title: In-vitro simulation of luminal conditions for evaluation of performance of oral drug products: Choosing the appropriate test media.
abstract: BACKGROUND
  Biorelevant media for evaluation of dosage form performance in the gastrointestinal lumen were first introduced in the late 1990s. Since then, a variety of additional media have been proposed, making it now possible to simulate most regions in the gastrointestinal tract in both prandial states. However, recent work suggests that the complexity and degree of biorelevance required to predict in-vivo release varies with the drug, dosage form and dosing conditions.
  
  
  OBJECTIVE
  The aim of this commentary was to establish which levels of biorelevant media are appropriate to various combinations of active pharmaceutical ingredient(s), dosage form and dosing conditions. With regard to their application, a decision tree for the selection of the appropriate biorelevant medium/media is proposed and illustrative case scenarios are provided. Additionally, media to represent the distal small intestine in both prandial states are presented.
  
  
  CONCLUSIONS
  The newly proposed levels of biorelevance and accompanying decision tree may serve as a useful tool during formulation development in order to ensure high quality, predictive performance results without unnecessary complexity of media. In future work, further specific case examples will be evolved, which will additionally address the need to take gastrointestinal passage times and type and intensity of agitation into consideration.
authors.affiliation: Faculty of Pharmacy, National and Kapodistrian University of Athens, Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Markopoulos
authors.affiliation: Department of Pharmaceutical Technology, Goethe University, Frankfurt/Main, Germany.
authors.forename: Cord J
authors.initials: CJ
authors.lastname: Andreas
authors.affiliation: Faculty of Pharmacy, National and Kapodistrian University of Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Vertzoni
authors.affiliation: Department of Pharmaceutical Technology, Goethe University, Frankfurt/Main, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Dressman
authors.affiliation: Faculty of Pharmacy, National and Kapodistrian University of Athens, Greece. Electronic address: reppas@pharm.uoa.gr.
authors.forename: Christos
authors.initials: C
authors.lastname: Reppas
mesh_terms: D000284:Administration, Oral; D002626:Chemistry, Pharmaceutical; D003663:Decision Trees; D004304:Dosage Forms; D004355:Drug Stability; D005750:Gastric Juice / Q000737:chemistry*; D005769:Gastrointestinal Motility; D006863:Hydrogen-Ion Concentration; D007419:Intestinal Secretions / Q000737:chemistry*; D007700:Kinetics; D008954:Models, Biological; D009994:Osmolar Concentration; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry*; D012995:Solubility; D013678:Technology, Pharmaceutical / Q000379:methods*; D014783:Viscosity
chemical_list: D004304:Dosage Forms; D004364:Pharmaceutical Preparations
keywords: Biorelevant media; Classification; DCS classes; Decision tree; Fasted state; Fed state