Oxymorphone-naltrexonazine, a mixed opiate agonist-antagonist.

Previous studies from our laboratories have reported the synthesis and pharmacological characteristics of a series of symmetrical opiate azines: naloxonazine, oxymorphonazine and naltrexonazine. We have now synthesized and characterized in binding assays and in vivo two asymmetrical azines: oxymorphone-naltrexonazine and oxymorphone-3-methoxynaltrexonazine. Oxymorphone-naltrexonazine, which theoretically could interact with the receptor as either an agonist or antagonist, displayed antagonist properties in vitro and in vivo. Oxymorphone-3-methoxynaltrexonazine, which theoretically could bind only as an agonist, possessed agonist properties in binding studies and was a potent analgesic in vivo.