Ligand Efficiency Index

Ligand Efficiency Index (LEI) is a measurement used in drug development to evaluate how effectively a molecule (ligand) binds to its target, relative to its size. It helps scientists determine if a compound's strong binding ability is efficient, meaning it achieves good interaction without being unnecessarily large or complex. LEI is calculated by dividing the binding strength by the molecule’s size. A higher LEI indicates a more efficient compound, which is desirable because smaller, efficient molecules often lead to better drugs with fewer side effects and easier development.