Boron-containing compound and medical drug containing the same

Abstract

To provide a novel compound suitable for use for boron neutron capture therapy.SOLUTION: Provided is a compound of the following formula (I). A-(-L-Q)p (I) (in the formula, A denotes a tumor accumulative polymer, L denotes a linker including a photocleavable group, Q denotes a group containing 10B, p denotes an integer of 5 to 75), A is preferably P (HPMA / APMA), Q is preferably a monovalent group consisting of boron cluster. A compound of the present invention is useful as a boron neutron capture therapeutic agent for cancer therapy.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a boron-containing compound and a medicine containing the same. [Background technology]

[0002] Boron neutron capture therapy (BNCT) is a method of converting boron atoms ( 10 BNCT is a treatment that kills cancer cells with alpha particles and lithium recoil nuclei produced by nuclear fission reactions. These two particles produced by nuclear fission reactions impart extremely high energy, but travel a shorter distance (i.e., less than 10 μm) than the diameter of a cell (10-30 μm), making it possible to selectively kill only the cells in which the boron drug has accumulated. Thermal neutrons irradiated into a living body scatter, reaching not only the tumor but also normal tissue to a significant extent. Therefore, in order to successfully treat cancer with BNCT, it is important to deliver boron specifically to cancer cells.

[0003] Current clinical BNCT requires that the boron concentration in the tumor be 25 ppm or higher to achieve an effective therapeutic effect, and that the ratio of boron concentrations between the tumor and blood (T / B ratio) or between the tumor and surrounding normal organs (T / N ratio) be 2.5 or higher to avoid harmful radiation damage to normal tissues. In other words, because the T / B ratio or T / N ratio determines the maximum radiation exposure, simply increasing the boron concentration in the tumor does not lead to improved therapeutic effects.

[0004] Currently, 4-borono-L-phenylalanine (BPA) is the most commonly used drug in clinical BNCT that can meet these requirements. Because BPA has a phenylalanine skeleton, it is taken up by cancer cells via amino acid transporters such as LAT1, which are overexpressed in cancer cells, and is known to selectively accumulate within target tumors. It has demonstrated particularly excellent clinical results in the treatment of locally recurrent head and neck cancer. However, the therapeutic effect of BPA on LAT1-negative cancers is considered limited. Therefore, to expand the scope of BNCT application, it is necessary to develop new boron drugs with a tumor accumulation mechanism different from that of BPA.

[0005] Against this background, efforts have been made to develop boron carriers that selectively deliver boron drugs to tumors using drug delivery systems (DDS) such as biocompatible polymers (Non-Patent Documents 1 and 2). However, while the use of conventional anticancer drug DDSs, which are designed to improve blood retention and increase drug exposure time and concentration in tumor tissue in order to increase the opportunity for penetration from tumor blood vessels into tumor tissue, has enabled the intratumoral drug concentration to be increased, it has not necessarily been possible to achieve a high T / B or T / N ratio at the time of neutron irradiation. In other words, improving the therapeutic effect of boron drugs for BNCT, which are derived from conventional anticancer drug DDSs, remains a challenge. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] T. Nomoto et al., Sci Adv. 6 (2020) eaaz1722. [Non-patent document 2] P. Mi et al., J. Control. Release. 254 (2017) 1-9. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide novel compounds suitable for use in boron neutron capture therapy. [Means for solving the problem]

[0008] The present inventors have recently prepared a novel compound in which a boron cluster molecule is introduced into the side chain of a biocompatible polymer via a photocleavable linker, and when this compound was administered to experimental animals, they found that the compound can be selectively accumulated within the target tumor, while light irradiation of sites other than the tumor can clear the boron drug from normal tissues and the blood. The present invention is based on these findings.

[0009] According to the present invention, the following inventions are provided. [1] A compound of the following formula (I), or a salt or solvate thereof: A-(-LQ)p (In the above formula, A is a tumor-accumulating polymer, L is a linker containing a photocleavable group, and Q is 10 B, and p is an integer of 5 to 75. [2] The compound according to [1] above, or a salt or solvate thereof, wherein the photocleavable group is selected from the group consisting of a nitrobenzyl linker, a phthalocyanine linker, a coumarin linker, and a benzoquinone linker. [3] The compound or salt or solvate thereof according to [1] or [2] above, wherein A is a polymer selected from the group consisting of a copolymer of HPMA with one or more other monomers, a homopolymer of HPMA, polyvinyl alcohol, polyamino acid, polyacrylic acid, polymethacrylic acid, polyoxazoline, dextran, hydroxyethyl starch, and derivatives thereof. [4] The compound or salt or solvate thereof according to any one of the above [1] to [3], wherein A is a copolymer of HPMA and APMA (P(HPMA / APMA)). [5] The compound according to [4] above, or a salt or solvate thereof, wherein the number average molecular weight of P(HPMA / APMA) is 50 to 500 kDa. [6] The compound or salt or solvate thereof according to [4] or [5] above, wherein the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of P(HPMA / APMA) is 1.1 to 3.0. [7] The compound according to any one of the above [1] to [6], or a salt or solvate thereof, wherein L is a divalent group consisting of a linear or branched hydrocarbon chain, and one or more -(CH2)- in the hydrocarbon chain may be substituted with one or more selected from the group consisting of -O-, -S-, -C(=O)- and -NH-. [8] The compound according to any one of the above [1] to [7], or a salt or solvate thereof, wherein B is a monovalent group consisting of a boron cluster. [9] The compound according to [8] above, or a salt or solvate thereof, wherein the boron cluster has a polyhedral structure.

[10] The compound according to [8] above, or a salt or solvate thereof, wherein the boron cluster is selected from the group consisting of mercaptoundecahydrododecaborate, closododecaborate, closocaborane, nidocarborane, bisdicarbollide metal complexes, GB10, 1,2-dicarbacloso-dodecaborane, 1,7-dicarba-closo-dodecaborane, 1,12-dicarba-closo-dodecaborane, and dicarba-closo-decaborane.

[11] A pharmaceutical composition comprising the compound according to any one of the above [1] to

[10] , or a salt or solvate thereof.

[12] The pharmaceutical composition according to

[11] above, for use in boron neutron capture therapy.

[13] The pharmaceutical composition according to

[11] or

[12] above, which is for the treatment of cancer.

[14] A boron neutron capture therapy agent for cancer treatment, comprising the compound according to any one of the above [1] to

[10] or a salt or solvate thereof.

[0010] SUMMARY OF THE INVENTION In accordance with the present invention, novel compounds are provided that are suitable for use in boron neutron capture therapy. [Brief explanation of the drawings]

[0011] [Figure 1]Figure 1A shows the H-NMR spectrum (400 MHz, DMSO-d) of the synthesized P(HPMA / APMA), and Figure 1B shows the GPC chart (column: OHpak SB-804 HQ, OHpak SB-806M HQ, eluent: 10 mM phosphoric acid, flow rate: 1.0 mL / min) of the synthesized P(HPMA / APMA). [Figure 2] Figure 2A shows the H-NMR spectrum (400 MHz, DMSO-d) of the synthesized P(HPMA / APMA(Fmoc-PL)). Figure 2B shows the GPC chart (column: TSKgel SuperAW4000, SuperAW3000, eluent: DMF, flow rate: 0.2 mL / min) of the synthesized P(HPMA / APMA(Fmoc-PL)). [Figure 3] Figure 3A shows the H-NMR spectrum (400 MHz, DMSO-d) of the synthesized P(HPMA / APMA(PL)). Figure 3B shows the GPC chart (column: OHpak SB-804 HQ, OHpak SB-806M HQ, eluent: 10 mM phosphoric acid, flow rate: 1.0 mL / min) of the synthesized P(HPMA / APMA(PL)). [Figure 4] Figure 4A shows the H-NMR spectrum (400 MHz, DMSO-d) of the synthesized P(HPMA / APMA(PL-Male)). Figure 4B shows the GPC chart (column: OHpak SB-804 HQ, OHpak SB-806M HQ, eluent: 10 mM phosphoric acid, flow rate: 1.0 mL / min) of the synthesized P(HPMA / APMA(PL-Male)). [Figure 5] Figure 5A shows the H-NMR spectrum (400 MHz, DMSO-d) of the synthesized P(HPMA / APMA(PL-BSH)). Figure 5B shows the GPC chart (column: TSKgel SuperAW4000, SuperAW3000, eluent: DMF, flow rate: 0.2 mL / min) of the synthesized P(HPMA / APMA(PL-BSH)). [Figure 6]Figure 6 shows the amount of boron released (Release (%)) from PHPMA-PL-BSH and PHPMA-BSH over time under conditions of light irradiation and non-irradiation. "BL-" indicates no light irradiation, and "BL+" indicates light irradiation (same below). The horizontal axis represents the recovery time of each sample, and in the case of BL+, it also represents the light irradiation time (minutes). Results are expressed as mean ± SD (n = 3). [Figure 7] Figure 7 shows the effect of compounds such as PHPMA-PL-BSH on cell viability (%). Cells were incubated with the test samples for 6 hours. The horizontal axis represents the boron concentration (μg / ml). The results are expressed as the mean ± SD (n=5). [Figure 8] Figure 8 shows the biodistribution of compounds such as PHPMA-PL-BSH administered to experimental animals. Figure 8A shows the tumor accumulation rate of each compound (% of 10B accumulation per gram of tumor tissue relative to the total dose (100%)). Figure 8B shows the blood retention rate of each compound (% of 10B accumulation per gram of blood relative to the total dose (100%)). Figure 8C shows the T / B ratio of PHPMA-PL-BSH and PHPMA-BSH after 48 hours. Figure 8D shows the accumulation rate of PHPMA-PL-BSH in each organ other than the tumor and blood (kidney, lung, liver, spleen, heart, and muscle) (% of 10B accumulation per gram of each organ tissue relative to the total dose (100%)). Figure 8E shows the accumulation rate of PHPMA-BSH in each organ other than the tumor and blood (kidney, lung, liver, spleen, heart, and muscle) (% of 10B accumulation per gram of each organ tissue relative to the total dose (100%)). All values were determined by the amount of boron quantified using ICP-MS. Results are expressed as mean ± SD (n = 4). [Figure 9]Figure 9 shows the biodistribution of PHPMA-PL-BSH after light irradiation. Figure 9A illustrates the experimental procedure. Figure 9B compares the T / B ratio between no light irradiation (48 h), 1 hour of light irradiation (48 h BL (1 h)), and 2 hours of light irradiation (48 h BL (2 h)). The results in Figure 9B are shown as mean ± SD (n = 4). Statistical significance was evaluated using Dunnett's multiple comparison test. *: p < 0.05. Figure 9C compares the boron concentration in urine (μg) between the control and control groups with and without light irradiation. The results in Figure 9C are shown as mean ± SD (n = 3). Statistical significance was evaluated using a two-tailed Student's t-test. Figure 9D shows the tumor accumulation rate (% 10B concentration per gram of tumor) in the absence of light (BL-), 1 hour of light irradiation (BL(1h)), and 2 hours of light irradiation (BL(2h)). Figure 9E shows the accumulation rate (% 10B concentration per gram of each organ) in each of the organs (kidney, lung, liver, spleen, heart, and muscle) in the absence of light (BL-), 1 hour of light irradiation (BL(1h)), and 2 hours of light irradiation (BL(2h)). The results in Figures 9D and 9E are shown as mean ± SD (n = 4). Statistical significance was evaluated using Dunnett's multiple comparison test. All values were determined by the boron content quantified using ICP-MS. [Figure 10]Figure 10 shows the therapeutic effect of boron neutron capture therapy. Figure 10A shows the experimental procedure. Figure 10B shows the antitumor effect of compounds such as PHPMA-PL-BSH on a subcutaneous CT26 tumor model. Tumors were irradiated with epi- or thermal neutrons 48 hours after intravenous injection on day -2. The vertical axis represents the relative tumor volume, with the tumor volume on day -2 set as 1. The horizontal axis represents time (days). Figure 10C shows the tumor size (tumor volume (cm3)) 23 days after treatment. Figure 10D shows the body weight of each experimental animal. The vertical axis represents the relative body weight, with the body weight on day -2 set as 1. The horizontal axis represents time (days). Body weight was expressed relative to the value on day -2. All results are expressed as mean ± SD (n = 6). Statistical significance was evaluated using Turkey's multiple comparison test. *:p<0.05, **:p<0.01, ****:p<0.0001. [Figure 11] Figure 11A shows the H-NMR spectrum (400 MHz, DMSO-d) of the synthesized P(HPMA / APMA(male)). Figure 11B shows the GPC chart (column: OHpak SB-804 HQ, OHpak SB-806M HQ, eluent: 10 mM phosphoric acid, flow rate: 1.0 mL / min) of the synthesized P(HPMA / APMA(male)). [Figure 12] Figure 12A shows the H-NMR spectrum (400 MHz, DMSO-d) of the synthesized P(HPMA / APMA(BSH)). Figure 12B shows the GPC chart (column: OHpak SB-804 HQ, OHpak SB-806M HQ, eluent: 10 mM phosphoric acid, 500 mM NaCl, flow rate: 1.0 mL / min) of the synthesized P(HPMA / APMA(BSH)). Specific Description of the Invention

[0012] <<Compound>> In formula (I), A represents a tumor-accumulating polymer. The tumor-accumulating polymer that can be used in the present invention is a biocompatible polymer, and examples thereof include copolymers of N-(2-hydroxypropyl)methacrylamide (HPMA) with one or more other monomers, HPMA homopolymers, polyvinyl alcohol, polyamino acids (e.g., polyaspartic acid, polyglutamic acid), polyacrylic acid, polymethacrylic acid, polyoxazoline, dextran, hydroxyethyl starch, and derivatives thereof.

[0013] The tumor-accumulating polymer represented by A may have a functional group in its structure that can be used for linking with the linker (L). That is, in formula (I), L may be bonded to A via a functional group present in A. Such functional groups present in the structure of A are not particularly limited as long as they are functional groups that can be used in a linking reaction, and examples include an amino group, a hydroxyl group, and a carboxy group. The number of functional groups present in A that can be used in a linking reaction with the linker (L) can have a lower limit of, for example, 5, 10, 15, 20, 25, 30, or 35, and an upper limit of, for example, 100, 85, 80, 75, 70, or 65. These lower and upper limits can be arbitrarily combined, and the number of functional groups can be, for example, 5 to 100, 5 to 85, or 5 to 70. All or some of the functional groups present in A may be bonded to the linker (L).

[0014] In formula (I), when A is a copolymer of HPMA and one or more other monomers, examples of the other monomers include N-(3-aminopropyl)methacrylamide (APMA), methacrylic acid (MAA), 2-sulfoethyl methacrylate (SEMA), and peptide-modified methacrylic acid (e.g., MA-GF-OH, MA-GFLG-OH, MA-GGFG-NH2, MA-GGLFG-NH2 (where MA represents methacrylic acid, G represents glycine, F represents phenylalanine, and L represents leucine)), with APMA being preferred. The copolymer may be in the form of a random copolymer, an alternating copolymer, or a block copolymer, but a random copolymer is preferred from the viewpoints of water solubility and ease of production.

[0015] In a copolymer of HPMA and APMA (hereinafter sometimes referred to as "P(HPMA / APMA)" or simply "PHPMA"), the ratio of HPMA to APMA, expressed as the ratio of the number of moles of APMA to the number of moles of HPMA and APMA, can be 1.0 to 10.0% (preferably 1.0 to 7.0%, more preferably 1.0 to 5.0%). The ratio of HPMA to APMA can also be determined using the amine in the APMA molecule as an indicator; the ratio of amine in P(HPMA / APMA) measured by TNBSA assay (see Examples below) can be 1.0 to 10.0 mol% (preferably 1.0 to 7.0 mol%, more preferably 1.0 to 5.0 mol%), expressed as the ratio of the number of moles of amine to the number of moles of monomer.

[0016] The molecular weight of P(HPMA / APMA) can be in the range of 50 to 500 kDa (preferably 200 to 400 kDa, more preferably 250 to 350 kDa) in terms of number average molecular weight (Mn). The molecular weight of P(HPMA / APMA) can also be in the range of 60 to 1200 kDa (preferably 220 to 1200 kDa, more preferably 300 to 800 kDa) in terms of weight average molecular weight (Mw). In this specification, the "number average molecular weight (Mn)" and "weight average molecular weight (Mw)" refer to absolute molecular weights obtained by absolute molecular weight measurement by static light scattering using a multi-angle light scattering (MALS) detector.

[0017] P(HPMA / APMA) can also be specified by the ratio of weight average molecular weight to number average molecular weight (PDI). The PDI (Mw / Mn) of P(HPMA / APMA) can be in the range of 1.1 to 3.0 (preferably 1.3 to 2.5, more preferably 1.3 to 2.3).

[0018] In formula (I), the tumor-accumulating polymer A is bonded to p groups Q via a linker L. p is an integer from 5 to 75, and the lower limit can be, for example, 5, 10, 15, 20, 25, 30, or 35, and the upper limit can be, for example, 75, 70, 65, 60, 55, or 50. These lower and upper limits can be arbitrarily combined, and the above p can be, for example, an integer from 30 to 50 or an integer from 15 to 65. L may be the same or different and can be represented by a divalent group consisting of a saturated hydrocarbon chain. The hydrocarbon chain may be linear or branched, and one or more -(CH2)- groups in the hydrocarbon chain may be substituted with one or more groups selected from the group consisting of -O-, -S-, -C(=O)-, and -NH-. The hydrocarbon chain may have a 5- or 6-membered cyclic structure, and one or two of the ring atoms in this cyclic structure may be the same or different and may be heteroatoms selected from the group consisting of oxygen, nitrogen, and sulfur. The lower limit of the number of carbon atoms in the hydrocarbon chain may be, for example, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, or 24, and the upper limit may be, for example, 100, 96, 92, 88, 84, 80, 76, 72, 68, 64, 60, 56, 52, 48, 44, 40, 36, 32, or 28. These lower and upper limits may be arbitrarily combined, and the number of carbon atoms in the hydrocarbon chain may be, for example, 2 to 100, 16 to 68, or 16 to 40. In addition, when one or more -(CH2)- groups in the hydrocarbon chain are replaced with a group selected from the group consisting of -O-, -S-, -C(=O)-, and -NH-, the replaced group is counted as having one carbon atom in the carbon number of the hydrocarbon chain, and the number of carbon atoms of the cleavable group is not included in the carbon number of the hydrocarbon chain.

[0019] From the viewpoint of enhancing the water solubility of the compound of formula (I), it is preferable that at least a portion of the hydrocarbon chain of L is a polyethylene glycol (PEG) group. A PEG group is a divalent group composed of multiple oxyethylene units and can be specifically represented by -(OCH2CH2)m-. When at least a portion of the hydrocarbon chain is a PEG group, m is, for example, an integer of 2 to 28, and preferably an integer of 4 to 24, an integer of 4 to 20, an integer of 4 to 16, an integer of 4 to 12, or an integer of 4 to 8.

[0020] In formula (I), L can be represented by the group *-L1-PL-L2-. Here, PL is a photocleavable group, L1 and L2 may be the same or different and represent a single bond or an alkylene group, provided that both L1 and L2 do not represent single bonds, and * indicates that L1 or PL is bonded to A. The alkylene group is a divalent group consisting of a linear or branched saturated hydrocarbon, and one or more -(CH2)- in the alkylene group may be substituted with one or more atoms selected from the group consisting of -O-, -S-, -C(=O)-, and -NH-. The alkylene group may have a 5- or 6-membered cyclic structure, and one or two ring atoms of this cyclic structure may be the same or different and may be heteroatoms selected from the group consisting of oxygen, nitrogen, and sulfur. The lower limit of the number of carbon atoms in the alkylene group can be, for example, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, or 24, and the upper limit can be, for example, 100, 96, 92, 88, 84, 80, 76, 72, 68, 64, 60, 56, 52, 48, 44, 40, 36, 32, or 28. These lower and upper limits can be arbitrarily combined, and the number of carbon atoms in the alkylene group can be, for example, 2 to 100, 16 to 68, or 16 to 40. In addition, when the alkylene group has a structure in which one or more -(CH)- groups are replaced with groups selected from the group consisting of -O-, -S-, -C(=O)-, and -NH-, the substituted groups are counted as having one carbon atom in the number of carbon atoms in the hydrocarbon chain.

[0021] From the viewpoint of enhancing the water solubility of the compound of formula (I), it is preferable that at least a part of the alkylene group which may be represented by L1 and L2 is a PEG group. A PEG group is a divalent group composed of a plurality of oxyethylene units and can be represented by -(OCH2CH2)m- as described above. When at least a part of the alkylene group is a PEG group, m is, for example, an integer of 2 to 28, and preferably an integer of 4 to 24, an integer of 4 to 20, an integer of 4 to 16, an integer of 4 to 12, or an integer of 4 to 8.

[0022] The compound of formula (I) has at least one photocleavable group in the linker L. In the present invention, a known photocleavable linker that can be cleaved by visible or UV light can be used as the photocleavable group. Non-limiting examples of the photocleavable group include a nitrobenzyl linker, a phthalocyanine linker, a coumarin linker, and a benzoquinone linker, with a nitrobenzyl linker being preferred.

[0023] Non-limiting examples of nitrobenzyl linkers include 4-(4-(1-aminoethyl)-2-methoxy-5-nitrophenoxy)butanoic acid, 4-(4-(1-hydroxyethyl)-2-methoxy-5-nitrophenoxy)butanoic acid.

[0024] Non-limiting examples of phthalocyanine linkers include 4-((E)-2-((E)-2-(2-((2-((tert-butoxycarbonyl)(pent-4-yn-1-yl)amino)ethyl)(methyl)amino)-3-((E)-2-(3,3-dimethyl-1-(4-sulfonatobutyl)-3H-indol-1-ium-2-yl)vinyl)cyclohex-2-en-1-ylidene)ethylidene)-3,3-dimethylindolin-1-yl)butane-1-sulfonate.

[0025] Non-limiting examples of coumarin linkers include 4-(ethyl(4-(hydroxymethyl)-2-oxo-2H-chromen-7-yl)amino)butanoic acid, H-chromen-2-one, 7-(2-azidoethoxy)-4-(hydroxymethyl)-2H-chromen-2-one.

[0026] A non-limiting example of a benzoquinone linker includes 3-(4-bromo-2,5-dimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)-3-methylbutanoic acid.

[0027] In the linker (L), both L1 and L2 do not represent single bonds. When L1 represents a single bond, A and PL are directly bonded, and when L2 represents a single bond, PL and Q are directly bonded. Therefore, the structures that the linker in formula (I) can take are listed as follows: *-L1-PL-L2- *-PL-L2- *-L1-PL- (In the above, * indicates that L1 or PL is bonded to A.)

[0028] In formula (I), the structure that the linker may take is preferably "*-PL-L2-" or "*-L1-PL-".

[0029] A and L1 or PL may be bonded via a bond between functional groups. When the functional group present in A is an amino group or a hydroxyl group, the functional group present in L1 or PL can be a carboxy group, and in this case, the bond between A and L1 or PL is an amide bond (-(NH)-C(=O)-) or an ester bond (-(CH2)-OC(=O)-), respectively. When the functional group present in A is a carboxy group, the functional group present in L1 or PL can be an amino group or a hydroxyl group, and in this case, the bond between A and L1 or PL is an amide bond (-C(=O)-(NH)-) or an ester bond (-C(=O)-O-(CH2)-), respectively. The above bond structures are only examples, and those skilled in the art can select an appropriate bond structure between A and L1 or PL.

[0030] In formula (I), Q is 10 Q is a group containing B. 10 There is no particular limitation on the group containing B, and a group derived from a boron cluster is preferred. The boron cluster is not particularly limited as long as it has a polyhedral structure that can be used in boron neutron capture therapy. Non-limiting examples of boron clusters include mercaptoundecahydrododecaborate and closododecaborate ([B 12 H 12 ] 2- ), ionic closocarborane ([CB 11 H 12 ] - ), lipophilic closocarborane ([C2B 10 H 12 ]), nidocarborane ([C2B9H 11 ] - ), bisdicarbollide metal complexes ([(C2B9H 11 )2M] (M is metal), GB 10 ([B 10 H 12 ] 2- ), 1,2-dicarbacloso-dodecaborane, 1,7-dicarbacloso-dodecaborane, 1,12-dicarbacloso-dodecaborane, dicarbacloso-decarborane ([C2B8H 10]). All boron atoms contained in the boron cluster are 10 It may be B, but only a part of it 10 It may be B. The term "group derived from a boron cluster" refers to a group derived by removing one hydrogen atom in a boron cluster.

[0031] The compound of formula (I) may be in the form of a salt. The salt is not particularly limited as long as it is pharmaceutically acceptable, and examples thereof include base addition salts and acid addition salts. Examples of base addition salts include alkaline earth metal salts such as sodium salt, potassium salt, calcium salt, and magnesium salt, and organic amine salts such as ammonium salt, triethylamine salt, piperidine salt, and morpholine salt. Examples of acid addition salts include mineral acid salts such as hydrochloride, hydrobromide, sulfate, nitrate, and phosphate; and organic acid salts such as methanesulfonic acid, benzenesulfonic acid, paratoluenesulfonic acid, acetic acid, propionate, tartaric acid, fumaric acid, maleic acid, malic acid, oxalic acid, succinic acid, citric acid, benzoic acid, mandelic acid, cinnamic acid, lactic acid, glycolic acid, glucuronic acid, ascorbic acid, nicotinic acid, and salicylic acid. The compound of formula (I) may be in the form of a solvate. The solvent that forms the solvate is not particularly limited as long as it is a pharmaceutically acceptable solvent, and examples thereof include water, ethanol, etc. In the present specification, the term "compound of the present invention" is used to include salts and solvates.

[0032] As will be shown in the Examples below, the compounds of the present invention have the characteristic of exhibiting high intratumoral boron concentrations upon thermal neutron irradiation while being cleared from the blood and normal organs upon light irradiation, and are therefore expected to have a high therapeutic effect in boron neutron capture therapy for the treatment of cancer.

[0033] <<Pharmaceutical Composition>> According to the present invention, there is provided a pharmaceutical composition comprising the compound of the present invention. 10Since the compound of the present invention has a group containing B, the pharmaceutical composition of the present invention can be used in boron neutron capture therapy. Since the compound of the present invention is also tumor-accumulating, it can be used in boron neutron capture therapy, in which the active ingredient accumulates in cancer cells and is then irradiated with thermal neutrons. Therefore, the pharmaceutical composition of the present invention can be used in the treatment of cancer. The present invention also provides a boron neutron capture therapy agent for cancer treatment, which comprises the compound of the present invention.

[0034] The pharmaceutical composition of the present invention can be administered to a subject, followed by irradiation of the subject with low-energy thermal neutrons, thereby selectively destroying tumor cells. Non-limiting examples of diseases to be treated include malignant tumors, such as brain tumors, malignant melanoma, head and neck cancer, lung cancer, liver cancer, thyroid cancer, skin cancer, bladder cancer, mesothelioma, pancreatic cancer, breast cancer, meningioma, and sarcoma. The subject to which the pharmaceutical composition of the present invention is administered can be a human or a non-human mammal (e.g., mouse, rat, hamster, rabbit, cat, dog, cow, sheep, or monkey).

[0035] The route of administration of the pharmaceutical composition of the present invention is not particularly limited and may be parenteral (e.g., intravenous or subcutaneous) or oral. Examples of parenteral preparations include injections, suppositories, inhalants, and transdermal absorbents. Examples of oral preparations include tablets, capsules, granules, powders, pills, lozenges, chewable tablets, syrups, liquids, emulsions, and suspensions. These preparations can be formulated using pharmaceutically acceptable carriers by methods commonly used in the art (e.g., known methods described in the General Provisions for Preparations of the Japanese Pharmacopoeia, 18th Edition). Examples of pharmaceutically acceptable carriers include excipients, binders, diluents, lubricants, additives, flavorings, buffers, thickeners, colorants, stabilizers, emulsifiers, dispersants, suspending agents, and preservatives. Liquid preparations may be dissolved or suspended in water or other suitable solvents prior to use.

[0036] When the pharmaceutical composition of the present invention is administered to humans, the dosage of the compound of the present invention can be determined depending on the sex, age, and weight of the subject, symptoms, dosage form, and route of administration. The dosage of the compound of the present invention per adult can be determined, for example, in the range of 0.1 to 100 g, but is not limited thereto. For treatment, the above-mentioned dosage of the active ingredient can be administered in multiple divided doses.

[0037] In the present invention, boron neutron capture therapy can be carried out as follows using the compound of the present invention or the pharmaceutical composition of the present invention.

[0038] First, a subject administered with the compound of the present invention or the pharmaceutical composition of the present invention is irradiated with light of a wavelength that cleaves the photocleavable linker. The purpose of irradiating the subject with light is to decompose the compound of the present invention present in the blood and normal tissues other than tumors by light irradiation, thereby clearing the compound of the present invention from the body. Therefore, light irradiation can target the subject's blood and / or normal tissues other than tumors. When light irradiation is performed targeting blood, light irradiation can be performed on the body surface of the living body (e.g., the surface of the hands, upper limbs, abdomen, back, feet, lower limbs, etc.). Alternatively, in the present invention, blood may be removed from the body, irradiated with light, and then returned to the body.

[0039] The wavelength of light for light irradiation can be selected so that the photocleavable linker decomposes. When a nitrobenzyl linker is used as the photocleavable linker, light of 365 to 405 nm can be irradiated; when a phthalocyanine linker is used, light of 650 to 700 nm can be irradiated; when a coumarin linker is used, light of 310 to 495 nm can be irradiated; and when a benzoquinone linker is used, light of 400 to 600 nm can be irradiated. The light intensity can be appropriately determined taking into account the penetration of light into the blood or normal tissue of the target.

[0040] The timing of light irradiation can be after the compound of the present invention has sufficiently accumulated in the target tumor cells. The degree of accumulation of the compound of the present invention can be determined, for example, using boron concentration as an index. In this case, the subject can be irradiated with light when the boron concentration in the cancer cells reaches a level suitable for boron neutron capture therapy (e.g., 20 ppm or more).

[0041] After photoirradiation, the tumor site where the compound of the present invention has accumulated is irradiated with thermal neutrons to destroy the cancer cells. For thermal neutron irradiation, a nuclear reactor or accelerator-type neutron generator commonly used in boron neutron capture therapy is used, and the various conditions required for treatment, such as neutron dose, neutron spectrum, and irradiation time, are determined. The energy of the irradiated neutrons is typically around 0.025 eV for thermal neutrons and 0.5 eV to 40 keV for epithermal neutrons.

[0042] According to another aspect of the present invention, there is provided a method for treating cancer, comprising the steps of: (A) administering a compound of the present invention or a pharmaceutical composition of the present invention to a subject in need thereof; (B) after step (A) and before step (C), irradiating the object with light of a wavelength that cleaves the photocleavable group; and (C) Accumulation in the target tissue of the subject 10 A process of irradiating B atoms with neutrons, thereby performing boron neutron capture therapy on the target tissue.

[0043] The therapeutic method of the present invention can be carried out according to the description of the pharmaceutical composition of the present invention. [Example]

[0044] The present invention will be described in more detail based on the following examples, but the present invention is not limited to these examples.

[0045] reagent HPMA (2-hydroxypropyl methacrylamide): Tokyo Chemical Industry Co., Ltd. APMA (3-aminopropylmethacrylamide): Tokyo Chemical Industry Co., Ltd. V50 (2,2'-azobis(2-methylpropionamidine) dihydrochloride): Fujifilm Wako Pure Chemical Industries, Ltd. CTA (4-cyano-4-(phenylcarbonothioylthio)pentanoic acid): Sigma-Aldrich V65 (2,2'-azobis(2,4-dimethylvaleronitrile)): Fujifilm Wako Pure Chemical Industries, Ltd. Fmoc-Photolinker: Santa Cruz Male-PEG4-Acid (19-maleimido-17-oxo-4,7,10,13-tetraoxa-16-azanonadecanoic acid): Tokyo Chemical Industry Co., Ltd. BSH (Disodium mercaptoundecahydrododecaborate): Stella Pharma DMT-MM (4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride): Fujifilm Wako Pure Chemical Industries, Ltd. TEA (triethylamine): Fujifilm Wako Pure Chemical Corporation DMSO (dimethyl sulfoxide): Fujifilm Wako Pure Chemical Industries, Ltd. NMP (N-methylpyrrolidone): Fujifilm Wako Pure Chemical Industries, Ltd. Piperidine: Fujifilm Wako Pure Chemical Corporation DMF (N,N-dimethylformamide): Fujifilm Wako Pure Chemical Industries, Ltd. Disodium phosphate: Fujifilm Wako Pure Chemical Corporation Sodium dihydrogen phosphate: Fujifilm Wako Pure Chemical Industries, Ltd. TNBSA (2,4,6-trinitrobenzenesulfonic acid): Tokyo Chemical Industry Co., Ltd. 5N HCl: Nacalai Tesque Sodium bicarbonate: Fujifilm Wako Pure Chemical Industries, Ltd. Sodium carbonate: Fujifilm Wako Pure Chemical Corporation ·CT26 cells: ATCC RPMI-1640 (10% fetal bovine serum, 1% penicillin-streptomycin): Sigma Aldrich D-PBS(-): Nacalai Tesque Fetal bovine serum (FBS): Biosera Trypsin-EDTA solution: Sigma Aldrich Penicillin-streptomycin: Sigma Aldrich 69% Nitric acid: Fujifilm Wako Pure Chemical Industries, Ltd. Boron standard solution 1000 ppm: Fujifilm Wako Pure Chemical Industries, Ltd. Balb / c: Charles River Japan Epilat Hair Removal Home: Kracie Co., Ltd. ANESSA Sunscreen Cream: Shiseido Co., Ltd.

[0046] measuring equipment ·Nuclear magnetic resonance (NMR) Bruker biospin AVANCE III 400 (Bruker corporation) High-performance liquid chromatography (HPLC) (aqueous) Autosampler: AS-4050 (JASCO Corporation) Pump: PU-4180 (JASCO Corporation) RI detector: RI-4030 (JASCO Corporation) UV detector: UV-4070 (JASCO Corporation) Multi Angle Light Scattering Detector (MALS) (Shoko SCIENCE) Column: OHpak SB-804 HQ, OHpak SB-806M HQ (Shodex) High-performance liquid chromatography (HPLC) (organic) Autosampler: AS-4050 (JASCO Corporation) Pump: PU-4180 (JASCO Corporation) RI detector: RI-4030 (JASCO Corporation) UV detector: UV-4070 (JASCO Corporation) Column: TSKgel SuperAW4000, SuperAW3000 (TOSOH) ·Ultra-trace spectrophotometer (NanoDrop One / OneC) (Thermo Fisher SCIENTIFIC) IVIS imaging system (Sumisho Pharmaceuticals International Corporation) TECAN SPARK™ multi-mode microplate reader (TECAN) High-sensitivity differential refractometer (DRM-3000) 365nm power UV-LED irradiation device, high power type Inductively Coupled Plasma Time of Flight (ICP-TOF-MS) ·Agilent 7700x ICP-MS(Agilent technologies, Inc.)

[0047] Measurement of absolute weight average molecular weight and absolute number average molecular weight by static light scattering method The absolute weight-average molecular weight and absolute number-average molecular weight were measured using gel permeation chromatography (GPC) and a multi-angle light scattering (MALS) detector under the following conditions. Specifically, the method was as follows: 1 mg, 2 mg, 4 mg, and 8 mg of the polymer to be measured were each dissolved in 1 mL of 10 mM PBS. The refractive index at each concentration was then measured using a high-sensitivity differential refractometer (DRM-3000, Otsuka Electronics Co., Ltd.). The dn / dc ratio was then calculated from the slope plotted against the concentration. The sample was then analyzed by gel permeation chromatography and MALS using the following columns. Based on the dn / dc values obtained above and the results obtained from SEC-MALS, the absolute weight-average molecular weight and absolute number-average molecular weight of the polymer were calculated using the software (DAWN8M) provided with the instrument. Columns: Shodex OHpak SB-G 6B (6.0 x 50 mm, Shodex), OHpak SB-804 HQ (8.0 x 300 mm, Shodex), and OHpak SB-806M HQ (8.0 x 300 mm, Shodex) connected in series. Eluent: Phosphate buffer (140 mM NaCl, pH 7.4) Column and detector temperature: 40°C Flow rate: 1.0mL / min Detector: MALS (Shoko Science) Sample concentration: 2 mg / mL (polymer dissolved in phosphate buffer) Injection volume: 100μL

[0048] Determination of amines in polymers The amines contained in P(HPMA / APMA) were quantified by the TNBSA (2,4,6-trinitrobenzenesulfonic acid) assay. Specifically, the assay was performed as follows. The mass of P(HPMA / APMA) was measured in advance and dissolved in 0.5 mL of 0.1 M carbonate buffer. 0.5 mL of a 0.01% (w / v) TNBSA solution dissolved in 0.1 M carbonate buffer was added to this sample solution. The reaction solution was then incubated at 37°C for 2 hours. After incubation, the reaction was stopped by adding 0.25 mL of 1 N HCl. The amines contained in P(HPMA / APMA) were then quantified by measuring the absorbance at 350 nm.

[0049] Example 1: Preparation of photoresponsive metabolically controlled boron drug In this example, a photoresponsive metabolically controlled boron drug was prepared using P(HPMA / APMA) as a tumor-accumulating polymer.

[0050] (1) Synthesis of P(HPMA / APMA) P(HPMA / APMA) was synthesized according to the following scheme. [ka]

[0051] HPMA (1.104 g, 7.71 mmol) and APMA (44.0 mg, 0.246 mmol) were dissolved in 10 mL of ultrapure water. Then, 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CTA) (0.30 mg, 1.07 μmol) dissolved in methanol and the azo polymerization initiator V50 (0.074 mg, 0.27 μmol) dissolved in ultrapure water were added. After five freeze-degassing cycles, the RAFT polymerization reaction was carried out at 65 °C for 48 h. The reaction solution was then transferred to a dialysis membrane (MWCO 3.5 kDa) and dialyzed three times against ultrapure water. The dialyzed sample solution was lyophilized to remove the solvent, yielding 755.3 mg of a white solid (65.8% yield).

[0052] The resulting polymer RAFT terminals were removed with V65 (initiator). The polymer (440.5 mg) synthesized above and V65 (1.64 mg, approximately 25 equivalents relative to the polymer) were placed in a flask and dissolved in methanol under an argon (Ar) atmosphere. The flask was placed on ice, and nitrogen was bubbled through for 5 minutes, followed by reaction at 50 °C for 3 hours. The resulting mixture was then dialyzed against methanol and deionized water at room temperature using a dialysis membrane (MWCO: 3500) and lyophilized to obtain 360.2 mg of P(HPMA / APMA).

[0053] The obtained P(HPMA / APMA) 1 The polymers were analyzed by H-NMR spectroscopy. The molecular weight and dispersity of the polymers were measured by MALS using size exclusion chromatography (OHpak SB-804 HQ and OHpak SB806M HQ). The molar concentration of APMA (amine molar concentration) in P(HPMA / APMA) was evaluated by the TNBSA assay.

[0054] The synthesized sample P(HPMA / APMA) 1 The H-NMR spectrum is shown in FIG. 1A, and the GPC chart is shown in FIG. 1B.

[0055] The synthetic feed ratios and the molecular weight and PDI values measured by MALS are shown in Table 1.

[0056] [Table 1]

[0057] Here, "I" refers to the initiator used in the synthesis. MALS analysis revealed that a PHPMA derivative with a molecular weight of approximately 300 kDa, the molecular weight of the PHPMA that most frequently accumulated in tumors in a preliminary study, was obtained. The PDI (Mw / Mn), which is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), was 1.87. However, considering that the PDI of the P(HPMA / APMA) polymerization performed in a preliminary study was 1.2 at a molecular weight of 54,600, this is considered reasonable since the polymerization system had a higher monomer-to-CTA ratio than the previous polymerization systems. Furthermore, the ratio of APMA (amine) in P(PMA / APMA) determined by TNBSA assay was 3.0 mol%. This is equivalent to the APMA ratio of 3.0 mol% relative to the total monomers used in the reaction. Furthermore, as shown in Reference Example 1 below, the amount of APMA contained in the synthesized P(HPMA / APMA) was almost the same as the HPMA to APMA feed ratio for the other four P(HPMA / APMA)s. Therefore, it was found that the amount of APMA contained in the polymer could be controlled arbitrarily by changing the HPMA to APMA feed ratio. Furthermore, the degree of polymerization of the synthesized P(HPMA / APMA) was calculated using the obtained Mn and amine mol%.

[0058] (2) Introduction of a photocleavable linker A photocleavable linker was introduced according to the following scheme. [ka]

[0059] The P(HPMA / APMA) (563.5 mg) prepared in (1) above, Fmoc-photocleavable linker (284.7 mg, 0.55 mmol, 5 equivalents relative to APMA), and DMT-MM (242.3 mg, 0.88 mmol, 8 equivalents relative to APMA) were dissolved in 50 mL of DMSO. 50 μL of TEA was then added, and the reaction was carried out at room temperature for 24 hours in the dark. The reaction solution was then transferred to a dialysis membrane (MWCO 3.5 kDa) and dialyzed three times against DMSO and ultrapure water. The dialyzed sample solution was freeze-dried to remove the solvent, yielding 778.6 mg of the PHPMA derivative (see Scheme 2). The synthesized P(HPMA / APMA (Fmoc-photocleavable linker)) 1 The H-NMR spectrum is shown in FIG. 2A, and the GPC chart is shown in FIG. 2B.

[0060] (3) Deprotection of the photocleavable linker The photocleavable linker was deprotected according to the following scheme. [ka]

[0061] P(HPMA / APMA (Fmoc-photocleavable linker)) (768.6 mg) was added to a 45 mL DMF solution containing 5 M piperidine and stirred at room temperature for 24 hours in the dark. The reaction solution was then transferred to a dialysis membrane (MWCO 3.5 kDa) and dialyzed three times against methanol and ultrapure water. The dialyzed sample solution was freeze-dried to remove the solvent, yielding 537.2 mg of a yellow solid, P(HPMA / APMA (photocleavable linker)). 1 The H-NMR spectrum is shown in Figure 3A, and the GPC chart is shown in Figure 3B. Fmoc deprotection was carried out in 7-8 PPM The disappearance of the peak at

[0062] (4) Introduction of a water-soluble linker A water-soluble linker was introduced according to the following scheme. [ka]

[0063] P(HPMA / APMA (photocleavable linker)) (530.0 mg), Male-PEG4-Acid (214.3 mg, 0.51 mmol, 5 equivalents relative to the amine), and DMT-MM (227.9 mg, 0.82 mmol, 8 equivalents relative to the amine) were dissolved in 50 mL of DMSO. 30 μL of TEA was then added and the reaction was carried out at room temperature for 24 hours. The reaction solution was then transferred to a dialysis membrane (MWCO 3.5 kDa) and dialyzed four times against ultrapure water. The dialyzed sample solution was freeze-dried to remove the solvent, yielding 671.4 mg of a yellow solid, P(HPMA / APMA(PL-Male)). 1 The H-NMR spectrum is shown in Figure 4A, and the GPC chart is shown in Figure 4B. Whether the linker was successfully introduced was confirmed by the peak of the double bond (ε) of the maleimide moiety.

[0064] (5) Introduction of BSH BSH was introduced according to the following scheme. [ka]

[0065] P(HPMA / APMA(PL-Male)) (671.4 mg) was dissolved in a pH 6.5 PBS:NMP (40 mL:10 mL) solution. After 20 minutes of Ar bubbling, BSH was added under an Ar atmosphere and the reaction was carried out at room temperature for 24 hours. To remove unreacted BSH, the mixture was dialyzed three times against 500 mM NaCl aqueous solution and miLiQ water, and then lyophilized to obtain a yellow solid, P(HPMA / APMA(PL-BSH)) (PHPMA-PL-BSH).

[0066] Synthesized P(HPMA / APMA(PL-BSH)) 1The H-NMR spectrum is shown in Figure 5A, and the GPC chart is shown in Figure 5B. The introduction of BSH was confirmed by the disappearance of the peak (ε) of the double bond in the maleimide moiety. The boron content in P(HPMA / APMA(PL-BSH)) was actually quantified by ICP-MS, and was found to be 3.05 wt%.

[0067] Example 2: Characterization of photoresponsive metabolically regulated boron drugs In this example, the photoresponsive metabolically regulating boron drug prepared in Example 1 was evaluated for its drug release ability and cytotoxicity upon light irradiation.

[0068] (1) Drug release by light irradiation To evaluate the release of BSH by light irradiation, PHPMA-PL-BSH and PHPMA-BSH (Reference Example 2) were exposed to light (BL-) and light (BL+) under physiological conditions at pH 7.4, and the release rate of BSH was quantified by ICP-MS before and after the exposure. Light irradiation was performed using a power LED irradiation device (Optocode, light intensity: 37 mW / cm). 2 The measurement was carried out for 5 minutes using a light source (wavelength: 365 nm, distance from light source: 3.5 cm). The emission rate was calculated using the following formula (A).

[0069]

number

[0070] The results showed that PHPMA-PL-BSH was able to release almost all of the boron drug after only 5 minutes of light irradiation (Fig. 6). On the other hand, the BSH release rate of PHPMA-BSH remained almost unchanged, less than 15%, even after 2 hours of light irradiation (Fig. 6).

[0071] (2)Cytotoxicity To evaluate the toxicity of PHPMA-BSH and PHPMA-PL-BSH to cells, NIH3T3 mouse embryonic fibroblast cells were incubated for 6 hours, and the cell viability was analyzed by CCK8 assay. The cell viability was calculated using the following formula (B).

[0072]

number

[0073] Considering the possibility that cleavage of the photocleavable linker by light irradiation may affect cytotoxicity, we also tested unexposed PHPMA-PL-BSH (BL-) and photocleaved PHPMA-PL-BSH (BL+) by irradiating with 365 nm light for 1 hour before incubation with cells. As a result, cell viability was extremely high in all cases up to a boron concentration of 200 μg / ml (Figure 7). This indicates that the PHPMA copolymer, photocleavable linker, and BSH do not exhibit acute toxicity to normal cells. Furthermore, this suggests that degradation products generated by light treatment do not affect cytotoxicity.

[0074] Example 3: In vivo testing of photoresponsive metabolically controlled boron drugs In this example, an in vivo test was conducted on the photoresponsive metabolically regulated boron drug prepared in Example 1 to evaluate its pharmacokinetics, clearance from the blood, and therapeutic effect.

[0075] (1) Kinetics in the body Four-week-old Balb / c mice were purchased and, at 5 weeks of age, 2 × 10 CT26 cells were inoculated into them. 5 The cells were subcutaneously transplanted at a dose of 100 μL per mouse, and after 23 weeks, the tumor size reached 200 mm 3 Mice that reached this stage (CT26-bearing Balb / c mice) were used in the experiment.

[0076] PHPMA-PL-BSH and PHPMA-BSH prepared in Example 1 and BSH alone were used. 10 B was administered at 8.3 mg / kg base via the tail vein to CT26-bearing Balb / c mice. For PHPMA-PL-BSH and PHPMA-BSH, tumor, blood, kidney, lung, liver, spleen, heart, and muscle were collected at 1, 6, 12, 24, 36, and 48 hours after administration. For the BSH-only group, tumor, blood, kidney, lung, liver, spleen, heart, and muscle were similarly collected at 1 and 6 hours after administration. The tubes containing the collected organs were ashed by adding 1 mL of 70% nitric acid and heating at 50°C for 15 minutes, 70°C for 15 minutes, and 90°C for 1 hour. Milli-Q water was then added to bring the total volume to 10 mL, and the tissue was filtered through a PVDF filter (0.45 μm). The boron content in the tissues was measured by inductively coupled plasma-mass spectrometry (ICP-MS) (n = 4).

[0077] The tumor accumulation rate of boron drugs was 1.13% dose / g (tumor) at 1 hour and 0.17% dose / g (tumor) at 6 hours after administration for BSH alone. At 48 hours after administration, the tumor accumulation rates of PHPMA-PL-BSH and PHPMA-BSH were 7.86% and 6.88%, respectively (Figure 8A). This high tumor accumulation rate of boron drugs is thought to be due to the high blood retention of PHPMA. While BSH alone was almost completely eliminated from the blood, reaching 2.56% dose / g (blood) at 1 hour and 0.15% dose / g (blood) at 6 hours after administration, PHPMA-PL-BSH and PHPMA-BSH significantly increased their blood retention to 7.73% dose / g (blood) at 48 hours after administration (Figure 8B). Overall, the addition of a photocleavable linker to the PHPMA copolymer had little effect on its tumor accumulation rate or blood retention. Furthermore, the T / B ratios were 1.02 and 0.90 for both PHPMA-PL-BSH and PHPMA-BSH at 48 hours post-administration (Figure 8C), both of which were below the reference values for clinical BNCT. Regarding organ distribution outside the tumor and blood, a slight increase in accumulation was observed in the liver and spleen due to the increased hydrophobicity of the photocleavable linker, but no effect was observed in other organs (Figure 8D, E).

[0078] (2) Clearance from blood by light irradiation Four-week-old Balb / c mice were purchased and, at 5 weeks of age, 2 × 10 CT26 cells were inoculated into them. 5 The cells were subcutaneously implanted at 100 μL per mouse, and after 2 to 3 weeks, the tumor size reached 200 mm 3 Mice (CT26-bearing Balb / c mice) with tumors of approximately 100 nm in diameter were used for the experiment. To enhance the penetration of 365 nm light, the abdomen and back of the mice were depilated. Furthermore, to prevent light exposure to the tumor, sunscreen cream was applied to the tumor, and the tumor was then shielded from light with aluminum foil.

[0079] P(HPMA / APMA(PL-BSH)) and BSH alone prepared in Example 1 were administered to CT26-bearing Balb / c mice via the tail vein at 50 mg / kg base. Forty-six hours after administration, P(HPMA / APMA(PL-BSH)) was externally irradiated with 365 nm blue light for one or two hours using an LED device. Then, 48 hours after administration, tumor, blood, kidney, lung, liver, spleen, heart, and muscle were collected. One mL of 70% nitric acid was added to the tube containing the collected organs, and the organs were heated at 50°C for 15 minutes, 70°C for 15 minutes, and 90°C for 1 hour for ashing. Milli-Q water was then added to bring the total volume to 10 mL, filtered through a PVDF filter (0.45 μm), and the boron content in the tissues was measured using inductively coupled plasma-mass spectrometry (ICP-MS) (n = 4).

[0080] To promote the excretion of boron drugs still resident in the blood during high tumor accumulation, mice were exposed to light via the abdominal cavity to cleave the photolinker moiety of PHPMA-PL-BSH. The timing of light exposure was determined to be 46 hours after administration, two hours before the 48-hour mark, when the highest tumor accumulation was observed (Figure 9A). As a result, the T / B ratio increased significantly by 2.1-fold after 1 hour of light exposure and by 3.0-fold after 2 hours of light exposure (Figure 9B). This indicates that a T / B ratio of 2.5 or greater, which is required for safe BNCT, was achieved. To confirm the excretion pathway of the photocleaved boron drug, PHPMA-PL-BSH was administered, and then immediately exposed to light. Urine was collected from the mice, and the amount of boron in the urine was measured. One hour of light exposure significantly increased the amount of boron excreted in urine (Figure 9C). These results indicate that the boron drug cleaved by light is transferred from the blood into the urine and excreted from the body.

[0081] Furthermore, the promotion of blood clearance of the boron drug by light irradiation did not affect the boron concentration in the tumor (Fig. 9D).Furthermore, no significant changes were observed in the accumulation and distribution of the boron drug in normal tissues after light irradiation (Fig. 9E).

[0082] (3) Therapeutic effects of BNCT Four-week-old Balb / c mice were purchased, and at the age of five weeks, CT26 cells were inoculated at 1 × 10 5 The cells were subcutaneously transplanted at a dose of 100 μL per mouse, and after 2 to 3 weeks, the tumor size reached 100 mm 3 Mice (CT26-bearing Balb / c mice) with tumors of approximately 100 nm in diameter were used for the experiment. To enhance the penetration of 365 nm light, the abdomen and back of the mice were depilated. Furthermore, to prevent light exposure to the tumor, sunscreen cream was applied to the tumor, and the tumor was then shielded from light with aluminum foil.

[0083] To evaluate the therapeutic effects of BNCT, we used the Kyoto University Research Reactor (KUR), a research reactor owned by Kyoto University, as a thermal neutron source in cooperation with the Kyoto University Institute for Integrated Radiation and Nuclear Science. Samples of PHPMA-PL-BSH, PHPMA-BSH (Reference Example 2), and BSH alone were dissolved in 300 μL of PBS and administered via the tail vein to CT26-bearing Balb / c mice. After 46 hours, the blue-irradiated group was externally irradiated for 2 hours using a 365 nm LED irradiator. All mice were then placed in acrylic holders. These acrylic holders were fixed to a 5 mm-thick thermoplastic plate containing 40% 6LiF (96% 6Li) by weight for thermal neutron shielding, with a circular hole in the center, so that the right thigh containing the subcutaneous tumor was exposed through the hole. The thigh was then irradiated with 5 MW thermal neutrons at the KUR for 10 minutes.

[0084] Dosage of each drug ( 10 Bmg / kg) were as follows: BSH 60.0 PHPMA-BSH 8.3 PHPMA-PL-BSH(BL-) 8.3 PHPMA-PL-BSH(BL+) 25.0

[0085] Fluence (thermal neutrons): 3.5~3.8×10 12 neutrons / cm 2 Fluence (epithermal neutrons): 6.2~6.8×10 11 neutrons / cm 2

[0086] The day of neutron irradiation was designated as day 0, and tumor size and body weight were measured thereafter. Tumor volume (V) was calculated using the following ellipse volume approximation formula: V=ab 2 / 2, (a and b are the long and short axes of the tumor, respectively) Furthermore, for comparison, a control (cold) was prepared in which no sample was administered and no thermal neutrons were irradiated, and a control (hot) was prepared in which no sample was administered and only thermal neutrons were irradiated.

[0087] The BNCT effect was evaluated in a CT26 tumor model by intravenous injection of PHPMA-PL-BSH or PHPMA-BSH and BSH followed by epi- / thermal neutron irradiation 48 hours after injection (1 hour after administration for BSH) (Figure 10A). In clinical trials, the dose is determined by the T / B ratio of the drug. Compared to the T / B ratio of 1 for PHPMA-PL-BSH (BL-) and PHPMA-BSH revealed in the pharmacokinetic study in Section 4, the T / B ratio of 3 for PHPMA-PL-BSH (BL+) after photoirradiation was tripled. Therefore, based on the %ID in the pharmacokinetic study in Section 4.2, we calculated the boron concentration in the blood 48 hours after administration to be 10 ppm, and used the corresponding dose. As a result, the light-irradiated PHPMA-PL-BSH(BL+) group significantly inhibited tumor growth compared to the conventional boron carrier PHPMA-BSH and the non-light-irradiated PHPMA-PL-BSH(BL-) group, which had a low T / B ratio (Figure 10B, C). These results suggest that light irradiation can promote the metabolism of boron drugs from the blood, thereby overcoming the T / B ratio limitations imposed by neutron irradiation and achieving a high therapeutic effect.

[0088] Reference Example 1: Preparation of various P(HPMA / APMA) In this reference example, five types of P(HPMA / APMA) were prepared at various mixing ratios and their properties were evaluated. The mixing ratios are shown in Table 2, and the preparation was carried out according to the procedure described in Example 1(1). The number-average molecular weight (Mn), weight-average molecular weight (Mw), ratio of weight-average molecular weight to number-average molecular weight (PDI), and molar ratio of amine of the resulting P(HPMA / APMA) are shown in Table 2.

[0089] [Table 2]

[0090] The yields of the polymers obtained were all around 50–70%. Polymers obtained by RAFT polymerization are expected to have low dispersity due to controlled polymerization. Polymer 1, with the smallest molecular weight, had a PDI of 1.2. Increasing the molecular weight, however, required fewer initiators (I) and RAFT agents (CTA) relative to the monomers. Therefore, the PDI was around 1.7–1.9. The amount of amine quantified by the TNBSA assay was roughly equivalent to the ratio of HPMA to APMA used during the reaction. Therefore, it was found that the amount of amine required for side chain introduction could be freely controlled by varying the ratio of HPMA to APMA used.

[0091] Reference Example 2: Preparation of PHPMA-BSH (1) Introduction of Male-PEG4-Acid P(HPMA / APMA) (546.5 mg), Male-PEG4-Acid (221.0 mg, 0.53 mmol, 5 equivalents relative to the amine), and DMT-MM (235.0 mg, 0.85 mmol, 8 equivalents relative to the amine) were dissolved in 50 mL of DMSO. 30 μL of TEA was then added, and the reaction was carried out at room temperature for 24 hours. The reaction solution was then transferred to a dialysis membrane (MWCO 3.5 kDa) and dialyzed three times against ultrapure water. The dialyzed sample solution was freeze-dried to remove the solvent, yielding 690.0 mg of PHPMA derivative. P(HPMA / APMA(Male)) 1 The H-NMR spectrum is shown in Figure 11A, and the GPC chart is shown in Figure 11B. Whether or not the maleimide linker was successfully introduced was confirmed by peak (v).

[0092] (2) Introduction of BSH P(HPMA / APMA(Male)) (690.0 mg) was dissolved in a pH 6.5 PBS:NMP = 40 mL:10 mL solution. After 20 minutes of bubbling with Ar, BSH was added under an Ar atmosphere and the reaction was carried out at room temperature for 24 hours. To remove unreacted BSH, the solution was dialyzed three times each against a 500 mM NaCl aqueous solution and MiLiQ water, and then freeze-dried to obtain a yellow solid, P(HPMA / APMA(BSH)). P(HPMA / APMA(BSH)) 1 The H-NMR spectrum is shown in Figure 12A, and the GPC chart is shown in Figure 12B. Whether BSH was successfully introduced was confirmed by the shift of peak (v).

Claims

1. A compound of the following formula (I), or a salt or solvate thereof: A-(-L-Q)p (I) (In the above formula, A is a tumor-accumulating polymer, L is a linker containing a photocleavable group, and Q is １０ B, and p is an integer from 5 to 75.

2. 2. The compound of claim 1, or a salt or solvate thereof, wherein the photocleavable group is selected from the group consisting of a nitrobenzyl linker, a phthalocyanine linker, a coumarin linker, and a benzoquinone linker.

3. 3. The compound, salt, or solvate thereof according to claim 1 or 2, wherein A is a polymer selected from the group consisting of a copolymer of HPMA with one or more other monomers, a homopolymer of HPMA, polyvinyl alcohol, polyamino acid, polyacrylic acid, polymethacrylic acid, polyoxazoline, dextran, hydroxyethyl starch, and derivatives thereof.

4. 3. The compound, salt, or solvate thereof according to claim 1, wherein A is a copolymer of HPMA and APMA (P(HPMA / APMA)).

5. The compound, salt, or solvate thereof according to claim 4, wherein the number average molecular weight of P(HPMA / APMA) is 50 to 500 kDa.

6. The compound, salt, or solvate thereof according to claim 4, wherein the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of P(HPMA / APMA) is 1.1 to 3.

0.

7. L is a divalent group consisting of a linear or branched hydrocarbon chain, and one or more -(CH ２ 3. The compound according to claim 1, or a salt or solvate thereof, wherein - is optionally substituted by one or more selected from the group consisting of -O-, -S-, -C(=O)- and -NH-.

8. 3. The compound according to claim 1, or a salt or solvate thereof, wherein B is a monovalent group consisting of a boron cluster.

9. The compound, or a salt or solvate thereof, according to claim 8 , wherein the boron cluster has a polyhedral structure.

10. The compound according to claim 8, or a salt or solvate thereof, wherein the boron cluster is selected from the group consisting of mercaptoundecahydrododecaborate, closododecaborate, closocarborane, nidocarborane, bisdicarbollide metal complexes, GB10, 1,2-dicarbacloso-dodecaborane, 1,7-dicarba-closo-dodecaborane, 1,12-dicarba-closo-dodecaborane, and dicarba-closo-decaborane.

11. A pharmaceutical composition comprising a compound according to claim 1 or 2, or a salt or solvate thereof.

12. 12. The pharmaceutical composition of claim 11 for use in boron neutron capture therapy.

13. The pharmaceutical composition according to claim 11 or 12, which is for treating cancer.

14. A boron neutron capture therapy agent for cancer treatment, comprising the compound according to claim 1 or 2, or a salt or solvate thereof.

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