Nifekalant  (Synonyms: MS-551 free base)

Nifekalant (MS-551), a class III antiarrhythmic agent, is a IKr potassium channel blocker with an IC₅₀ of 10 μM. Nifekalant can be used for refractory ventricular tachyarrhythmias research^[1][2].

Nifekalant interacts with the cardiac M2 and the peripheral M3 receptors with a K_i value of 27 and 74 mM, respectively. Nifekalant dose dependently blocks HERG channels with an IC₅₀ value of 7.9 mM, but Nifekalant does not block minK currents in the Xenopus oocyte expression system. Nifekalant blocks HERG channels mainly in their open state in a frequency dependent manner. As a pure K⁺ channel blocker, Nifekalant does not have negative inotropic effects which amiodarone has via a β-blocking action and does not affect cardiac conduction^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

In rats (a species deficient in functional cardiac IK), before coronary ligation, 3 mg/kg and 10 mg/kg MS-551 decreased the heart rate by 6% and 12%, and increased mean arterial pressure (MAP) by 14% and 33%, respectively. MS-551 prolongs the QT interval and reduced the incidence of sustained ventricular fibrillation (VF) after reperfusion^[3].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

405.45

C₁₉H₂₇N₅O₅

130636-43-0

O=C1N(C)C(C=C(NCCN(CCO)CCCC2=CC=C([N+]([O-])=O)C=C2)N1C)=O

Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Lü-Pei Du, et al. The pharmacophore hypotheses of I(Kr) potassium channel blockers: novel class III antiarrhythmic agents. Bioorg Med Chem Lett. 2004 Sep 20;14(18):4771-7.  [Content Brief]

  [2]. Ioannis N Pantazopoulos, et al. Nifekalant in the treatment of life-threatening ventricular tachyarrhythmias. World J Cardiol. 2011 Jun 26;3(6):169-76.  [Content Brief]

  [3]. J Chen, et al. IK independent class III actions of MS-551 compared with sematilide and dofetilide during reperfusion in anaesthetized rats. Br J Pharmacol. 1996 Nov;119(5):937-42.  [Content Brief]