Micro- and Nanoemulsions (Controlled Release Parenteral Drug Delivery Systems)

Abstract

Parenteral emulsions may be utilized to overcome major formulation challenges such as solubilization of poorly aqueous-soluble drugs and/or protection of drugs susceptible to hydrolysis. In addition, they can be used for the purposes of controlled and sustained drug release, drug targeting, and/or reduction of toxic effects to sensitive tissues. Emulsions are thermodynamically unstable and do not form spontaneously; however, emulsion stability can be substantially improved using suitable emulsifiers and viscosity enhancing agents. Drug release rates from emulsion systems are determined by both the carrier and the drug characteristics. It is not an easy task to characterize in vitro drug release from emulsions due to the physical obstacles associated with separation of the dispersed and continuous phases; however, various techniques have been successfully used. This chapter provides an overview of the physicochemical properties, methods of preparation, stability, and application of emulsion formulations. Controlled Release Society 2012.