The degree of penetration of an
antibiotic into the
infection site is an important factor for its therapeutic efficacy, particularly in
respiratory tract infections. In the present study, we examined the lung tissue diffusion of
moxifloxacin at a dose of 400 mg administered intravenously or orally once-daily, and the results were correlated to microbiological data to estimate the clinical efficacy of
moxifloxacin in lower community-acquired
respiratory infections. This was a prospective, randomized, parallel-group trial, open-label, single-center study. Patients undergoing lung surgery for bronchial
cancer which necessitates the removal of an anatomical piece of lung tissue were randomized into twelve treatment groups, dependent upon the time of surgery and the
moxifloxacin formulation, i.v. or oral, administered. During surgery, one blood sample was taken at the time of tissue collection to determine
moxifloxacin plasma concentration. At the same time, tissue samples were taken by pulmonary exeresis. A validated new high performance liquid chromatography assay was used to determine
moxifloxacin concentrations in plasma and lung tissue. A total of 49 patients (25 for i.v. administration, 24 for
oral administration, 44 men and 5 women, mean age, 61 years, mean
body weight, 72 kg, mean
creatinine clearance was 84 ml/min/1.73 m2) were enrolled. The mean +/- SD steady-state
moxifloxacin ratios between lung and plasma concentrations were respectively: 3.53 +/- 1.89 and 4.36 +/- 1.48 for i.v. and
oral administration. The mean steady-state
moxifloxacin maximal lung concentrations (Cmax) were respectively 12.37 microg/g and 16.21 microg/g for i.v. and
oral administration.
Moxifloxacin both intravenously and orally exhibits high penetration in lung tissue, with tissue concentrations far above the MIC90s for most of the susceptible pathogens commonly involved, thus underlining its suitability for the treatment of community-acquired, lower
respiratory tract infections.