Comparison of antibiotic assays using different experimental models and their possible clinical significance.

Different experimental models were applied to study the pharmacokinetics of antibiotics in "interstitial fluid" ("i.f.") in rabbits. Two types of tissue cages were used and the results from these experiments were compared with those obtained analysing the antibiotic concentration in the mucous membrane of the oral bucca and maxillary sinus in rabbits. A similar determination was done in the mucous membrane of sinus in man. The concentration of antibiotics in the "i.f." from steel-net chambers in rabbits closely follows that of the mucous membranes of the maxillary sinus in man and the oral bucca in rabbits. Experimental bacterial infections of the tissue cages resulted in decreased amounts of biologically active antibiotics in the "i.f." for some antibiotics compared to that of the uninfected cages. An increase of the concentration of antibiotics in the infected cages was noted simultaneously with a decrease in the number of viable bacteria during the healing process. The clinical significance of the models will be discussed.