Pharmacokinetics (PK)

Pharmacokinetics is the study of how the body absorbs, distributes, metabolizes, and eliminates a substance over time, often summarized as what the body does to a drug.

Researchers measure pharmacokinetics by giving a known amount, sampling blood at intervals, and calculating parameters such as maximum concentration, time to peak, area under the curve, half-life, and clearance. These values describe the exposure a formulation produces and allow comparisons between routes, products, and conditions such as fed versus fasted. Pharmacokinetics is the foundation for setting dosing schedules in drug development.

Cannabidiol pharmacokinetics are notably variable. Oral absorption is low and strongly affected by food and carrier; the compound is metabolized by cytochrome P450 enzymes, stored in fat, and eliminated slowly after repeated use. Animal pharmacokinetics differ from human, and dogs differ from cats. Readers meet the term in study abstracts and in explanations of why the same labeled amount can produce different blood levels. Pharmacokinetic data describe exposure, not effect, and results vary between individuals.