toxicological studies on certain aminoalkyl ethers as potential long-acting local anaesthetics

the acute intravenous toxicities of a selection of three potential long-acting local anaesthetics belonging to the series of2- phenoxyethyldialkylamine were determined in mice. two of the compounds were tertiary amines and the third a quaternary ammonium derivative.the i.v. median lethal dose, (ldso) of one of the tertiary compounds, 21a [n, n- diethyl-2- (2,6- diisopropyl) ethyl amine hydrochloride 1 was over 2.5 times that of lignocaine, while the other, 30a [n, n- diethyl-2- (4-sec-butyl) ethyl amine hydrochloride 1 had an ld50 of 1.5 times. on the other hand, the quaternary ammonium derivative fa [ n- benzyl-n-n- dimethyl -2- (2- tert- butyl) ethylamine chloride 1 was more toxic, with an ld50 value of one quarter of the standard. the test compounds, particularly compound 21a, seem to have good properties that would warrant further investigation as potential long-acting local anaesthetic agents.