Reaction rate and oral effectiveness of certain adrenergic blocking compounds.

Six pairs of beta -bromo- and beta -chloroalkylamines have been compared from the standpoint of intravenous and oral adrenolytic activity and in vitro reaction rate with sodium thiosulfate. An inverse relationship between chemical reactivity and oral effectiveness was found in all cases. It appears that a slow reaction rate favors absorption of the unaltered beta -haloalkylamine after oral administration. It is concluded that this factor may, in part, explain the lack of a direct correlation between intravenous and oral potency which was observed in previous experiments on the beta -haloalkylamines.