Pharmacokinetics (PK) and Pharmacodynamics (PD) is the main focus of the division of Pharmacology, embedded in the institute : Leiden Academic Centre for Drug Research. To extrapolate findings from a (pre)-clinical situation to a real life situation in the clinic, a lot of effort is done to model existing data from hospital and/or the research institute. These so called models describe the relation between drug concentration (PK) and its effect (PD). Via a mathematical equation in which often realistic values for parameters (e.g. bloodflow) are introduced, a realistic prognosis may be made of dosing regimen, clinical outcome in a systems pharmacology approach.