Abstract
Twenty derivatives of cinchona-alkaloids were tested for their activity against fibrillating ventricle under continued faradization. 1) Ethylapoquinine chloride possesses a very potent antifibrillatory activity : The compound, caused, in concentrations of 1 : 30, 000-50, 000, a complete reversion from ventricular fibrillation to a normal sinus rhythm, while ethylapoquinine, quinine and quinidine were found to be effective as to cause slight reduction of fibrillation under the same experimental conditions. Quinine chloride and quinidine chloride were also more effective than the respective parent alkaloids. Cinchonine chloride, cinchonidine and quinotoxin were found to be less effective. Quinine sulfonic acid, quitenine, hydrochloroquinine, cinchonine, cinchonidine sulfonic acid, apoquinine, optochin, optochin-chloromethylate, quininetetrasulfate, cinchonidine tetrasulfate, all were found to be far less effective. 2) Ethylapoquinine chloride is less toxic than quinine and quinidine for mice. 3) Acetylquinidine is as active in stopping the fibrillation as ethylapoquinine chloride, but the former is far toxic than the latter for animals.
