The Clinical Relevance of in vitro Investigations for Percutaneous Absorption

When we apply a drug preparation to diseased skin, the clinical response arises from a sequence of three drug-related processes — release of the medicament from the vehicle, followed by its penetration through the skin barriers and finally its activation of the desired pharmacological response. Effective topical therapy optimizes these processes as they are affected by three components — the drug, the vehicle and the skin1.