Pharmacokinetics of sulbactam and ampicillin following oral administration of sultamicillin with probenecid.

Eight volunteers each received lg of probenecid followed immediately by 1.5 g sultamicillin, both given by the oral route. Plasma concentrations of ampicillin and sulbactam were measured using a differential bioassay method. An ampicillin mean peak plasma concentration of 23.1 mg/l was found typically 1.5 h after dosing; the mean peak plasma concentration of sulbactam (10.0 mg/l) occurred at the same time. The mean plasma half-life of ampicillin was 1.45 h and that of sulbactam 1.3 h. The mean urinary recovery of ampicillin was 65% and that of sulbactam 62%. Five of the volunteers reported minor changes in bowel habits.