Pharmacokinetics; Pharmacokinetic factors affecting epidermal penetration and percutaneous absorption

Dermal pharmacokinetics has to do with the rate processes involved in dissolution, diffusion, and/or release of the drug substance from its vehicle, transit to the absorption site, penetration through the limiting barrier to the site of action, and subsequent elimination of that compound. Dermatology is almost exclusively interested in the pharmacologic and therapeutic effects of drugs within the skin. Emphasis will be primarily made in this presentation to the epidermal penetration of drugs so as to induce no local responses. However, comments will be made later related to percutaneous absorption with the intent to elicit systemic response.