Skin Pharmacology 2024 PDF

School of Biomedical Sciences MEDI7100 Pharmacology 2024 Pharmacology of the Skin Mary-Louise Manchadi, PhD School of Biomedical Sciences, UQ [email protected] G&G...

School of Biomedical Sciences MEDI7100 Pharmacology 2024 Pharmacology of the Skin Mary-Louise Manchadi, PhD School of Biomedical Sciences, UQ [email protected] G&G Chapter 65  Learning Objectives This lectorial aims to briefly discuss some unique features about skin and how it can be used for drug delivery treatment of various skin disorders, such as inflammation, acne, psoriasis, infestations (lice and mites), prevention of sunburn, hair loss, skin hyper-pigmentation and wrinkles. drug classes include corticosteroids, retinoids, antihistamines, antibiotics, antifungals, antivirals, and others; reinforcing MOAs from across your studies.  Skin Introduction the largest organ of the body (3.5 kg, 2 m2) multifunctional and multicompartment structure is a portal for drug delivery to other tissues has diseases and conditions for treatment Skin as an organ Skin Structure: Striatum corneum the major barrier for absorption; can act as a functional reservoir for slow diffusion of drugs. Viable epidermis (next slide) Dermis contains a superficial capillary plexus - which may be involved in absorption of cutaneous drugs collagen and proteoglycans which may bind drug, along with mast cells which may be targeted. hair follicles - lipid-rich drug absorption, sweat glands sites for drug excretion via sweat. Cutaneous drug delivery. Diagrammatic representation of the 3 compartments of the skin as they relate to drug delivery: surface, stratum (Str.), and viable tissues. After application of a drug to the surface, evaporation and structural/compositional alterations occur that determine the drug's bioavailability. The stratum corneum limits diffusion of compounds into the viable skin and body. After absorption, compounds either bind targets in viable tissues or diffuse within the viable tissue or into the cutaneous vasculature, and thence to internal cells and organs. Structure of the viable epidermis Melanocytes produce melanin which is deposited into melanosomes which function to prevent UV-induced nuclear DNA damage of human skin cells by screening out harmful UV radiation. Melanosomes are transferred from melanocytes to neighboring keratinocytes. Keratinocytes migrate progressively to the skin surface where they are gradually shed and replaced by new skin cells. How does percutaneous absorption of topical drugs occur? Passage through outermost layer is rate-limiting Metabolism of drugs can also occur in the low molecular mass (