title: In vivo studies to highlight possible illegal treatments of rabbits with carbadox and olaquindox.
abstract: For the treatment of rabbit dysentery and bacterial enteritis, veterinary practitioners often adopt veterinary medicinal products authorised for other food-producing species, but in some cases non-authorised drugs frequently used in the past, such as carbadox and olaquindox, might be illegally adopted. To verify the carbadox and olaquindox distribution and persistence in rabbit tissues, two independent in vivo studies were carried out. In the first study, 24 healthy rabbits received water medicated with carbadox at 100 mg l(-1) over a period 28 days, whereas in the second one, 24 healthy rabbits were administered water containing olaquindox at 100 mg l(-1). In each study rabbits were randomly assigned to four groups to be sacrificed respectively at 0, 5, 10 and 20 days from treatment withdrawal, for depletion studies. A control group of six animals was adopted for control and as a reservoir of blank tissues. Muscle and liver samples collected from each treated animal were stored at -20°C pending the analysis. Sensitive and robust liquid chromatography-tandem mass spectrometry analytical methods were set up for the parent compounds and their main metabolites quinoxaline-2-carboxylic acid, desoxycarbadox and 3-methylquinoxaline-2-carboxylic acid to verify their residual. Data collected demonstrate that the combination of liver as target matrix, quinoxaline-2-carboxylic acid and 3-methylquinoxaline-2-carboxylic acid as marker residue and enzymatic digestion is strategic to evidence carbadox and/or olaquindox illegal treatments in rabbits, even 20 days after treatment withdrawal at concentration levels higher than 0.5 µg kg(-1). This findings suggests that liver should be proposed as target matrix for official control in national monitoring plan.
authors.affiliation: a Food Safety Department - Chemistry Laboratory , Istituto Zooprofilattico Sperimentale delle Venezie , Legnaro , Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Segato
authors.affiliation: a Food Safety Department - Chemistry Laboratory , Istituto Zooprofilattico Sperimentale delle Venezie , Legnaro , Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Biancotto
authors.affiliation: b Diagnostic Laboratory , Istituto Zooprofilattico Sperimentale delle Venezie , Fontane di Villorba , Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Agnoletti
authors.affiliation: b Diagnostic Laboratory , Istituto Zooprofilattico Sperimentale delle Venezie , Fontane di Villorba , Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Berto
authors.affiliation: c Department of Comparative Biomedicine and Food Science , Università degli Studi di Padova , Legnaro , Italy.
authors.forename: Clara
authors.initials: C
authors.lastname: Montesissa
authors.affiliation: a Food Safety Department - Chemistry Laboratory , Istituto Zooprofilattico Sperimentale delle Venezie , Legnaro , Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Benetti
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000302:isolation & purification* / Q000378:metabolism / Q000493:pharmacokinetics; D001711:Biotransformation; D002218:Carbadox / Q000302:isolation & purification* / Q000378:metabolism / Q000493:pharmacokinetics; D002273:Carcinogens / Q000302:isolation & purification* / Q000378:metabolism / Q000493:pharmacokinetics; D002853:Chromatography, Liquid; D004350:Drug Residues / Q000302:isolation & purification / Q000378:metabolism; D005504:Food Analysis / Q000379:methods; D008099:Liver / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism; D011810:Quinoxalines / Q000302:isolation & purification* / Q000378:metabolism / Q000493:pharmacokinetics; D011817:Rabbits; D053719:Tandem Mass Spectrometry; D019155:Veterinary Drugs / Q000302:isolation & purification* / Q000378:metabolism / Q000493:pharmacokinetics
chemical_list: C581287:3-methylquinoxaline-2-carboxylic acid; D000890:Anti-Infective Agents; D002273:Carcinogens; D011810:Quinoxalines; D019155:Veterinary Drugs; C013168:olaquindox; D002218:Carbadox; C042218:quinoxaline-2-carboxylic acid
keywords: HPLC-MSMS; carbadox; depletion study; marker residue; olaquindox; rabbit