EC50

Definition

EC50 (half maximal effective concentration) is the concentration of a drug or ligand that produces 50% of its maximum possible biological response or effect. This pharmacological parameter is fundamental for characterizing drug potency and comparing the efficacy of different compounds targeting the same biological pathway. EC50 values are determined through dose-response curves, where increasing concentrations of a compound are plotted against the measured biological response. Lower EC50 values indicate higher potency, meaning less drug is needed to achieve the desired effect. EC50 is distinct from IC50, which measures inhibition rather than activation, and from Kd, which measures binding affinity rather than functional response. Understanding EC50 is critical in drug discovery for lead optimization, therapeutic window determination, and predicting clinical dosing regimens.

Visualize EC50 in Nodes Bio

Researchers can visualize EC50 data across drug-target networks to identify compounds with optimal potency profiles. By mapping EC50 values onto molecular interaction networks, users can compare multiple drug candidates simultaneously, reveal structure-activity relationships, and identify off-target effects. Network visualization enables pattern recognition across compound libraries, helping prioritize leads based on potency distributions across related targets and pathways.

Example Use Case

A pharmaceutical team developing kinase inhibitors for cancer therapy measures EC50 values for 50 candidate compounds against a panel of 20 kinases. They discover their lead compound has an EC50 of 5 nM against the primary target (EGFR) but also shows sub-micromolar EC50 values against three off-target kinases. By visualizing this data as a drug-target network with EC50-weighted edges, they identify structural modifications that could improve selectivity while maintaining potency, ultimately guiding their medicinal chemistry strategy toward a more specific therapeutic candidate.

Related Terms