Pharmacological evaluation of certain novel prolonged-acting local anaesthetics. In vivo rat sciatic nerve block.

Some new 2-phenoxyethyldialkylamines in previous studies had proved to be superior to other standard drugs in respect of local anaesthetic activity. To confirm their intensity and duration of action, the two outstanding compounds were selected for further pharmacological studies on the rat sciatic nerve preparation in vivo. Their activity and duration of action were determined by a double-blind controlled trial (at the later stage) and in two stages. The test compounds showed comparable rates of onset of motor analgesia (5-10 min). They also displayed quick recovery from complete analgesia, typically being around 10 min after the first sign of a recovery of motor function was observed. In addition, no systemic or local untoward effects were noticed. Bupivacaine produced drowsiness in the rats.