Penetration of antibiotics into bile.

In experimental cholecystitis in dogs, the eradication of E. coli with ampicillin, chloramphenical and kanamycin, all of which showed nearly the same MICs for this bacterial species, varied according to the differences in the penetration of the antibiotics through the liver into the bile. Antibiotics such as cephalothin and rifampicin, which are partially metabolized in the liver to inactive forms, showed higher biliary levels in CCl4-damaged animals than in the normal ones. The results were considered to be due to a reduction in the inactivating effect of esterases in the liver cells. These esterases were mainly found in the cytosol fraction and their intracellular distribution differed from that of esterases for aspirin and/or phenyl acetate.