Polar surface area

From Wikipedia, the free encyclopedia

The Polar Surface Area (PSA) is defined as the surface sum over all polar atoms, (usually oxygen and nitrogen), including also attached hydrogens.

PSA is a commonly used medicinal chemistry metric for the optimisation of cell permeability. Molecules with a polar surface area of greater than 140 angstroms squared are usually believed to be poor at permeating cell membranes. For molecules to penetrate the blood-brain barrier (and thus acting on receptors in the central nervous system), PSA should be less than 60 angstroms squared.

[edit] See also

• Lipinski's Rule of Five
• Biopharmaceutics Classification System
• Implicit solvation
• Cheminformatics
  • Chemistry Development Kit
  • JOELib

[edit] External links

• Interactive Polar Surface Area calculator
• Free, Programmable TPSA Calculator

[edit] References

• Ertl, P., Rohde, B., Selzer, P. Fast calculation of molecular polar surface area as a sum of fragment based contributions and its application to the prediction of drug transport properties. J. Med. Chem. 2000, 43, 3714-3717. (doi:10.1021/jm000942e)