There are many problems in physics, biology, medicine, where the length and time scales of interest remain entirely beyond the computational capacity currently available, and will remain out of reach in the foreseeable future. As a consequence, there is an increasing need for simplified, reduced descriptions.
Simulation of signal pathways and gene-regulatory networks often requires a stochastic formulation of the reaction kinetics in order to correctly capture the influence of small numbers of molecules and relevant fluctuations. However, with increasing number of molecules, the computational effort drastically increases.
Pharmacokinetics is the study of the drug/xenobiotic-organism interaction, in particular the investigation of absorption, distribution, metabolism, excretion and toxicological (ADMETox) processes. In the past decade, considerable progress has been made with the use of computational approaches, in particular in the early stage of the drug discovery process. As a result, modelling and simulation is possible prior to any in vivo experiments.