TY - CHAP M1 - Book, Section TI - Principles of Topical Therapy A1 - Saleem, Mohammed D. A1 - Maibach, Howard I. A1 - Feldman, Steven R. A2 - Kang, Sewon A2 - Amagai, Masayuki A2 - Bruckner, Anna L. A2 - Enk, Alexander H. A2 - Margolis, David J. A2 - McMichael, Amy J. A2 - Orringer, Jeffrey S. PY - 2019 T2 - Fitzpatrick's Dermatology, 9e AB - AT-A-GLANCEEfficacy of a topically applied drug depends on three things: whether the drug is applied, the delivery of the active molecule by its vehicle, and the inherent potency of the active molecule.Adherence to topical treatment is often poor and decreases over time.Factors that affect penetration of applied drug include soluble medication concentration, regional variations in skin barrier properties, application frequency, and effects of the vehicle on barrier function.The primary barrier that limits the percutaneous absorption of compounds is the stratum corneum.The delivery of a topical agent is highly dependent on the physicochemical properties of the vehicle; this influences the kinetics of release and absorption and the onset, duration, and extent of a biologic response.Either the vehicle or its active ingredient(s) may cause local toxicity, systemic toxicity, or both. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1161343177 ER -