Comparative pharmacokinetics of diminazene in lactating goats and sheep

The pharmacokinetic aspects of diminazene aceturate were studied in lactati ng goats and sheep after single intravenous and intramuscular administratio ns of 3.5 mg/kg b.wt. Plasma and milk concentrations were determined by use of reversed phase high-performance liquid chromatography (HPLC) after ion- pair extraction. Following intravenous injection, the disposition of dimina zene in goats and sheep conformed to a two-compartment model with rapid dis tribution and slower elimination phases. Values of (t(1/2 beta)) were obtai ned indicating a slower final disappearance of the drug from plasma of shee p (21.17 h) than in goats (16.39 h). Diminazene concentrations were maintai ned for more than 4 days in the plasma of goats and sheep. In both species of animals, diminazene was rapidly absorbed following intramuscular adminis tration of 3.5 mg/kg b.wt. The peak plasma concentrations (C-max) were 7.00 and 8.11 mu g/ml and were attained at (T-max) 0.92 and 1.12 hours in goats and sheep, respectively. The elimination half-life (t(1/2el)) of diminazen e after intramuscular administration was shorter in goats (16.54 h) than in sheep (18.80 h). Systemic bioavailabilities (F%) of diminazene after intra muscular administration were 94.94% and 82.64% in goats and sheep, respecti vely. Diminazene could be detected in milk of goats and sheep within 10 min postinjection. Milk concentrations of the drug were lower in goats than in sheep and were detected for 5 and 6 days following both routes of administ ration, respectively.