(±)-Ibutilide (hemifumarate)

(±)-Ibutilide is a class III antiarrhythmic agent. It inhibits the rapidly activating delayed-rectifier potassium current (IKr) in AT-1 myocytes with an IC50 value of 20 nM. (±)-Ibutilide also enhances the late inward sodium current (INa) and increases the action potential duration in isolated guinea pig ventricular cells. It decreases ventricular fibrillation induced by the ATP-dependent potassium channel activator pinacidil (Cay-15416) in Langendorff isolated perfused rabbit hearts when used at concentrations ranging from 3 to 30 µM. (±)-Ibutilide (15 µg/kg, i.v.) increases the effective refractory period (ERP) of the left and right atrium in anesthetized pigs. It prevents rapid pacing-induced atrial flutter in dogs when administered orally at doses ranging from 0.25 to 5 mg/kg. Formulations containing ibutilide have been used in the treatment of atrial arrhythmias.Formal Name: N-[4-[4-(ethylheptylamino)-1-hydroxybutyl]phenyl]-methanesulfonamide, 2E-butenedioate (2:1). CAS Number: 122647-32-9. Synonyms: U-70226E. Molecular Formula: C20H36N2O3S . 1/2C4H4O4. Formula Weight: 442.6. Purity: >98%. Formulation: (Request formulation change), A crystalline solid. Solubility: DMF: 30 mg/ml, DMSO: 30 mg/ml, Ethanol: 5 mg/ml, PBS (pH 7.2): 1 mg/ml. lambdamax: 229 nm. SMILES: CS(NC1=CC=C(C(O)CCCN(CC)CCCCCCC)C=C1)(=O)=O.O=C(O)/C=C/C(O)=O. InChi Code: InChI=1S/2C20H36N2O3S.C4H4O4/c2*1-4-6-7-8-9-16-22(5-2)17-10-11-20(23)18-12-14-19(15-13-18)21-26(3,24)25,5-3(6)1-2-4(7)8/h2*12-15,20-21,23H,4-11,16-17H2,1-3H3,1-2H,(H,5,6)(H,7,8)/b,,2-1+. InChi Key: PCIOHQNIRPWFMV-WXXKFALUSA-N.