This proposal will develop a sustained release formulation of naltrexone to be given subcutaneously. The formulation will deliver therapeutic concentrations of naltrexone for 30 days. Pharmacokinetic testing will be conducted in rats and later in primates while local irritability testing will be carried out in rabbits. Subsequently, the investigators plan to proceed rapidly into clinical trials to demonstrate safety and efficacy of the formulation with the goal of achieving regulatory approval to market the new product for the treatment of alcoholic patients.