Transdermal drug delivery is a passive diffusion process of an active compound through the skin which is affected by drug solubility in the multilamellar lipidic matrix of the stratum corneum (SC). Widely used non-ionic surfactants (NIS) can be added into transdermal formulations to enhance the penetration of drugs by influencing the packing of the stratum corneum lipidic matrix. Objective of our study was to analyse the interaction between selected NIS and a simple SC lipidic matrix model system using a variety of surface-sensitive techniques based on the application of Langmuir monolayers. In this work, the well-known surfactant Polysorbate 80 was compared with a modern surfactant Sucrose monolaurate. Infrared reflection-absorption spectroscopy (IRRAS) and epifluorescence microscopy provide information about the effects of those surfactants on the SC model system. Monolayer isotherms of the SC model mixture indicate a very stiff and well-packed layer, however, packing defects are evidenced in epifluorescence studies. The injection of the two NIS underneath the SC monolayers proved their potential to penetrate into the SC model at the air-water interface having a maximum insertion pressure (MIP) above the assumed lateral pressure of biological membranes. The NIS adsorbed preferentially into packing defects seen in epifluorescence microscopy studies with Sucrose monolaurate being more active than Polysorbate 80 in disordering the SC monolayer.

Charles University Faculty of Pharmacy in Hradec Kralove Akademika Heyrovskeho 1203 Hradec Kralove 500 05 Czech Republic

Institute of Applied Dermatopharmacy at Martin Luther University Halle Wittenberg Weinbergweg 23 D 06120 Halle Germany

Institute of Chemistry Physical Chemistry Martin Luther University Halle Wittenberg Von Danckelmann Platz 4 D 06120 Halle Germany

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