Dermal drug delivery is an attractive alternative to conventional drug administration due to its advantages. However, the outermost layer of the skin, the stratum corneum (SC), provides an effective barrier against dermal permeation. Permeation enhancement techniques, such as chemical permeation enhancer glycols, are widely used to overcome the barrier function of the skin.
The aim of this research work was to examine three well-known glycols to define their effects on the SC structure and define the correlation with their permeation enhancer properties. We used NMR spectroscopy to characterize the molecular structure of SC, and Raman spectroscopy to examine the permeation of a model drug into the different skin layers.
The results of NMR measurements reviled that the glycols increase the mobility of SC components, furthermore, they affect the mobility of keratin filaments. A saturation level for all glycols was detected, after which the addition of chemicals did not increase the mobility. The results of Raman spectroscopy correlated well with the results of NMR measurements because a significant permeation enhancer effect of glycols was observed.