structure-activity relationship

The term "structure-activity relationship" (SAR) describes how a chemical compound's structure relates to its biological or pharmacological activity. This concept was pioneered by Paul Ehrlich, who synthesized and tested various related chemical compounds to find the most effective treatment for syphilis.1

SAR is crucial in drug development. By making small modifications to a known compound's chemical structure, scientists can create new drugs with desired effects, such as increasing absorption or duration of action. Understanding the three-dimensional structure of both the drug and its target receptor allows for more precise drug design. This field has evolved into quantitative structure-activity relationship (QSAR), which uses mathematical models to predict activity based on chemical structure. Pharmaceutical companies maintain extensive libraries of chemical compounds, often derived from natural sources or synthesized through combinatorial chemistry, to screen for potential drug candidates. The shape and arrangement of atoms within a molecule (molecular structure) are fundamental to its properties and function.123