title: Development of a method by UPLC-MS/MS for the quantification of tizoxanide in human plasma and its pharmacokinetic application.
abstract: BACKGROUND
  Nitazoxanide (NTZ) is used for the treatment of gastrointestinal tract colonization by anaerobic bacteria, viruses and other pathogens that represent a major cause of morbidity in Latin America. The aim of the present work was to develop and validate a UPLC-MS/MS method for the selective quantification of tizoxanide (TZN, the major metabolite of NTZ) in human plasma using niclosamide as internal standard; and examine its pharmacokinetic application in healthy volunteers. Nine male subjects received a single oral dose of a NTZ 500-mg tablet under fasting conditions.
  
  
  RESULTS
  The method was linear between 0.1 and 10 µg/ml and capable of separating signals from free-TZN and those delivered by in-source collision-induced dissociation of TZN-glucuronide, quantifying it with accuracy and precision. Mean maximum plasma concentration was 6.79 µg/ml and was reached at 2.4 h post-dose.
  
  
  CONCLUSIONS
  The method was validated, fulfilling regulatory guidelines. Results suggest low pharmacokinetic variability in the assayed population.
authors.affiliation: Global Bioanalytical Consulting, SC, Mexico City, México, Av. Cuauhtémoc No. 722, Ofna. 220, Col. Piedad-Narvarte, 03020 México DF, México. gabmarcelin@pharmometrica.com.mx
authors.forename: Gabriel
authors.initials: G
authors.lastname: Marcelín-Jiménez
authors.forename: Leticia
authors.initials: L
authors.lastname: Contreras-Zavala
authors.forename: Martha
authors.initials: M
authors.lastname: Maggi-Castellanos
authors.forename: Alionka P
authors.initials: AP
authors.lastname: Angeles-Moreno
authors.forename: Alberto
authors.initials: A
authors.lastname: García-González
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013844:Thiazoles / Q000097:blood* / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D013844:Thiazoles; C104067:tizoxanide