Cefoperazone and piperacillin levels in plasma and bile were studied in 12 patients with various degree of obstructive jaundice who had undergone cholecystectomy. The antibiotic levels in plasma and bile were assayed by the six-cylinder plate method without pretreatment.
The mean peak levels of the antibiotics in bile[cefoperazone: 236.81 (372.14-101.48) mcg/ml, N=3; piperacillin: 119.42 (152.32-86.52) mcg/ml, N=5]were found within one hour after a single dose of 2-gm potency of each antibiotic was intravenously administered to respective group ,of patients with low degree of jaundice [serum total bilirubin, s.t.b.=1.1 (1.O-1.3) mg/dl; N=5].
In patients with moderate degree of jaundice[s.t.b.=15 (12-18) mg/dl; N=3],the peak levels[cefoperazone: 23.40 mcg/ml, N=1; piperacillin: 37.20 (13.64-60.76)mcg/ml; N=2]appeared at the third or fourth hour after the same dosing, which were lower than tho8e of the lightly jaundiced group.
In case of a heavily jaundiced patient[s.t.b.=28.2 mg/dl; N=1], only trace amount of antibiotic (piperacillin) was found in the bile. However, the antibiotic evel8 in all bile sample8 could be raised, although nonsignificantly by concurrent administration of 100 mg of hydrocortisone.
The mean unbound serum levels of respective antibiotic were found to be almost the same in either lightly Or moderately jaundiced groups at the first hour after dosing[cefoperazone: 6.27 (7.06-5.50) mcg/ml. N=5: piperacillin: 82.62 (95.82-69.42) mcg/ml, N=4].
The preliminary results in this study might indicate that the bile levels of both antibiotics, in either lightly or moderately and heavily jaundiced groups, could reach concentrations higher than their respective minimal inhibitory levels when hydrocortisone was given concurrently.