Lipinski’s rule of five is probably one of the first principles taught to a medicinal chemist, as it defines the chemical space likely to yield a successful oral drug. However, in recent years some drugs have moved beyond traditional rule of five space in order to access alternative or challenging targets.
By determining the propensity of molecules to form intramolecular hydrogen bonds David S. Millan and colleagues at Pfizer R&D are able to revise previous assumptions about where certain molecules sit in chemical space. They find that when hydrogen bonding is taken into account these drugs sit much closer to rule of five space – thereby explaining the successful absorption of drugs that otherwise violate rule of five principles.
Reproduced by permission from The Royal Society of Chemistry from MedChemComm Blog at http://blogs.rsc.org/md