The polar surface area (PSA) or topological polar surface area (TPSA) of a
molecule
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...
is defined as the surface sum over all
polar
Polar may refer to:
Geography
Polar may refer to:
* Geographical pole, either of two fixed points on the surface of a rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates
* Polar climate, the c ...
atoms or molecules, primarily
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
and
nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
, also including their attached hydrogen atoms.
PSA is a commonly used
medicinal chemistry
Medicinal or pharmaceutical chemistry is a scientific discipline at the intersection of chemistry and pharmacy involved with designing and developing pharmaceutical drugs. Medicinal chemistry involves the identification, synthesis and developm ...
metric for the optimization of a drug's ability to permeate cells. Molecules with a polar surface area of greater than 140
angstrom
The angstromEntry "angstrom" in the Oxford online dictionary. Retrieved on 2019-03-02 from https://en.oxforddictionaries.com/definition/angstrom.Entry "angstrom" in the Merriam-Webster online dictionary. Retrieved on 2019-03-02 from https://www.m ...
s squared (Å
2) tend to be poor at permeating cell membranes.
For molecules to penetrate the
blood–brain barrier
The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of ...
(and thus act on receptors in the
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
), a PSA less than 90 Å
2 is usually needed.
See also
*
Biopharmaceutics Classification System
The Biopharmaceutics Classification System is a system to differentiate the drugs on the basis of their solubility and permeability.
This system restricts the prediction using the parameters solubility and intestinal permeability. The solubility ...
*
Cheminformatics
Cheminformatics (also known as chemoinformatics) refers to use of physical chemistry theory with computer and information science techniques—so called "''in silico''" techniques—in application to a range of descriptive and prescriptive problem ...
**
Chemistry Development Kit
The Chemistry Development Kit (CDK) is computer software, a library in the programming language Java, for chemoinformatics and bioinformatics. It is available for Windows, Linux, Unix, and macOS. It is free and open-source software distributed und ...
**
JOELib
JOELib is computer software, a chemical expert system used mainly to interconvert chemical file formats. Because of its strong relationship to informatics, this program belongs more to the category cheminformatics than to molecular modelling. ...
*
Implicit solvation Implicit solvation (sometimes termed continuum solvation) is a method to represent solvent as a continuous medium instead of individual “explicit” solvent molecules, most often used in molecular dynamics simulations and in other applications of ...
*
Lipinski's rule of five
Lipinski's rule of five, also known as Pfizer's rule of five or simply the rule of five (RO5), is a rule of thumb to evaluate druglikeness or determine if a chemical compound with a certain pharmacological or biological activity has chemical pro ...
References
*
*
*
*
* Ertl, P
Polar Surface Area in ''Molecular Drug Properties'', R. Mannhold (ed), Wiley-VCH, pp. 111–126, 2007
*
External links
Interactive Polar Surface Area calculatorFree, Programmable TPSA Calculator
Cheminformatics
Medicinal chemistry
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