Pharmacokinetics of moxifloxacin in non-inflamed cerebrospinal fluid of humans: implication for a bactericidal effect

Objectives: To evaluate the ability of moxifloxacin to penetrate healthy brain barriers. Methods: Fifty patients received a single oral dose of 400 mg as an antimicrobial prophylaxis regimen for a short urological procedure under spinal anaesthesia. Serum and cerebrospinal fluid (CSF) were sampled at different time intervals post-drug intake and patients were divided into five groups, as follows: group I: 0.5-1 h; group II: 1-2 h; group III: 2-4 h; group IV: 4-6 h; and group V: 6-8 h. Concentrations of moxifloxacin were estimated after analysis by an HPLC system. Bactericidal activity of CSF samples of groups III and IV was assessed by a microdilution technique against two penicillin-resistant isolates of Streptococcus pneumoniae with MICs of moxifloxacin of 0.19 and 0.125 mg/L, respectively. Results: Mean CSF concentrations of moxifloxacin of groups I, II, III, IV and V were 0.19, 0.87, 3.00, 4.07 and 1.82 mg/L, respectively. The mean bactericidal activity of CSF of group III was 8 and that of group IV was 4. Conclusions: Single oral intake of 400 mg moxifloxacin is accompanied by good penetration through healthy meninges within 2-6 h post-dose and reached adequately high levels in human CSF exerting satisfactory bactericidal activity against penicillin-resistant S. pneumoniae. These results render novel perspectives for a role of moxifloxacin in CNS infections.