2. Qualitative methods for studying the relationship between structure and activity (RSA)

This approach is based on the following relationship :

in which biological activity is quantified as a function of the basic chemical structure, or pharmacophore, responsible for the biological activity and containing certain substituents. In the past, a pharmacophore was defined in terms of a static, often planar, molecular structure. Recent advances in chemistry and molecular modeling have made it possible to take into account its three-dimensional structure, as well as its dynamic properties, contributing to the improvement of SAR studies.