Proteins have been traditionally out of reach of electronic structure methods.But with technological advances in the development of powerful computers and the need to extend the methods of computational chemistry to problems of biological interest, such as the rational design of drugs, new technologies in silico have been developed that allow to study condensed systems of phase, which consist of thousands of atoms.Here, there are some techniques that combine two or more methods of calculating in a calculation that allows precise chemical exploration of very large systems.The aim of this work is to find the binding affinity of CDK2 inhibitors calculating their electronic densities and then comparing the similarities of these with the biological activity of ligands developing a QSAR in order to establish correlations between quantum similarity, which is a physical-chemical property and biological activity of said set of molecules that change their properties by varying any of their substituents.