Population pharmacokinetics (PK) modeling is not a new concept it was first introduced in 1972 by Sheiner et al.

Population modeling is a tool to identify and describe relationships between a subject's physiologic characteristics and observed drug exposure or response. A sound understanding of the influence of factors such as body weight, age, genotype, renal/hepatic function, and concomitant medications on drug exposure and response is important for refining dosage recommendations, thereby improving the safety and efficacy of a drug agent by appropriately controlling variability in drug exposure. The expanded use of PK/PD-modelling is assumed to be highly beneficial for drug development as well as applied pharmacotherapy and will most likely improve the current state of applied therapeutics.Modeling and simulation during drug development.Īll drugs exhibit between-subject variability (BSV) in exposure and response, and many studies performed during drug development are aimed at identifying and quantifying this variability. In general, PK/PD-modelling based on the underlying physiological process should be preferred whenever possible.

soft link and fourth, the time dependency of the involved pharmacodynamic parameters, time-variant vs. indirect response third, the information used to establish the link between measured concentration and observed effect, hard vs.

indirect link second, the response mechanism that mediates the observed effect, direct vs. Four basic attributes may be used to characterize PK/PD-models: First, the link between measured concentration and the pharmacologic response mechanism that mediates the observed effect, direct vs. Under non steady-state conditions, more complex integrated PK/PD-models are necessary to link and account for a possible temporal dissociation between the plasma concentration and the observed effect. Under pharmacokinetic steady-state conditions, concentration-effect relationships can be described by several relatively simple pharmacodynamic models, which comprise the fixed effect model, the linear model, the long-linear model, the Emax-model and the sigmoid Emax-model. The rationale for PK/PD-modelling is to link pharmacokinetics and pharmacodynamics in order to establish and evaluate dose-concentration-response relationships and subsequently describe and predict the effect-time courses resulting from a drug dose.

Pharmacokinetics describes the drug concentration-time courses in body fluids resulting from administration of a certain drug dose, pharmacodynamics the observed effect resulting from a certain drug concentration. Pharmacokinetic (PK) and pharmacodynamic (PD) information from the scientific basis of modern pharmacotherapy.

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