PHRM 211 Lecture Notes - Lecture 15: Stratum Corneum, Percutaneous, Partition Coefficient
Document Summary
Pharmaceutics of patch dosage form (part 1) Promote drug migration through the skin to the underlying blood supply without buildup in the skin. Stratum corneum is the rate-limiting barrier to transdermal drug transport. 40% protein (keratin), 40% water, 20% lipids (tgs, fas, cholesterols, phospholipids) The rate of drug movement across stratum corneum depends on: Aqueous solubility determines drug concentration at the absorption site. Lipid solubility determines the partition coefficient, which affects the rate of transport across the membrane barriers. form. Drugs penetrate the skin better in unionized. Nonpolar drugs cross the cell membrane through the lipid-rich region (transcellular route), whereas the polar drugs favor transport between cells (intercellular route) Drugs that have good aqueous and lipid solubility are preferred candidates. Good hydration of skin patches can act as an occlusive moisture barrier. An application area with a thin layer of skin. Fentanyl base drugs penetrate the skin better in their non-ionized form.
