Many pharmacodynamic or pharmacokinetic approaches for in vivo assessment of local cutaneous bioavailability are currently available, but there is a growing need for more universal and economic methods. Among these, the direct measurement of the drug concentration in the skin is gaining much importance. This thesis is based on that approach, in particular using the tape stripping technique, which consists of the sequential removal from the treated site of very thin layers of stratum corneum, by the application and removal of an adhesive tape. The method has the advantage of being simple, painless, and relatively non-invasive. Furthermore, due to the reservoir capacity of stratum corneum, drug levels are substantial and correlate with the absorbed amount.