title: Residues of oxytetracycline and its 4'-epimer in edible tissues from turkeys.
abstract: Residues of oxytetracycline (OTC) in edible tissues (muscle, liver, and kidney) of 18 turkeys were determined after continuous administration of the drug for 3 days in drinking water at the maximum recommended concentration of 400 mg/L. The European Union (EU) maximum residue limits (MRLs) set for OTC are 100 microg/kg in muscle tissues, 300 microg/kg in liver, and 600 microg/kg in kidney, as the sum of the parent compound and its derivative 4'-epi-oxytetracycline (4-epi-OTC). Cleanup of tissue samples was performed by metal chelate affinity chromatography (MCAC), but the original technique was miniaturized by the adoption of a mini solid-phase extraction column, allowing reduction of solvents, time, and hazardous waste. OTC and its 4'-epimer were quantitated by an isocratic liquid chromatography elution with UV detection. After 1 day of withdrawal, OTC plus 4-epi-OTC residues were greater than MRL values in muscle and liver; 3 days after the end of treatment, all tissue residues were far lower than the MRL values. At the first day after the end of treatment, 4-epi-OTC was detected at very low concentrations only in muscle, in liver after 1 and 3 days of withdrawal, and in kidney at all sampling times. The withdrawal time was calculated according to EU recommendations and was set at 5 days.
authors.affiliation: Università degli Studi di Padova, Istituto di Patologia e Igiene Veterinaria, Agripolis Legnaro Padova, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Capolongo
authors.forename: Annalisa
authors.initials: A
authors.lastname: Santi
authors.forename: Luciana
authors.initials: L
authors.lastname: Tomasi
authors.forename: Paola
authors.initials: P
authors.lastname: Anfossi
authors.forename: Mauro
authors.initials: M
authors.lastname: Missagia
authors.forename: Clara
authors.initials: C
authors.lastname: Montesissa
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D002853:Chromatography, Liquid; D004350:Drug Residues; D005260:Female; D007202:Indicators and Reagents; D007536:Isomerism; D007668:Kidney / Q000737:chemistry; D008099:Liver / Q000737:chemistry; D008297:Male; D008460:Meat / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry; D010118:Oxytetracycline / Q000032:analysis*; D015203:Reproducibility of Results; D012996:Solutions; D014422:Turkeys / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D007202:Indicators and Reagents; D012996:Solutions; D010118:Oxytetracycline