Definition:

A promising newly discovered compound with antibacterial properties that has been selected for more intensive testing.

Following screening for active compounds, those with antibacterial properties (hits) are chemically modified during the stages of hit confirmation and hit-to-lead to enhance their activity and drug-like properties. This typically generates a series of related compounds differing slightly in their chemical properties. The molecule with the most promising overall set of properties is selected as the lead compound for further detailed investigation.