Bis-arenoxypropanolamines as potential beta-adrenolytics: a reinvestigation

A number of symmetrical as well as asymmetrical bis-arenoxypropanolamines have been synthesized and evaluated for their beta-adrenolytic properties. The pharmacological characterization of these compounds was performed in vitro by direct studies (3H-dihydroalprenolol was used as the specific ligand for beta-receptors), and by determining the beta-blocking capacity on isoproterenol (ISO)-induced increased heart rate (isolated guinea-pig atrium); and in vivo by evaluating the antagonism on ISO-induced hypotension and tachycardia, as well as the intrinsic sympathomimetic activity (ISA) on reserpinized and vagotomized rats. The best result was observed with the simplest derivative, i.e. the bis-phenoxypropanolamine compound, which shows in vitro and in vivo potencies almost comparable to propranolol and, moreover, significant bronchodilating activity.