Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.3390/pharmaceutics16010132
Lizenz creative commons licence
Titel (primär) Effects of aqueous boundary layers and paracellular transport on the efflux ratio as a measure for active transport across cell layers
Autor Kotze, S.; Ebert, A. ORCID logo ; Goss, K.-U.
Quelle Pharmaceutics
Erscheinungsjahr 2024
Department COMPBC
Band/Volume 16
Heft 1
Seite von art. 132
Sprache englisch
Topic T9 Healthy Planet
Supplements https://www.mdpi.com/article/10.3390/pharmaceutics16010132/s1
Keywords efflux transporters; MDCK; Caco-2; active transport; P-glycoprotein; permeability
Abstract The efflux ratio (ER), determined by Caco-2/MDCK assays, is the standard in vitro metric to establish qualitatively whether a compound is a substrate of an efflux transporter. However, others have also enabled the utilisation of this metric quantitatively by deriving a relationship that expresses the ER as a function of the intrinsic membrane permeability of the membrane (P0) as well as the permeability of carrier-mediated efflux (Ppgp). As of yet, Ppgp cannot be measured directly from transport experiments or otherwise, but the ER relationship provides easy access to this value if P0 is known. However, previous derivations of this relationship failed to consider the influence of additional transport resistances such as the aqueous boundary layers (ABLs) and the filter on which the monolayer is grown. Since single fluxes in either direction can be heavily affected by these experimental artefacts, it is crucial to consider the potential impact on the ER. We present a model that includes these factors and show both mathematically and experimentally that this simple ER relationship also holds for the more realistic scenario that does not neglect the ABLs/filter. Furthermore, we also show mathematically how paracellular transport affects the ER, and we experimentally confirm that paracellular dominance reduces the ER to unity and can mask potential efflux.
dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=28609
Kotze, S., Ebert, A., Goss, K.-U. (2024):
Effects of aqueous boundary layers and paracellular transport on the efflux ratio as a measure for active transport across cell layers
Pharmaceutics 16 (1), art. 132 10.3390/pharmaceutics16010132