Disperse Systems: Emulsions

Abstract

This chapter provides an overview of emulsion types, their methods for manufacture, and their suitability for various routes of administration. Excipients and their function in promoting emulsion stability are discussed. A review of micro-emulsions and liposomes is also provided. Keywords Emulsion · Dispersion · Liposomes · Emulsion stability · Emulsifying agents · Hydrophile-lipophile balance system · Surface active agent · Surfactant · Colloidal dispersion Learning Objectives • Describe an emulsion. • Define the different types of emulsions. • Describe the role of the emulsifying agent in preparing an emulsion. • Describe the HLB system of categorizing emulsifying or surface-active agents. • Describe the different types of emulsifying agents and provide an example for each. • Explain how colloidal delivery systems are used in the following: microemul-sions and liposomes. • Explain aggregation and coalescence of emulsion droplets as related to emulsion stability, and describe how this relates to Stoke's law. Key Concepts Students should know and be able to describe each of the following concepts as they review this chapter: • Aggregation • Coalescence • Dry gum method • Emulsifying agent (emulsifier) • Emulsion • Emulsion cracking/breaking • Emulsion creaming