Interstitial fluid concentrations of cefsulodin, azlocillin and carbenicillin.

Cefsulodin, azlocillin and carbenicillin were administered by intramuscular injection to rats in a dose of 100 mg/kg. THe serum concentration in frequent samples after administration was determined and compared with the interstitial fluid (IF) concentration, measured with implanted paper discs enveloped in a dialysis tube. The IF concentration of cefsulodin was significantly higher than that of the other two antibiotics. The AUC in the IF was also larger for cefsulodin.