Delivery of antibiotics by phagocytes

Mobile phagocytes, especially polymorphonuclear neutrophils, accumulate at the site of many infections. This homing activity of phagocytes can be exploited as a mechanism for the delivery of antibiotics. To be effectively transported by neutrophils, antibiotics must be concentrated in neutrophils, must not interfere with the function of neutrophils, must remain present at high concentration long enough to be transported, and must be released in active form at the site of infection. Experimental studies have demonstrated that these criteria are fulfilled by azithromycin and, to a lesser extent, by rifampin.