[Kinetics of cefixime biliary clearance in cholecystectomized patients]

Cefixime is an orally administered cephalosporin with physicochemical properties able to account for a possibly significant biliary excretion. In addition, over 50% of total clearance of the drug has been shown to operate through extra renal pathways in healthy volunteers. The aim of the study was to quantify and to delineate the kinetics of cefixime biliary elimination in ten patients provided with external drainage. Following a single 200 mg oral dose of cefixime, biliary clearance of the drug appears to vary from 0.85 to 27.3 ml/min. Contribution of the latter to the apparent total clearance is relatively low since ranging from 0.8 to 18.6% (mean 5%). Additionally, biliary clearance kinetics of the drug proves non linear and well described according to a sigmoidal model. On account of these results, and given the dianionic charge of the molecule as well as the absence of any metabolite reported so far, an intrahepatic binding and accumulating process, mediated by ligandin, seems to underlie the hepatobiliary excretion of cefixime, as previously reported for other anionic beta-lactam antibiotics.