The Influence of Protein Binding upon Tissue Fluid Levels of Six β-Lactam Antibiotics

The effect of protein binding upon the penetration of six fJ-Iactam (three penicillins and three cephalosporins) antibiotics into tissue fluid was studied in humans. A cantharides blister technique was used. It was found that there was a linear relationship between the percentage of protein binding and the penetration into the blister fluid of the antibiotic as measured by the area under the curve of the protein-free fraction. This finding is further evidence that protein binding may have important influence upon the likely efficacy of an antimicrobial agent.