[Biliary excretion of mezlocillin]

2 g of mezlocillin were given at different time intervals (1/4, 1/2, 1, 2, 4, 10, 14, 18 hours) to patients in whom endoscopic retrograde cholangiography (ERC) was scheduled for antibiotic prophylaxis. Prior to the instillation of the contrast medium 5 ml of bile were aspirated and the concentration of the antibiotic determined via agar diffusion in comparison to the serum level. Serum levels reached a peak of 105 micrograms/ml whereas bile levels reached a mean level of 4000 micrograms/ml. In patients with intact liver function mezlocillin is concentrated to a factor of 40 within bile. Complete elimination in serum occurs after 4 to 5 hours, in bile after 18 to 24 hours.