RS-87337

RS-87337 is an orally active piperazine-amidine hybrid class Ia (inhibiting V_max, IC₅₀ = 17 μM)/class III (prolonging ADP90, EC₁₅ = 2 μM) antiarrhythmic agent with selectivity for ventricular conduction. RS-87337 inhibits cardiac sodium channel, thereby reducing the maximum depolarization rate of action potential, with moderate onset and recovery kinetics. RS-87337 reduces cardiac outward potassium conductance (I_K), thus prolonging action potential duration. RS-87337 is applicable to research related to arrhythmia, ventricular arrhythmia, ventricular fibrillation, and myocardial ischemia-reperfusion injury^[1][2]. In Vitro:RS-87337 (0.1-30 μM; 30 min) produces class III (ADP90 prolongation, EC₁₅ = 2 μM) and class Ia (Vmax inhibition, IC₅₀ = 17 μM) antiarrhythmic effects in isolated guinea pig right ventricular papillary muscles, with intermediate sodium channel block kinetics^[2].
RS-87337 (10-1000 nM) does not impair baseline function of isolated working rat hearts, and at 1000 nM, it prevents reperfusion-induced ventricular fibrillation and maintains cardiac function following coronary ischemia^[2]. In Vivo:RS-87337 (10 mg/kg; i.v.) shows no effects on intra-atrial or intra-ventricular conduction parameters, only one incidence of atrioventricular block at a pacing frequency of 261 beat/min, and no cardiodepressant effects on normal canine myocardium^[1].
RS-87337 (1-5 mg/kg; i.v.) significantly reduces the incidence of reperfusion-induced ventricular tachycardia, fibrillation, and mortality in anaesthetized Sprague-Dawley rats^[2].
RS-87337 (3-10 mg/kg; i.v.; 15-60 mg/kg; p.o.) reduces ectopic complex incidence in conscious dogs with post-coronary ligation arrhythmia, with rapid activity via i.v. (3, 10 mg/kg) and sustained activity via oral (30, 60 mg/kg) routes^[2].
RS-87337 (0.02-5.0 mg/kg; i.v.; cumulative doses) dose-dependently reduces S-T segment elevation during transient myocardial ischemia and speeds reperfusion recovery in anaesthetized beagle dogs without significant cardiodepression^[2].