Computer Aided Drug Design (CADD) used to streamline drug discovery process, extract chemical and biological information about ligands and proteins/DNA/RNA. CADD is utilized to expedite the identification of active drug lead candidates (by virtual screening), and optimize leads to improve their potency (by structure based modification of leads) and transform biologically active compounds into suitable drugs (by employing filters to improve their physico-chemical, pharmaceutical and ADME-T/PK properties.

CADD employs virtual screening to discover new drug candidates from different chemical scaffolds by searching commercial, public, or private 3-dimensional chemical structure databases. It is intended to reduce the size of chemical space and thereby allow focus on more promising candidates for lead discovery and optimization. The goal is to enrich set of molecules with desirable properties (active, drug-like, lead-like) and eliminate compounds with undesirable properties (inactive, reactive, toxic, poor ADMET/PK). CADD significantly minimize time and resource requirements of chemical synthesis and biological testing. In fact there are more than fifteen drugs out in the market are based on CADD.

CADD include 1. Structure-based drug design; virtual screening (using docking simulations) of small organic molecules to fit into the active site of a protein 2. Ligand-based drug design; pharmacophore models i.e. a 3-D/2D spatial arrangement of chemical features essential for biological activity, and quantitative structure-activity and quantitative structure-property relationships (QSAR and QSPR); Correlation of known structure with its activity, and property descriptors. Pharmacophore models are matched against small molecule database that contain millions of compounds.