DoseAUC

DoseAUC is a term used in pharmacokinetics to describe the relationship between the administered dose of a drug and its systemic exposure, as quantified by the area under the plasma concentration–time curve (AUC). It is used to assess and compare exposure across doses, routes of administration, and patient populations, and to support dose selection and scaling.

In linear pharmacokinetics, AUC is proportional to the dose. For intravenous administration, AUC = Dose / Clearance (CL). For oral administration, AUC = F × Dose / CL, where F is oral bioavailability. When PK is linear, doubling the dose doubles the AUC, enabling straightforward extrapolation of exposure across doses.

Nonlinear pharmacokinetics produce DoseAUC relationships that deviate from proportionality, due to saturable metabolism or transport, or nonlinear distribution. In such cases, AUC may increase less or more than proportionally with dose, complicating dose prediction and safety assessments.

Estimating DoseAUC relies on concentration–time data. Noncompartmental analysis uses methods like the trapezoidal rule to compute AUC from observed concentrations, while compartmental and population PK models describe how AUC changes with covariates such as weight, age, and organ function. DoseAUC is a central metric in exposure–response analyses and is used to compare formulations, optimize dosing regimens, or extrapolate exposure across patient groups.

Limitations include dependence on sampling schedules, assay accuracy, and model assumptions. Factors such as food intake, formulation differences, and interindividual variability can affect bioavailability and clearance, thereby influencing DoseAUC and its interpretation.