Oral bioavailability and in vitro stability of pivampicillin, bacampicillin, talampicillin, and ampicillin in horses.

Objectives: To determine the oral bioavailabilities of 3 ampicillin esters (pivampicillin, bacampicillin, and talampicillin) and ampicillin sodium, and to determine in vitro stability of the ampicillin esters in ileal contents (pH 8.3 to 8.5).