Pharmacokinetics of amikacin in lactating sheep.

The pharmacokinetics of amikacin (AMK) were investigated after intravenous (i.v.) and intramuscular (i.m.) administration of 7.5 mg/kg bw in 6 healthy lactating sheep. After i.v. AMK injection (as a bolus), the elimination half-life (t1/2beta), the volume of distribution (Vd,area), the total body clearance (ClB) and the area under the concentration-time curve (AUC) were 1.64 +/- 0.06 h, 0.19 +/- 0.02 L/kg, 1.36 +/- 0.1 ml/min per kg and 94.09 +/- 6.95 (microg.h)/ml, respectively. The maximum milk concentration of AMK (Cmax), the area under the milk concentration-time curve (AUCmilk) and the ratio AUCmilk/AUCserum were 1.18 +/- 0.22 microg/ml, 22.45 +/- 3.21 (micro.h)/ml and 0.24 +/- 0.02, respectively. After i.m. administration of AMK the t1/2beta, Cmax, time of Cmax (tmax) and absolute bioavailability (Fabs) were 1.29 +/- 0.1 h, 16.97 +/- 1.54 microg/ml, 1.0 +/- 0 h and 64.88% +/- 6.16%, respectively. The Cmax, AUCmilk and the ratio AUCmilk/AUCserum were 0.33 microg/ml, 1.67 (microg.h)/ml and 0.036, respectively.