Treatment of hyperammonemia

Abstract

The present invention relates to a compound of the following formula (I): (I) or a pharmaceutically acceptable salt, hydrate, or solvate thereof, for use in the prevention or treatment of hyperammonemia in an individual. (no figure)

Description

Title of the invention: Treatment of hyperammonemia Scope of the invention

[0001] This application relates to pharmaceutical compounds and compositions useful in the prevention or treatment of hyperammonemia, in particular drug-induced hyperammonemia. Technical background

[0002] Hyperammonemia is a metabolic disorder characterized by high levels of ammonia, a nitrogen-containing compound, in the blood. Ammonia is an important source of nitrogen and is necessary for the synthesis of amino acids. It is also necessary for normal acid-base balance. However, when present in high concentrations, ammonia is toxic.

[0003] Normally, ammonia is produced in the colon and small intestine from where it is transported to the liver to be converted via the urea cycle into urea, a water-soluble compound which will then be excreted by the kidneys.

[0004] The consequences of hyperammonemia are varied and can be serious. Indeed, ammonia is a potent neurotoxin, and its entry into the brain causes neurological disorders that can lead to seizures, ataxia, stroke-like lesions, coma, psychosis, vision loss, acute encephalopathy, and cerebral edema. Other symptoms such as vomiting, respiratory alkalosis, hypothermia, and liver damage that can lead to death are also observed in individuals with hyperammonemia.

[0005] Hyperammonemia must be detected early and treated immediately to avoid the development of life-threatening complications such as cerebral edema or cerebral herniation.

[0006] Currently, the management of hyperammonemia involves a combination of several measures to reduce the level of ammonia in the blood. Generally, patients receive a low-protein diet combined with medications to promote nitrogen elimination, such as sodium phenylbutyrate, sodium benzoate, and glycerol phenylbutyrate (Enns et al., (2007) New Engl J Med., 356:2282-2292).

[0007] However, these medications must be administered several times a day and cause numerous side effects, particularly nausea, vomiting, irritability, and anorexia. Furthermore, due to the need to calculate dosages, an overdose can easily occur and lead to adverse effects. serious metabolic side effects and death.

[0008] Thus, there remains a need for effective alternative treatment and prevention of hyperammonemia. Summary of the invention

[0009] The present invention arises from the unexpected discovery by the inventors that stiripentol made it possible to reduce methionine sulfoximine (MSO) induced hyperammonemia as well as convulsions related to methionine sulfoximine (MSO) induced hyperammonemia.

[0010] Thus, the present invention relates to a compound of the following formula (I):

[0011] [Chem.l] HAS.

[0012] (I)

[0013] in which:

[0014] - n represents 1 or 2,

[0015] - Ai, A2 and A3, identical or different, represent a hydrogen atom, an atom of halogen, or a linear or branched alkyl group having 1 to 4 carbon atoms,

[0016] - Ri, R2 and R3 independently represent a hydrogen atom or a group linear or branched alkyl having 1 to 4 carbon atoms, and

[0017] - Y represents -OH, =0 or -SH;

[0018] or a pharmaceutically acceptable salt, hydrate or solvate thereof,

[0019] for use in the prevention or treatment of hyperammonemia in an individual.

[0020] The present invention also relates to the compound of formula (I) or the pharmaceutically acceptable hydrated or solvated salt thereof for use as defined above in combination with at least one additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia.

[0021] The present invention also relates to a pharmaceutical composition comprising as an active substance at least one compound of formula (I) as defined above, or a pharmaceutically acceptable salt, hydrate or solvate thereof, optionally in association with a pharmaceutically acceptable vehicle, for use in the prevention or treatment of hyperammonemia.

[0022] The present invention also relates to a pharmaceutical composition comprising as an active substance at least one compound of formula (I) as defined above, or a pharmaceutically acceptable salt, hydrate or solvate thereof, optionally in association with a pharmaceutically acceptable vehicle, and optionally comprising at least one additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia.

[0023] The present invention also relates to a pharmaceutical composition comprising as an active substance at least one compound of formula (I) as defined above, or a pharmaceutically acceptable salt, hydrate or solvate thereof, optionally in association with a pharmaceutically acceptable vehicle, and optionally comprising at least one additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia selected from the group consisting of neuroprotective drugs, anti-inflammatory drugs, sodium benzoate, sodium phenylbutyrate, glycerol phenylbutyrate, N-carbamylglutamate, sodium benzoate, sodium phenylacetate, lactulose, arginine hydrochloride, L-arginine, carglumic acid, L-ornithine, L-aspartate, citrulline and mixtures thereof.

[0024] The present invention also relates to products containing:

[0025] - at least one compound of formula (I) as defined above, or a pharmaceutically acceptable salt, hydrate or solvate thereof, and - at least one additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia,

[0026] as a combination product for use, including simultaneous, separate or spread over time, for the prevention or treatment of hyperammonemia in an individual.

[0027] The present invention also relates to a method for preventing or treating hyperammonemia in an individual comprising administering to the individual an effective amount of a compound of formula (I) as defined above, or of a pharmaceutically acceptable salt, hydrate or solvate thereof.

[0028] In one embodiment of the invention, the method as defined above also includes the administration of at least one additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia.

[0029] The present invention also relates to the use of a compound of formula (I) as defined above, or of a pharmaceutically ac salt, hydrate or solvated acceptable from this, for the preparation of a drug intended for the prevention or treatment of hyperammonemia in an individual.

[0030] In one embodiment of the invention, the drug as defined above comprises at least one additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia. Detailed description of the invention

[0031] As understood here, the term "comprising" is synonymous with "including," "containing," or "encompassing," meaning that when an object "comprising" one or more characteristics, other characteristics besides those mentioned may also be included in the object. Conversely, the expression "consisting of" means "made up of," meaning that when an object "consists of" one or more characteristics, the object cannot include any characteristics other than those mentioned.

[0032] Compound of formula (I)

[0033] Preferably, the compound of formula (I) as defined above is represented by the following formula (II):

[0034] [Chem.2] HAS

[0035] (II)

[0036] in which n, Ai, A2, A3 and Ri are as defined above.

[0037] More preferably, the compound of formula (I) or (II) defined above is represented by the following formula (III):

[0038] [Chem.3]

[0039] (III)

[0040] The preferred alkyl groups according to the invention include methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl and t-butyl groups.

[0041] Cl, I, Br or F atoms are preferred halogen atoms according to the invention.

[0042] French patent FR 2 173 691, incorporated herein by reference, describes the synthesis of the sti- ripentol, notably from methylenedioxy-3,4-phenyl-l-dimethyl-4,4-penten-l-on-3. It is entirely within the ordinary competence of a person skilled in the art to synthesize the other compounds of formula (I) from this teaching.

[0043] As will be clear to those skilled in the art, the formulas (I), (II) and (III) defined above represent either the various stereoisomers encompassed by these formulas, or their mixtures, in particular their racemic mixtures.

[0044] Thus, the compound of formula (III) can be a compound of formula (Ilia), a compound of formula (Illb), or a mixture of a compound of formula (Ilia) and a compound of formula (Illb), in particular a racemic mixture of these.

[0045] [Chem.3a] OH

[0046] (Ilia)

[0047] [Chem.3b] OH

[0048] (Illb)

[0049] Prevention or treatment

[0050] Hyperammonemia refers to an increase in ammonia concentrations in the body. Thus, hyperammonemia according to the invention can be caused, for example, by an increase in ammonia production or by a decrease in the body's ammonia detoxification processes.

[0051] Ammonia (NH3), which can coexist in the body with the ammonium cation (NH4+) depending on the pH, is a product of the catabolism of proteins and other nitrogenous compounds. It is converted by the enzymes of the urea cycle into a less toxic substance, urea, before its excretion in the urine by the kidneys.

[0052] The urea cycle, which also functions as a source of production for certain amino acids (arginine, citrulline, and omithine) in the body, comprises six enzymes: carbamoyl phosphate synthase I (CPS), omithine transcarbamylase (OTC), argininosuccinate synthetase (ASS), argininosuccinate lyase (ASL), arginase, and N-acetylglutamate synthase (NAGS), and two transport proteins: omithine translocase (ORNT1) and citrin. A defect can occur in one or more of these eight proteins, leading to hyperammonemia, also known as

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] of primary hyperammonemia. As an example of a urea cycle disorder leading to primary hyperammonemia according to the invention, the following may be cited: • a deficiency in N-acetylglutamate synthase; • a deficiency in carbamoylphosphate synthetase 1; • omithine transcarbamylase deficiency; • a deficiency in argininosuccinate synthetase; • an argininosuccinate lyase deficiency; • a deficiency in arginase 1; • the hyperornithinemia-hyperammonemia-homocitrullinuria syndrome; • a citrulline deficiency (citrullinemia type 2). Hyperammonemia according to the invention can also be due to inhibition of the urea cycle because of errors in intermediate metabolism characterized by reduced activity of enzymes or proteins that are not part of the urea cycle; this is also referred to as secondary hyperammonemia. As an example of an anomaly causing inhibition of the urea cycle leading to secondary hyperammonemia according to the invention, the following may be cited: • Propionic acidemia leading to glutamate deficiency; • methylmalonic acidemias leading to the production of methyl citrate; • isovaleric acidemia; • a deficiency in 3-hydroxy-3-methylglutaryl-CoA-lyase; • an ATP deficiency, leading to a secondary CPS1 deficiency. - As an example of secondary hyperammonemia according to the invention, hyperammonemia caused by a deficiency in substrates, in particular by: • a defect in the oxidation of fatty acids leading to a CoA deficiency; • disorders of the camitine cycle leading to a CoA deficiency; • pyruvate dehydrogenase complex disorders leading to a deficiency in CoA; • acute or chronic liver failure resulting in CoA deficiency; • an intolerance to lysinuric proteins resulting in a deficiency in citrulline, arginine and ornithine; • the hyperinsulinism-hyperammonemia syndrome leading to glutamate deficiency; • a deficiency in pyruvate carboxylase leading to an aspartate deficiency; • a deficiency in pyrroline-5-carboxylate synthetase leading to a deficiency in ci trulline, arginine and ornithine.

[0060] Hyperammonemia according to the invention may also be related to or caused by other pathologies, particularly those selected from the group of liver diseases, such as acute or chronic liver failure, viral hepatitis, cirrhosis, impaired liver function, and a liver vascular bypass resulting in decreased blood filtration in the liver. This is also referred to as acquired hyperammonemia.

[0061] Hyperammonemia according to the invention can also result from taking medication or be due to chemotherapy; this is referred to as drug-induced hyperammonemia. Examples of medications that can cause hyperammonemia include sodium valproate, barbiturates such as primidone, glycine gel, L-asparaginase, 5-fluorouracil, sunitinib, asparaginase chemotherapy, and regorafenib.

[0062] Hyperammonemia according to the invention can also result from the complication of a solid organ transplant, such as a lung transplant, this is called postoperative hyperammonemia.

[0063] Hyperammonemia prevented or treated according to the invention can also be transient hyperammonemia of the newborn.

[0064] In one embodiment, the present invention relates to the prevention or treatment of disorders associated with hyperammonemia, preferably selected from the group consisting of convulsions related to hyperammonemia and seizures related to hyperammonemia.

[0065] Individual

[0066] The individual according to the invention is preferably a human being.

[0067] Preferably, the individual according to the invention suffers from hyperammonemia, in particular drug-induced hyperammonemia.

[0068] In one embodiment of the invention the individual is a term infant having a plasma ammonia concentration of at least 40 qM / L, at least 45 qM / L, at least 50 qM / L, at least 80 qM / L, or at least 90 qM / L.

[0069] In one embodiment of the invention, the individual is a premature infant with a plasma ammonia concentration of at least 70 qM / L, at least 80 qM / L or at least 90 qM / L.

[0070] In one embodiment of the invention the individual is a child over one month old having a plasma concentration of ammonia of at least 40 qM / L, at least 45 qM / L, at least 50 qM / L, at least 80 qM / L, or at least 90 qM / L.

[0071] In one embodiment of the invention, the individual is an adult with a plasma ammonia concentration of at least 30 qM / L, at least 40 qM / L, at least 50 qM / L, at least 80 qM / L, at least 150 qM / L, at least 180 qM / L, at least 200 qM / L, at least 300 qM / L or at least 400 qM / L.

[0072] In one embodiment of the invention, the individual according to the invention presents a disorder of the urea cycle.

[0073] In one embodiment of the invention, the individual according to the invention exhibits a disturbance of brain functions. Preferably, the individual according to the invention exhibits at least one disorder selected from the group consisting of convulsions, seizures, confusion, agitation, impaired consciousness, lethargy, ataxia, stroke-like lesions, coma, psychosis, vision loss, acute encephalopathy, cerebral edema, and cerebral herniation. More preferably, the individual according to the invention exhibits convulsions or seizures.

[0074] Administration

[0075] Preferably, the compound of formula (I) as defined above, or its pharmaceutically acceptable salt, hydrate, or solvate, is administered or administrable in a unit dose, or is packaged in a unit dose, of about 50 mg to about 1500 mg, in particular from about 150 mg to 300 mg. Also preferably, the compound of formula (I) as defined above, or its pharmaceutically acceptable salt, hydrate, or solvate, is administered or administrable with a dosing regimen of 5 g / day to about 45 g / day. Preferably, the compound of formula (I) as defined above or its pharmaceutically acceptable salt, hydrate or solvate is administered or administrable with a dosing regimen of 50 mg / kg / day to 500 mg / kg / day, preferably 250 mg / kg / day to 350 mg / kg / day, more preferably about 300 mg / kg / day.

[0076] Preferably, the compound of formula (I) as defined above, or its pharmaceutically acceptable salt, hydrate, or solvate, the pharmaceutical composition as defined above, or the drug as defined above, is in a form acceptable for oral or rectal administration. Preferably, the compound of formula (I) as defined above, or its pharmaceutically acceptable salt, hydrate, or solvate, the pharmaceutical composition as defined above, or the drug as defined above, is administered or administrable in the form of a powder, tablets, capsules, sachets, or suppositories.

[0077] Preferably, the additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia according to the invention is intended to prevent or treat hyperammonemia, in particular by decreasing the production of ammonia in the blood or by increasing the mechanisms of elimination of ammonia in the blood.

[0078] Preferably also, the additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia may include all compounds intended to alleviate or treat one or more symptoms associated with hyperammonemia, such as neuroprotective or anti-inflammatory drugs.

[0079] Examples of symptoms associated with hyperammonemia include vomiting, loss of appetite, respiratory alkalosis, hypothermia, liver damage, neurological disorders such as convulsions, seizures, confusion, agitation, impaired consciousness, lethargy, ataxia, stroke-like lesions, coma, psychosis, vision loss, acute encephalopathy, cerebral edema, and cerebral herniation.

[0080] Preferably, the additional compound useful for the prevention or treatment of hyperammonemia is selected from the group consisting of neuroprotective drugs such as N-acetylcysteine, indomethacin, propofol, minocycline and mannitol, anti-inflammatory drugs, sodium benzoate, sodium phenyl butyrate, glycerol phenyl butyrate, N-carbamylglutamate, sodium benzoate / sodium phenylacetate, lactulose, arginine hydrochloride, L-arginine, carglumic acid, a mixture of L-ornithine and L-aspartate, citrulline, and mixtures thereof.

[0081] The compound of formula (I) as defined above, or its pharmaceutically acceptable salt, hydrate or solvate, the pharmaceutical composition as defined above or the drug as defined above may also be associated with therapies intended to alleviate or reduce one or more symptoms associated with hyperammonemia or to prevent or treat hyperammonemia such as hemofiltration, intermittent hemodialysis, peritoneal dialysis, induced hypothermia, renal replacement therapy.

[0082] The compound of formula (I) as defined above, or its pharmaceutically acceptable salt, hydrate or solvate, the pharmaceutical composition as defined above or the drug as defined above may also be associated with a low-protein diet and / or a diet in which caloric intake is replaced by sugar and lipids.

[0083] As understood herein, the expression "combined" or "in combination" or "combination product" means that the compound of formula (I) as defined above, or a pharmaceutically acceptable salt, hydrate, or solvate thereof, in particular stiripentol, and the additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia as defined above, may be combined within the same pharmaceutical composition or drug, and thus administered together, or may be administered separately, i.e., by separate routes of administration and / or regimens separate administrations, provided that when administered separately the period of time during which the compound of formula (I) as defined above or its pharmaceutically acceptable salt, hydrate or solvate exerts its pharmacological effects on the individual and the period of time during which the additional compound as defined above exerts its pharmacological effects on the individual overlap in whole or in part.

[0084] The invention will be further explained with the aid of the following non-limiting Examples and Figure. [Fig. 1]

[0085] Fig. 1 represents the effect of stiripentol (STP) administered intraperitoneally on ammonia levels (expressed as qM, y-axis) after treatment with 50 mg / kg of methionine sulfoximine (MSO) in mice.

[0086] * p < 0.05: ANOVA statistical test of the treated groups compared to the control group.

[0087] # p < 0.05: ANOVA statistical test of the groups receiving MSO and stiripentol by report to the group receiving only MSO. Examples

[0088] The inventors studied the efficacy of stiripentol on hyperammonemia and on seizures associated with hyperammonemia in a model of seizures induced by methionine sulfoximine (MSO) according to Hevor et al. (1985) Neuropathol. Appl. Neurobiol. 11: 129-139, as follows. A. Materials and methods

[0089] 1. Animals

[0090] Male CBA (January) mice weighing between 23 and 27 grams are used after acclimatization of at least 4 days in the animal facility (t° = 22 ± 2°C; the housing conditions are as follows: SAFE "A04" food; drinking water: tap water; circadian rhythm: 12 h / 12 ​​h (light: 7 h / 19 h - darkness: 19 h / 7 h)).

[0091] Upon receipt, the mice are grouped in groups of 8 to 10 in 1500U cages (floor area 1500 cm2) with bedding and enrichment by sizzle dry (SDS), following the ethical recommendations of Directive 2010 / 63 / EU of the European Parliament (22 / 09 / 2010).

[0092] 2. Protocol

[0093] On the day of the test, the mice are weighed, tagged, and placed in individual cages. At t = 0 minutes, MSO (0.1 mL / 10 g) is administered intraperitoneally, and the mice are closely observed for 8 hours. The animals are normal for the first four hours. Tonic and clonic seizures occur for a few hours, then gradually disappear.

[0094] The parameters assessed are the animals' general condition according to the Irwin scale (Irwin 1968), the number of seizures, their time of onset, and mortality. The animals are euthanized as soon as the thresholds are reached, or at the end of the 8-hour observation period, according to procedure ANI07 approved by the Ethics Committee.

[0095] Blood and whole brain samples with cerebellum will be taken during certain studies to determine ammonia levels at the time of sacrifice or at the time of death for animals not completing the study.

[0096] Blood is collected under isoflurane anesthesia by cardiac puncture (0.5 to 1.0 mL per mouse) to determine the ammonia level. If brain and blood are collected, the mouse is quickly sacrificed by decapitation: the brain is removed and frozen in liquid nitrogen. The liver can then be removed and quickly frozen in liquid nitrogen. The samples are stored at -80°C.

[0097] Stiripentol (0.1 mL / lOg) is administered intraperitoneally at different times relative to MSO.

[0098] 3. Measurement of blood ammonia levels with the ABCAM kit

[0099] Blood is collected after decapitation or by cardiac puncture, under isoflurane anesthesia (flow rate 1.5 L / min, 4.3% vaporizer for induction and maintenance) using a 25G orange needle (Terumo, NN2516R) and a 1.3 ml S-Monovette tube containing EDTA (purple cap, ref. 41.1395.105, Sarstedt). The tube is centrifuged at 2000 g for 10 minutes in a Beckman Allegra centrifuge refrigerated at 4°C. The plasma is collected in a 1 ml microtube (Brand, ref. 780500). The microtubes are placed in a freezer at -80°C before analysis, or alternatively on crushed ice.

[0100] Ammonia is determined colorimetrically using a microplate reader (Dynex, model MRX) and an ABCAM kit (ref. AB83360, ammonia assay kit) containing several reagents. This kit allows for the quantitative enzymatic determination of ammonium present in the samples. During the test, the ammonium is transformed to give a product that reacts with the OxiRed probe for quantification at 570 nm using a microplate reader. This test can detect 1 nmol (20 pM) of ammonium. The kit, stored at -20°C, includes the following components:

[0101] - Ammonia assay buffer (25 mL): ready to use, bring to room temperature before use; - OxiRed probe (200 pL): ready to use, warm to 37°C to properly defrost the DMSO; - Developer (1 bottle): reconstitute with 220 pL of Ammonia assay buffer; - Enzyme Mix (1 bottle): reconstitute with 220 pL of Ammonia assay buffer; - Converting Enzyme (1 bottle): reconstitute with 220 pL of Ammonia assay buffer; - NH4C1 standard at 10 mM (100 pL): ready to use, keep on ice during use.

[0102] Calibration curve with the NH4Cl standard

[0103] - To be done at each use; - Prepare 100 pL of Standard NH4C1 at 1 mM; - 10 pL of Standard NH4C1 at 10 mM + 90 pL ED; - Using the 1 mM NH4C1 standard, prepare dilutions according to the following table 1:

[0104] [Tables 1] Standard Volume (pL) Assay Buffer (pL) Final Volume of Standard in Wells (pL) Final Ammonia Concentration in Wells 1 0 150 50 0 nmol / well 2 6 144 50 2 nmol / well 3 12 138 50 4 nmol / well 4 18 132 50 6 nmol / well 5 24 126 50 8 nmol / well 6 30 120 50 10 nmol / well

[0105] Table 1: Dilution table

[0106] Standard at 1 mM i.e. 1 mmol in 1 L or 1 nmol in IpL, therefore 6 nmol in 6 pl. Taking 50 pL out of the 150 pL (6 + 144), we have 2 nmol / well.

[0107] Sample preparation:

[0108] - Plasma or serum can be tested directly; - Dilutions of 1 / 2, 1 / 5 and 1 / 10; - A volume of 5-15 pL of plasma / serum per well.

[0109] Procedure for measuring blood ammonia levels:

[0110] - Equilibrate all standards / samples / materials at room temperature; - Perform each measurement twice; - Filling the wells;

[0111] • standard: 50 pL of the standard dilution • Sample: 2 to 50 pL of the sample and adjust to 50 pL with Assay Buffer

[0112] - Preparation of the "reaction mix" according to the following table 2:

[0113] [Tables2] Component Reaction Mix Samples (qL) Ammonia Assay Buffer 42 OxiRed Probe 2 Enzyme Mix 2 Developer 2 Converting Enzyme 2

[0114] Table 2: Preparation of the "reaction mix"

[0115] • add 50 p,L of reaction mix to the standards and samples; • mix and incubate at 37°C for 60 minutes, protecting from light; • measure at 570 nm.

[0116] Calculation of ammonia concentrations

[0117] - Values ​​that are too high (outside the standard range) must be remeasured after dilution; - Averaging duplicated values; - Subtract the value of the "blank" to obtain the corrected DO; - Create a curve using the standards to obtain the equation and the slope; - Calculate the quantity of ammonium in nmol / well (Sa)

[0118] Sa = (corrected DO - y) / slope

[0119] - Calculate the concentration of the samples (Sa / Sv) *D with Sv: volume of the sample; D: dilution factor; Molar mass NH4+ = 18.04 g / mol.

[0120] 4. Products

[0121] Methionine sulfoximine (Sigma, ref M5379, lots SLBN0115V, SLBP0971V) was solubilized in NaCl at 0.9%.

[0122] Stiripentol (lot 176) was suspended in Tween 80 at 5%(v / v) and NaCl at 0.9%.

[0123] The ABCAM assay kit (ref AB83360, ammonia assay) and NH4C1 (ammonium chloride, Sigma, ref 254134, molar mass 53.49 g) are used for ammonia assays.

[0124] 5.Statistical Analysis

[0125] The results are expressed as the mean value ± ESM. The statistical tests used are:

[0126] - Fisher's exact test for the percentages of seizures and mortality, to determine a significant difference between the groups at the 5% level, - A one-way analysis of variance for the dosages, to determine if the observed pharmacological effect is significant at the 5% level (software SigmaPlot 3.1). B. Results

[0127] l. Dose-effect of methionine sulfoximine

[0128] Intraperitoneal administration of methionine sulfoximine (MSO) was performed at various concentrations. The behavior and mortality of mice were observed up to 8 hours after administration of the product:

[0129] - At 40 mg / kg, MSO produces moderate behavioral effects: from the 4th hour onwards, hypotonia, hypomotility, accelerated respiration, ptosis, and mydriasis are observed. At the end of the observation period (between 7 and 8 hours), 2 out of 10 mice convulsed, and one of them died. - At doses of 50 mg / kg and above, signs of toxicity appear as early as the 3rd hour. Convulsions and mortality begin from the 4th hour after MSO injection. 80% of mice convulse, with a 90% mortality rate. - At 60 mg / kg, methionine sulfoximine causes convulsions in 100% of mice, with a 90% mortality rate. - At 80 mg / kg, methionine sulfoximine causes convulsions in 100% of mice, with a 100% mortality rate.

[0130] Following these results, the dose of 50 mg / kg of methionine sulfoximine was retained to study the protective effects of stiripentol on disorders induced by MSO.

[0131] 2. Specific effect of stiripentol on blood ammonia

[0132] Stiripentol was administered at 300 mg / kg intraperitoneally without administration of methionine sulfoximine.

[0133] Stiripentol was observed to not alter ammonia levels (176 ± 14 pM) compared to the control group (179 ± 11 pM).

[0134] 3. Effects of stiripentol after administration of 50 mg / kg of MSO

[0135] 2.1. Stiripentol administered just before MSO

[0136] Stiripentol is administered just before methionine sulfoximine according to Hevor et al. (1985) Neuropathol. Appl. Neurobiol. 11: 129-139.

[0137] Administration of 50 mg / kg of methionine sulfoximine resulted in the appearance of behavioral signs of toxicity with a seizure rate of 90% and a mortality rate of 75%.

[0138] Administration of 300 mg / kg of stiripentol, just before MSO, significantly reduced the seizure rate to 50% and the mortality rate to 25%, suggesting a protective effect.

[0139] During this study, the ammonia level measurements yielded the following results:

[0140] - in controls not receiving methionine sulfoximine or any other treatment, The baseline ammonia level is measured at 174+18 pM;

[0141] - Administration of 50 mg / kg of methionine sulfoximine resulted in an increase significant increase in ammonia levels to 609+51 pM;

[0142] - Administration of 300 mg / kg of stiripentol, just before MSO, reduced by 32% this hyperammonemia at 417+51 pM.

[0143] 2.2. Stiripentol administered 30 minutes before MSO

[0144] Stiripentol is administered intraperitoneally 30 minutes before methionine sulfoximine according to Cloix et al. (2010). Epilepsia, 51: 118-128.

[0145] Administration of 50 mg / kg of methionine sulfoximine resulted in the appearance of behavioral signs of toxicity with a seizure rate of 100% and a mortality rate of 80%.

[0146] Administration of 300 mg / kg of stiripentol, 30 minutes before MSO, significantly reduced the seizure rate to 45% and the mortality rate to 25%, suggesting a protective effect.

[0147] During this study, the ammonia level measurements gave the following results ([Fig.1]):

[0148] - In controls not receiving methionine sulfoximine or any other treatment, The ammonia level is measured at 184+12 pM.

[0149] - Administration of 50 mg / kg of methionine sulfoximine resulted in an increase significant increase in ammonia levels to 763+71 pM,

[0150] - The administration of 300 mg / kg of stiripentol, 30 minutes before the MSO, has significant tively reduced this hyperammonemia by 41% to 448+65 pM, compared to the group receiving only MSO. C. Conclusion

[0151] In the methionine sulfoximine (MSO)-induced seizure model, the inventors have shown that a single dose of MSO at 50 mg / kg administered intraperitoneally results in hyperammonemia and seizures and mortality in 80 to 100% of mice.

[0152] The inventors have shown that administration of stiripentol at 300 mg / kg intraperitoneally significantly reduces seizures and mortality induced by methionine sulfoximine, suggesting a protective effect.

[0153] MSO, whose main mechanism of action is the irreversible inhibition of glutamine synthetase, an enzyme involved in ammonia detoxification, particularly in the brain, leads to hyperammonemia (Ratnakumari et al. (1985) J. Neurosci. Res., 14: 449-59). In astrocytes, glutamine synthetase uses ammonium and glutamate to produce glutamine; therefore, inhibition of its activity by MSO results in an increase in ammonia levels.

[0154] At the level of blood ammonia, the inventors have shown that the administration of sti- Ripentol at 300 mg / kg via intraperitoneal route significantly reduces MSO-induced hyperammonemia.

Claims

1.

2.

3. Claims Compound of the following formula (I): [Chem.l] in which: - n represents 1 or 2, - Ai, A2 and A3, identical or different, represent a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms, - Rb R2 and R3 independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and - Y represents -OH, =0 or -SH; or a pharmaceutically acceptable salt, hydrate or solvate thereof here, for use in the prevention or treatment of hyperammonemia in an individual. A pharmaceutically acceptable compound or salt, hydrate or solvate of the latter for use according to claim 1, wherein the compound of formula (I) is of the following formula (II): [Chem. 2] (II) wherein n, Al, A2, A3 and Ri are as defined in claim 1. A pharmaceutically acceptable compound or salt, hydrate or solvate of the latter for use according to claim 1 or 2, wherein the compound of formula (I) is of the following formula (III): [Chem. 3] OH (III).

4. A compound or pharmaceutically acceptable salt, hydrate or solvate thereof for use according to any one of claims 1 to 3, for the prevention or treatment of convulsions related to hyperammonemia.

5. A compound or pharmaceutically acceptable salt, hydrate or solvate thereof for use according to any one of claims 1 to 4, for the prevention or treatment of drug-induced hyperammonemia.

6. A compound or pharmaceutically acceptable salt, hydrate or solvate thereof for use according to any one of claims 1 to 5, packaged in a unit dose of 50mg to 1500mg.

7. A compound or pharmaceutically acceptable salt, hydrate or solvate thereof for use according to any one of claims 1 to 6, suitable for oral administration.

8. A compound or pharmaceutically acceptable salt, hydrate or solvate thereof for use according to any one of claims 1 to 7, in the form of a powder, tablets, capsules, sachets or suppositories.

9. Pharmaceutical composition comprising as active substance at least one compound of formula (I) as defined in any one of claims 1 to 3, or a salt, hydrate or solvate thereof, optionally in association with a pharmaceutically acceptable vehicle, and optionally comprising at least one additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia.

10. Pharmaceutical composition comprising as active substance at least one compound of formula (I) as defined in any one of claims 1 to 3, or a salt, hydrate or solvate thereof, optionally in association with a pharmaceutically acceptable vehicle, and comprising at least one additional compound for the prevention or treatment of hyperammonemia or for the prevention or treatment of one or more symptoms associated with hyperammonemia selected from the group consisting of neuroprotective drugs, anti-inflammatory drugs, sodium benzoate, sodium phenylbutyrate, glycerol phenylbutyrate, N-carbamylglutamate, sodium benzoate, sodium phenylacetate, lactulose, arginine hydrochloride, L-arginine, carglumic acid, L-ornithine, L-aspartate, ci-trulline and their mixture.