Slow release bolus for small ruminants: in vitro release of tetracycline compared with serum concentrations of the antibiotic in sheep.
Two formulations of slow release boluses for small ruminants containing tetracycline hydrochloride in a compressed form were investigated in vitro and in vivo in adult sheep. An in vitro dissolution test was used for the preliminary selection of the 2 boluses. It was shown that the non-cumulative kinetics of tetracycline release in vitro were predictive of the tetracycline serum levels in sheep treated orally with the 2 boluses. The maximum concentrations revealed by the in vitro and in vivo curves were obtained at almost the same Tmax and, in vivo, the therapeutic serum levels were maintained for about 5 days. It is concluded that an in vitro approach is of value in predicting the kinetic profiles of a long-acting tetracycline bolus in sheep.
Droumev
D
D
Higher Institute of Zootechnics and Veterinary Medicine, Department of Pharmacology, Stara Zagora, Bulgaria.
Pashov
D
D
Droumev
M
M
Vangelov
S
S
Velikova
E
E
Kanelov
I
I
Lashev
L
L
Moutafchieva
R
R
D000284:Administration, Oral; D000818:Animals; D003692:Delayed-Action Preparations; D005260:Female; D006207:Half-Life; D066298:In Vitro Techniques; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D012418:Ruminants / Q000378:metabolism*; D012756:Sheep / Q000378:metabolism*; D013752:Tetracycline / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D014018:Tissue Distribution
D003692:Delayed-Action Preparations; D013752:Tetracycline