Pharmacokinetics, distribution and dosage regimen of cefuroxime in lacfating goats after intravenous administration*

Pharmacokinetic study of cefuroxime, a second generation cephalosporin was conducted in six lactating goats after i.v. administration (20 mg/kg). The therapeutic concentration (≥1.0 μg/ml) was maintained from 2.5 min to 1 h, 30 to 45 min and 2.5 min to 12 h in plasma, milk and urine, respectively. Distribution half life (t_½ α) of 0.58±0.09 h and elimination half life (t_½ β) of 3.35±0.09 h were obtained for cefuroxime in goats. A high Vd_area of 5.88±0.48 L/kg denotes greater distribution of the drug in different body fluids and tissues. This fact is supported by higher approximate tissue to plasma concentration ratio (T ≈ P) ratio of 4.80±1.84 and also higher drug concentrations obtained in milk. Total body clearance (Cl_B) value of 20.23±1.39 ml/kg/min was obtained in goats in the present study. For treating mild to moderate systemic infections (C_p^∞ min = 0.5 μg/ml), the required loading (D*) and maintenance (Do) doses calculated as 15 and 12 mg/kg at the dosage interval (γ) of 8 h while for treating severe systemic infections (C_p^∞ min =1.0 μg/ml), D* and Do of 20 and 14 mg/kg at the dosage interval (γ), respectively are calculated following i.v. administration.