Disposition of ampicillin administered intravenously and intratracheally to young calves.

The profile of the blood concentration of ampicillin vs time was compared in 24 calves after ampicillin administration (10 mg/kg body weight) by the intratracheal (i.t.) and the intravenous (i.v.) routes in a crossover study. In a subsequent study, 12 of the calves were given ampicillin i.v. and 12 were given ampicillin i.t.; at 15 min and 2 h after drug administration, the calves were killed and lungs, kidneys, liver, urine and plasma were collected for ampicillin assay. The mean ampicillin concentration in blood after i.v. treatment was significantly (P less than 0.01) higher than after i.t. treatment. The mean ampicillin level in lungs after i.t. treatment was significantly higher than the level after i.v. treatment, but concentrations in kidneys, liver, urine and plasma after i.v. treatment were higher (but not significantly) than those after i.t. treatment.