title: Polar molecular surface properties predict the intestinal absorption of drugs in humans.
abstract: OBJECTIVE
  A theoretical method has been devised for prediction of drug absorption after oral administration to humans.
  
  
  METHODS
  Twenty structurally diverse model drugs, ranging from 0.3 to 100% absorbed, were investigated. The compounds also displayed diversity in physicochemical properties such as lipophilicity, hydrogen bonding potential and molecular size. The dynamic molecular surface properties of the compounds were calculated, taking into account their three-dimensional shape and flexibility.
  
  
  RESULTS
  An excellent sigmoidal relationship was established between the absorbed fraction after oral administration to humans (FA) and the dynamic polar molecular surface area (PSAd) (r2 = 0.94). The relationship was stronger than those obtained for more established predictors of drug absorption. Drugs that are completely absorbed (FA > 90%) had a PSAd < or = 60 A2 while drugs that are < 10% absorbed had a PSAd > or = 140 A2.
  
  
  CONCLUSIONS
  The results indicate that PSAd can be used to differentiate poorly absorbed drugs at an early stage of the drug discovery process.
authors.affiliation: Department of Pharmaceutics, Uppsala University, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Palm
authors.forename: P
authors.initials: P
authors.lastname: Stenberg
authors.forename: K
authors.initials: K
authors.lastname: Luthman
authors.forename: P
authors.initials: P
authors.lastname: Artursson
mesh_terms: D055598:Chemical Phenomena; D002626:Chemistry, Pharmaceutical; D002627:Chemistry, Physical; D006801:Humans; D006860:Hydrogen Bonding; D007408:Intestinal Absorption / Q000502:physiology*; D008962:Models, Theoretical; D010539:Permeability; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D012995:Solubility; D013499:Surface Properties
chemical_list: D004364:Pharmaceutical Preparations