In vivo comparison of two galenic forms of ampicillin-trihydrate.

In order to evaluate a new galenic form of ampicillin-trihydrate, individual blood serum levels and urine excretion of ampicillin-trihydrate were compared in a crossover study after oral absorption of 1-gram captab formulation (this being the new galenic form) versus 2x500 mg of the same product. Analyses performed by two different laboratories indicate that clinically insignificant slightly higher serum concentrations can be obtained with captabs, and that very individual absorption profiles should make one take a sceptic viewpoint as to mean serum concentrations computed from larger series of experiments. To obtain a valid blood serum level in as many patients as possible, a posology of 3-4 captabs, spaced over a 24-hour period is suggested for the treatment of infections with ampicillin-sensitive germs. For less sensitive micro-organisms, one should switch to parenteral therapy or to other antibiotics.