ITX 5061 quantitation in human plasma with reverse phase liquid chromatography and mass spectrometry detection

Jill Hochreiter, Jill Lapham, Flossie Wong-Staal, Jeffrey McKelvy, Mark Sulkowski, Marshall J. Glesby, Victoria A. Johnson, Gene D. Morse

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background: ITX 5061 is a highly potent small molecule inhibitor of scavenger receptor-B1, an integral transmembrane protein that is found in liver cells and is actively involved in the transport of HCV into hepatocytes. Currently, ITX 5061 is being investigated in monoinfected hepatitis C patients in a proof-of-concept clinical trial carried out by the AIDS Clinical Trial Group (ACTG). Methods: To provide quantitative results in human plasma for pharmacokinetic analysis, an assay for ITX 5061 was validated. ITX 5061 and the internal standard, a deuterated analogue, were separated by isocratic reverse phase chromatography using a Polar RP column (Phenomenex Synergi™; 2.0 mmx50 mm, 4 μm) and detected via electrospray coupled to a triple quadrupole mass spectrometer with a run time of 5 min. Multiple reaction monitoring in positive mode was used with ITX 5061 at 585/114 m/z and the internal standard at 592/122 m/z with a linear range of 2.50-5,000 ng/ml. Human plasma was extracted using a protein precipitation combing 400 μl of acetonitrile with 100 μl of EDTA plasma. Results: The interassay variation ranged from 1.19 to 13.2%, while the intraassay variation ranged from 0.394 to 12.9% over 6 days of testing. The method was successfully applied to the samples collected for the ACTG Protocol A5277. Plasma concentrations at 1 h and 24 h following 150 mg ITX 5061 daily in HCV monoinfected patients (n=3) ranged from 138 to 518 ng/ml and 33 to 111 ng/ml, respectively. Conclusions: The ITX 5061 assay is accurate and reproducible with a wide linear range and will be used for pharmacokinetic analysis and dose-finding studies in HCV-monoinfected patients.

Original languageEnglish (US)
Pages (from-to)329-336
Number of pages8
JournalAntiviral therapy
Issue number3
StatePublished - 2013

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases


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