On human biotransformation of some penicillins.

Urinary excretion of ampicillin, amoxicillin and oxacillin was studied in five healthy volunteers. Determinations were carried out by chemical methods (PC, TLC, spectrophotometry). Beside the parent compounds and their penicilloic acids, an alphaamino-substituted derivative was demonstrated. The total recovery of amoxicillin was nearly complete, recovery of ampicillin and oxacillin was about 50%. The combination of aminopenicillins with oxacillin did not alter significantly the excretion of the individual compounds.