Pharmacological evaluation of narcotic antagonist delivery systems in rhesus monkeys

Rhesus monkeys were chronically restrained, intravenously catheterized, and allowed to self-administer morphine, methamphetamine, and saline. Various sustained-release systems containing naltrexone were then implanted in the animals and examined for selective morphine blockade. Similarly, continuous intravenous infusions of naltrexone, buprenorphine, and methadone were tested against morphine or heroin self-administration.