Abstract
To support drug development and registration, Caco-2 cell monolayer assays have previously been set up and validated to determine whether candidate drugs are substrates or inhibitors of human P-glycoprotein (P-gp). In this study, the drug-drug interaction (DDI) potential of N-(1-{(3R)-3-(3,5-difluorophenyl)-3-[4-methanesulfonylphenyl]propyl}piperidin-4-yl)-N-ethyl-2-[4-methanesulfonylphenyl]acetamide (AZD5672) was assessed accordingly, and a subsequent clinical digoxin interaction study was performed. AZD5672 (1–500 μM) demonstrated concentration-dependent efflux across cell monolayers, which was abolished in the presence of ketoconazole and quinidine, identifying AZD5672 as a P-gp substrate. In addition, P-gp-mediated digoxin transport was inhibited in a concentration-dependent manner by AZD5672 (IC50 = 32 μM). Assessment of the calculated theoretical gastrointestinal inhibitor concentration ([I2]) and predicted steady-state maximum total plasma inhibitor concentration ([I1]) indicated the potential for a DDI at the intestinal but not the systemic level after the predicted therapeutic dose of AZD5672 (100 mg). A clinical study was performed and the plasma pharmacokinetics [observed maximum plasma drug concentration (Cmax) and area under the plasma concentration versus time curve from 0 to 72 h postdose (AUC0–72 h)] of orally dosed digoxin (0.5 mg) were found to be unaffected by coadministration of AZD5672 (50 mg) at steady state. In contrast, a 150-mg dose of AZD5672 significantly increased digoxin Cmax and AUC0–72 h by 1.82- and 1.33-fold, respectively. Concentration-time profile comparisons indicated that digoxin elimination was unchanged by AZD5672, and the interaction was most likely to have resulted from inhibition of intestinal P-gp leading to increased digoxin absorption. The observed dose-dependent clinically significant interaction was accurately predicted using calculated [I2] and in vitro P-gp inhibition data, confirming AZD5672 to be a P-gp inhibitor in vivo.
Footnotes
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
doi:10.1124/dmd.110.035881.
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ABBREVIATIONS:
- P-gp
- P-glycoprotein
- DDI
- drug-drug interaction
- AZD5672
- N-(1-{(3R)-3-(3,5-difluorophenyl)-3-[4-methanesulfonylphenyl] propyl}piperidin-4-yl)-N-ethyl-2-[4-methanesulfonylphenyl]acetamide
- FDA
- U.S. Food and Drug Administration
- EMA
- European Medicines Agency
- ITC
- International Transporter Consortium
- TEER
- transepithelial electrical resistance
- ER
- efflux ratio
- AUC
- area under the plasma concentration versus time curve
- OATP
- organic anion-transporting polypeptide.
- Received August 16, 2010.
- Accepted November 12, 2010.
- Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics
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