The rationale for advancing the formulation of azelaic acid vehicles.

When first approved in December 2002, 15% azelaic acid (AzA) gel represented a significant advance over the available 20% AzA cream. Although a smaller amount of AzA was present in the new formulation, the gel medium provided a highly effective system for delivering the active ingredient, thus providing more effective treatment. This article explores the nature of these 2 vehicles and highlights the importance of the formulation in which dermatologic drugs are delivered.