Antibiotic concentrations in hepatic interstitial and wound fluid.

This study in dogs using tissue-implanted capsules indicates that cephalothin, cefazolin, ampicillin and tetracycline are excreted in the bile, appearing in this fluid at concentrations greater than the concomitant serum levels. Hepatic interstitial fluid concentrations of these agents differed little from levels achieved in soft tissues elsewhere in the body, indicating that compounds which are concentrated in bile do not necessarily achieve high levels in the hepatic parenchyma. The selection of an antimicrobial agent for the therapy of hepatic parenchymal infection or obstructive cholecystitis should, therefore, be based on susceptibilities of the suspected organism rather than on the relative tendencies of various agents to be concentrated in bile.