CONCENTRATIONS OF CEFTIBUTEN IN PLASMA AND THE RESPIRATORY-TRACT FOLLOWING A SINGLE 400 MG ORAL DOSE

Concentrations of ceftibuten in bronchial mucosa, epithelial lining fluid (ELF) and alveolar macrophages were determined from samples taken from 15 subjects at bronchoscopy following a single 400 mg oral dose. Concentrations at all sites were determined using a microbiological assay method which was unaffected by the trans-isomer of ceftibuten. The time from dosage to bronchoscopy ran ed from 1.4 to 20.3 h and the subjects were analysed in three groups according to time after dosing. Group A had a mean time since dosing of 1.9 h with mean serum, mucosal and ELF concentrations of 15.2 mg/l, 5.7 mg/kg and 1.6 mg/l. Group B had a mean time of 6.5 h after dosing with mean serum, mucosal and ELF concentration of 14.0 mg/l, 3.2 mg/kg and 1.6 mg/l. Group C had a mean time of 13.3 h with mean serum, mucosal and ELF levels of 4.1 mg/l, 1.8 mg/kg and 1.2 mg/l. Macrophage-related ceftibuten could only be detected in two subjects. These levels are related to the minimum inhibitory concentrations of ceftibuten against common respiratory pathogens with the exception of Strep. pneumoniae.