Oral Bioavailability of Ampicillin and Amoxycillin Alone and Bound in Fixed Proportions to Sulbactam and Clavulanic Acid

Abstract

Oral bioavailability of ampicillin when bound to sulbactam (sultamicillin) compared with ampicillin alone and that of amoxycillin with a ligand of clavulanic acid versus amoxycillin alone were assessed in 16 healthy subjects using an open label, multiple crossover study. After a single administration of the drugs, the bioavailability of ampicillin released from sultamicillin was more than twice (2.17) that of ampicillin administered alone, whereas that of amoxycillin was increased by a factor of 1.64 by the presence of clavulanic acid. Higher peak concentrations and areas under the curves, along with shorter lag times, were observed in both cases. The increased oral bioavailability of these aminopenicillins when associated with a β-lactamase inhibitor was well demonstrated in this study, the bioavailability of ampicillin being more enhanced by sulbactam than that of amoxycillin by clavulanic acid.