Figure 1.

Schematic representation of the different types of lipid-based vesicular delivery systems. (A) Conventional liposomes generally consist of a lipid bilayer composed of phospholipids and cholesterol, which encloses an aqueous core. Liposome characteristics can be modified by the addition of surfactants to form (B) Transfersomes^® and (C) niosomes (depending on the ratio of phospholipid to surfactant), or relatively high concentrations of ethanol to form (D) ethosomes. Modified from Hua.³³