http://www.nature.com/nbt/journal/v2...ll/nbt928.html

This is about TDS delivery of larger molecular substances (typicaly not condusive to TDS delivery), with minimal irritation.
Someone with more knowledge then I may be able to find some interesting info buried there, though.

"Validation of the hits from INSIGHT screening and safety studies using FDCs is reported in Figure 2c. Skin permeabilities to inulin from two leading hits were measured, and it was confirmed that formulations discovered by INSIGHT screening increase permeability to inulin by a factor of 30−80. Inulin was chosen as a validating marker because it is a poorly permeable hydrophilic macromolecule and provides a standard high enough to select formulations for transdermal delivery of macromolecules. Inulin permeability enhancement obtained by tape stripping the stratum corneum is also shown in Figure 2c. This number simply serves as an approximate upper limit on transdermal transport enhancement. SCOPE formulations induced an enhancement approaching that induced by tape stripping, yet without a high IP."