Abstract
For many years there has been an extensive search for agents as effective as morphine in the relief of pain yet free from the hazard of addiction. Until recently it had appeared that this search would be fruitless.
Authors have investigated acetylpiperazine derivatives, and found that 1, 4-bis (2-methoxy-4-propylphenoxyacetyl) piperazine had an analgesic activity without narcotic action (1). This drug, however, does not have good solubility in water and cannot be absorbed from the intestine easily. Thus, this drug appeared to have less analgesic potency when administered orally.
In order to overcome this disadvantage, we have carried out further investigations on many other piperazines and found that 1-butyryl-4-cinnamylpiperazine hydrochloride (hereafter referred to as AP-237) had high analgesic potency (2) and good solubility in water. This paper describes the results of more detailed studies on the analgesic effects of AP-237.
