Determination of a new 5-lipoxygenase inhibitor, zileuton, and its inactive N-dehydroxylated metabolite in plasma by high performance liquid chromatography.
A rapid and sensitive assay was developed for the measurement of plasma concentrations of zileuton racemate, a potent inhibitor of 5-lipoxygenase. Zileuton and its inactive N-dehydroxylated metabolite were extracted from human, monkey, and rat plasma by use of a solid-phase extraction column (Analytichem Bond Elut). The compounds were then separated by reverse-phase high performance liquid chromatography (HPLC) on a Supelcosil LC-18 column and quantified on the basis of ultraviolet absorption at 260nm relative to an internal standard. The extraction recovery of zileuton, as determined by HPLC assay, was 77.9 +/- 1.7%. Recovery of the metabolite was 85.8 +/- 0.7%. Calibration curves for both compounds were linear over the zileuton concentration range 0.01 to 10.0 mg/L (correlation coefficients > 0.987), while the intra- and interassay coefficients of variation were < 15.6%. In practice, > 97% of blinded daily spiked control samples for zileuton and > 90% of those for the metabolite were within 10% of their target concentrations.
Granneman
G R
GR
Abbott Laboratories, Pharmacokinetics and Biopharmaceutics Department, Abbott Park, Illinois, USA.
Braeckman
R A
RA
Erdman
K A
KA
D000818:Animals; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D000882:Haplorhini; D006801:Humans; D006900:Hydroxylation; D006918:Hydroxyurea / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics; D016859:Lipoxygenase Inhibitors / Q000097:blood* / Q000378:metabolism / Q000493:pharmacokinetics; D051381:Rats; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D014508:Urea / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics
D016859:Lipoxygenase Inhibitors; C097393:N-dehydroxyzileuton; C099268:N-methylzileuton; D014508:Urea; C063449:zileuton; D006918:Hydroxyurea