Transdermal and dermal drug delivery

One of the major problems in transdermal and dermal delivery is overcoming the skin barrier properties. In this respect iontophoretic (electrically driven) delivery and passive delivery are both evaluated. Compartmental based mass transfer models have been developed and combined with pharmacokinetic parameters aiming to predict plasma levels in vivo from iontophoretic transport data in vitro. Passive delivery is focused on elastic vesicles that act as carrier systems for membrane associated drugs and antigens. A strong focus in the skin research is to characterize in detail skin properties and drug transport through it. In order to achieve this, broad spectrums of visualization and biophysical techniques have been adjusted specifically for skin research applications in vitro and in vivo. Available techniques include lipid analysis, small/wide angle X-ray diffraction, electron diffraction, confocal laser scanning microscopy, electron microscopy and ATR-FTIR.

As lipids play a crucial role in the skin barrier, besides transport studies one of the focuses is to elucidate the lipid organization in normal subjects and patients. Lipid model systems based on natural and synthetic lipids are used to examine the role the various lipids play in lipid organization. Recently a lipid membrane system has been generated to study the relation between lipid composition, organization and skin barrier properties. This system is referred to as the stratum corneum substitute.

Interactions between novel biofilms or cosmetic ingredients and human skin are also studied in vitro and in vivo. Specifically we are interested in their interaction with the skin lipids in relation to the ability to increase the water holding properties of the skin or to promote skin barrier repair. In this respect water distribution and natural moisturizing factor concentration are monitored in vitro and in vivo. One of the model systems currently available in the group is a human skin equivalent, which mimics the properties of human skin very closely.