Oral absorption of pivampicillin and ampicillin in young children: cross-over study using equimolar doses of a suspension.

In a cross-over study, the oral absorption following equimolar doses of ampicillin corresponding to 16.7 mg/kg administrered as pivampicillin ('Pondocillin') suspension and ampicillin ('Doktacillin') suspension respectively, was investigated in 11 children aged from 8 months to 4.5 years. Pivampicillin produced a mean peak serum concentration of 10.7 microgram ampicillin/ml compared with 5.8 microgram/ml after ampicillin. The mean area under the serum concentration-time curves was 29.2 microgram/ml-h after pivampicillin and 16.7 microgram/ml-h after ampicillin, reflecting the superior bioavailability of the ester form. In 4 of the children aged between 8 and 12 months, the serum levels after pivampicillin were consistenly lower than those recorded in the remaining 7 children beyound the age of 1 year. The mechanism and therapeutic implications of this finding require further study.