10, preferably an integer of 2 to 4.

[0048] Furthermore, the "anion-containing group" represented by D is any suitable group containing an anion, such as a carboxyl group. The structural units having an anion-containing group, monomers (Ib) and (II-b), are not essential for the polymer of the present invention. However, by including such monomers, a polyanion segment is formed within the haloalkylated segment, and the polymer of the present invention can more effectively form a complex with a biopolymer used as a drug (e.g., a platinum complex anticancer drug such as cisplatin or DACH-platin) under physiological conditions. Specifically, a carboxyl group is a suitable "anion-containing group."

[0049] Furthermore, the monomers (Ib) and (II-b) having the "group represented by formula (VII)" represented by D are not essential for the polymer of the present invention. However, by including such monomers, a polyanion segment is formed within the haloalkylated segment, and the polymer of the present invention can more effectively form a complex with a biopolymer used as a drug (e.g., paclitaxel) under physiological conditions.

[0050] The NHCOR group, NHCOOR group, CONHR group, or COOR group represented by E is a segment obtained by converting the terminal of the NH2 group, which is a cation-containing group represented by D, or the COOH group, which is an anion-containing group. Specifically, the above (i) is converted to the following (i'): The same applies to other groups. (i') -J-(CH2) l1 -(NH-(CH2) m1 -) n1 -NHCOR Here, R represents an alkyl group having 3 to 20 carbon atoms or a group derived from a lipid. The "alkyl group having 3 to 20 carbon atoms" includes "C 1-20 For the "haloalkyl group," reference can be made to the alkyl portion described above. Examples of the "lipid-derived group" include groups in which a hydrogen atom has been removed from the OH group of tocopherol or cholesterol.

[0051] The monomers (Ic) and (II-c) constituting the "haloalkylated segments" in the polymers represented by formulas (I) and (II) are each independently derived from any amino acid. 3 represents the "side chain of any amino acid" selected for the monomers (Ic) and (II-c). For example, the monomer (Ic) and the monomer (II-c) may each independently be any suitable cationic amino acid having a cationic group (e.g., an amino group, a guanidyl group, an imidazolyl group, etc.) in the side chain. Examples include basic amino acids such as lysine, arginine, histidine, and ornithine. Alternatively, to increase the hydrophobicity of the cationic polyamino acid segment, a hydrophobic amino acid (e.g., leucine, isoleucine, valine, phenylalanine, proline, etc.) and a cationic amino acid may be included. Therefore, R 3 Suitable examples of the side chains include the side chains of such amino acids.

[0052] L 2 is a single bond or L 3 represents L 3 represents a linker represented by formula (V) or (VI).

[0053] [ka]

[0054] (In the formula, m and n each independently represent an integer of 0 to 5, The * on the left represents the bond position to the -NH- group, and The * on the right indicates the bond position to the carbonyl group. However, in each of the polymers represented by formulae (III) and (IV), (i) when A represents a single bond, (ii) m represents an integer of 0 to 2.

[0055] p, q, and r each independently represent an integer of 1 to 10. s represents an integer of 0 to 10.

[0056] (2) Hydrophilic polymer segment In each of the polymers represented by formulas (I) to (IV), A represents a single bond or a hydrophilic polymer chain. When A represents a hydrophilic polymer chain, it corresponds to a "hydrophilic polymer segment."

[0057] The hydrophilic polymer chain may be composed of any suitable hydrophilic polymer. Examples of such hydrophilic polymers include poly(ethylene glycol), polysaccharides, poly(vinylpyrrolidone), poly(vinyl alcohol), poly(acrylamide), poly(acrylic acid), poly(methacrylamide), poly(methacrylic acid), poly(methacrylic acid esters), poly(acrylic acid esters), polyamino acids, poly(malic acid), poly(oxazoline), and derivatives thereof. Specific examples of polysaccharides include starch, dextran, fructan, and galactan. Polyethylene glycol may be terminally modified with a group such as a C1-C6 alkyl group. Furthermore, polyethylene glycols having various functional groups at their terminals for bonding to cationic polyamino acid segments or linking groups (also referred to as "linkers") are commercially available. Polyethylene glycols with various molecular weights and branched forms are also commercially available, making them preferred for their ease of availability.

[0058] The weight average molecular weight of the hydrophilic polymer segment may be set to preferably 10,000 to 80,000, more preferably 10,000 to 60,000, for example 10,000 to 40,000 per segment.

[0059] (3) Other polymer components L in each polymer represented by formulas (I) to (IV) 1a and L 1b each independently represents a single bond or a linking group. L 1a and L 1bWhen represents a "linking group", it serves as a linking moiety between the "haloalkylated segment" and the "hydrophilic polymer segment" in the polymer of the present invention. Specifically, L 1a Examples of the linking group represented by -NH-, -O-, -O-L4-NH-, -CO-, -CH2-, and -O-L5-S-L6-NH- (In the formula, L4 to L6 each independently represent C 1-6 represents an alkylene group. On the other hand, L 1b Examples of the linking group represented by -OCO-L7-CO-, -NH- and -NHCO-L8-CO- (Wherein L7 and L8 are each independently C 1-6 represents an alkylene group. Examples of the linking group include a linking group selected from groups represented by the following formula: Here, "C 1-6 Examples of the "alkylene group" include -CH2-, -(CH2)2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -CH(CH3)-, -C(CH3)2-, -CH(C2H5)-, -CH(C3H7)-, -CH(CH(CH3)2)-, -(CH(CH3))2-, -CH2-CH(CH3)-, -CH(CH3)-CH2-, -CH2-CH2-C(CH3)2-, -C(CH3)2-CH2-CH2-, -CH2-CH2-CH2-C(CH3)2-, and -C(CH3)2-CH2-CH2-CH2-CH2-. Among the above, particularly preferred linking groups are L 1a As for -CO-, L 1b Examples of the alkyl group include -NH-.

[0060] R in each polymer represented by formulas (I) to (IV) 1 and R 2 represents "optionally substituted C 1-12 "C" in "Alkyl group" 1-12The term "alkyl group" refers to a linear or branched alkyl group having 1 to 12 carbon atoms, and specific examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, 1-ethylpropyl, hexyl, isohexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, octyl, 3-methyloctyl, nonyl, decyl, undecyl, and dodecyl. The above "C 1-12 The "alkyl group" may be substituted at substitutable positions with 1 to 8 (preferably 1 to 5) substituents. Examples of such substituents include an azide group, an alkynyl group (e.g., ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, 5-hexynyl, 4-methyl-2-pentynyl, etc.), a thiol group, a maleimide group, an acetalformyl group, a cyano group, a formyl group, a carboxy group, an amino group, a (C 1-6 ) alkoxycarbonyl group, (C 2-7 ) acylamide group, siloxy group, silylamino group, and trialkylsiloxy group (the alkylsiloxy groups are mutually independent and each has 1 to 6 carbon atoms).

[0061] R 1 When the substituent in is, for example, a formyl group, a carboxy group, or an amino group, the target binding site is connected to C via these substituents. 1-12 It may be bonded to an alkyl group. Here, the target binding site is a site that has a biological recognition function and can specifically bind to substances derived from living organisms and viruses to form a biological binding pair with the substance, and examples include antibodies or fragments thereof, other functional or target-specific proteins, peptides, aptamers, sugars such as lactose, physiologically active substances such as folic acid, sugars such as lactose and glucose, etc. The target binding site is preferably, for example, a peptide having a weight-average molecular weight of 50 to 20,000, more preferably a peptide having a weight-average molecular weight of 100 to 10,000, and even more preferably a peptide having a weight-average molecular weight of 150 to 3,000. Furthermore, the above peptide is preferably a peptide having 1 to 200 amino acid residues, more preferably a peptide having 1 to 100 amino acid residues, and even more preferably a peptide having 1 to 30 amino acid residues.

[0062] Examples of the peptides include those capable of specifically binding to integrins involved in angiogenesis, intimal hyperplasia, and malignant tumor growth, specifically RGD peptides. Here, the RGD peptide refers to a peptide containing an arginine-glycine-aspartic acid (RGD) sequence. Preferably, the RGD peptide may be a cyclic RGD (cRGD) peptide. As described above, in one embodiment, the polymer of the present invention is 1 The polymer of the present invention has the great advantage that it can also function as a drug carrier having a target binding site, since a target binding site can be attached as a substituent in the polymer. This feature enables the polymer of the present invention to effectively deliver drugs to target sites.

[0063] In the polymer of the present invention, the structural units (monomers) constituting the above-mentioned "haloalkylated segment" may be the same or different. Taking the monomer (Ia) as an example, the same monomer (Ia) (for example, a monomer (Ia-1(1)) in which p is 1) may be polymerized, or two structurally different monomers (Ia) (for example, a monomer (Ia-1(1)) in which p is 1 and a monomer (Ia-1(2)) in which p is 10) may be polymerized. Those skilled in the art will be able to carry out the present invention by making an appropriate selection depending on the purpose.

[0064] Although not limited thereto, preferred examples of the polymer of the present invention include polymers represented by formula (I) or (II), and particularly, polymers in which A represents a hydrophilic polymer chain and zxy or zxyw represents 0.

[0065] II. Production of the Polymer of the Present Invention The polymer of the present invention can be appropriately produced by a method known per se that is commonly used by those skilled in the art in this technical field. In producing the polymer of the present invention, the raw materials such as monomers can be produced by a method known per se, but if they are commercially available, the commercially available products can be used. in particular, i) a step of sequentially polymerizing a pre-prepared hydrophilic polymer chain and predetermined monomers (Ia) to (Ic), (II-a) to (II-c), (III-a), (III-b), (IV-a) or (IV-b) according to the desired polymer structure; or ii) A step of bonding a previously polymerized haloalkylated segment with a hydrophilic polymer segment, and a step of introducing other groups (e.g., haloalkyl groups) that constitute the polymer of the present invention. can be produced by appropriately combining More specifically, for example, N-carboxylic anhydrides (NCAs) of specific amino acids (monomers) with optionally introduced protecting groups can be sequentially polymerized using the terminal amino groups of a hydrophilic polymer (e.g., polyethylene glycol) with an aminated ω-terminus as an initiator, followed by deprotection or side chain conversion to introduce haloalkyl groups and convert the polymers into haloalkylated segments. Alternatively, polyamino acids with optionally introduced protecting groups can be first synthesized, which can then be coupled to a hydrophilic polymer, followed by deprotection or side chain conversion to synthesize a block copolymer having haloalkylated segments. Various methods can be used to couple polyamino acids and hydrophilic polymers, but a typical example is a method in which reactive functional groups are introduced into the respective termini and then coupled. Examples include a method in which a carboxyl group and an amino group are coupled using a condensing agent or by active esterification, a method using maleimide and thiol, and a so-called click chemistry method using an alkyne and azide. Those skilled in the art can appropriately design the structure and plan the synthesis of such polymers of the present invention. For example, when the drug to be conjugated is a "nucleic acid," the ratio of the number of amines (N) contained in the polymer to the number of phosphate groups (P) contained in the nucleic acid can be adjusted by adjusting the mixing ratio of the polymer and the nucleic acid. While not limited thereto, the N / P ratio can be designed to be within the range of 0.1 to 5.0, for example.

[0066] III. Use of the polymer of the present invention as a drug carrier (1) Polymer-drug conjugates The polymers of the present invention can form complexes (e.g., polyion complexes (PICs)) through interaction with drugs. The polymers of the present invention improve the stability of the "polymer-drug complex" through effects attributable to the "haloalkylated segment" (e.g., the effect of interactions between polyfluorinated compounds). This allows for improved blood retention and can improve the clinical efficacy of the drug. The polymers of the present invention can also be covalently bonded to drugs to form polymer-drug conjugates.

[0067] (2) Target drugs Although there is no particular limitation on the drugs to which the polymers of the present invention can be applied, suitable examples include anionic compounds that have more negative charges than positive charges in an aqueous medium at physiological pH (e.g., pH 7.4). From this perspective, biopolymers are preferred. Here, biopolymers refer to polymers derived from living organisms and polymers structurally similar to these, specifically proteins, lipids, and nucleic acids. The biopolymer is preferably at least one selected from the group consisting of proteins and nucleic acids. Here, proteins include peptides.

[0068] The nucleic acid refers to a polynucleotide or oligonucleotide whose basic unit is a nucleotide composed of a purine or pyrimidine base, a pentose, and a phosphate. Examples include oligo- or poly-double-stranded RNA, oligo- or poly-double-stranded DNA, oligo- or poly-single-stranded DNA, and oligo- or poly-single-stranded RNA. It also includes oligo- or poly-double-stranded nucleic acids and oligo- or poly-single-stranded nucleic acids in which RNA and DNA are mixed in the same strand. The nucleotides contained in the nucleic acid may be natural or chemically modified non-natural, and may also contain molecules such as amino groups, thiol groups, or fluorescent compounds. While not limited to these, the nucleic acid may be composed of 4 to 20,000 bases, preferably 10 to 10,000 bases, and more preferably 12 to 30 bases. Considering the function or action, examples of the nucleic acid include plasmid DNA, siRNA, microRNA, mRNA, shRNA, antisense nucleic acid, decoy nucleic acid, aptamer, and ribozyme.

[0069] Other suitable examples of drugs to which the polymer of the present invention can be applied include platinum complex anticancer drugs such as cisplatin and DACH-platin, which can form complexes via coordinate bonds.

[0070] Further suitable examples of drugs to which the polymer of the present invention can be applied include hydrophobic anticancer drugs such as paclitaxel, which can form complexes via hydrophobic interactions.

[0071] The drugs to which the present invention is applicable may or may not have a haloalkyl group attached. Such chemical modification can be carried out appropriately by those skilled in the art in consideration of the structure of the target drug.

[0072] (3) Preparation of polymer-drug conjugates The polymer-drug conjugate can be prepared by those skilled in the art using known methods. For example, it can be prepared by stirring a mixture of the polymer of the present invention and a drug while applying energy by ultrasonic irradiation. Alternatively, the conjugate can be prepared by mixing the polymer of the present invention and a drug in any buffered aqueous solution (e.g., Tris buffer, phosphate-buffered saline, HEPES buffer, etc.).

[0073] The size of the complex can be set to any appropriate size depending on the purpose. For example, the average particle size measured by dynamic light scattering (DLS) is preferably 5 nm to 200 nm, more preferably 10 nm to 100 nm.

[0074] (4) Drugs consisting of polymer-drug complexes The polymer-drug conjugate of the present invention can be administered to a subject in need thereof as a medicine (drug delivery formulation) either as such or in the form of a pharmaceutical composition containing the conjugate as an active ingredient. The subjects of administration are preferably mammals, such as humans, dogs, cats, horses, cattle, and other mammals, with humans being particularly preferred.

[0075] In the formulation, in addition to the active ingredient drug, a carrier or diluent and additives may be mixed to form a pharmaceutical composition. If necessary, other drugs to be used in combination may also be contained in the pharmaceutical composition. The dosage form is preferably a parenteral administration agent such as an injection or drip infusion. Carriers or diluents include aqueous solvents such as distilled water, sterilized water, Ringer's solution, physiological saline, buffer solutions, and the like. Examples of the additives include pharmaceutically acceptable additives such as bulking agents, dispersing agents, buffering agents, preservatives, solubilizing agents, stabilizers, tonicity adjusting agents, and pH adjusting agents. Preferred administration routes include intravenous administration, intraarterial administration, and intracerebral administration.

[0076] The content of the drug in the pharmaceutical composition and the method of administration (dosage and administration) can be appropriately determined by a person skilled in the art depending on individual circumstances such as the specific embodiment of the polymer of the present invention and the drug used. For example, when a nucleic acid is used as a drug, the dosage of the nucleic acid is, but is not limited to, about 0.0001 mg to about 1,000 mg of siRNA or antisense nucleic acid molecules per kg of adult body weight per administration in humans. Generally, the dosage or administration amount is selected taking into consideration the gender, age, body weight, symptoms, severity, side effects, etc. of the recipient. Administration can be carried out, for example, at intervals of one week, two weeks, three weeks, or four weeks, or, if necessary, at intervals of more than one month. The route of administration can be selected, as described above, for example, intravenous administration, intraarterial administration, intracerebral administration, etc. [Example]

[0077] The present invention will be explained in more detail below by examples of producing the polymer of the present invention, examples of preparing its conjugate with a drug, and examples of animal experiments for evaluating its efficacy, but these examples do not limit the present invention and may be changed without departing from the scope of the present invention.

[0078] 1. Reagents, cells, experimental animals, etc. (1) Synthetic reagents PEG-NH2 was purchased from NOF Corporation (product name: SUNBRIGHT MEPA-12T). Methanol, thiourea, N,N-dimethylformamide (DMF), calcium hydride, and triethylamine were purchased from Fujifilm Wako Pure Chemical Industries, Ltd. DMF was purified by vacuum distillation in the presence of calcium hydride before use. ε-Trifluoroacetyl-L-lysine N-carboxylic anhydride was purchased from Chuo Kasei Co., Ltd. Diethyl ether was purchased from Showa Ether Co., Ltd. Dialysis tubing was purchased from Spectrum. C7F 15 -COOCH3 (hereinafter also referred to as "Rf-A"; see the structural formula on the left below), C5F 11 O2COOCH3 (hereinafter also referred to as "Rf-B"; see the structural formula on the right below) was a commercially available product.

[0079] [ka]

[0080] Hereinafter, the "haloalkyl group" introduced into a polymer or the like by reaction with the above-mentioned Rf-A or Rf-B will be abbreviated as an Rf group, and one derived from Rf-A will be abbreviated as an Rf-1 group, and one derived from Rf-B will be abbreviated as an Rf-2 group. (2) Nucleic acid We used single-stranded antisense oligonucleotides (ASOs) and heterogeneous oligonucleotides (HDOs) consisting of a double-stranded ASO and its complementary strand (purchased from GeneDesign). Both ASOs and HDOs targeted the mouse MALAT1 (metastasis associated in lung adenocarcinoma transcript-1) sequence.

[0081] (Nucleic acid sequence) 1) ASO array: 5'-C(L)^T(L)^A(L)^g^t^t^c^a^c^t^g^a^a^T(L)^G(L)^C(L)-3' 2) HDO HDO array 1: ASO array (5'-C(L)^T(L)^A(L)^g^t^t^c^a^c^t^g^a^a^T(L)^G(L)^C(L)-3') HDO sequence 2: complementary sequence (5'-G(M)^C(M)^A(M)^UUCAGUGAAC^U(M)^A(M)^G(M)-3')

[0082] In the above formula, a) The notation "N(L)" represents bridged nucleic acid (LNA), specifically, C(L) represents LNA 5-methylcytosine, T(L) represents LNA thymine, A(L) represents LNA adenine, and G(L) represents LNA guanine. b) Nucleotides in lowercase represent DNA. c) Nucleotides in capital letters represent RNA, and N(M) represents 2'-O-methyl RNA. d)^ represents phosphorothioate modification. (Nucleic acid production) HDO was used by annealing HDO sequence 1 and HDO sequence 2. The Rf-1 group was introduced into HDO at the end of the sequence by a known method. (3)Animals BALB / c mice (female, 6 weeks old) were used.

[0083] 2. Synthesis of polyethylene glycol-poly(L-lysine) block copolymer (PEG-PLys(Rf)) with Rf group ( Preparation of the Polymers of the Invention ) (1) 300 mg of PEG-NH2 with an average molecular weight of 12,000 and 456 mg of thiourea were dissolved in 6 mL of N,N-dimethylformamide (DMF). The resulting solution was then added to a solution of 310 mg of N-carboxylic anhydride of ε-trifluoroacetyl-L-lysine (Lys(TFA)-NCA)) and 456 mg of thiourea dissolved in 6 mL of DMF, and the mixture was allowed to react at 25 °C for 3 days. The reaction solution was added dropwise to 200 mL of a diethyl ether / methanol (v / v: 15 / 1) mixture, yielding a white precipitate. This precipitate was then dissolved in methanol and added dropwise to 200 mL of diethyl ether twice. The resulting white precipitate was filtered and dried under vacuum to yield PEG-PLys(TFA). 200 mg of the obtained PEG-PLys (TFA) was dissolved in 18 mL of methanol, and 2 mL of 1 M sodium hydroxide solution was added and reacted at 35 °C for 24 hours. The reaction solution was placed in a dialysis tube (molecular weight cutoff 6,000-8,000 Da) and dialyzed four times using 0.01 M NaOH solution as the external solution and three times using pure water as the external solution. The solution inside the dialysis membrane was recovered and freeze-dried to obtain PEG-PLys as a white powder. The compound obtained was confirmed to be the target product. 1 The degree of PLys polymerization was confirmed by H-NMR and was found to be 40. The structure is shown below.

[0084] [ka]

[0085] (2) 20 mg of PEG-PLys was dissolved in 2 mL of methanol and 1.2 equivalents of triethylamine relative to the primary amino groups of PEG-PLys, and 0.1, 0.3, or 0.5 equivalents of Rf-A or Rf-B relative to the primary amino groups of PEG-PLys were added, respectively, and the reaction was carried out by stirring overnight. Each reaction solution was placed in a dialysis tube and dialyzed twice against methanol (for at least 12 hours each), three times against 10 mM phosphate buffer (pH 7.4) (for at least 2 hours each), three times against 100 mM NaCl aqueous solution (for at least 2 hours each), and three times against pure water (for at least 2 hours each). After lyophilization, PEG-PLys(Rf-AX) and PEG-PLys(Rf-BX) (where X corresponds to the amount of the feed, 0.1, 0.3, and 0.5) were obtained as white powders.

[0086] 3. Preparation of polymer-drug conjugate particles by mixing nucleic acid with PEG-PLys(Rf) ASO, HDO, and Rf-1-HDO (hereinafter sometimes referred to simply as "Rf-HDO") were prepared using 10 mM HEPES (pH 7.3) to concentrations of 80 μM and 40 μM, respectively. PEG-PLys (control polymer), PEG-PLys (Rf-A0.3) (polymer of the present invention), and PEG-PLys (Rf-B0.5) (polymer of the present invention) were prepared using 10 mM HEPES (pH 7.3) to concentrations of 1 mg / mL. Each solution was mixed at the following volume ratio and vortexed for 1 minute to prepare particles. (Preparation of Particle 1) PEG-PLys conjugate (N / P ratio = 1.4) Nucleic acid / PEG-PLys / HEPES=60 / 47 / 133 (Preparation of Particle 2) PEG-PLys (Rf-A0.3) conjugate (N / P ratio = 1.2) Nucleic acid / PEG-PLys(Rf-A0.3) / HEPES=60 / 71 / 109 (Preparation of Particle 3) PEG-PLys (Rf-B0.5) conjugate (N / P ratio = 1.4) Nucleic acid / PEG-PLys(Rf-B0.5) / HEPES=60 / 123 / 57 *) N / P ratio: The ratio (= ratio of positive to negative charges) where [N] is the number of primary amines in the polymer and [P] is the number of phosphate groups in the nucleic acid.

[0087] 4. Animal experiments (blood retention) (1) Particles used in the test Using AlexaFluoro647-labeled ASO and HDO (labeled by standard methods), the nucleic acid alone and the complex particles prepared under the conditions described in 3 above were subjected to evaluation in animal experiments. 1) Particles using ASO as nucleic acid (ASO series) Test particle A: Labeled ASO alone (used as control 1) (200 μL of a 20 μM solution was administered) (referred to as "Naked ASO" in Figure 1) Test particle B: Polymer-ASO complex prepared under the conditions of 3. (Preparation of particle 1) above (used as control 2) (referred to as "ASOxLys" in Figure 1) Test particle 1: Polymer-ASO complex prepared under the conditions of 3. (Preparation of particle 2) above (referred to as "ASOxRf-1" in Figure 1). Test particle 2: Polymer-ASO complex prepared under the conditions of 3. (Preparation of particle 3) above (referred to as "ASOxRf-2" in Figure 1). 2) Particles using HDO as nucleic acid (HDO series) Test particle C: Labeled HDO alone (used as control 1) (200 μL of 10 μM solution administered) ) (Indicated as "Naked HDO" in Figure 2) Test particle D: Polymer-HDO complex prepared under the conditions of 3. (Preparation of particle 1) above (used as control 2) (referred to as "HDOxLys" in Figure 2) Test particle 3: Polymer-HDO complex prepared under the conditions of 3. (Preparation of particle 2) above (referred to as "HDOxRf-1" in Figure 2). Test particle 4: Polymer-HDO complex prepared under the conditions of 3. (Preparation of particle 3) above (referred to as "HDOxRf-2" in Figure 2). 3) Particles using HDO modified with Rf-1 groups as nucleic acids (Rf-HDO series) Test particle E: Labeled Rf-1-HDO alone (used as control 1) (referred to as "Naked Rf-HDO" in Figure 3) Test particle F: Polymer-Rf-1-HDO complex prepared under the conditions of 3. (Preparation of particle 1) above (used as control 2) (referred to as "Rf-HDOxLys" in Figure 3) Test particle 5: Polymer-Rf-1-HDO complex prepared under the conditions of 3. (Preparation of particle 2) above (referred to as "Rf-HDOxRf-1" in Figure 3). Test particle 6: Polymer-Rf-1-HDO complex prepared under the conditions of 3. (Preparation of particle 3) above (referred to as "Rf-HDOxRf-2" in Figure 3).

[0088] (2) Evaluation of blood retention 200 μL of each of the above test particles was administered to the tail vein of a mouse. Blood was collected from the tail vein 10, 30, 60, and 180 minutes after administration. The fluorescence intensity in the blood was measured using a fluorescence microplate reader (Tecan Spark) to quantify the amount remaining in the blood (Dose% / g).

[0089] (3) Evaluation results The evaluation results are shown in FIGS. 1 to 3 below. Figure 1 shows the evaluation results when ASO was used as the nucleic acid. FIG. 2 shows the evaluation results when HDO was used as the nucleic acid. FIG. 3 shows the evaluation results when HDO modified with an Rf-1 group was used as the nucleic acid. In each figure, the horizontal axis indicates the time after administration, and the vertical axis indicates the blood concentration (Dose% / g). The above evaluation results demonstrated that the blood retention of nucleic acids can be significantly improved by conjugating them with the haloalkylated polymers of the present invention (Figures 1 and 2).Furthermore, it was also demonstrated that a similar improvement effect can be obtained when haloalkylated nucleic acids are conjugated with the haloalkylated polymers of the present invention (Figure 3). [Industrial Applicability]

[0090] The present invention provides a polymer that is useful as a carrier for effectively delivering drugs such as nucleic acid medicines to target sites, and is useful, for example, in the field of the pharmaceutical industry. This application is based on patent application No. 2021-038762 filed in Japan (filing date: March 10, 2021), the contents of which are incorporated in full herein.

Claims

1. A polymer represented by the following formula (I), (II), (III) or (IV): 【Chemical 1】 [In each formula, R １ and R ２ are each independently a hydrogen atom or an optionally substituted C １－１２ represents an alkyl group, R ３ represents the side chain of any amino acid, A represents a single bond or a hydrophilic polymer chain; L １a and L １ｂ each independently represents a single bond or a linking group, L ２ is a single bond or L ３ represents L ３ represents a linker represented by formula (V) or (VI), 【Chemistry 2】 (In the formula, m and n each independently represent an integer of 0 to 5, The * on the left indicates the position of attachment to the -NH- group, and The * on the right indicates the bond position to the carbonyl group. B is a group in which all hydrogen atoms are substituted with fluorine atoms and which has one or more oxygen atoms forming an ether bond as constituent atoms of its carbon chain at positions where it can be inserted. １－２０ is an alkyl group, D represents a cation-containing group, an anion-containing group, or a group represented by formula (VII), 【Chemistry 3】 (wherein t represents an integer of 0 to 5, ** is -(CH ２ ) represents the position of attachment to the q-group, and G represents O or NH. E represents an NHCOR group, an NHCOOR group, a CONHR group, or a COOR group; R represents an alkyl group having 3 to 20 carbon atoms or a group derived from a lipid; z represents an integer of 2 to 500; x represents an integer equal to or greater than 40% of z; y represents an integer, which may be 0; w represents an integer, which may be 0; z-x-y-w represents an integer, which may be 0; zx represents an integer, which may be 0; p, q, and r each independently represent an integer of 1 to 10; s represents an integer of 0 to 10. (However, in formulas (III) and (IV), (i) when A represents a single bond, (ii) m represents an integer of 0 to 2.)

2. 2. The polymer according to claim 1, wherein in formula (I) or (II), the sum of x, y and w is 95% or more of z.

3. 3. The polymer of claim 1, wherein A is a hydrophilic polymer chain.

4. 3. The polymer of claim 1, wherein A is a single bond.

5. A polymer-drug conjugate comprising a polymer represented by the following formula (I), (II), (III) or (IV) conjugated with a drug: 【Chemistry 4】 [In each formula, R １ and R ２ are each independently a hydrogen atom or an optionally substituted C １－１２ represents an alkyl group, R ３ represents the side chain of any amino acid, A represents a single bond or a hydrophilic polymer chain; L １a and L １ｂ each independently represents a single bond or a linking group, L ２ is a single bond or L ３ represents L ３ represents a linker represented by formula (V) or (VI), 【Chemistry 5】 (In the formula, m and n each independently represent an integer of 0 to 5, The * on the left indicates the position of attachment to the -NH- group, and The * on the right indicates the bond position to the carbonyl group. B is a C 1-20 alkyl group in which all hydrogen atoms are substituted with fluorine atoms and which has one or more oxygen atoms forming an ether bond as constituent atoms of its carbon chain at positions where it can be inserted; D represents a cation-containing group, an anion-containing group, or a group represented by formula (VII), 【Chemistry 6】 (wherein t represents an integer of 0 to 5, ** is -(CH ２ ) represents the position of attachment to the q-group, and G represents O or NH. E represents an NHCOR group, an NHCOOR group, a CONHR group, or a COOR group; R represents an alkyl group having 3 to 20 carbon atoms or a group derived from a lipid; z represents an integer of 2 to 500; x represents an integer equal to or greater than 40% of z; y represents an integer, which may be 0; w represents an integer, which may be 0; z-x-y-w represents an integer, which may be 0; zx represents an integer, which may be 0; p, q, and r each independently represent an integer of 1 to 10; s represents an integer of 0 to 10. (However, in formulas (III) and (IV), (i) when A represents a single bond, (ii) m represents an integer of 0 to 2.)

6. The polymer-drug conjugate of claim 5, wherein the drug is a biopolymer.

7. A pharmaceutical comprising the polymer-drug conjugate according to claim 5 or 6 as an active ingredient.

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