Drug Discovery Process

The modern drug discovery process proceeds through a defined sequence of stages, each acting as a scientific and economic filter that concentrates resources...

The modern drug discovery process proceeds through a defined sequence of stages, each acting as a scientific and economic filter that concentrates resources on the most promising candidates. Target identification establishes the biological macromolecule whose modulation is expected to produce therapeutic benefit; target validation confirms, through genetic or pharmacological probe evidence, that modulating this target genuinely alters the disease phenotype. Hit identification then screens chemical libraries — physically, through high-throughput biological assay, or virtually, through the computational methods detailed in Phase 1 of this text — to identify chemically tractable starting compounds showing measurable target activity. Hit-to-lead chemistry converts a promising hit into a validated lead series through initial structure–activity exploration, and lead optimization, the most resource-intensive discovery stage, iteratively refines potency, selectivity, and pharmacokinetic behaviour until a preclinical candidate suitable for regulatory submission and human trials is identified.