Spring Intro 2023

Mike Kelly

Basic Principles: Pharmacokinetics - Elimination

Extent of elimination is measured by clearance and half Life • t1/2 (h) - time taken for drug concentration to reduce by a half • Plasma clearance (l/h) – volume of plasma cleared of drug per unit time

High Clearance and short half life = rapid elimination from the body

Drug concentration

Time after dose

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Role of Transporters in Drug Absorption, Distribution and Excretion

Diagram reproduced from a presentation By M E Taub, Boehringer Ingelheim, ACPS 2006

• Transporters are membrane bound proteins that transport drugs and molecules across membranes i.e. into and out of cells • Contribute to the absorption, distribution and elimination of drugs, metabolites, various endogenous molecules, vitamins and nutrients. • Transporters are saturable, may be inhibited or induced and have polymorphisms • Important to understand if your drug is a substrate for a transporter

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