Ampicillin concentration in normal and pathological lung tissues after oral administration of bacampicillin.

Following oral administration of 800 mg bacampicillin, the concentrations of ampicillin were determined in normal (n = 16) and pathological (n = 12) lung tissue after 3.6 and 9 hours in a total of 28 patients. The serum concentration was determined simultaneously. The mean peak serum concentration (+/- SD) after one hour was 9.7 +/- 7.2 micrograms/ml. The mean concentration (+/- SD) in normal lung tissues were, after 3, 6 and 9 hours, 3.73 +/- 1.10 micrograms/ml, 1.06 +/- 0.99 micrograms/ml, 0.15 +/- 0.30 microgram/ml respectively, and in pathological lung tissues 0.95 +/- 0.31 microliters/ml, 0.86 +/- 1.11 micrograms/ml and 0.40 +/- 0.24 micrograms/ml respectively. Thus bacampicillin produced concentrations well above the MIC of the most important pathogen, Haemophilus influenzae, in both pathological and normal lung tissue.