Spring Intro 2023

Mike Kelly

Basic Principles: Pharmacokinetics - Bioavailability

 Bioavailability (F) is a relative term and is a comparison of exposure after two administrations

Absolute F compares extravascular dose to iv dose

AUC po AUC iv

Dose iv Dose po

F =

x

x 100

AUC2 Dose1 AUC1 Dose2 F rel = x x 100 Relative F rel compares two extravascular doses/routes

Bioavailability is expressed as a percentage

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Basic Principles: Pharmacokinetics - Distribution

 Distribution ● Reversible movement of a drug to and from the systemic circulation ● Very difficult to measure drug concentrations in the tissues

Volume Distribution (L) = Amount drug in body Plasma Drug Concentration

● Volume of distribution is a theoretical value – Gives an indication of how widely spread our drug is within body tissues

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