The process of finding new medications based on knowledge of a biological target.Drug design is the rational, target-driven process of discovering new medications. Instead of blindly screening thousands of random molecules, researchers start with a specific biological target — usually a protein whose malfunction causes a disease — and then search for molecules that will bind to it and modulate its activity. This approach transforms drug discovery from a lottery into an engineering discipline, where knowledge of the target's structure and dynamics guides every decision.
The concept emerged in the 1980s with the rise of structure-based drug design, pioneered by researchers like Irving Kuntz and Peter Goodford, who developed early computational tools for docking and binding-site analysis.
The process begins with identifying and characterizing the target, often using structural biology to obtain its 3D shape. Computational methods then screen large chemical libraries, scoring candidate molecules for their predicted binding affinity and specificity. Modern approaches incorporate machine learning to explore 'chemical space' — the vast universe of possible molecules — and to predict how modifications to a lead compound will affect its properties. The best candidates are synthesized and tested experimentally, with the results feeding back into the next round of design.
Used in virtually all modern pharmaceutical research, from designing HIV protease inhibitors to developing targeted cancer therapies and COVID-19 antivirals.
The chemical space of possible drug-like molecules is estimated to contain more than 10^60 compounds — more than the number of atoms in the observable universe.


















