A study of the diffusion in bile of tazocillin in humans.

The objective of this study was to determine the extent of biliary excretio n of tazocillin, a combination of piperacillin and tazobactam administered as an intravenous infusion in a dose of 4 g of piperacillin and 0.5 g of ta zobactam. In 10 patients, piperacillin and tazobactam levels were determine d in serum, main bile duct bile, gallbladder bile, and gallbladder wall spe cimens harvested during a cholecystectomy procedure 1 h after completion of a tazocillin infusion. In five other patients, piperacillin and tazobactam levels were determined in bile collected from a main bile duct T-tube duri ng 12 h following a tazocillin infusion given seven days after cholecystect omy. HPLC was used to assay both compounds. Piperacillin and tazobactam lev els in the intraoperative specimens were as follows: 69.1+/-13.8 and 9.9+/- 1.7 mu g/ml, respectively, in the serum; 630+/-133 and 11.9+/-2.2 mu g/ml, respectively, in the main bile duct bile; 342+/-114 and 7.7+/-2.3 mu g/ml, respectively, in the gallbladder bile; and 49.3+/-20.2 and 2.9+/-0.6 mu g/g , respectively, in the gallbladder wall. In the T-tube bile specimens, peak piperacillin and tazobactam levels were 358+/-281 and 9.9+/-3.3 mu g/ml, r espectively, after 1 h; total biliary excretion over 12 hours was 28.3+/-18 .0 mg and 1.0+/-0.5 mg, i.e., 0.7+/-0.4% and 0.2+/-0.1% of the dose, respec tively. The levels of piperacillin and tazobactam found in bile and gallbla dder wall specimens in this study suggest that tazocillin may prove valuabl e for the prevention and treatment of biliary infections.