Solid solutions as long-acting naltrexone delivery systems

Solid solutions and solid dispersions have been used both to increase and to decrease solubility. Solid solutions may extend the release of naltrexone depending upon composition and production methods. Several combinations of naltrexone and cholesterol esters were prepared and evaluated. These combinations did prolong release of the drug in some cases, but none acceptably long enough. Preparation of these solutions and dispersions involved compression and heat as well as solvent mixing. Drug release from particles is dependent upon surface area, composition, and method of preparation. Suspendable, injectable particles can be produced which will give acceptable release rates. The preparation and evaluation are complex and will require much more research effort.