Pharmacokinetics and bioavailability of doxycycline in turkeys

• Published in: Journal of veterinary pharmacology and therapeutics Vol. 19; no. 4; p. 274
• Main Authors: Santos, M D, Vermeersch, H, Remon, J P, Schelkens, M, De Backer, P, Van Bree, H J, Ducatelle, R, Haesebrouck, F
• Format: Journal Article
• Language: English
• Published: England 01.08.1996
• Subjects: Administration, Oral; Adsorption; Aging - metabolism; Animals; Anti-Bacterial Agents - administration & dosage; Anti-Bacterial Agents - blood; Anti-Bacterial Agents - pharmacokinetics; Anti-Bacterial Agents - pharmacology; Biological Availability; Chromatography, High Pressure Liquid - veterinary; Dose-Response Relationship, Drug; Doxycycline - administration & dosage; Doxycycline - blood; Doxycycline - pharmacokinetics; Doxycycline - pharmacology; Gastrointestinal Transit - drug effects; Half-Life; Injections, Intravenous - veterinary; Protein Binding; Turkeys - metabolism
• ISSN: 0140-7783
• DOI: 10.1111/j.1365-2885.1996.tb00049.x

The pharmacokinetic parameters of doxycycline (DOX) were determined in 3 day, 3-, 6- and 12-week-old fasted turkeys, after a single intravenous (i.v.) dose of 25 mg doxycycline. HCl/kg body weight. Doxycycline disposition fitted an open two-compartment model. The mean (+/-SD) elimination half-life was 10.6 +/- 0.7, 10.8 +/- 1.5, 7.9 +/- 1.4 and 10.0 +/- 0.9 h in 3 day, 3-, 6- and 12-week-old turkeys, respectively. Mean (+/- SD) total body clearance was 0.19 (+/-0.01), 0.27 (+/-0.03), 0.11 (+/-0.03) and 0.06 (+/-0.01) L/h.kg in 3 day, 3-, 6- and 12-week-old turkeys, respectively. The steady-state volume of distribution was 1.77 (+/-0.2), 2.1 (+/-0.2), 0.7 (+/-0.4) and 0.5 (+/-0.2) L/kg in turkeys of the above mentioned ages, respectively. The AUC value significantly increased with the age of the turkeys. An oral doxycycline solution at a single dose of 25 mg/kg of body weight was administered to 3 day. 3-, 6- and 12-week-old turkeys. The maximal plasma concentrations in fasted turkeys were 3.8, 5.6, 7.4 and 5.7 micrograms/mL. with tmax values of 4.7, 1.5, 2.8 and 5.4 h, for the different ages, respectively. In fed turkeys the Cmax values were 2.5, 6.1, 4.8 and 3.0 micrograms/mL. with tmax values of 4.2, 5.3, 4.5 and 7.5 h, respectively. The absolute bioavailability in fasted turkeys varied between 25.0 +/- 9.0% (for 12-week-old birds) and 63.5 +/- 7.1% (for 3-week-old birds). The relative bioavailability varied between 40.0 +/- 13.0% (for 12-week-old birds) and 83.7 +/- 14.3% (for 3-week-old birds).