ABSTRACT
There are many similarities, but also differences, in delivering medicinal agents for dermal as opposed to transdermal use. In the former, uptake into the systemic circulation is not required and is probably unwanted, whereas in the latter, it is a prerequisite. In transdermal applications the medicine will be delivered to intact, healthy skin. In contrast, in dermal applications often the barrier properties are impaired as the formulation is being used to treat a diseased state. This adds the complexity that high drug amounts will reach the underlying tissues during the first applications, but as the disease state is treated and the skin heals, drug permeation becomes more and more difficult and lower concentrations will be reached. This problem is particularly pronounced in the area of wound healing, as discussed elsewhere in this book. As our knowledge of the biochemical needs for treatment of disease advances, it should be possible to provide dermal formulations with programmed delivery that address at least some of these difficulties.
II. THE CHALLENGE
