What has polar surface area ever done for drug discovery?

Over the last decade, polar surface area (PSA) has become a ubiquitous term in medicinal and computational chemistry circles. This article charts the development of the increasingly efficient methods for the calculation of PSA before illustrating its usefulness through selected examples drawn from the medicinal chemistry literature. Consideration of PSA is shown to assist in the improvement of cellular potency, intestinal absorption and blood-brain barrier permeation or restriction to the peripheral circulation.