Pharmacokinetic and pharmacodynamic modelling

Compartmental pharmacokinetic models describe absorption, distribution and clearance; pharmacodynamic models relate exposure to effect. In oncology they underpin body-surface-area and weight-based dosing, carboplatin dosing by kidney function (the Calvert formula), therapeutic drug monitoring of methotrexate and busulfan, the design of continuous infusions and depot formulations, and the exposure-response analyses that regulators now expect. Population models with individual variability explain why fixed doses of some antibodies work, and physiologically based models scale doses to children and to organ impairment.