Modest but Increased Penetration through Damaged Skin: An Overview of the in vivo Human Model

BACKGROUND/AIM: Quantifying percutaneous penetration of topical drugs as well as those compounds relevant to occupational exposure is important for assessing their delivery, efficacy and toxicology. Methods for assessing penetration are established for intact skin; however, what may be equally relevant is how much penetration occurs through damaged skin. METHODS: The Embase database was accessed online in March 2009 in search of human in vivo studies measuring penetration through damaged or diseased skin. RESULTS: Few studies have measured penetration through damaged human skin in vivo. A majority demonstrate a modest enhancement in penetration, with the exception of microdialysis studies that show a significant enhancement. The enhancement generally favored hydrophilic molecules over lipophilic molecules. CONCLUSIONS: Damaged or diseased skin may display a modest increase in penetration compared to intact skin, which is dependent on the method of measurement; however, additional studies with consistent methods are needed to fully elucidate how much penetration occurs through the many types and degrees of damaged skin.