Abstract
Darunavir is a second-generation protease inhibitor designed to have antiviral efficacy against HIV-1 with multiple resistance mutations to protease inhibitors. It is always coadministered with a subtherapeutic dose of ritonavir. It has been shown that darunavir and ritonavir are substrates of P-glycoprotein (P-gp). We explored the contribution of P-gp to the transport characteristics of darunavir (up to 100 μM) using Caco-2 monolayers and the recently developed in situ intestinal perfusion technique using wild-type and mdr1a/1b(−/−) mice. We observed that, in vitro, P-gp has a modulatory effect on the absorption of darunavir, even at a concentration of 100 μM (efflux ratio = 25). Simulated intestinal fluids partially inhibited P-gp functionality, which was further inhibited by adding the P-gp inhibitors verapamil, 6-[(2S,4R,6E)- 4-methyl-2-(methylamino)-3-oxo-6-octenoic acid]cyclosporine D (PSC833), N-(4-[2-(1,2,3,4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl) ethyl]-phenyl)-9,10-dihydro-5-methoxy-9-oxo-4-acridine carboxamide (GF120918), or ritonavir. Using the in situ intestinal perfusion technique, we demonstrated that coperfusion with ritonavir resulted in a similar apparent permeability coefficient to that observed using P-gp knockout mice, which was 2.7-fold higher than in control mice. We conclude that, in mice, even at a relevant intraluminal concentration of darunavir, P-gp has a modulatory effect on the absorption of darunavir. However, this P-gp-mediated darunavir transport is inhibited when it is combined with ritonavir.
Footnotes
This work was funded by grants from the Institute for the Promotion of Innovation through Science and Technology in Flanders; the Fund for Scientific Research in Flanders; and Onderzoeksfonds of the K.U.Leuven in Belgium.
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
doi:10.1124/dmd.110.032771.
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ABBREVIATIONS:
- RTV
- ritonavir
- DRV
- darunavir
- PI
- protease inhibitor
- P-gp
- P-glycoprotein
- MDR1
- multidrug resistance 1
- FaSSIF
- fasted state simulated intestinal fluid
- PSC833
- 6-[(2S,4R,6E)-4-methyl-2-(methylamino)-3-oxo-6-octenoic acid]cyclosporine D
- GF120918
- N-(4-[2-(1,2,3,4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl)ethyl]-phenyl)-9,10-dihydro-5-methoxy-9-oxo-4-acridine carboxamide
- HBSS
- Hanks' balanced salt solution
- FeSSIF
- fed state simulated intestinal fluid
- HIF
- human intestinal fluid
- Papp
- apparent permeability coefficient.
- Received February 12, 2010.
- Accepted June 15, 2010.
- Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics
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