title: Effects of permeation enhancers on the transport of a peptidomimetic thrombin inhibitor (CRC 220) in a human intestinal cell line (Caco-2).
abstract: OBJECTIVE
  The effects of five different permeation enhancer systems on the transport properties of a peptidomimetic thrombin inhibitor. CRC 220, were investigated in monolayers of a human intestinal cell line (Caco-2).
  
  
  METHODS
  The transepithelial transport rates and additionally the cytotoxic properties of these enhancers were characterized using the following tests: measurement of the transepithelial electrical resistance (TEER), the MTT-transformation, the protein content and the release of cytosolic lactate dehydrogenase (LDH), as well as FITC-phalloidin and propidium iodide staining.
  
  
  RESULTS
  All permeation enhancer systems showed concentration-dependent effects on cell permeability and toxicity. The most prominent effects on peptide transport were seen at the highest concentration (40 mM), yielding the rank order, NaTC > NaTC/Cholesterol > Solulan C24 > NaTC/Oleic acid > NaTC/PC18. Using the TEER after 120 min exposure as the most sensitive parameter describing cytotoxicity, the following order was obtained: Solulan C24 > NaTC > NaTC/PC18 = NaTC/Cholesterol > NaTC/Oleic acid > NaTC/PC. Generally, efficient enhancement of peptide transport was associated with a noticeable influence on cell viability under in-vitro conditions.
  
  
  CONCLUSIONS
  Taking into account permeation and cytotoxicity as a function of concentration, both NaTC at 15 mM and the mixed micellar system NaTC/oleic acid at 0.75 mM offer interesting enhancement properties, showing an 18-fold increase in CRC 220 transport rates. The effects on cell viability and cytotoxicity were comparatively low and of reversible nature.
authors.affiliation: Department of Pharmaceutics and Biopharmacy, University of Marburg, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Werner
authors.forename: T
authors.initials: T
authors.lastname: Kissel
authors.forename: M
authors.initials: M
authors.lastname: Reers
mesh_terms: D000991:Antithrombins / Q000493:pharmacokinetics*; D001692:Biological Transport; D018938:Caco-2 Cells; D004151:Dipeptides / Q000493:pharmacokinetics*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D006801:Humans; D008564:Membrane Potentials; D008823:Micelles; D010539:Permeability / Q000187:drug effects; D010743:Phospholipids / Q000378:metabolism; D010880:Piperidines / Q000493:pharmacokinetics*
chemical_list: D000991:Antithrombins; C093375:CRC 220; D004151:Dipeptides; D008823:Micelles; D010743:Phospholipids; D010880:Piperidines