Ligand-based approaches in virtual screening

Although there are many more receptor structures than there were in the 1970s and 1980s, drug discovery remains dominated by empirical screening and substrate-based drug design. Computer-aided drug design methods have become value-adding disciplines that now contribute to the early stage of the drug discovery process [1, 2]. Computational methods encompass all aspects of drug discovery from target assessment to lead optimization. The computational strategy varies from case to case and can be influenced by several situational variables: lead hunting or lead optimization, requirement for a novel lead class, type of biological assay, structural information available, known classes of ligands, allocated chemistry resources. Today, drug discovery is still a complex and approximate science. Thus, incorporating knowledge-based approaches like ligand-based screenings may bias the process towards success. This review describes these strategies with practical applications and presents future perspectives of ligand-based screening.