Pharmacokinetics: Drug Distribution

Flashcards covering key vocabulary and concepts related to pharmacokinetics and drug distribution.

Pharmacokinetics

The study of how drugs are absorbed, distributed, metabolized, and excreted in the body.

Drug Distribution

The reversible transfer of drug between the blood and the extravascular fluids and tissues of the body.

Extracellular Fluid (ECF)

Fluid that exists outside of cells, encompassing interstitial fluid.

ISF

Interstitial fluid, which is a part of extracellular fluid.

Lipophilic

A property of a substance that describes its ability to dissolve in fats, oils, and lipids.

Plasma Protein Binding

The process by which drugs bind to proteins in blood, affecting their distribution and activity.

Volume of Distribution (Vd)

The theoretical volume of fluid into which a drug appears to distribute, indicating the extent of distribution in the body.

Biological Membranes

The semipermeable membranes that separate the interior of a cell from the outside environment, influencing drug permeability.

pKa

The pH at which a drug exists in equal parts ionized and nonionized form, influencing its absorption and distribution.

Acidic Drugs

Drugs that have a low pKa and are mainly ionized in alkaline environments, affecting their ability to cross membranes.

Blood Brain Barrier (BBB)

A selective barrier that prevents certain substances from entering the brain from the bloodstream.

High Molecular Weight Drugs

Drugs that have difficulty crossing membranes due to their large size; often remain in the plasma.

MDR1 Mutation

A genetic mutation in dogs that affects drug transport mechanisms, potentially leading to drug accumulation and toxicity.

Lipophilic Drugs

Drugs that are easily absorbed through membranes and distributed widely in the body.

Free Drug Hypothesis

The concept that only unbound or free drug can exert a therapeutic effect and cross biological membranes.

Physiological Factors

Body characteristics like age, weight, and water content that influence drug distribution.