Eutectic systems for penetration enhancement

Abstract

As disease etiologies are becoming more complex and comorbidity more common, the prospect of combining two therapeutic agents in a single topical preparation is increasingly attractive. In spite of this welcoming clinical context, eutectic systems, which are specifically designed to generate highly effective medicines using drug combinations, have not achieved the commercial success that was once predicted. One reason for this is that the manner in which they act to promote transport across biological barriers remains unclear, and this slows down the development process for these products. This chapter reviews the current understanding of eutectic systems for penetration enhancement and uses the oft-cited example of lidocaine and prilocaine, commercialized as EMLA cream, to try and gain a better understanding of how eutectic systems work in promoting drug delivery into and across the skin.