Christopher A. Lipinski formulated a so-called rule of five as criteria for oral bioavailability. (See ADME) These four "rules" are common characteristics found in most drugs available today. The rule of five derives its name from the fact that the relevant cutoffs are all multiples of five:

• not more than 5 hydrogen bond donors (OH and NH groups)
• no more the 10 hydrogen bond acceptors (notably N and O)
• molecular weight under 500
• LogP under 5

References

• CA Lipinski, Adv. Drug Del. Rev. 1997, 23, 3

External links

• Interactive Rule of Five calculator