Spring Intro 2023

Mike Kelly

Basic Principles: Pharmacokinetics - Distribution

• Drug enters the bloodstream • Drug starts to distribute throughout body • Drug levels in plasma start to decrease • Slope of the graph depicts the

combination of absorption, distribution and elimination

Drug concentration

Time after dose

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Basic Principles: Pharmacokinetics - Metabolism

 Metabolism ● Chemical alteration of a drug by a biological system (enzymes) – Usually makes drug more polar and more water soluble for elimination via the urine ● Metabolism is an elimination pathway  Metabolism may result in ● Active drug (e.g. in the case of pro-drugs) ● Inactive, active or toxic metabolites  Liver is major site – Other organs e.g. Kidney, gastrointestinal tract, have some drug metabolism capacity

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