Determination of the biliary excretion of piperacillin in humans using a novel method

Aim To evaluate the applicability of a novel method to determine the biliary excretion of piperacillin. Methods Healthy volunteers were administered piperacillin i.v. Duodenal aspirates were collected via a custom-made oroenteric catheter; blood and urine also were collected. Gallbladder ejection fraction (EF) was determined by gamma scintigraphy and pharmacokinetic parameters were calculated using noncompartmental analysis. Results The fraction of the piperacillin dose excreted unchanged into bile was 1.1 +/- 0.3% (biliary clearance corrected for EF was 0.032 +/- 0.008 ml min(-1) kg(-1)). Conclusions This methodology can be used to determine reliably the biliary clearance of drugs that are excreted only marginally into bile. Normalization of biliary clearance for EF significantly reduces intersubject variability of this parameter.