Biliary excretion and concentration of cefazolin.

The excretion of cefazolin into the human biliary tract in health and disease was investigated in 34 patients undergoing surgical procedures. The patients included: I. Four controls. IIA. Eleven patients with cholelithiasis and/or cholecystitis and a radiological visualized gallbladder. IIB. Nine patients with cholethiasis and cholecystitis and a radiologically nonvisualized gallbladder. III. Five patients with obstructive jaundice. IV. Five patients with a T-tube in the common bile duct. Two dose regimes: 1. A single dose of 500 mg and 2. four doses each of 500 mg. given every six hours, were used. Samples of serum, gallbladder bile, common duct bile and gallbladder tissue were assayed for antibiotic activity by the cylinder plate method with Bacillus subtilis. Following administration of four doses of the antibiotic, the mean level of the drug in the gallbladder bile, in controls was 127.0 mug/ml. In the group with cholelithiasis and cholecystitis and a gallbladder that is visualized, a similar high level was noted (mean = 132.2 mug/ml.). In the presence of a nonvisualized gallbladder or obstructive jaundice, the levels in bile were lower. Two hours following a single injection of the drug, the level in the common duct bile reaches a peak of 10 mug/ml and at eight hours falls to less than one mug/ml. In the absence of obstruction cefazolin reaches a significantly high level in bile and could be valuable in treatment of biliary infections.