Levels of antibiotic in human blood and interstitial fluid after oral administration of bacampicillin or phenoxymethyl penicillin and intravenous administration of amoxicillin or ampicillin.

Levels of antibiotic in the serum and interstitial fluid were determined for 11 volunteers who received conventional doses of either phenoxymethyl penicillin (penicillin V) or bacampicillin orally and for 11 volunteers who received either amoxicillin or ampicillin intravenously. The levels of antibiotic achieved in both blood and interstitial fluid were higher in the volunteers who received bacampicillin than in those who received penicillin V. The levels of antibiotic in serum and interstitial fluid of participants in the study who received amoxicillin or ampicillin intravenously were comparable with those achieved with equivalent doses of oral bacampicillin. The lowest levels of antibiotic in serum and interstitial fluid were obtained in volunteers who received oral penicillin V, whereas the highest levels were obtained in those given ampicillin and amoxicillin intravenously.