Pharmacokinetics and bioavailability of doxycycline in fasted and nonfasted broiler chickens.
The pharmacokinetics and the influence of food on the kinetic profile and bioavailability of doxycycline was studied after a single intravenous (i.v.) and oral dose of 10.0 mg/kg body weight in 7-week-old broiler chickens. Following i.v. administration the drug was rapidly distributed in the body with a distribution half-life of 0.21 +/- 0.01 h. The elimination half-life of 6.78 +/- 0.06 h was relatively long and resulted from both a low total body clearance of 0.139 +/- 0.007 L/h.kg and a large volume of distribution of 1.36 +/- 0.06 L/kg. After oral administration to fasted chickens, the absorption of doxycycline was quite fast and substantial as shown by the absorption half-life of 0.39 +/- 0.03 h, the maximal plasma concentration of 4.47 +/- 0.16 micrograms/mL and the time to reach the Cmax of 1.73 +/- 0.06 h. The distribution and the final elimination of the drug were slower than after i.v. administration. The absolute bioavailability was 73.4 +/- 2.5%. The presence of food in the intestinal tract reduced and extended the absorption (t1/2a = 1.23 +/- 0.21 h; Cmax = 3.07 +/- 0.23 micrograms/mL; tmax = 3.34 +/- 0.21 h). The absolute bioavailability was reduced to 61.1% +/- 4.4%.
Laczay
P
P
Department of Pharmacology and Toxicology, Faculty of Veterinary Science, Szent István University, H-1400 Budapest, P.O. Box 2, Hungary. placzay@univet.hu
Semjén
G
G
Lehel
J
J
Nagy
G
G
D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D002645:Chickens / Q000378:metabolism*; D004318:Doxycycline / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D005215:Fasting / Q000502:physiology*; D005260:Female; D006207:Half-Life; D007275:Injections, Intravenous; D008297:Male
D000900:Anti-Bacterial Agents; D004318:Doxycycline