Interaction of nonpeptidic δ agonists with P-glycoprotein by in situ mouse brain perfusion: Liquid chromatography–mass spectrometry analysis and internal standard strategy

✍ Scribed by Claude Dagenais; Julie Ducharme; Gary M. Pollack

• Book ID: 102399052
• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 172 KB
• Volume: 91
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.1175

✦ Synopsis

Many opioids are substrates of the ef¯ux transporter P-glycoprotein (P-gp) in the blood±brain barrier (BBB). In situ brain perfusion in wild-type and mdr 1a(À/À) P-gp-de®cient mice was utilized to investigate potential P-gp-mediated transport of novel nonpeptidic d agonists (AR-M d compounds). Because radioactive compounds were not available for this series, liquid chromatography±mass spectrometric detection (LC± MS) was the assay methodology of choice. Verapamil in the perfusion buffer (0.5 mM) served as a positive control for P-gp-mediated ef¯ux and as an experimental internal standard for P-gp modulation by AR-M d compounds. LC±MS provided excellent assay sensitivity with no signi®cant interferences. In P-gp-competent mice, the brain extraction of AR-M d compounds ranged from 1.1 to 96%. The ratio of initial brain uptake clearances (Cl up ) in P-gp-de®cient and wild-type mice (P-gp effect) ranged from 0.96 to 4.91. Some compounds increased the Cl up of verapamil in P-gp-competent mice, consistent with P-gp inhibition. These results demonstrate that LC±MS is an appropriate assay methodology for mouse brain perfusion samples, that AR-M d compounds may interact with P-gp in the BBB, and that the internal strategy can provide useful information concerning P-gp modulation by compounds of interest. ß 2002 Wiley-