title: Novel in vitro transport method for screening the reversibility of P-glycoprotein inhibitors.
abstract: The purpose of this study was to establish a novel in vitro method for screening reversibility of P-glycoprotein (P-gp) inhibitors. Caco-2 cells with 21days of cultivation were used as an in vitro model. Transport of rhodamine 123 in the presence of various inhibitors and after removing of inhibitors was determined. Transport of rhodamine 123 at 4°C and in the secretory direction assured that Caco-2 cells exhibited P-gp function at all time of experiment. The apparent permeability coefficient (Papp) of rhodamine 123 in the presence of verapamil, cyclosporin A, ritonavir, quinidine, N-ethylmaleimide, Cremophor® EL, Tween 80 and poly(acrylic acid)-cysteine-2-mercaptonicotinic acid (PAA-cys-2MNA) was 2.3-, 3.8-, 2.3-, 3.1, 7.5-, 2.1-, 2.9- and 2.5-fold higher than Papp of rhodamine 123 alone. After removing of the inhibitors, Papp decreased to the same range of control except in the case of N-ethylmaleimide which was 2.4-fold higher than the control. These results revealed a reversible inhibition of verapamil, cyclosporin A, ritonavir, quinidine, Cremophor® EL, Tween 80 and PAA-cys-2MNA and an irreversible inhibition of N-ethylmaleimide for P-gp. Thus, this novel established that in vitro method might be an effective tool for screening the reversibility of inhibition of P-gp inhibitors.
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
authors.forename: Kesinee
authors.initials: K
authors.lastname: Netsomboon
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
authors.forename: Flavia
authors.initials: F
authors.lastname: Laffleur
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
authors.forename: Wongsakorn
authors.initials: W
authors.lastname: Suchaoin
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria. Electronic address: andreas.bernkop@uibk.ac.at.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bernkop-Schnürch
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D018938:Caco-2 Cells; D018929:Cell Culture Techniques / Q000379:methods*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D016572:Cyclosporine / Q000378:metabolism / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D006801:Humans; D011802:Quinidine / Q000378:metabolism / Q000494:pharmacology; D014700:Verapamil / Q000378:metabolism / Q000494:pharmacology
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D016572:Cyclosporine; D014700:Verapamil; D011802:Quinidine
keywords: Caco-2; Cremophor® EL; Cyclosporin A; N-ethylmaleimide; Preactivated thiomers; Quinidine; Rhodamine 123; Ritonavir; Tween 80; Verapamil