Simultaneous quantification of tizoxanide and tizoxanide glucuronide in mouse plasma by liquid chromatography–tandem mass spectrometry

Abstract

Nitazoxanide (NTZ) is a broad-spectrum antimicrobial agent. Tizoxanide (T) and tizoxanide glucuronide (TG) are the major circulating metabolites after oral administration of NTZ. A rapid and specific LC-MS/MS method for the simultaneous quantification of T and TG in mouse plasma was developed and validated. A simple acetonitrile-induced protein precipitation method was employed to extract two analytes and the internal standard glipizide from 50 μL of mouse plasma. The purified samples were resolved using a C column with a mobile phase consisting of acetonitrile and 5 mm ammonium formate buffer (containing 0.05% formic acid) following a gradient elution. An API 3000 triple quadrupole mass spectrometer was operated under multiple reaction-monitoring mode with electrospray ionization. The precursor-to-product ion transitions m/z 264 → m/z 217 for T and m/z 440 → m/z 264 for TG were used for quantification. The developed method was linear in the concentration ranges of 1.0-500.0 ng/mL for T and 5.0-1000.0 ng/mL for TG. The intra- and inter-day precision and accuracy of the quality control samples at low, medium and high concentrations exhibited an RSD of <13.2% and the accuracy values ranged from -9.6 to 9.3%. We used this validated method to study the pharmacokinetics of T and TG in mice following oral administration of NTZ. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of metal complex formation on the antibacterial activity of nitazoxanide: Spectroscopic and density functional theory calculations

“…The reduction of ferredoxin or flavodoxin in presence of the coenzyme thiamine pyrophosphate is one of the suggested pathways of the antiprotozoal activity of NTZ. [10] The quantitative determination of NTZ and its metabolic products (tizoxanide) [11][12][13][14][15][16][17][18][19] was carried out using different spectral tools, [11,17,18] electrochemical methods [19] and chromatographic techniques [liquid chromatography-mass spectroscopy (MS)/MS, [12,13] ultra-performance liquid chromatography, [14] LC [15] and high-performance liquid chromatography [16] ].…”