Absorption of ampicillin from the human lung.

The absorption of ampicillin from the lungs after intratracheal administration was studied in a healthy human. Doses of 50 mg, 250 mg, and 1,250 mg were given by intratracheal injection, and absorption of ampicillin from the lungs was assessed by measuring plasma levels, the area under the plasma level-time curve, and urinary excretion. All these indices of absorption increased with the dose of ampicillin. An intratracheal dose of 100 mg of probenecid together with 250 mg of ampicillin failed to reduce the absorption of ampicillin from the lungs. The uptake of ampicillin by human foetal bronchial slices in vitro was also studied; although viable, they did not accumulate ampicillin. These preliminary results suggest that ampicillin is absorbed from the lungs by passive diffusion.