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Identification
NameEzogabine
Accession NumberDB04953
TypeSmall Molecule
GroupsApproved
Description

Ezogabine (D23129) is a close structural analog of the centrally acting analgesic flupitrine. It is a neuronal potassium channel opener being developed as a first-in-class antiepileptic drug (AED) and is currently being studied in Phase 3 trials as an adjunctive treatment for partial-onset seizures in adult patients with refractory epilepsy. FDA approved in June 10, 2011 under the name of ezogabine.

Structure
Thumb
Synonyms
SynonymLanguageCode
D-23129Not AvailableNot Available
Ethyl {2-amino-4-[(4-fluorobenzyl)amino]phenyl}carbamateNot AvailableNot Available
Ethyl 2-amino-4-((P-fluorobenzyl)amino)carbanilateNot AvailableNot Available
EZGNot AvailableNot Available
N-(2-Amino-4-(4-fluorobenzylamino)-phenyl) carbamic acid ethyl esterNot AvailableNot Available
N-(2-Amino-4-(4-fluorobenzylamino)phenyl)carbamic acid ethyl esterNot AvailableNot Available
PotigaNot AvailableNot Available
RetigabineNot AvailableNot Available
RTGNot AvailableNot Available
SaltsNot Available
Brand names
NameCompany
Potiga GlaxoSmithKline
Brand mixturesNot Available
Categories
CAS number150812-12-7
WeightAverage: 303.3314
Monoisotopic: 303.13830504
Chemical FormulaC16H18FN3O2
InChI KeyPCOBBVZJEWWZFR-UHFFFAOYSA-N
InChI
InChI=1S/C16H18FN3O2/c1-2-22-16(21)20-15-8-7-13(9-14(15)18)19-10-11-3-5-12(17)6-4-11/h3-9,19H,2,10,18H2,1H3,(H,20,21)
IUPAC Name
ethyl N-(2-amino-4-{[(4-fluorophenyl)methyl]amino}phenyl)carbamate
SMILES
CCOC(=O)NC1=C(N)C=C(NCC2=CC=C(F)C=C2)C=C1
Mass SpecNot Available
Taxonomy
KingdomOrganic Compounds
SuperclassBenzenoids
ClassBenzene and Substituted Derivatives
SubclassPhenylcarbamates
Direct parentPhenylcarbamates
Alternative parentsAnilines; Fluorobenzenes; Aryl Fluorides; Primary Aromatic Amines; Carbamic Acids and Derivatives; Ethers; Secondary Amines; Polyamines; Organofluorides
Substituentsaniline; fluorobenzene; aryl halide; primary aromatic amine; aryl fluoride; carbamic acid derivative; polyamine; ether; secondary amine; organofluoride; organohalogen; amine; primary amine; organonitrogen compound
Classification descriptionThis compound belongs to the phenylcarbamates. These are compounds containing a phenylazide moiety, which consists of a carbamic acid substituent attacthed to a phenyl group.
Pharmacology
IndicationAdjuvant treatment of partial-onset seizures.
PharmacodynamicsAs compared to other antiepileptic agents, ezogabine is unique in that it selectively activates potassium ion channels Kv 7.2-Kv7.5 and not cardiac Kv 7.1, thereby avoiding cardiac side effects. The antiepileptics, as a drug class, are routinely used in the treatment of a number of disease states in addition to epilepsy. Ezogabine is highly efficacious in a broad-spectrum of in vivo epilepsy and seizure models. A comparison of antiepileptic form activity of ezogabine with that of conventional anticonvulsants in in vitro models suggests that retigabine is especially likely to be useful in the treatment of pharmacoresistant epilepsy. Retigabine clearly attenuates pain-like behaviors in various animal models of neuropathic pain; it may also prove to be useful in treatment of clinical anxiety disorders. Clinical data obtained thus far indicate that retigabine is well tolerated in humans when titrated up to its therapeutic dose range. No tolerance, drug dependence, or withdrawal liability has been reported. Thus, retigabine may prove to be useful in the treatment of a diverse range of disease states in which neuronal hyperexcitability is a common underlying factor.
Mechanism of actionEzogabine has a novel mechanism of action that involves opening of neuronal Kv7.2-7.5 (formerly KCNQ2-5) voltage activated potassium channels. These channels (primarily Kv7.2/7.3) enable generation of the M-current, a sub-threshold potassium current that serves to stabilize the membrane potential and control neuronal excitability. In addition to acting on potassium ion channels, retigabine also affects GABA neurotransmission in the GABA-A receptor, which is a key inhibitory receptor in the central nervous system and is implicated in epilepsy. Malfunctioning of the GABA-A receptor leads to hyperexcitability in the brain, which causes seizures, making this receptor an important target for antiepileptic therapeutics. Apart from increasing the concentration of GABA in the brain (by either enhancing GABA synthesis or blocking GABA metabolism), retigabine allosterically potentiates GABA-induced current in rat cortical neurons in a concentration-dependent manner. Numerous studies have demonstrated that retigabine is effective in a broad spectrum of in vivo epilepsy and seizure models.
AbsorptionRapidly absorbed and distributed, with an absolute oral bioavailability of 60%. Pharmacokinetics of ezogabine suggest first-order kinetics. Tmax, single oral dose = 30-120 minutes; Time to steady state = 3 days
Volume of distribution

8.7 L/kg

Protein bindingApproximately 80% protein bound.
Metabolism

Ezogabine is metabolized exclusively via phase II hepatic N-glucurodination and acetylation. N-glucurodination is the major metabolic pathway of the two and form two major N-glucuronide metabolites. The enzymes involved are UGT1A1, 1A9, 1A4, and 1A3. However, the product of the N-acetyl pathway is a weak, active metabolite referred to as NAMR. The enzyme that is involved in the N-acetyl pathway is called N-acetyltransferase 2. The pharmacokinetics of NAMR and ezogabine are similar. The cytochrome P450 enzyme system is not involved with the metabolism of ezogabine.

Route of eliminationUrine (85%, 36% of total dose as unchanged drug, 18% of total dose as NAMR) and feces (14%, 3% of total dose as unchanged drug)
Half lifeTerminal half-life = 7.5 hours
Clearance

0.58 – 0.76 L/h·kg. Clearance may differ between ethnic groups with Black Americans having 20% lower clearance than Caucasian Americans.

ToxicityLethal Dose, acute, oral, rat = 100 mg/kg; Lethal Dose, chronic, oral, rat = 5.1 mg/kg/day, 90-day; Most common adverse effects that lead to discontinuation of therapy include dizziness and somnolence.
Affected organisms
  • Humans and other mammals
PathwaysNot Available
SNP Mediated EffectsNot Available
SNP Mediated Adverse Drug ReactionsNot Available
ADMET
Predicted ADMET features
Property Value Probability
Human Intestinal Absorption + 0.9876
Blood Brain Barrier + 0.9382
Caco-2 permeable - 0.5245
P-glycoprotein substrate Non-substrate 0.5295
P-glycoprotein inhibitor I Non-inhibitor 0.6642
P-glycoprotein inhibitor II Non-inhibitor 0.9155
Renal organic cation transporter Non-inhibitor 0.8998
CYP450 2C9 substrate Non-substrate 0.8602
CYP450 2D6 substrate Non-substrate 0.8045
CYP450 3A4 substrate Non-substrate 0.679
CYP450 1A2 substrate Inhibitor 0.8417
CYP450 2C9 substrate Non-inhibitor 0.607
CYP450 2D6 substrate Inhibitor 0.5995
CYP450 2C19 substrate Non-inhibitor 0.5221
CYP450 3A4 substrate Inhibitor 0.5085
CYP450 inhibitory promiscuity High CYP Inhibitory Promiscuity 0.6414
Ames test Non AMES toxic 0.5119
Carcinogenicity Non-carcinogens 0.621
Biodegradation Not ready biodegradable 1.0
Rat acute toxicity 2.4793 LD50, mol/kg Not applicable
hERG inhibition (predictor I) Weak inhibitor 0.9807
hERG inhibition (predictor II) Non-inhibitor 0.6007
Pharmacoeconomics
ManufacturersNot Available
PackagersNot Available
Dosage forms
FormRouteStrength
TabletOral50 mg, 200 mg, 300 mg, 400 mg
PricesNot Available
PatentsNot Available
Properties
Statesolid
Experimental Properties
PropertyValueSource
pKa10.8Not Available
Predicted Properties
PropertyValueSource
Water Solubility0.0307ALOGPS
logP3.07ALOGPS
logP2.7ChemAxon
logS-4ALOGPS
pKa (Strongest Acidic)13.6ChemAxon
pKa (Strongest Basic)3.99ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count3ChemAxon
Polar Surface Area76.38 Å2ChemAxon
Rotatable Bond Count6ChemAxon
Refractivity87.02 m3·mol-1ChemAxon
Polarizability31.97 Å3ChemAxon
Number of Rings2ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Spectra
SpectraNot Available
References
Synthesis ReferenceNot Available
General Reference
  1. Porter RJ, Nohria V, Rundfeldt C: Retigabine. Neurotherapeutics. 2007 Jan;4(1):149-54. Pubmed
  2. Hermann R, Ferron GM, Erb K, Knebel N, Ruus P, Paul J, Richards L, Cnota HP, Troy S: Effects of age and sex on the disposition of retigabine. Clin Pharmacol Ther. 2003 Jan;73(1):61-70. Pubmed
  3. Hermann R, Knebel NG, Niebch G, Richards L, Borlak J, Locher M: Pharmacokinetic interaction between retigabine and lamotrigine in healthy subjects. Eur J Clin Pharmacol. 2003 Apr;58(12):795-802. Epub 2003 Feb 28. Pubmed
  4. Dost R, Rostock A, Rundfeldt C: The anti-hyperalgesic activity of retigabine is mediated by KCNQ potassium channel activation. Naunyn Schmiedebergs Arch Pharmacol. 2004 Apr;369(4):382-90. Epub 2004 Mar 9. Pubmed
  5. Mikkelsen JD: The KCNQ channel activator retigabine blocks haloperidol-induced c-Fos expression in the striatum of the rat. Neurosci Lett. 2004 May 27;362(3):240-3. Pubmed
  6. Punke MA, Friederich P: Retigabine stimulates human KCNQ2/Q3 channels in the presence of bupivacaine. Anesthesiology. 2004 Aug;101(2):430-8. Pubmed
  7. Wuttke TV, Seebohm G, Bail S, Maljevic S, Lerche H: The new anticonvulsant retigabine favors voltage-dependent opening of the Kv7.2 (KCNQ2) channel by binding to its activation gate. Mol Pharmacol. 2005 Apr;67(4):1009-17. Epub 2005 Jan 20. Pubmed
  8. Fatope MO: Retigabine (ASTA Medica). IDrugs. 2001 Jan;4(1):93-8. Pubmed
  9. Orhan G, Wuttke TV, Nies AT, Schwab M, Lerche H: Retigabine/Ezogabine, a KCNQ/K(V)7 channel opener: pharmacological and clinical data. Expert Opin Pharmacother. 2012 Aug;13(12):1807-16. doi: 10.1517/14656566.2012.706278. Epub 2012 Jul 12. Pubmed
  10. Amabile CM, Vasudevan A: Ezogabine: a novel antiepileptic for adjunctive treatment of partial-onset seizures. Pharmacotherapy. 2013 Feb;33(2):187-94. doi: 10.1002/phar.1185. Pubmed
External Links
ResourceLink
KEGG DrugD09569
KEGG CompoundC13826
PubChem Compound121892
PubChem Substance10239851
ChemSpider108740
BindingDB50143558
ChEBI68584
ChEMBLCHEMBL41355
PharmGKBPA144997862
RxListhttp://www.rxlist.com/potiga-drug.htm
Drugs.comhttp://www.drugs.com/mtm/ezogabine.html
WikipediaRetigabine
ATC CodesN03AX21
AHFS Codes
  • 28:12.92
PDB EntriesNot Available
FDA labelshow(516 KB)
MSDSshow(132 KB)
Interactions
Drug Interactions
Drug
CarbamazepineEzogabine increases the clearance of carbamazepine (30%). The mechanism of this interaction is unknown.
LamotrigineIn healthy adults, the AUCs of lamotrigine and ezogabine were both increased. The clinical significance of this is still unknown. Multiple doses of ezogabine also increase the clearance and decrease the terminal half-life of lamotrigine.
OndansetronConcurrent use of ezogabine and ondansetron can increase QTc interval. Consider alternate therapy.
PhenytoinEzogabine increases the clearance of phenytoin (30%). The mechanism of this interaction is unknown.
Food Interactions
  • With a high-fat meal, Cmax is moderately increased.

Targets

1. Potassium voltage-gated channel subfamily KQT member 2

Kind: protein

Organism: Human

Pharmacological action: unknown

Components

Name UniProt ID Details
Potassium voltage-gated channel subfamily KQT member 2 O43526 Details

References:

  1. Wuttke TV, Seebohm G, Bail S, Maljevic S, Lerche H: The new anticonvulsant retigabine favors voltage-dependent opening of the Kv7.2 (KCNQ2) channel by binding to its activation gate. Mol Pharmacol. 2005 Apr;67(4):1009-17. Epub 2005 Jan 20. Pubmed
  2. Hirano K, Kuratani K, Fujiyoshi M, Tashiro N, Hayashi E, Kinoshita M: Kv7.2-7.5 voltage-gated potassium channel (KCNQ2-5) opener, retigabine, reduces capsaicin-induced visceral pain in mice. Neurosci Lett. 2007 Feb 14;413(2):159-62. Epub 2006 Dec 20. Pubmed
  3. Punke MA, Friederich P: Amitriptyline is a potent blocker of human Kv1.1 and Kv7.2/7.3 channels. Anesth Analg. 2007 May;104(5):1256-64, tables of contents. Pubmed
  4. Main MJ, Cryan JE, Dupere JR, Cox B, Clare JJ, Burbidge SA: Modulation of KCNQ2/3 potassium channels by the novel anticonvulsant retigabine. Mol Pharmacol. 2000 Aug;58(2):253-62. Pubmed
  5. Wickenden AD, Yu W, Zou A, Jegla T, Wagoner PK: Retigabine, a novel anti-convulsant, enhances activation of KCNQ2/Q3 potassium channels. Mol Pharmacol. 2000 Sep;58(3):591-600. Pubmed

2. Potassium voltage-gated channel subfamily KQT member 3

Kind: protein

Organism: Human

Pharmacological action: unknown

Components

Name UniProt ID Details
Potassium voltage-gated channel subfamily KQT member 3 O43525 Details

References:

  1. Hirano K, Kuratani K, Fujiyoshi M, Tashiro N, Hayashi E, Kinoshita M: Kv7.2-7.5 voltage-gated potassium channel (KCNQ2-5) opener, retigabine, reduces capsaicin-induced visceral pain in mice. Neurosci Lett. 2007 Feb 14;413(2):159-62. Epub 2006 Dec 20. Pubmed
  2. Punke MA, Friederich P: Amitriptyline is a potent blocker of human Kv1.1 and Kv7.2/7.3 channels. Anesth Analg. 2007 May;104(5):1256-64, tables of contents. Pubmed
  3. Main MJ, Cryan JE, Dupere JR, Cox B, Clare JJ, Burbidge SA: Modulation of KCNQ2/3 potassium channels by the novel anticonvulsant retigabine. Mol Pharmacol. 2000 Aug;58(2):253-62. Pubmed
  4. Wickenden AD, Yu W, Zou A, Jegla T, Wagoner PK: Retigabine, a novel anti-convulsant, enhances activation of KCNQ2/Q3 potassium channels. Mol Pharmacol. 2000 Sep;58(3):591-600. Pubmed

3. Potassium voltage-gated channel subfamily KQT member 4

Kind: protein

Organism: Human

Pharmacological action: unknown

Components

Name UniProt ID Details
Potassium voltage-gated channel subfamily KQT member 4 P56696 Details

References:

  1. Hirano K, Kuratani K, Fujiyoshi M, Tashiro N, Hayashi E, Kinoshita M: Kv7.2-7.5 voltage-gated potassium channel (KCNQ2-5) opener, retigabine, reduces capsaicin-induced visceral pain in mice. Neurosci Lett. 2007 Feb 14;413(2):159-62. Epub 2006 Dec 20. Pubmed
  2. Schroder RL, Jespersen T, Christophersen P, Strobaek D, Jensen BS, Olesen SP: KCNQ4 channel activation by BMS-204352 and retigabine. Neuropharmacology. 2001 Jun;40(7):888-98. Pubmed
  3. Borlak J, Gasparic A, Locher M, Schupke H, Hermann R: N-Glucuronidation of the antiepileptic drug retigabine: results from studies with human volunteers, heterologously expressed human UGTs, human liver, kidney, and liver microsomal membranes of Crigler-Najjar type II. Metabolism. 2006 Jun;55(6):711-21. Pubmed]

4. Potassium voltage-gated channel subfamily KQT member 5

Kind: protein

Organism: Human

Pharmacological action: unknown

Components

Name UniProt ID Details
Potassium voltage-gated channel subfamily KQT member 5 Q9NR82 Details

References:

  1. Hirano K, Kuratani K, Fujiyoshi M, Tashiro N, Hayashi E, Kinoshita M: Kv7.2-7.5 voltage-gated potassium channel (KCNQ2-5) opener, retigabine, reduces capsaicin-induced visceral pain in mice. Neurosci Lett. 2007 Feb 14;413(2):159-62. Epub 2006 Dec 20. Pubmed
  2. Hermann R, Ferron GM, Erb K, Knebel N, Ruus P, Paul J, Richards L, Cnota HP, Troy S: Effects of age and sex on the disposition of retigabine. Clin Pharmacol Ther. 2003 Jan;73(1):61-70. Pubmed
  3. Borlak J, Gasparic A, Locher M, Schupke H, Hermann R: N-Glucuronidation of the antiepileptic drug retigabine: results from studies with human volunteers, heterologously expressed human UGTs, human liver, kidney, and liver microsomal membranes of Crigler-Najjar type II. Metabolism. 2006 Jun;55(6):711-21. Pubmed]

Enzymes

1. UDP-glucuronosyltransferase 1-1

Kind: protein

Organism: Human

Pharmacological action: unknown

Actions: substrate

Components

Name UniProt ID Details
UDP-glucuronosyltransferase 1-1 P22309 Details

References:

  1. Hiller A, Nguyen N, Strassburg CP, Li Q, Jainta H, Pechstein B, Ruus P, Engel J, Tukey RH, Kronbach T: Retigabine N-glucuronidation and its potential role in enterohepatic circulation. Drug Metab Dispos. 1999 May;27(5):605-12. Pubmed]
  2. Borlak J, Gasparic A, Locher M, Schupke H, Hermann R: N-Glucuronidation of the antiepileptic drug retigabine: results from studies with human volunteers, heterologously expressed human UGTs, human liver, kidney, and liver microsomal membranes of Crigler-Najjar type II. Metabolism. 2006 Jun;55(6):711-21. Pubmed]

2. UDP-glucuronosyltransferase 1-3

Kind: protein

Organism: Human

Pharmacological action: unknown

Actions: substrate

Components

Name UniProt ID Details
UDP-glucuronosyltransferase 1-3 P35503 Details

References:

  1. Hiller A, Nguyen N, Strassburg CP, Li Q, Jainta H, Pechstein B, Ruus P, Engel J, Tukey RH, Kronbach T: Retigabine N-glucuronidation and its potential role in enterohepatic circulation. Drug Metab Dispos. 1999 May;27(5):605-12. Pubmed]

3. UDP-glucuronosyltransferase 1-4

Kind: protein

Organism: Human

Pharmacological action: unknown

Actions: substrate

Components

Name UniProt ID Details
UDP-glucuronosyltransferase 1-4 P22310 Details

References:

  1. Hiller A, Nguyen N, Strassburg CP, Li Q, Jainta H, Pechstein B, Ruus P, Engel J, Tukey RH, Kronbach T: Retigabine N-glucuronidation and its potential role in enterohepatic circulation. Drug Metab Dispos. 1999 May;27(5):605-12. Pubmed]

4. UDP-glucuronosyltransferase 1-9

Kind: protein

Organism: Human

Pharmacological action: unknown

Actions: substrate

Components

Name UniProt ID Details
UDP-glucuronosyltransferase 1-9 O60656 Details

References:

  1. Hiller A, Nguyen N, Strassburg CP, Li Q, Jainta H, Pechstein B, Ruus P, Engel J, Tukey RH, Kronbach T: Retigabine N-glucuronidation and its potential role in enterohepatic circulation. Drug Metab Dispos. 1999 May;27(5):605-12. Pubmed]

5. Cytochrome P450 2A6

Kind: protein

Organism: Human

Pharmacological action: unknown

Actions: inhibitor

Components

Name UniProt ID Details
Cytochrome P450 2A6 P11509 Details

References:

  1. Orhan G, Wuttke TV, Nies AT, Schwab M, Lerche H: Retigabine/Ezogabine, a KCNQ/K(V)7 channel opener: pharmacological and clinical data. Expert Opin Pharmacother. 2012 Aug;13(12):1807-16. doi: 10.1517/14656566.2012.706278. Epub 2012 Jul 12. Pubmed

6. Arylamine N-acetyltransferase 2

Kind: protein

Organism: Human

Pharmacological action: unknown

Actions: substrate

Components

Name UniProt ID Details
Arylamine N-acetyltransferase 2 P11245 Details

References:

  1. Amabile CM, Vasudevan A: Ezogabine: a novel antiepileptic for adjunctive treatment of partial-onset seizures. Pharmacotherapy. 2013 Feb;33(2):187-94. doi: 10.1002/phar.1185. Pubmed

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Drug created on October 21, 2007 16:23 / Updated on September 16, 2013 17:26