Evaluation of the enrofloxacin excretion in Anatolian buffalo milk

Enrofloxacin (ENR) is a broad-spectrum fluoroquinolone antibiotic widely used in both human medicine and veterinary medicine. In this study, the milk-excretion patterns of ENR and its metabolite ciprofloxacin (CIP) were determined up to the 10th milking following the intramuscular administration of ENR (2.5mg/kg of body weight) to lactating dairy buffaloes. The milk of each animal was collected and the concentrations of ENR and CIP were detected in milk by LC-MS/MS. The detection limits of the method were determined for ENR and CIP as 0.35 μg/kg and 0.12 μg/kg, respectively. The highest total mean concentrations of ENR and its metabolite CIP was determined in the second milking after injection as 603 μg/kg. The residue level in all buffalo milk samples was found to be lower than the maximum residue limit (100 μg/kg) at the fifth milking. In addition, the employed method is successfully applied to evaluate the presence of ENR and CIP residue in 50 marketed buffalo milk samples and none of the samples contained these antibiotics. Consequently, the present study provided information on the milk excretion levels of ENR and CIP in Anatolian buffalo milks by an LC-MS/MS method.