ABSTRACT
INTRODUCTION High throughput screening (HTS) has progressively evolved since the late 1980s as an important approach for new lead discovery and a chemistry starting point (1). The size of compound collections used in HTS campaigns has also increased significantly from under 100,000 to a few million in major pharmaceutical companies. In the 1990s, pooling approaches, in which 10 to 20 compounds were contained in one well, were widely used for compound screening due to the limited screening throughput (2). Frequent interference from compounds in pooled samples and time-consuming hit deconvolution from the primary screen impaired the ability of lead identification using early pooling strategies. In the late 1990s and early 2000s, single-compound screening became the main platform with the advances in HTS technology and increases in screening throughput. However, primary screening of compound collections is routinely performed at a single concentration, typically as a single replicate, due to the high cost and time requirement for screening such large compound collections (usually in millions of compounds). Screening at a single concentration provides only a limited window of opportunity to identify the useful lead compounds.
