Quantitative structure–activity relationships (QSAR)

This chapter analyzes quantitative structure-activity relationships (QSARs), which is considered a well-established tool in medicinal chemistry. It details how QSAR attempts to relate the physicochemical properties of compounds to their biological activity in a quantitative fashion by using equations. It also describes traditional QSAR and shows that this typically involves synthesizing a series of analogues with different substituents and studying how the physicochemical properties of the substituents affect the biological activities of the analogues. The chapter covers the hydrophobic, steric, and electronic properties and looks at how these are considered when setting up a QSAR equation. It emphasizes how traditional QSAR studies have been largely superseded by three dimensional QSARs (3D QSAR) where the physicochemical properties of the complete molecule are calculated and then related to biological activity.