Joachim Brouwers, Jan Tack, Frank Lammert, Patrick Augustijns
Laboratory for Pharmacotechnology and Biopharmacy, Katholieke Universiteit Leuven, Belgium.
Journal of pharmaceutical sciences 2006 FebThe purpose of this study was to assess the effect of biorelevant apical conditions on intestinal permeability estimation in the Caco-2 system for amprenavir, a poorly water-soluble substrate of the efflux carrier P-glycoprotein (P-gp). To establish biorelevant conditions, human intestinal fluids (HIF) were aspirated from the duodenum and jejunum in fasted subjects, before and during 4 h after the intake of a standard formulation of amprenavir (Agenerase). The HIF samples were characterized with respect to the concentrations of phospholipids, individual bile salts, amprenavir, and the excipient d-alpha-tocopheryl polyethyleneglycol 1000 succinate (TPGS); subsequently, the use of these samples in the Caco-2 system during permeability estimation for amprenavir was compared to standard conditions (amprenavir 10 microM dissolved in HBSS-based transport medium). The presence of the solubilizing excipient TPGS resulted in high intraluminal amprenavir concentrations (mM-range) and affected the permeability in a concentration-dependent way. At the observed intraluminal TPGS concentrations (mM-range), TPGS appeared to completely inhibit the interaction between amprenavir and P-gp, suggesting that the effect of P-gp on transepithelial transport of amprenavir in a clinical setting is probably negligible. This study illustrates the importance of the evaluation of intraluminal conditions after drug intake and their integration in permeability estimation in vitro. Copright 2005 Wiley-Liss, Inc.
Joachim Brouwers, Jan Tack, Frank Lammert, Patrick Augustijns. Intraluminal drug and formulation behavior and integration in in vitro permeability estimation: a case study with amprenavir. Journal of pharmaceutical sciences. 2006 Feb;95(2):372-83
PMID: 16374852
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