Pharmacokinetics of oxytetracycline in broiler chickens following different routes of administration.

The aim of this study was to determine the pharmacokinetics of oxytetracycline (OTC) in broiler chickens following intravenous (IV), intramuscular (IM), subcutaneous (SC) and oral (PO) administrations at a dose of 15 mg/kg bodyweight. Plasma concentrations of OTC were determined using liquid chromatography-tandem mass spectrometry and non-compartmental pharmacokinetic analysis was then conducted. The absorption half-life time was 1.23 ± 0.36 h, 1.19 ± 0.52 h, and 0.49 ± 0.38 h after IM, SC and PO administration, respectively. The elimination half-life time was 27.41 ± 6.06 h, 10.23 ± 4.20 h, 7.83 ± 0.56 h, and 14.86 ± 9.23 h, and the mean residence time was 9.67 ± 1.7 h, 11.45 ± 1.76 h, 11.38 ± 0.59 h, and 10.37 ± 3.91 h after IV, IM, SC and PO administration, respectively. Bioavailability was 76.88 ± 12.90%, 92.20 ± 10.53% and 12.13 ± 4.56% after IM, SC and PO administration, respectively, which indicated that OTC is poorly absorbed from the gastrointestinal tract in broiler chickens.