Comparative pharmacokinetics of bacampicillin and ampicillin suspensions in infants and children

The pharmacokinetics of ampicillin and two preparations of bacampicillin, Veegum and microcapsules, were studied in 24 infants and children. For bacampicillin, mean peak concentrations of 7.6 and 14.4 micrograms/ml were found in the sera of fasting patients after administration of 27.8 mg of drug/ml in Veegum and microcapsular suspensions, respectively. Bacampicillin (27.8 mg/kg) and ampicillin (25 mg/kg) were compared in crossover fashion in 21 of the 24 children. Although the dosage of bacampicillin was 25% smaller on an equimolar basis than that of ampicillin, drug concentrations in serum were consistently higher with bacampicillin than with ampicillin; the differences were statistically significant 0.5, 1, and 2 hr after administration. The bioavailability of bacampicillin was two-to threefold greater than that of ampicillin. Urinary concentrations of drug were twofold higher with bacampicillin than with ampicillin. The proportion of saliva samples with detectable antimicrobial activity was similar among patients who received bacampicillin (31%) and those who received ampicillin (25%); however, the mean salivary concentrations 2 and 4 hr after administration of bacampicillin were substantially higher than those after ampicillin.