Skin Pharmacology

Percutaneous absorption assays assess the safety of substances that may contact the skin, such as topical medications, skin/hair care products, industrial chemicals, and pesticides. In this chapter, we will discuss the rationale, procedure, accuracy, safety, advantages, and disadvantages of these assays when experimented with in vitro and in vivo, both in animals (mice, guinea pigs, …) and humans. The Organisation for Economic Co-operation and Development (OECD), one of the organizations that promote animal welfare, has been closely observing these experiments and publishing policies ensuring humanity for those animals in toxicity studies. These OECD guidelines will also be mentioned in the hope that researchers will strictly comply. As more in-depth knowledge is acquired during the years of usage, most of these assays have their modified versions, which will also be further discussed in this chapter. These modifications target not just the accuracy and safety but also increase the reproducibility of the original assays. We believe this approach will give examples of the thought processes from former successful studies, thus being helpful for future researchers to adjust and update their respective procedures.