Fluorescent Penetration Enhancers Reveal Complex Interactions among the Enhancer, Drug, Solvent, and Skin.

Skin penetration/permeation enhancers facilitate drug delivery through the skin barrier. However, the specific mechanisms that govern the enhancer interactions with the skin, drug, and donor solvent are not fully understood. We designed and synthesized fluorescent-labeled enhancers by attaching 7-nitrobenzo[c][1,2,5]oxadiazol-4-yl (NBD) groups to 6-aminohexanoic acid esters.

Permeability and microstructure of cholesterol-depleted skin lipid membranes and human stratum corneum.

Cholesterol (Chol) is one of the major skin barrier lipids. The physiological level of Chol in the stratum corneum (SC) appears to exceed its miscibility with other barrier lipids, as some Chol is phase separated. Chol synthesis is essential for epidermal homeostasis, yet the role of these Chol domains in SC permeability is unknown.