[Diffusion of an orally administered single dose of ofloxacin into human bronchial mucus]

As part of a systematic investigation of the penetration of antibiotics into human bronchial mucus, we assayed ofloxacin concentrations following ingestion of a single dose. 25 patients with acute superinfection of a chronic lower respiratory tract disease were studied. Each patient had single drug therapy with ofloxacin in a daily dosage of 200 mg taken in the morning on an empty stomach. Patients were divided into five groups according to the time interval between ingestion of ofloxacin and collection of samples (bronchial mucus and serum): 1 hour, 3 hours, 6 hours, 12 hours or 24 hours. Duplicate determinations of ofloxacin on individual samples were done using a microbiologic method. Mean serum concentrations were 1.85, 1.64, 1.32, 0.75 and 0.20 mg/l respectively, with a half-life of 6.7 hours; the corresponding concentrations in mucus were 1.83, 1.51, 1.20, 0.66 and 0.19. These results demonstrate ofloxacin's outstanding penetration into bronchial mucus.