Models of physiology and physiologically based models in clinical pharmacology.

As science matures, it becomes more mathematical, progressing from enumeration to the use of equations to the formulation of models. Clinical pharmacology has developed to the stage where models play an increasingly important role in predicting and analyzing drug pharmacokinetics and pharmacodynamics, and even in characterizing disease progression and therapeutic response. Useful models have two characteristics that are in ostensible conflict: (i) they must accurately represent the essential features of the underlying system and (ii) the representation must be sufficiently simplified to enable its salient features to be identified and investigated through further experimentation.