Characterization of in vitro metabolism of capsazepine, a vanilloid transient receptor potential channel antagonist, by liquid chromatography quadrupole ion trap mass spectrometry.

Abstract

Capsazepine is an antagonist of the transient receptor potential channel vanilloid 1 (TRPV1), which is known to play an important role in the regulation of pain and inflammation. A selective and sensitive quantitative method for the determination of capsazepine by HPLC-ESI/MS/MS was developed. The method consisted of a protein precipitation extraction followed by analysis using liquid chromatography electrospray quadrupole ion trap mass spectrometry. The chromatographic separation was achieved using a 100 × 2 mm C(18) Waters Symmetry column combined with a gradient mobile phase composed of acetonitrile and 0.1% formic acid aqueous solution at a flow rate of 220 µL/min. The mass spectrometer was operating in full-scan MS/MS mode using two-segment analysis. An analytical range of 10-5000 ng/mL was used in the calibration curve constructed in rat plasma. The inter-batch precision and accuracy observed were 10.1, 6.4 and 6.1% and 100.8, 98.5 and 106.2% at 50, 500 and 5 000 ng/mL, respectively. An in vitro metabolic stability using rat, dog or mouse liver microsomes was performed to determine the intrinsic clearance of capsazepine. The results suggest a very rapid degradation with T(1/2) ranging from 2.6 to 4.3 min and a high clearance, suggesting that drug bioavailability is considerably reduced following extravascular administrations, consequently affecting drug response. Three metabolites were identified by HPLC-MS/MS. S-hydroxylation (M + 16), oxidative desulfuration (M - 16) and desulfuration (M - 32) metabolites of capsazepine were observed following exposure to rat, dog and mouse microsomes.

• Authors: Jennifer Douat, Pascal Vachon, Francis Beaudry
• Journal: Biomedical chromatography : BMC (Biomed Chromatogr) Vol. 25 Issue 4 Pg. 479-92 (Apr 2011) ISSN: 1099-0801 [Electronic] England
• PMID: 20586106 (Publication Type: Journal Article)
• Copyright: Copyright © 2010 John Wiley & Sons, Ltd.

Chemical References

• TRPV Cation Channels
• Trpv1 protein, rat
• capsazepine
• Capsaicin

Topics

• Animals
• Capsaicin (analogs & derivatives, analysis, metabolism)
• Chromatography, High Pressure Liquid (methods)
• Dogs
• Drug Stability
• Mass Spectrometry (methods)
• Mice
• Microsomes, Liver (metabolism)
• Rats
• TRPV Cation Channels (antagonists & inhibitors)