Pharmacokinetics of amikacin after repetitive intravenous administration in healthy goats

Pharmacokinetic of amikacin was carried out in clinically healthy female goats of Sirohi breed following multiple once daily dose (@ 10 mg/kg bwt I/V) for five days. Concentrations of amikacin in blood plasma were estimated by microbiological assay technique and various kinetic parameters were calculated using two compartment open model. The minimum therapeutic concentration (≥ 1.0 μg/ml) was maintained up to 12 h in both 1^st and 5^th day of drug administration. The drug was detectable up to 24 h. Significantly higher plasma concentrations of the drug appeared at 0.042, 0.83, 0.50, 0.75, 2, 4, 8, 12 h except 0.166, 0.25, 1.0, 1.5, 6, 24 h on 5^th day as compared to 1^st day of drug administration. Following multiple once daily I/V administration, the values of the extrapolated zero time concentration of the drug during distribution phase (A), theoretical zero time concentration (C_p^o), mean residential time (MRT) and elimination of drug from central compartment (Kel) remained non-significant, while significantly lower value of elimination rate constant (β), significantly increased value of elimination phases (B), area under curve (AUC), area under first moment curve (AUMC) and total body clearance (Cl_B)were observed in 5^th day as compared to 1^st day of amikacin administration. From these kinetic parameters, the loading (D*) and maintenance (D⁰) doses of 07.02 ± 0.36 and 05.91 ± 0.15 mg/kg bwt I/V, respectively were calculated for maintaining the therapeutic concentration (C_p^∞ min = MIC) of 1.0 μg/ml at the dosage interval of 12 h.

HIGHLIGHTS

Pharmacokinetics of amikacin after repetitive intravenous administration in goats.

The elimination half-life (t_1/2β) of amikacin was 4.75h.

The loading doses (D*) of amikacin was 07.02 mg/kg bwt I/V.