title: An integrated model for determining causes of poor oral drug absorption.
abstract: OBJECTIVE
  To develop an integrated absorption model for estimating the fraction of dose absorbed and determining the causes of poor oral drug absorption.
  
  
  METHODS
  Both analytical and numerical methods were used to estimate the fraction of dose absorbed.
  
  
  RESULTS
  An integrated absorption model was developed by considering transit flow, dissolution, and permeation processes, simultaneously. A framework was proposed to determine permeability-, dissolution-, and solubility-limited absorption. Digoxin, griseofulvin, and panadiplon were employed to illustrate the applications of the integrated model in identifying the causes of poor absorption and guiding formulation development.
  
  
  CONCLUSIONS
  The integrated absorption model was successfully applied to digoxin, griseofulvin, and panadiplon to estimate the fraction dose absorbed and to roughly determine the causes of poor oral drug absorption.
authors.affiliation: Glaxo Wellcome, Inc., Research Triangle Park, North Carolina 27709, USA. yul@cder.fda.gov
authors.forename: L X
authors.initials: LX
authors.lastname: Yu
mesh_terms: D000284:Administration, Oral; D000465:Algorithms; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D000935:Antifungal Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D003198:Computer Simulation; D004077:Digoxin / Q000008:administration & dosage / Q000493:pharmacokinetics; D005746:Gastric Emptying; D006118:Griseofulvin / Q000008:administration & dosage / Q000493:pharmacokinetics; D007408:Intestinal Absorption; D008962:Models, Theoretical; D010069:Oxadiazoles / Q000008:administration & dosage / Q000493:pharmacokinetics; D010316:Particle Size; D010539:Permeability; D010599:Pharmacokinetics; D011237:Predictive Value of Tests; D011810:Quinoxalines / Q000008:administration & dosage / Q000493:pharmacokinetics; D012995:Solubility
chemical_list: D014151:Anti-Anxiety Agents; D000935:Antifungal Agents; D002316:Cardiotonic Agents; D010069:Oxadiazoles; D011810:Quinoxalines; D006118:Griseofulvin; D004077:Digoxin; C069443:panadiplon