Dermal sampling techniques with focus on dermal Open Flow Microperfusion

Assessment of percutaneous drug penetration is highly relevant for the development of dermal topical drug products, as these drug products aim to penetrate the skin, deliver a therapeutically effective drug concentration, and exert a local effect. Dose–response assessment, which requires the availability of pharmacokinetics (PK) profiles, is therefore a key step in drug development. Dermal PK can be mapped by sampling and analyzing dermal interstitial fluid (ISF). ISF represents the immediate environment of cells and serves as a transport medium for nutrients, signaling molecules, and for waste products among cells, as well as blood and cells. Techniques to monitor percutaneous drug penetration and to assess dermal PK data by extracting and analyzing dermal ISF samples include a range of models and may be applied ex vivo and in vivo. Dermal ISF can be collected using wicks or capsules implanted into tissue.