Drug design and discovery is a powerful, time-consuming and an interdisciplinary effort and is mostly defined as a straight, consecutive progress that includes the definition of targets (mostly proteins) and lead discovery. The optimization of selected lead compound requires pre-clinical in vitro and in vivo studies to resolve wheather the compound is emerged to fulfill most of the pre-set criteria for initiating clinical requirements.
In the earlier decades, most drugs have been discovered in random findings. However, computers (in-silico design) and appropriate new techniques are now being available for rational approaches to design and development of novel drugs.