[0001] This invention was made with United States Government support under Grant No. U44NS093160 awarded by the National Institute Of Neurological Disorders And Stroke of the National Institutes of Health. The United States Government has certain rights in the invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Application No. 15/591,884 filed May 10, 2017, which is hereby incorporated by reference in its entirety.

SUMMARY

[0003] Potassium (jC) channels, present on the plasma membranes of most cell types, are the most diverse class of all ion channels and are associated with a wide range of physiological functions including the regulation of the electrical properties of excitable cells. The primary pore-forming (a) subunits of these highly selective cation channels are divided into three primary structural classes based on the number of transmembrane (TM)-spanning regions and pore (P) regions: currently there are known to be 6TM/1P, 2TM/1P and 4TM/2P K ⁺ channels. The Kv7 genes (originally termed KCNQ, a name assigned by the HUGO Gene Nomenclature Committee (HGNC)) were assigned to a subfamily of voltage-gated K ⁺ channels by the International Union of Pharmacology (IUPHAR). The Kv7 subfamily consists of five homologous pore-forming a subunits, Kv7.1-7.5, that have a structure typical of voltage-gated K ⁺ channels with 6TM-spanning regions (S1-S6) flanked by intracellular N- terminal and C-terminal domains, a typical voltage-sensor domain located in S4 comprised of alternating positively-charged residues and a single P region between S5 and S6 of each subunit. The channels are formed as tetramers of the primary a subunits, either as homotetramers or heterotetramers. Neurons are known to express Kv7 channels comprised of Kv7.2-7.5 a subunits. Some of these gene products may be exclusively neuronal while others, such as Kv7.4 and Kv7.5, can be found in other tissues such as smooth and skeletal muscle.

[0004] Retigabine is modestly potent, not highly specific, but it is a very effective opener of Kv7.2, Kv7.5, and heteromultimeric Kv7 channels. Provided herein are compounds that can be potent and/or at least biased for the Kv7.2/7.3 heteromultimer over the Kv7.4 homomultimer. These compounds may have reduced untoward side effects as compared to retigabine. DETAILED DESCRIPTION

[0005] Before the present compositions and methods are described, it is to be understood that any invention is not limited to the particular processes, compositions, or methodologies described, as these may vary. Moreover, the processes, compositions, and methodologies described in particular embodiments are interchangeable. Therefore, for example, a composition, dosage regimen, route of administration, and so on described in a particular embodiment may be used in any of the methods described in other particular embodiments. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present invention, which will be limited only by the appended claims. Unless clearly defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Although any methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, the preferred methods are now described. All publications and references mentioned herein are incorporated by reference. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.

[0006] It must be noted that, as used herein, and in the appended claims, the singular forms "a", "an", and "the" include plural reference unless the context clearly dictates otherwise.

[0007] As used herein, the term "about" means plus or minus 10% of the numerical value of the number with which it is being used. Therefore, about 50% means in the range of 45%-55%. Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0008] "Administering," when used in conjunction with a therapeutic, means to administer a therapeutic directly into or onto a target tissue or to administer a therapeutic to a subject whereby the therapeutic positively impacts the tissue to which it is targeted. ''Administering" a composition may be accomplished by oral administration, injection, infusion, absorption or by any method in combination with other known techniques. "Administering ^" ' may include the act of self-administration or administration by another person such as a healthcare provider or a device.

[0009] As used herein, the terms "comprising," "comprise," "comprises," and "comprised" are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0010] As used herein, the term "consists of or "consisting of means that the composition or method includes only the elements, steps, or ingredients specifically recited in the particular embodiment or claim.

[0011] As used herein, the term "consisting essentially of or "consists essentially of means that the composition or method includes only the specified materials or steps and those that do not materially affect the basic and novel characteristics of the claimed invention.

[0012] In each of the embodiments disclosed herein, the compositions and methods may be utilized with or on a subject in need of such treatment, which may also be referred to as "in need thereof." As used herein, the phrase "in need thereof means that the subject has been identified as having a need for the particular method or treatment and that the treatment has been given to the subject for that particular purpose.

[0013] As used herein, the term "patient" and "subject" are interchangeable and may be taken to mean any living organism, which may be treated with compounds of the present invention. As such, the terms '"patient" and "subject" may include, but is not limited to, any non-human mammal, primate, or human. In some embodiments, the "patient" or "subject" is an adult, child, infant, or fetus. In some embodiments, the "patient" or "subject" is a human. In some embodiments, the "patient" or "subject" is a mammal, such as mice, rats, other rodents, rabbits, dogs, cats, swine, cattle, sheep, horses, primates, or humans.

[0014] The terms "therapeutically effective amount" or "therapeutic dose" is used herein are interchangeable and may refer to the amount of an active agent or pharmaceutical compound or composition that elicits a clinical, biological or medicinal response in a tissue, system, animal, individual, or human that is being sought by a researcher, veterinarian, medical doctor, or other clinical professional. A clinical, biological, or medical response may include, for example, one or more of the following: (1) preventing a disease, condition, or disorder in an individual that may be predisposed to the disease, condition, or disorder but does not yet experience or display pathology or symptoms of the disease, condition, or disorder, (2) inhibiting a disease, condition, or disorder in an individual that is experiencing or displaying the pathology or symptoms of the disease, condition, or disorder or arresting further development of the pathology and/or symptoms of the disease, condition, or disorder, and (3) ameliorating a disease, condition, or disorder in an individual that is experiencing or exhibiting the pathology or symptoms of the disease, condition, or disorder or reversing the pathology and/or symptoms experience or exhibited by the individual.

[0015] The term "treating" may be taken to mean prophylaxis of a specific disorder, disease, or condition, alleviation of the symptoms associated with a specific disorder, disease or condition, and/or prevention of the symptoms associated with a specific disorder, disease, or condition. In some embodiments, the term refers to slowing the progression of the disorder, disease, or condition or alleviating the symptoms associated with the specific disorder, disease, or condition. In some embodiments, the term refers to alleviating the symptoms associated with the specific disorder, disease, or condition. In some embodiments, the term refers to alleviating the symptoms associated with the specific disorder, disease, or condition. In some embodiments, the term refers to restoring function which was impaired or lost due to a specific disorder, disorder, or condition.

[0016] "Pharmaceutically acceptable salt" is meant to indicate those salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of a patient without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, Berge et al. (1977) J. Pharm. Sciences, Vol. 6, 1-19, describes pharmaceutically acceptable salts in detail. A pharmaceutical acceptable "salt" is any acid addition salt, preferably a pharmaceutically acceptable acid addition salt, including, but not limited to, halogenic acid salts such as hydrobromic, hydrochloric, hydrofluoric, and hydroiodic acid salt; an inorganic acid salt such as, for example, nitric, perchloric, sulfuric, and phosphoric acid salt; an organic acid salt such as, for example, sulfonic acid salts (methanesulfonic, trifluoromethan sulfonic, ethanesulfonic, benzenesulfonic, or p-toluenesufonic, acetic, malic, fumaric, succinic, citric, benzonic gluconic, lactic, mandelic, mucic, pamoic, pantothenic, oxalic, and maleic acid salts; and an amino acid salt such as aspartic or glutamic acid salt. The acid addition salt may be a mono- or di-acid addition salt, such as a di-hydrohalogic, di-sulfuric, di-phosphoric, or di-organic acid salt. In all cases, the acid addition salt is used as an achiral reagent which is not selected on the basis of any expected or known preference for the interaction with or precipitation of a specific optical isomer of the products of this disclosure.

[0017] In some embodiments, provided herein are any one of the following compounds, or a pharmaceutically acceptable salt thereof:

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[0018] Embodiments herein are directed to pharmaceutical compositions comprising a therapeutically effective amount of a compound described herein or acceptable salts thereof, such as a compound of paragraph [0016] or Table 1 or pharmaceutically acceptable salts thereof. Pharmaceutical compositions containing such compounds and a suitable carrier can be in various forms including, but not limited to, solids, solutions, powders, fluid emulsions, fluid suspensions, semi -solids, and dry powders including an effective amount of a compound of the invention. It is also known in the art that the active ingredients can be contained in such formulations with pharmaceutically acceptable diluents, fillers, disintegrants, binders, lubricants, surfactants, hydrophobic vehicles, water soluble vehicles, emulsifiers, buffers, humectants, moisturizers, solubilizers, antioxidants, preservatives, and the like. Hie means and methods for administration are known in the art and an artisan can refer to various pharmacologic references for guidance. For example. Modem Pharmaceutics, Banker & Rhodes, Marcel Dekker, Inc. (1979); and Goodman & Oilman's, The Pharmaceutical Basis of Therapeutics, 6th Edition, MacMillan Publishing Co., New York (1980) both of which are hereby incorporated by reference in their entireties can be consulted.

[0019] The compounds can be formulated for parenteral or intravenous administration by injection, e.g., by bolus injection or continuous infusion. Formulations for injection can be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions can take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and can contain formulatory agents such as suspending, stabilizing, and/or dispersing agents.

[0020] Injectable preparations may be formulated according to the known art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a nontoxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution, and isotonic sodium chloride solution.

[0021] Other embodiments include a compound prepared as described above which are formulated as a solid dosage form for oral administration including capsules, tablets, pills, powders, and granules. In such embodiments, the active compound may be admixed with one or more inert diluent such as sucrose, lactose, or starch. Such dosage forms may also comprise, as in normal practice, additional substances other than inert diluents, e.g., lubricating agents such as magnesium stearate. In the case of capsules, tablets, and pills, the dosage forms may also comprise buffering agents and can additionally be prepared with enteric coatings.

[0022] Preparation of a compound of the invention in solid dosage form may vary. For example, in one embodiment, a liquid or gelatin formulation may be prepared by combining a compound, such as those described above, and adding a thickening agent to the liquid mixture to form a gelatin. The gelatin may then be encapsulated in unit dosage form to form a capsule. In another exemplary embodiment, an oily preparation of a compound prepared as described above may be lyophilized to for a solid that may be mixed with one or more pharmaceutically acceptable excipient, carrier or diluent to form a tablet. [0023] Further embodiments which may be useful for oral administration of a compound for the invention include liquid dosage forms. In such embodiments, a liquid dosage may include a pharmaceutically acceptable emulsion, solution, suspension, syrup, and elixir containing inert diluents commonly used in the art, such as water. Such compositions may also comprise adjuvants, such as wetting agents, emulsifying and suspending agents, and sweetening, flavoring, and perfuming agents.

[0024] In still further embodiments, the compounds described herein can be formulated as a depot preparation. Such long acting formulations can be administered by implantation (for example, subcutaneously or intramuscularly) or by intramuscular injection. Depot injections can be administered at about 1 to about 6 months or longer intervals. Thus, for example, the compounds can be formulated with suitable polymeric or hydrophobic materials (for example, as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.

Methods of Use

[0025] Embodiments of the present invention relate to a method of treating a disorder comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. The disorder is selected from epilepsy, epileptic spasms, neonatal spasms, neonatal seizures, benign familial neonatal epilepsy, epileptic encephalopathy, pain, migraine, a disorder of neurotransmitter release, a smooth muscle contractility disorder, early infantile epileptic encephalopathy with delayed psychomotor development, generalized tonic seizures, abnormal globus pallidus morphology, apnea, cerebral edema, a dyskinesia, dystonia, facial erythema, muscular hypotonia, febrile seizures, hypoplasia of the corpus callosum, hypsarrhythmia, focal clonic seizure, generalized tonic-clonic seizures, myokymia, spastic tetraparesis, myokymia, mania, a hearing disorder, neuropathic pain, inflammatory pain, persistent pain, cancer pain, postoperative pain, anxiety, substance abuse, schizophrenia, a bladder disorder, a vasculature disorder, tinnitus and combinations thereof. In embodiments, such compound may be administered in a pharmaceutical composition as described herein.

[0026] KCNQ genes encode five Kv7 potassium channel subunits (1-5). A functional Kv7 potassium channel can be assembled using a combination of these five subunits arranged as homotetramers or heterotetramers. KCNQ2, KCNQ3, KCNQ4, and KCNQ5 are expressed in the nervous system and have been associated with a range of disorders involving neuronal excitability.

[0027] Embodiments herein are directed to methods of treating a disorder associated with a KCNQ subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. Embodiments herein are directed to methods of treating a disorder associated with a KCNQ2 subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. Embodiments herein are directed to methods of treating a disorder associated with a KCNQ3 subunit comprising administering a therapeutically effective amount of a compound as described in paragraph

[0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. Embodiments herein are directed to methods of treating a disorder associated with a KCNQ4 subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. Embodiments herein are directed to methods of treating a disorder associated with a KCNQS subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof.

[0028] Embodiments herein are directed to methods of treating a disorder associated with a mutation in a KCNQ subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. Embodiments herein are directed to methods of treating a disorder associated with a mutation in a KCNQ2 subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. Embodiments herein are directed to methods of treating a disorder associated with a mutation in a KCNQ3 subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. Embodiments herein are directed to methods of treating a disorder associated with a mutation in a KCNQ4 subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof. Embodiments herein are directed to methods of treating a disorder associated with a mutation in a KCNQ5 subunit comprising administering a therapeutically effective amount of a compound as described in paragraph [0016] or Table 1, or any other compound as described herein, or a pharmaceutically acceptable salt thereof, to a subject in need thereof.

[0029] In embodiments, such compound may be administered in a pharmaceutical composition as described herein.

[0030] Therapeutically effective amounts of the compounds disclosed herein range from about 0.1 mg to about 1000 mg. Such therapeutically effective amounts may be administered once a day or in equal, divided doses twice a day, three times a day, or four times a day.

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Biological Assay Methods

[0031] KV7.2/7.3 Activation Assay

[0032] The ability of compounds to potentiate K-currents in Kv7.2/7.3 containing HEK cells was assessed using planar patch-clamp on the QPatch automated screening platform.

[0033] Cell Line: The hKv7.2/7.3 cell line was obtained from Chantest (Cleveland, OH 44128) catJ CT6147. These HEK cells will express the Kv7.2/7.3 ion channels when induced.

[0034] Cell Culture: Cells were maintained in a media containing DMEM/F12; 50/50 (GIBCO cat.# 11330), 10% Fetal Bovine Serum (FBS) (GIBCO catJ 26140), 100 units/mL Penicillin-Streptomycin (GIBCO cat.# 15140), 0.005 mg/rtiL Blasticidin (INVIVOGEN catJ ant-bl-1), 0.5 mg/mL Geneticin (GIBCO cat.# 10131), 0.1 mg/mL Zeocin (GIBCO catJ R25001). Cells used in the electrophysiology assay were maintained in a media without Blasticidin, Geneticin and Zeocin for 2 days and channel expression was induced by adding tetracycline (BIOLINE cat.# BIO-87030) at a final concentration of 1 mg/mL. Cells were grown in T-175 flask to ~75% confluency. Currents were recorded 24 hours after channel induction.

[0035] Compound Plates: Test compounds were prepared by performing serial dilutions on a Biomek NX ^P (BECKMAN COULTER). Final dilutions were made in external recording solution with a final DMSO concentration of 0.1% DMSO. For single concentration screens each plate had 10 μΜ retigabine as a positive control and 0.1% DMSO as a negative control.

[0036] Electrophysiology: On the day of the experiment cells were washed with Hank's Balanced Salt Solution (HBBS) (GIBCO cat.#14175) and harvested with Tryple (GIBCO catJ 12604). Cells were then centrifuged at 2000 rpm for 5 minutes and resuspended in CHO-S-SFM (GIBCO cat.# 12052) at ~3xl0 ⁶ cells/mL. Cells were stirred for 30 minutes before experiments were started. External recording solution contained (in mM): NaCl (145), KC1 (4), CaCl ₂ (2), MgCl ₂ (1), HEPES (10) and Glucose (10); pH was adjusted to 7.4 with NaOH and the osmolality was adjusted to 300-305 mOsM with sucrose if necessary. Internal solution contained (in mM): KC1 (125), KF (10), EGTA (5), Na2ATP (5), MgC.2 (3.2), HEPES (5); pH was adjusted to 7.2 with KOH and the osmolality was adjusted to 298-302 mOsM with sucrose. [0037] Potassium channel activity was measured on the QPatch HTX (Sophion Bioscience) using QPlates with 48-wells/plate. Each cell was taken as an independent experiment and only one compound was tested per well. Potassium channel activity was elicited by holding at -80 mV and stepping to -30 mV for 2 s followed by a 100 ms pulse to - 120 mV.

[0038] Single concentration screen: Baseline conditions were obtained by recording 5 sweeps in the external solution only, this was repeated for three applications of the external solution. The effect of test compounds on elicited current was then assessed by recording 5 sweeps in the presence of a 3 uM compound solution. The steady-state current at the end of the 2 s pulse to -30 mV was measured to determine the fold increase from baseline.

[0039] Groupings of alternative elements or embodiments disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

[0040] Certain embodiments are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than specifically described herein. Accordingly, the claims include all modifications and equivalents of the subject matter recited in the claims as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is contemplated unless otherwise indicated herein or otherwise clearly contradicted by context.

[0041] In closing, it is to be understood that the embodiments disclosed herein are illustrative of the principles of the claims. Other modifications that may be employed are within the scope of the claims. Thus, by way of example, but not of limitation, alternative embodiments may be utilized in accordance with the teachings herein. Accordingly, the claims are not limited to embodiments precisely as shown and described.