alexa Pharmacokinetics, metabolism, and excretion of linezolid following an oral dose of [(14)C]linezolid to healthy human subjects.
Pharmaceutical Sciences

Pharmaceutical Sciences

Journal of Bioequivalence & Bioavailability

Author(s): Slatter JG, Stalker DJ, Feenstra KL, Welshman IR, Bruss JB,

Abstract Share this page

Abstract Linezolid (Zyvox), the first of a new class of antibiotics, the oxazolidinones, is approved for treatment of Gram-positive bacterial infections, including resistant strains. The disposition of linezolid in human volunteers was determined, after a 500-mg (100-microCi) oral dose of [(14)C]linezolid. Radioactive linezolid was administered as a single dose, or at steady-state on day 4 of a 10-day, 500-mg b.i.d. regimen of unlabeled linezolid (n = 4/sex/regimen). Mean recovery of radioactivity in excreta was 93.8 +/- 1.1\% (range 91.2-95.2\%, n = 15), of which 83.9 +/- 3.3\% (range 76.7-88.4\%) was in urine and 9.9 +/- 3.4\% (range 5.3-16.9\%) was in feces. There was no major difference in rate or route of excretion of radioactivity by dose regimen. Linezolid was excreted primarily intact, and as two inactive, morpholine ring-oxidized metabolites, PNU-142586 and PNU-142300. Other minor metabolites were characterized by high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry and (19)F NMR spectroscopy. After the single radioactive dose, linezolid was the major circulating drug-related material accounting for about 78\% (male) and 93\% (female) of the radioactivity area under the curve (AUC). PNU-142586 (T(max) of 3-5 h) accounted for about 26\% (male) and 9\% (female) of the radioactivity AUC. PNU-142300 (T(max) of 2-3 h) accounted for about 7\% (male) and 4\% (female) of the radioactivity AUC. Overall, mean linezolid and PNU-142586 exposures at steady-state were similar across sex. In conclusion, linezolid circulates in plasma mainly as parent drug. Linezolid and two major, inactive metabolites account for the major portion of linezolid disposition, with urinary excretion representing the major elimination route. Formation of PNU-142586 was the rate-limiting step in the clearance of linezolid.
This article was published in Drug Metab Dispos and referenced in Journal of Bioequivalence & Bioavailability

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Relevant Topics

Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version