Drug hybridization strategies: before or after lead identification?

The molecular hybridization approach is one of the most valuable structural modification tools useful for the discovery of ligands and prototypes presenting either optimized affinity for one bioreceptor or the ability to modulate more than one bioreceptor associated with the target disease. The growing efforts to discover hybrid drugs resulting from the combination of pharmacophoric moieties of different known lead compounds have brought a new hope for the treatment of multifactorial diseases in recent years. This editorial describes possible ways of exploring molecular hybridization strategies to plan new effective dual or symbiotic drug candidates.