Determination of the rifamycin antibiotics rifabutin, rifampin, rifapentine and their major metabolites in human plasma via simultaneous extraction coupled with LC/MS/MS

Lee C. Winchester, Anthony T. Podany, Joshua S. Baldwin, Brian L. Robbins, Courtney V. Fletcher

Research output: Contribution to journalArticle

10 Scopus citations


A novel assay using high pressure liquid chromatography (HPLC) coupled to mass spectrometer (MS) detection was developed and validated for the rifamycin anti-tuberculosis antibiotics rifampicin (RIF), rifabutin (RBT), rifapentine (RPT) and their active desacetyl metabolites (dRIF, dRBT and dRPT, respectively) in human plasma. The assay uses 50. μL of human plasma with a quick and simple protein-precipitation extraction to achieve a dynamic range of 75-30,000. ng/mL for RIF, RBT and RPT and 37.5-15,000. ng/mL for dRIF, dRBT and dRPT, respectively. The average %CV and %deviation were less than 20% at the lower limit of quantitation and less than 15% over the range of the curve. The method was fully validated according to FDA criteria for bioanalytical assays and has successfully been used to support three large international tuberculosis trials.

Original languageEnglish (US)
Pages (from-to)55-61
Number of pages7
JournalJournal of Pharmaceutical and Biomedical Analysis
StatePublished - Feb 1 2015



  • Bioanalysis
  • Rifabutin
  • Rifampin
  • Rifapentine
  • Tuberculosis

ASJC Scopus subject areas

  • Analytical Chemistry
  • Pharmaceutical Science
  • Drug Discovery
  • Spectroscopy
  • Clinical Biochemistry

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