Editing Drug design (section)

=== Ligand-based ===

Ligand-based drug design (or ''indirect drug design'') relies on knowledge of other molecules that bind to the biological target of interest. These other molecules may be used to derive a [[pharmacophore]] model that defines the minimum necessary structural characteristics a molecule must possess in order to bind to the target.<ref name="isbn0-9636817-6-1">{{cite book | vauthors = Guner OF | title = Pharmacophore Perception, Development, and use in Drug Design | publisher = International University Line | location = La Jolla, Calif | year = 2000 | isbn = 978-0-9636817-6-8 | name-list-style = vanc }}</ref> A model of the biological target may be built based on the knowledge of what binds to it, and this model in turn may be used to design new molecular entities that interact with the target. Alternatively, a [[quantitative structure-activity relationship]] (QSAR), in which a correlation between calculated properties of molecules and their experimentally determined [[biological activity]], may be derived. These QSAR relationships in turn may be used to predict the activity of new analogs.<ref name = "Tropsha_2010">{{cite book | vauthors = Tropsha A | chapter = QSAR in Drug Discovery | veditors = Reynolds CH, Merz KM, Ringe D | title = Drug Design: Structure- and Ligand-Based Approaches  | chapter-url = https://books.google.com/books?id=EOInhAYMae4C&q=QSAR%20drug%20design&pg=PA151 | pages = 151–164 | date = 2010 | publisher = Cambridge University Press | location = Cambridge, UK | isbn = 978-0521887236 | edition = 1st }}</ref>