Pharmacokinetics of chlorzoxazone in humans

J Pharm Sci. 1983 Sep;72(9):991-4. doi: 10.1002/jps.2600720905.

Abstract

Twenty-three normal male subjects received 900 mg of acetaminophen and 750 mg of chlorzoxazone as an oral suspension. Analysis of plasma samples indicated a rapid absorption and rapid elimination of chlorzoxazone. Average values of the elimination half-life and plasma clearance were 1.12 +/- 0.48 hr and 148.0 +/- 39.9 ml/min, respectively. Analysis of urine samples showed that chlorzoxazone was eliminated from the body as the glucuronide conjugate of the intermediate metabolite 6-hydroxychlorzoxazone, to the extent of 74% of the dose. The plasma and the urinary excretion data were fitted to theoretical equations, and excellent fits were obtained using a five-parameter pharmacokinetic model.

MeSH terms

  • Acetaminophen / metabolism
  • Adult
  • Benzoxazoles / metabolism*
  • Biotransformation
  • Chlorzoxazone / analogs & derivatives
  • Chlorzoxazone / metabolism*
  • Chlorzoxazone / urine
  • Drug Combinations
  • Half-Life
  • Humans
  • Kinetics
  • Male
  • Models, Biological

Substances

  • Benzoxazoles
  • Drug Combinations
  • 6-hydroxychlorzoxazone
  • Acetaminophen
  • Chlorzoxazone