Pharmacokinetic and tissue distribution of doxycycline in broiler chickens pretreated with either: Diclazuril or halofuginone

Following IV injection of doxycycline in a dose of 20 mg kg(-1) b.wt., its serum concentration was best fitted in two-compartment open model in chickens fed either on control or on anticoccidials-containing rations. Diclazuril and halofuginone resulted in a significant short distribution half-life (t(v2 alpha)) (7.17 +/- 0.39 and 11.88 +/- 1.05 min, respectively) and increased total body clearance (Cl(tot)) 0.37 +/- 0.024 and 0.295 +/- 0.034 L/kg/h, respectively. Following oral dosing the tested drug absorbed with t(v2ab) of 41.38 +/- 1.6, 17.48 +/- 0.86 and 41.83 +/- 1.8 min, respectively and their C(max) values (3.18 +/- 0.18. 5.425 +/- 0.48 and 0.986 +/- 0.0371 mu g/ml) were attained at 2.07 +/- 0.097, 1.403 +/- 0.074 and 2.55 +/- 0.106 h. For doxycycline alone and in presence of diclazuril and halofuginone, respectively. Systemic bioavailability was 22.64 +/- 3.46, 86.74 +/- 9.23 and 22.38 +/- 3.09%, respectively. Following IM injection t(v2ab) were 9.096 +/- 1.34 for doxycycline alone, 16.24 +/- 2.21 and 15.6 +/- 1.7 min in the presence of diclazuril and halofuginone, respectively. C(max) was 3.10 +/- 0.28, 4.63 +/- 0.57 and 0.55 +/- 0.07 mu g/ml reached at 0.8 +/- 0.083, 1.13 +/- 0.126 and 1.21 +/- 0.105 h. For the antibiotic alone, and in presence of either diclazuril and halofuginone, respectively. Systemic bioavailability was 22.41 +/- 3.86, 88.97 +/- 12.9 and 12.31 +/- 0.99% in chickens fed on anticoccidial-free, diclazuril- and halofuginone-containing rations, respectively. Both the tested anticoccidials induced higher doxycycline tissue residues in all tested tissue samples. (C) 2010 Elsevier Ltd. All rights reserved.