MEDICAMENT FOR THE TREATMENT OF PAIN

Abstract

The present invention relates to a pharmaceutical composition comprising a P2X.sub.3 and/or P2X.sub.2/3 receptor antagonist for the treatment of neuropathic pain, nociceptive pain or visceral pain, as well as interstitial cystitis and/or bladder pain syndrome.

It is a pharmaceutical composition for treating and/or preventing neuropathic pain, nociceptive pain, or visceral pain, as well as interstitial cystitis and/or bladder pain syndrome, comprising a compound represented by Formula (I):

##STR00001##

or a pharmaceutically acceptable salt thereof.

Claims

1-10. (canceled)

11. A method for treating, alleviating, and/or preventing neuropathic pain, nociceptive pain, or visceral pain, the method comprising the step of administering an effective amount of a compound represented by Formula (I): ##STR00013## or a pharmaceutically acceptable salt thereof to an individual in need of treatment, alleviation, and/or prevention of neuropathic pain, nociceptive pain, or visceral pain.

12. The treating, alleviating, and/or preventing method according to claim 11, wherein the neuropathic pain is peripheral neuropathic pain.

13. The treating, alleviating, and/or preventing method according to claim 11, wherein the neuropathic pain is diabetic neuropathic pain, postoperative neuropathic pain, or cancer pain.

14. The treating, alleviating, and/or preventing method according to claim 11, wherein the neuropathic pain is diabetic neuropathic pain.

15. The treating, alleviating, and/or preventing method according to claim 11, wherein the nociceptive pain is inflammatory pain, knee osteoarthritis pain, or cancer pain.

16. The treating, alleviating, and/or preventing method according to claim 11, wherein the visceral pain is cystitis pain, cancer pain, or pain associated with endometriosis.

17. The treating, alleviating, and/or preventing method according to claim 11, wherein the visceral pain is cystitis pain.

18. A method for treating, alleviating, and/or preventing interstitial cystitis and/or bladder pain syndrome, the method comprising the step of administering an effective amount of a compound represented by Formula (I): ##STR00014## or a pharmaceutically acceptable salt thereof to an individual in need of treatment, alleviation, and/or prevention of interstitial cystitis and/or bladder pain syndrome.

19. The treating, alleviating, and/or preventing method according to claim 11, wherein a daily dose of an active ingredient is 10 mg to 450 mg.

20. The treating, alleviating, and/or preventing method according to claim 11, wherein the administering step is performed once daily.

21-30. (canceled)

Description

BRIEF DESCRIPTION OF DRAWING

[0496] FIG. 1 shows effects on the voiding interval in an acetic acid-induced urination disorder model. Rates of changes in the voiding interval after administration of the compound represented by Formula (I) are shown, with the value (Pre) of the voiding interval before the administration being taken as 100%.

[0497] FIG. 2 shows effects on the amount of voided urine per urinating action in an acetic acid-induced urination disorder model. Rates of changes in the amount of voided urine per urinating action after administration of the compound represented by Formula (I) are shown, with the value (Pre) of the amount of voided urine per urinating action before the administration being taken as 100%.

MODE FOR CARRYING OUT THE INVENTION

[0498] The term “consist of” means that a constituent element(s) is/are included exclusively. The term “comprise” means that an element(s) included is/are not limited to a constituent element(s) described, and an undescribed element(s) is/are not excluded.

[0499] Hereinafter, the present invention will be described with reference to embodiments. Throughout the present specification, an expression in the singular form should be understood as also encompassing the concept of its plural form, unless otherwise stated. Therefore, the singular articles (for example, “a”, “an”, “the”, and the like in English) should be understood as also encompassing the concept of their plural form, unless otherwise stated.

[0500] In addition, the terms used in the present specification should be understood as being used in the meanings commonly used in the art unless otherwise stated.

[0501] Therefore, unless otherwise defined, all terminology and scientific terms used in the present specification have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. In case of conflict, the present specification (including definitions) shall prevail.

[0502] A pharmaceutical composition of the present invention for treating, alleviating, and/or preventing neuropathic pain, nociceptive pain, or visceral pain, as well as a pharmaceutical composition of the present invention for treating, alleviating, and/or preventing interstitial cystitis and/or bladder pain syndrome, are characterized by being a pharmaceutical composition comprising, as an active ingredient, a compound represented b Formula (I):

##STR00011##

or a pharmaceutically acceptable salt thereof. Note that in the present specification, the pharmaceutical composition of the present invention for treating, alleviating, and/or preventing neuropathic pain, nociceptive pain, or visceral pain is also referred to as a therapeutic, palliative, and/or prophylactic agent for neuropathic pain, a therapeutic, palliative, and/or prophylactic agent for nociceptive pain, or a therapeutic, palliative, and/or prophylactic agent for visceral pain. In addition, pharmaceutical composition of the present invention for treating, alleviating, and/or preventing interstitial cystitis and/or bladder pain syndrome is also referred to as a therapeutic, palliative, and/or prophylactic agent for interstitial cystitis and/or bladder pain syndrome.

[0503] The compound represented by Formula (I) or a pharmaceutically acceptable salt thereof used in the present invention may be a solvate thereof.

[0504] The compound represented by Formula (I) is (2S)-3-(3-[(4-chlorophenyl)methyl]-2,6-dioxo-4-([4-(pyridin-2-yloxy)phenyl]amino)-3,6-dihydro-1,3,5-triazin-1(2H)-yl)-2-methyl-propanoic acid, and has P2X.sub.3 and/or P2X.sub.2/3 receptor antagonist activity. In addition, the compound represented by Formula (I) includes the following tautomers:

##STR00012##

[0505] The compound represented by Formula (I) can be synthesized according to a known method, for example, the methods described in International Publication No. WO 2014/200078 and International Publication No. WO 2012/020749.

[0506] In the present description, as the “pharmaceutically acceptable salt”, examples of basic salts include alkali metal salts such as lithium salt, sodium salt and potassium salt; alkaline earth metal salts such as calcium salt and barium salt; transition metal salts such as zinc salt and iron salt; magnesium salt; ammonium salt; aliphatic amine salts such as trimethylamine salt, triethylamine salt, dicyclohexylamine salt, ethanolamine salt, diethanolamine salt, triethanolamine salt, ethylenediamine salt, meglumine salt and procaine salt; aralkylamine salts such as N,N-dibenzylethylenediamine; heterocyclic aromatic amine salts such as pyridine salt, picoline salt, quinoline salt and isoquinoline salt; quaternary ammonium salts such as tetramethylammonium salt, tetraethylammonium salt, benzyltrimethylammonium salt, benzyltriethylammonium salt, benzyltributylammonium salt, methyltrioctylammonium salt and tetrabutylammonium salt; and basic amino acid salts such as arginine salt and lysine salt. Examples of acidic salts include inorganic acid salts such as hydrochloride, sulfate, nitrate, phosphate, carbonate, hydrogen carbonate, hydrobromate, hydroiodide and perchlorate; organic acid salts such as formate, acetate, propionate, trifluoroacetate, citrate, lactate, tartrate, oxalate, maleate, fumarate, mandelate, glutarate, malate, benzoate, phthalate and ascorbate; sulfonates such as methanesulfonate, ethanesulfonate, isethionate, benzenesulfonate and p-toluenesulfonate; and acidic amino acid salts such as aspartate and glutamate.

[0507] Solvates include organic solvates in which any number of organic solvent molecules are coordinated and hydrates in which any number of water molecules are coordinated. In the present description, the term “solvate” means a solvate of the compound represented by the above Formula (I) or a pharmaceutically acceptable salt thereof, and examples thereof include a monosolvate, a disolvate, a monohydrate and a dihydrate.

[0508] Pharmaceutically acceptable salts and solvates can be synthesized according to a known method.

[0509] In addition, as other pharmaceutical raw materials, additives such as excipients, binders, disintegrants, lubricants, sweeteners, flavoring agents, preservatives, chelating agents, antioxidants, cooling agents, coating agents, stabilizers, fluidizers, viscous agents, solubilizers, thickeners, buffers, flavors, colorants, adsorbents, wetting agents, moisture-proof agents, antistatic agents, plasticizers, antifoaming agents, surfactants, and emulsifiers may be contained. Specifically, binders (for example, corn starch, and the like), fillers (for example, lactose, microcrystalline cellulose, and the like), disintegrants (for example, sodium starch glycolate, and the like), and lubricants (for example, magnesium stearate, and the like) can be mentioned. Their contents are not limited.

[0510] The pharmaceutical composition for the treatment of chronic cough of the present invention can be prepared according to a method known to those skilled in the art. Moreover, the shape and size of the therapeutic agent are not limited. However, oral preparations are preferable, and among these, solid preparations are more preferable. Examples of dosage forms of solid preparations can include tablets (including orally fast disintegrating tablets, chewable tablets, effervescent tablets, jelly drops, and the like), lozenges, granules, pills, powders (including fine granules), and capsules (including hard capsules and soft capsules). Moreover, when preparing these, a coating treatment may be performed by a known method.

[0511] The pharmaceutical composition of the present invention can be administered orally or parenterally. Examples of the parenteral administration method include percutaneous administration, subcutaneous administration, intravenous administration, intraarterial administration, intramuscular administration, intraperitoneal administration, transmucosal administration, inhalation, transnasal administration, eye drops, ear drops, and intravaginal administration.

[0512] For oral administration, any dosage form usually used such as a solid preparation for internal use (e.g., tablets, powders, granules, capsules, pills, and films) or a liquid preparation for internal use (e.g., suspensions, emulsions, elixirs, syrups, lemonades, spirits, aromatic water, extracts, decoctions, and tinctures) can be prepared according to a routine method and administered. The tablets may be sugar-coated tablets, film-coated tablets, enteric coated tablets, sustained-release tablets, troche tablets, sublingual tablets, buccal tablets, chewable tablets or orally disintegrating tablets. The powders and the granules may be dry syrups. The capsules may be soft capsules, microcapsules or sustained-release capsules.

[0513] For parenteral administration, any dosage form usually used such as an injection, drops, and an external preparation (e.g., eye drops, nasal drops, ear drops, aerosols, inhalants, lotions, injectable fillers, liniments, gargles, enemas, ointments, plasters, gels, creams, patches, poultices, powders for external use, and suppositories) can be suitably administered. The injection may be an emulsion of O/W, W/O, O/W/O, W/O/W type, or the like.

[0514] The dose of the ingredients when the pharmaceutical composition of the present invention is used as a pharmaceutical composition for treating, alleviating, and/or preventing neuropathic pain, nociceptive pain or visceral pain, as well as the dose of the ingredients when the pharmaceutical composition of the present invention is used as a pharmaceutical composition for treating, alleviating, and/or preventing interstitial cystitis and/or bladder pain syndrome differ depending on the mode of administration, patient symptoms, age, weight, gender, or other concomitant drugs (if any), and is ultimately left to the discretion of the physician. Examples thereof include an aspect in which a daily adult dose of 10 to 450 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0515] In one embodiment, a daily adult dose of 10 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0516] In one embodiment, a daily adult dose of 20 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0517] In one embodiment, a daily adult dose of 30 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0518] In one embodiment, a daily adult dose of 50 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0519] In one embodiment, a daily adult dose of 70 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0520] In one embodiment, a daily adult dose of 100 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0521] In one embodiment, a daily adult dose of 150 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0522] In one embodiment, a daily adult dose of 200 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0523] In one embodiment, a daily adult dose of 10 mg to 200 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0524] In one embodiment, a daily adult dose of 20 mg to 200 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0525] In one embodiment, a daily adult dose of 30 mg to 200 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0526] In one embodiment, a daily adult dose of 50 mg to 200 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0527] In one embodiment, a daily adult dose of 70 mg to 200 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0528] In one embodiment, a daily adult dose of 100 mg to 200 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0529] In one embodiment, a daily adult dose of 150 mg to 200 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0530] In one embodiment, a daily adult dose of 10 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0531] In one embodiment, a daily adult dose of 20 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0532] In one embodiment, a daily adult dose of 30 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0533] In one embodiment, a daily adult dose of 50 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0534] In one embodiment, a daily adult dose of 70 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0535] In one embodiment, a daily adult dose of 100 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0536] In one embodiment, a daily adult dose of, for example, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 105 mg, 110 mg, 115 mg, 120 mg, 125 mg, 130 mg, 135 mg, 140 mg, 145 mg, 150 mg, 155 mg, 160 mg, 165 mg, 170 mg, 175 mg, 180 mg, 185 mg, 190 mg, 195 mg, and 200 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0537] In one embodiment, a daily adult dose of, for example, 50 mg, 100 mg, 150 mg, 200 mg, 250 mg, or 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0538] The dose may be administered at once or in divided doses. For example, the above dose is administered once a day. For example, the above dose is administered in two divided doses per day. For example, the above dose is administered in three divided doses per day. For example, the above dose is administered in four divided doses per day.

EXAMPLES

[0539] Hereinafter, the present invention will be described based on examples. However, the present invention is not limited to these examples and the like.

(Test Example 1) Evaluation of Human P2X.SUB.3 .Receptor Inhibitory Activity

[0540] A stably expressing cell line in which C6BU-1 cells were transfected with human P2X.sub.3 receptor gene (GenBank accession number Y07683) was seeded on a PDL-coated 96-well microplate so as to have 8000 cells per well, and then, cultured in medium (DMEM containing 7.0% fetal bovine serum, 7.0% horse serum, 1% antibiotic-antimycotic mixed stock solution, 4.0 mM glutamine) at 37° C. and in 5% carbon dioxide for 1 day. The medium was replaced with a solution containing 4 μM of Fluo-3-AM (20 mM HEPES, 137 mM NaCl, 5.37 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.5% BSA, 0.04% Pluronic (registered trademark) F-127, pH 7.5), and then, incubation was carried out at 37° C. and in 5% carbon dioxide for 1 hour. The wells were washed with wash buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, pH 7.5) and the microplate was filled with 40 μL of wash buffer per well. The microplate was placed in the high-throughput screening system FDSS 7000EX (Hamamatsu Photonics). The measurement of fluorescence intensity by FDSS 7000EX was started, and 40 μL per well of a DMSO solution of the compound represented by Formula (I) diluted with a dilution buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.1% Pluronic (registered trademark) F-127, pH 7.5) to different concentrations was each dispensed by the automatic pipetting device built in the FDSS 7000EX. After 5 minutes, 50 μL of ATP solution diluted with the dilution buffer (final concentration of 50 nM) was dispensed by the automatic pipetting device built in the FDSS 7000EX, and then the measurement of the fluorescence intensity was continued for 4 minutes. From the measured fluorescence intensity values, the specific maximum fluorescence intensity, which is expressed as the ratio of the maximum fluorescence intensity value after addition of the ATP solution to the fluorescence intensity at the start of measurement, was calculated for each microplate well. With the value of the specific maximum fluorescence intensity when the compound represented by Formula (I) was not contained as 0% inhibition, and the value of the specific maximum fluorescence intensity when the dilution buffer was added instead of ATP as 100% inhibition, the concentration for 50% inhibition (IC.sub.50) was calculated to evaluate the inhibitory activity of the compound represented by Formula (I). The specific maximum fluorescence intensity was calculated using the FDSS software (Hamamatsu Photonics). The IC.sub.50 was calculated using the software Microsoft Excel (Microsoft) and XLfit (idbs).

(Results)

[0541] The IC.sub.50 was 0.004 μM.

(Test Example 2) Evaluation of Human P2X.SUB.3 .Receptor Inhibitory Activity in the Presence of Human Serum Albumin (HSA)

[0542] A stably expressing cell line in which C6BU-1 cells have been transfected with human P2X.sub.3 receptor gene (GenBank accession number Y07683) is seeded on a PDL-coated 96-well microplate so as to have 8000 cells per well, and then, cultured in medium (DMEM containing 7.0% fetal bovine serum, 7.0% horse serum, 1% antibiotic-antimycotic mixed stock solution, 2.0% glutamine) at 37° C. and in 5% carbon dioxide for 1 day. The medium is replaced with a solution containing 4 μM of Fluo-3-AM (20 mM HEPES, 137 mM NaCl, 5.37 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.5% BSA, 0.04% Pluronic F-127, pH 7.5), and then, incubation is carried out at 37° C. and in 5% carbon dioxide for 1 hour. The wells are washed with wash buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, pH 7.5) and the microplate is filled with 40 μL of wash buffer per well. The microplate is placed in the high-throughput screening system FDSS 7000EX (Hamamatsu Photonics). The measurement of fluorescence intensity by FDSS 7000EX is started, and 40 μL per well of a DMSO solution of the compound represented by Formula (I) diluted to different concentrations with a solution of a dilution buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.1% Pluronic (registered trademark) F-127, pH 7.5) to which human serum albumin is added to a final concentration of 1%, is each dispensed by the automatic pipetting device built in the FDSS 7000EX. After 5 minutes, 50 μL of ATP solution diluted with the dilution buffer (final concentration of 50 nM) is dispensed by the automatic pipetting device built in the FDSS 7000EX, and then the measurement of the fluorescence intensity is continued for 4 minutes. From the measured fluorescence intensity values, the specific maximum fluorescence intensity, which is expressed as the ratio of the maximum fluorescence intensity value after addition of the ATP solution to the fluorescence intensity at the start of measurement, is calculated for each microplate well. With the value of the specific maximum fluorescence intensity when the compound represented by Formula (I) is not contained as 0% inhibition, and the value of the specific maximum fluorescence intensity when the dilution buffer is added instead of ATP as 100% inhibition, the concentration for 50% inhibition (IC.sub.50) is calculated to evaluate the inhibitory activity of the compound represented by Formula (I). The specific maximum fluorescence intensity is calculated using the FDSS software (Hamamatsu Photonics). The IC.sub.50 is calculated using the software Microsoft Excel (Microsoft) and XLfit (idbs).

(Test Example 3) Evaluation of Rat P2X.SUB.3 .Receptor Inhibitory Activity

[0543] Stably expressing cells in which C6BU-1 cells have been transfected with rat P2X.sub.3 receptor gene (GenBank accession number NM_031075) are seeded on a PDL-coated 96-well microplate so as to have 8000 cells per well, then cultured in medium (DMEM containing 7.0% fetal bovine serum, 7.0% horse serum, 1% antibiotic-antimycotic mixed stock solution, 4.0 mM glutamine) at 37° C. and in 5% carbon dioxide for 1 day. The medium is replaced with a solution containing 4 μM of Fluo-3-AM (20 mM HEPES, 137 mM NaCl, 5.37 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2), 5.6 mM D-glucose, 2.5 mM probenecid, 0.5% BSA, 0.04% Pluronic F-127, pH 7.5), and then, incubation is carried out at 37° C. and in 5% carbon dioxide for 1 hour. The wells are washed with wash buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2), 5.6 mM D-glucose, 2.5 mM probenecid, pH 7.5) and the microplate is filled with 40 μL of wash buffer per well. The microplate is placed in the high-throughput screening system FDSS 7000EX (Hamamatsu Photonics). The measurement of fluorescence intensity by FDSS 7000EX is started, and 40 μL per well of a DMSO solution of the compound represented by Formula (I) diluted with a dilution buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.1% Pluronic (registered trademark) F-127, pH 7.5) to different concentrations is each dispensed by the automatic pipetting device built in the FDSS 7000EX. After 5 minutes, 50 μL of ATP solution diluted with the dilution buffer (final concentration of 50 nM) is dispensed by the automatic pipetting device built in the FDSS 7000EX, and then the measurement of the fluorescence intensity is continued for 4 minutes. From the measured fluorescence intensity values, the specific maximum fluorescence intensity, which is expressed as the ratio of the maximum fluorescence intensity value after addition of the ATP solution to the fluorescence intensity at the start of measurement, is calculated for each microplate well. With the value of the specific maximum fluorescence intensity when the compound represented by Formula (I) is not contained as 0% inhibition, and the value of the specific maximum fluorescence intensity when the dilution buffer is added instead of ATP as 100% inhibition, the concentration for 50% inhibition (IC.sub.50) is calculated to evaluate the inhibitory activity of the compound represented by Formula (I). The specific maximum fluorescence intensity is calculated using the FDSS software (Hamamatsu Photonics). The IC.sub.50 is calculated using the software Microsoft Excel (Microsoft) and XLfit (idbs).

(Test Example 4) Evaluation of Rat P2X.SUB.3 .Receptor Inhibitory Activity in the Presence of Rat Serum Albumin (RSA)

[0544] A stably expressing cell line in which C6BU-1 cells have been transfected with human P2X.sub.3 receptor gene (GenBank accession number NM_031075) was seeded so that 8000 cells were present per well, and then, cultured in medium (DMEM containing 7.0% fetal bovine serum, 7.0% horse serum, 1% antibiotic-antimycotic mixed stock solution) at 37° C. and in 5% carbon dioxide for 1 day. The medium was replaced with a solution containing 4 μM of Fluo-4-AM (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2), 5.6 mM D-glucose, 2.5 mM probenecid, 10% BSA, 0.08% Pluronic (registered trademark) F-127, pH 7.5), and then, incubation was carried out at 37° C. and in 5% carbon dioxide for 1 hour. The wells were washed with wash buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2), 5.6 mM D-glucose, 2.5 mM probenecid, pH 7.5) and the microplate was filled with 40 μL of wash buffer per well. The microplate was placed in the high-throughput screening system FDSS 7000EX (Hamamatsu Photonics). The measurement of fluorescence intensity by FDSS 7000EX was started, and 40 μL per well of a DMSO solution of the compound represented by Formula (I), diluted to different concentrations with a solution of a dilution buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2), 5.6 mM D-glucose, 2.5 mM probenecid, 0.1% Pluronic F-127, pH 7.5) to which rat serum albumin was added to a final concentration of 1%, was each dispensed by the automatic pipetting device built in the FDSS 7000EX. After 5 minutes, 50 μL of 50 nM ATP solution diluted with the dilution buffer was dispensed by the automatic pipetting device built in the FDSS 7000EX, and then the measurement of the fluorescence intensity was continued for 4 minutes. From the measured fluorescence intensity values, the specific maximum fluorescence intensity, which is expressed as the ratio of the maximum fluorescence intensity value after addition of the ATP solution to the fluorescence intensity at the start of measurement, was calculated for each microplate well. With the value of the specific maximum fluorescence intensity when the compound represented by Formula (I) was not contained as 0% inhibition, and the value of the specific maximum fluorescence intensity when the dilution buffer was added instead of ATP as 100% inhibition, the concentration for 50% inhibition (IC.sub.50) was calculated to evaluate the inhibitory activity of the compound represented by Formula (I). The specific maximum fluorescence intensity was calculated using the FDSS software (Hamamatsu Photonics). The IC.sub.50 was calculated using the software Microsoft Excel (Microsoft) and XLfit (idbs).

(Results)

[0545] The IC.sub.50 was 10 nM.

(Test Example 5) Assessment of Drug Efficacy in Seltzer Model

[0546] Partial Sciatic Nerve Ligation Model in Rats

[0547] Preparation of Model

[0548] Each rat was anesthetized with isoflurane and the hair of the left thigh was shaved. An incision was made in the skin just below the hip bone. The muscle was bluntly dissected to expose the sciatic nerve. ⅓ to ½ of the sciatic nerve was strongly ligated with a thread, and the muscle and the skin were sutured. This is referred to as a nerve ligated side. The right thigh underwent an identical procedure with the left hind limb except for the ligation of the sciatic nerve. This is referred to as a sham operated side.

[0549] Evaluation (1)

[0550] Two weeks after the operation, the effect on tactile allodynia was assessed using von Frey filaments. Two weeks after the operation, for habituation, the rats were placed into a plastic cage on a wire mesh bottom. Von Frey filaments (0.4 to 26 g) were applied to the plantar surface of the rat hind paws from the wire mesh side, and the value of the von Frey filament pressure at which the paw was withdrawn was used as a pain threshold. Pain thresholds were measured for the left and right hind limbs and these were used as pre-treatment pain thresholds. The rats showing the pain threshold of 0.6 to 2 g on the nerve ligated side and showing the threshold of 8 to 15 g on the sham operated side were employed in the experiments. Before the measurement of the pre-treatment pain thresholds, the rats had their hind paws set on the apparatus to familiarize them with the test procedure. The compound represented by Formula (I) was administered to the employed rats. The compound represented by Formula (I) was homogenized with mortar and pestle and suspended or diluted in 0.5% Methyl Cellulose to prepare a suspension, and it was orally administered at 10 mg/kg to the rats using a syringe attached with a sonde. Pain thresholds were measured for the right and left hind limbs at 3 hours after the drug administration, and these were used as post-treatment pain thresholds. A percent reversal value for each rat was calculated using the following formula. The analgesic effects of the compound were compared.

% Reversal value=100×[Log.sub.10(post-treatment pain threshold on nerve ligated side)−Log.sub.10(pre-treatment pain threshold on nerve ligated side)]/[Log.sub.10(pre-treatment pain threshold on sham operated side)−Log.sub.10(pre-treatment pain threshold in nerve ligated side)]

(Results)

[0551] A Percent Reversal Value of 65% was Indicated.

(Test Example 6) Assessment of Drug Efficacy in Diabetic Neuropathic Pain Model

[0552] Preparation of Rat Diabetic Neuropathic Pain Model

[0553] To overnight fasted rats, 60 mg of streptozotocin (STZ) was intravenously administered to prepare a diabetes model. As a control, rats to which saline was administered were also prepared.

[0554] Evaluation (1)

[0555] Two weeks after the administration of STZ, the analgesic effect of the compound represented by Formula (I) was evaluated by the Randall-Selitto method. In this test, a pressure stimulus was applied to the leg of the test animal, and the degree of the pressure stimulus was gradually increased to observe the response to pain, and the stimulus that caused the response was defined as a pain threshold. On the day of the test, the pain threshold before the administration of the compound represented by Formula (I) was measured, and then after the administration of the test substance, the pain threshold was measured. The compound represented by Formula (I) was homogenized with mortar and pestle and suspended in 0.5% Methyl Cellulose to prepare a suspension, and it was orally administered at 10 mg/kg to the animals using a syringe attached with a sonde. Pain thresholds were measured for the hind limbs at 3 hours after the administration of the test substance, and these were used as post-administration pain thresholds. A percent reversal value for each rat was calculated using the following formula. The analgesic effects of the compound were compared.

% Reversal value=(post-administration pain threshold−pre-administration pain threshold)/(pain threshold of saline-administered rat−pre-administration pain threshold)×100

(Results)

[0556] A Percent Reversal Value of 55% was Indicated.

(Test Example 7) Assessment of Drug Efficacy in Knee Osteoarthritis Pain Model

[0557] Preparation of Rat Knee Osteoarthritis Model

[0558] Under isoflurane anesthesia, a knee joint on one side was shaved, and a monoiode sodium acetate (MIA) solution (saline solution, up to 5 mg/50 μL/rat) was intraarticularly administered.

[0559] Evaluation (1)

[0560] Two weeks after the MIA administration, the analgesic effect of the compound represented by Formula (I) was evaluated. This test was based on a system for measuring a load distribution applied to hind limbs of a rat, and a ratio of load differences between left and right hind limbs was used as a pain threshold. On the day of the test, the pain threshold before the administration of the compound represented by Formula (I) was measured, and then after the administration of the test substance, the pain threshold was measured. The compound represented by Formula (I) was homogenized with mortar and pestle and suspended in 0.5% Methyl Cellulose to prepare a suspension, and it was orally administered at 10 mg/kg to the animals using a syringe attached with a sonde. Pain thresholds were measured for the hind limbs at 3 hours after the administration of the test substance, and these were used as post-administration pain thresholds. The load difference was measured up to three times, and the average value thereof was used as the pain threshold.

[0561] A percent reversal value for each rat was calculated using the following formula. The analgesic effects of the compound were compared.

% Reversal value=(post-administration pain threshold−pre-administration pain threshold)/(pain threshold of saline-administered rat−pre-administration pain threshold)×100

(Results)

[0562] A percent reversal value of 51% was indicated.

(Test Example 8) Assessment of Drug Efficacy in Inflammatory Pain Model

[0563] Preparation of Rat Inflammatory Pain Model

[0564] Under isoflurane anesthesia, FCA (12.5-100 μg) was subcutaneously injected into the hind limb of a rat to prepare an inflammatory pain model.

[0565] Evaluation (1)

[0566] Two weeks after the administration of FCA, the analgesic effect of the compound represented by Formula (I) was evaluated by the Randall-Selitto method. In this test, a pressure stimulus was applied to the leg of the test animal, and the degree of the pressure stimulus was gradually increased to observe the response to pain, and the stimulus that caused the response was defined as a pain threshold. On the day of the test, the pain threshold before the administration of the compound represented by Formula (I) was measured, and then after the administration of the test substance, the pain threshold was measured. The compound represented by Formula (I) was homogenized with mortar and pestle and suspended in 0.5% Methyl Cellulose to prepare a suspension, and it was orally administered at 10 mg/kg to the animals using a syringe attached with a sonde. Pain thresholds were measured for the hind limbs at 1 hour after the administration of the test substance, and these were used as post-administration pain thresholds. A percent reversal value for each rat was calculated using the following formula. The analgesic effects of the compound were compared.

% Reversal value=(post-administration pain threshold−pre-administration pain threshold)/(pain threshold of hind limb on FCA-non-administered side−pre-administration pain threshold)×100

(Results)

[0567] A Percent Reversal Value of 58% was Indicated.

(Test Example 9) Assessment of Drug Efficacy in Cystitis Pain Model

[0568] Preparation of Mouse Bladder Pain Model

[0569] Cyclophosphamide was dissolved in physiological saline or the like, and the solution was intraperitoneally administered to mice. Cyclophosphamide was administered at 150 mg/kg once daily consecutively for four days. As a control, mice to which saline was administered were also prepared.

[0570] Evaluation (1)

[0571] The analgesic effect of the compound represented by Formula (I) was evaluated the day after the final administration of cyclophosphamide. In this test, mechanical stimulation by an automatic von Frey device was applied to the periphery of the lower abdomen while holding the mouse, and with respect to the resulting escape behavior defined as pain-like behavior, the pain threshold was determined. On the day of the test, the pain threshold before the administration (pre-administration pain threshold) of the compound represented by Formula (I) was measured, and then after the administration of the test substance, the pain threshold was measured. The compound represented by Formula (I) was homogenized with mortar and pestle and suspended or diluted in 0.5% Methyl Cellulose to prepare a suspension, and it was orally administered at 3 mg/kg to the rats using a syringe attached with a sonde. Pain thresholds were measured at 1 hour after the administration of the test substance, and these were used as post-administration pain thresholds. A percent reversal value for each rat was calculated using the following formula. The analgesic effects of the compound were compared.

% Reversal value=(post-administration pain threshold−pre-administration pain threshold)/(pain threshold of saline-administered mouse−pre-administration pain threshold)×100

(Results)

[0572] A Percent Reversal Value of 46% was Indicated.

(Test Example 10) Assessment of Drug Efficacy in Mouse Bone Cancer Pain Model

[0573] Preparation of Mouse Bone Cancer Pain Model

[0574] The skin was incised under isoflurane anesthesia, the muscles were torn to expose the left femur, a hole was made in the bone marrow cavity using a 26 G needle, and tumor cells (NCTC2472 cells derived from C3H/HeN mice) were transplanted using a 30 G needle. The hole made in the femoral bone marrow cavity was closed with dental cement, and then the skin was sutured. Mice in sham-operated groups were prepared by administering HBSS instead of tumor cells.

[0575] Evaluation (1)

[0576] Two weeks after the operation, the effect on tactile allodynia was assessed using von Frey filaments. Two weeks after the operation, for habituation, the mice were placed into a plastic cage on a wire mesh bottom. Von Frey filaments were applied to the plantar surface of the mouse hind paws from the wire mesh side, and the value of the von Frey filament pressure at which the paw was withdrawn was used as a pain threshold. The pain threshold was evaluated for the operated hind limb and defined as a pre-administration pain threshold, and the compound represented by the formula (I) was administered to the animal at 10 mg/kg. The compound represented by Formula (I) was homogenized with mortar and pestle and suspended or diluted in 0.5% Methyl Cellulose to prepare a suspension, and it was orally administered to the rats using a syringe attached with a sonde. Pain thresholds were measured for the operated hind limbs after the administration of the test substance, and these were used as post-administration pain thresholds. A percent reversal value for each rat was calculated using the following formula. The analgesic effects of the compound were compared.

% Reversal value=100×[Log.sub.10(post-operation/administration pain threshold)−Log.sub.10(pre-operation/administration pain threshold)]/[Log.sub.10(pain threshold on sham operated side)−Log.sub.10(pre-operation/administration pain threshold)]

(Results)

[0577] A Percent Reversal Value of 55% was Indicated.

(Test Example 11) Assessment of Drug Efficacy in Acetic Acid-Induced Urination Disorder Model

[0578] Preparation of acetic acid-induced urination disorder model

[0579] A catheter was placed in a rat bladder under isoflurane anesthesia. After 2 days from the surgery for placing the catheter, 0.3% acetic acid was administered at 4 mL/hr over 30 minutes to induce cystitis. In this model, the amount of urine per urinating action and the voiding interval decreased.

[0580] Evaluation (1)

[0581] On the day after acetic acid was administered, the amount of urine per urinating action and the voiding interval before drug administration were evaluated. The compound represented by Formula (I) was homogenized with mortar and pestle and suspended in 0.5% Methyl Cellulose to prepare a suspension, and it was orally administered at 0.1 mg/kg, 0.75 mg/kg, or 3 mg/kg to the rats using a syringe attached with a sonde. The amount of urine per urinating action and the voiding interval during a period from 30 minutes to 150 minutes after administration were measured. The value before administration for each individual was assumed to be 100%, and the change rate after administration was calculated.

Rate of change in amount of voided urine per urinating action=(amount of urine per urinating action after drug treatment of cystitis rat+amount of voided urine per urinating action before drug treatment of cystitis rat)×100

Rate of change in voiding interval=(voiding interval after drug treatment of cystitis rat+voiding interval before drug treatment of cystitis rat)×100

(Results)

[0582] Rate of change in amount of voided urine per urinating action: 208.4% (3 mg/kg administration group)
Rate of change in voiding interval: 219.0% (3 mg/kg administration group)

[0583] As shown in FIGS. 1 and 2, a significant improving effect was shown by administration of 3 mg/kg of the compound represented by Formula (I).

[0584] All data are shown as mean±SEM.

$: p<0.05; significantly different from vehicle (Dunnett's multiple comparison test)

[0585] From the results of Test Example 5 to 10 described above, it was found that the compound represented by Formula (I), which is a P2X.sub.3 and/or P2X.sub.2/3 receptor antagonist, or a pharmaceutically acceptable salt thereof has a high improvement rate of pain and exhibits effectiveness in treating pain. In addition, from the results of Test Example 9 and Test Example 11, it was found that the composition was effective in treating cystitis pain, and further, it was found that the prolongation of the voiding interval and the associated increase in the amount of voided urine per urinating action were confirmed. Thus, it was found that the composition was effective in treating interstitial cystitis and/or bladder pain syndrome.

Formulation Example

[0586] The following Formulation Examples are only exemplified and not intended to limit the scope of the invention.

(Formulation Example 1) Suspension

[0587] For example, water for injection was added to the active pharmaceutical ingredient, the compound represented by Formula (I), to prepare a suspension.

(Formulation Example 2) Tablets

[0588] For example, lactose and magnesium stearate were added as additives to the active pharmaceutical ingredient, the compound represented by Formula (I), to prepare tablets.

INDUSTRIAL APPLICABILITY

[0589] A pharmaceutical composition comprising a compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is useful as a medicament for treating, alleviating, and/or preventing neuropathic pain, nociceptive pain, or visceral pain. In particular, it is useful as a medicament for treating, alleviating, and/or preventing peripheral neuropathic pain, diabetic neuropathic pain, cystitis pain, or pain associated with endometriosis. Furthermore, it is useful as a medicament for treating, alleviating, and/or preventing interstitial cystitis and/or bladder pain syndrome.