RESUMEN
N-[4-[4-(Ethylheptylamino)-1-hydroxybutyl]phenyl]methanesulfonamid e, (E)-2-butenedioate (2:1) salt (ibutilide fumarate, 2E), has been found to have Class III antiarrhythmic activity. In an in vitro rabbit heart tissue preparation designed to evaluate the cardiac electrophysiology of potential antiarrhythmic agents, it selectively prolongs the effective refractory period of papillary muscle. In vivo it increases the ventricular refractory period of the canine heart and prevents the ventricular arrhythmias induced by programmed electrical stimulation 3-9 days after a myocardial infarction. This paper describes the synthesis of 2E and a series of related compounds. The in vitro evaluation of the cardiac electrophysiology of these compounds has allowed us to determine the structural requirements for Class III antiarrhythmic activity in this series. Evaluation of the antiarrhythmic activity of 2E and one of the more potent analogues on the late postinfarction ventricular arrhythmias induced by programmed electrical stimulation of the canine myocardium is also described. This activity is compared with that of the Class III antiarrhythmic agent sotalol. Compound 2E appears to be as effective and 10-30 times more potent than sotalol in this model.
Asunto(s)
Antiarrítmicos/síntesis química , Corazón/fisiología , Contracción Miocárdica/efectos de los fármacos , Sulfonamidas/síntesis química , Animales , Arritmias Cardíacas/tratamiento farmacológico , Perros , Femenino , Corazón/efectos de los fármacos , Ventrículos Cardíacos/efectos de los fármacos , Técnicas In Vitro , Indicadores y Reactivos , Espectroscopía de Resonancia Magnética , Masculino , Estructura Molecular , Infarto del Miocardio/tratamiento farmacológico , Conejos , Relación Estructura-Actividad , Sulfonamidas/química , Sulfonamidas/farmacología , Sulfonamidas/uso terapéutico , Función VentricularRESUMEN
A series of 1-(2-amino-1-phenylethyl)-6-phenyl-4H- [1,2,4]triazolo[4,3-a][1,4]benzodiazepines was prepared and evaluated for diuretic activity. These compounds have diuretic and natriuretic activity but no kaliuretic activity when evaluated by oral administration to the conscious rat. The structure requirements for this activity are discussed. In particular it was found that the 2-aminoethyl side chain at C-1 with hydrogen or methyl substituents on the amino group was required for diuretic activity. A substituent at C-8 was also required; soft substituents such as methylthio and iodo at this position favored activity. Compounds with both phenyl and 2-pyridyl substituents at C-6 were active; substituents on the C-6 phenyl, however, reduced or eliminated the activity. Substituents other than phenyl at the 1-position of the 2-aminoethyl side chain were detrimental to activity; phenyl substitution at this position was required for activity when the substituent at C-8 was chloro but not when it was bromo.
