title: Pharmacokinetics of doxycycline in laying hens after intravenous and oral administration.
abstract: The pharmacokinetics of doxycycline in laying hens was investigated after a single intravenous (IV) or an oral (PO) dose at 20 mg/kg body weight. The concentrations of doxycycline in plasma samples were determined by high-performance liquid chromatography with an ultraviolet detector, and pharmacokinetic parameters were calculated using a compartmental model method. The disposition of doxycycline after one single IV injection was best described by a two-compartment open model and the main pharmacokinetic parameters were as follows: volume of distribution (Vd) was 865.15 ± 127.64 ml/kg, distribution rate constant (α) was (2.28 ± 0.38) 1/h, elimination rate constant (β) was 0.08 ± 0.02 1/h and total body clearance (Cl) was104.11 ± 18.32 ml/h/kg, while after PO administration, the concentration versus time curve was best described by a one-compartment open model and absorption rate constant (Ka), peak concentration (Cmax), time to reach Cmax (tmax) and absolute bioavailability (F) were 2.55 ± 1.40 1/h, 5.88 ± 0.70 μg/ml, 1.73 ± 0.75 h and 52.33%, respectively. The profile of doxycycline exhibited favourable pharmacokinetic characteristics in laying hens, such as quick absorption and slow distribution and elimination, though oral bioavailability was relatively low. A multiple-dosing regimen (a dose of 20 mg/kg/d for 3 consecutive days) of doxycycline was recommended to treat infections in laying hens. But a further study should be conducted to determine the withdrawal time of doxycycline in eggs.
authors.affiliation: a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China.
authors.forename: F
authors.initials: F
authors.lastname: Yang
authors.affiliation: b College of Animal Science and Technology , Guangxi University , Nanning , China.
authors.forename: H B
authors.initials: HB
authors.lastname: Si
authors.affiliation: a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China.
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Wang
authors.affiliation: a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China.
authors.forename: Z S
authors.initials: ZS
authors.lastname: Zhao
authors.affiliation: a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China.
authors.forename: B H
authors.initials: BH
authors.lastname: Zhou
authors.affiliation: a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Hao
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001682:Biological Availability; D002645:Chickens / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004318:Doxycycline / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D007275:Injections, Intravenous / Q000662:veterinary
chemical_list: D000900:Anti-Bacterial Agents; D004318:Doxycycline