PHARMACOLOGY Quiz: Dermatology
Document Summary
In dermatological disease, the thickened epidermis may further diminish the penetration of pharmacological agents into the dermis. Molecules can penetrate the skin by three routes: through intact stratum corneum through sweat ducts through the sebaceous follicle. The surface of the stratum corneum presents more than 99% of the total skin surface available for percutaneous drug absorption. Passage through this outermost layer is the rate- limiting step for percutaneous absorption. The major steps involved in percutaneous absorption: establishment of a concentration gradient. Provides the driving force for drug movement across the skin. Drug diffusion across the layers of the skin. Preferable characteristics of topical drugs: low molecular mass (600 da) Except for very small particles, water-soluble ions and polar molecules do not penetrate intact stratum corneum. Skin sites that are naturally occluded by apposing surfaces, such as the axillae, groin, and inframammary areas, also may be vulnerable to drug-related toxicity such as atrophy from potent topical glucorticoids: altered barrier function.
