Vitreous Penetration of Orally–Administered Moxifloxacin in Humans

Abstract

Abstract: : Purpose: To investigate the penetration of moxifloxacin (Avelox^R, Bayer) into the vitreous humor after oral administration in humans. Methods: A prospective, non–randomized clinical study of nine consecutive patients scheduled for vitrectomy surgery between June 2004 and October 2004 at the Medical College of Georgia or Southeastern Retina Center. Undiluted vitreous samples were obtained from three control patients (no medication) and six patients who received oral administration of two doses of moxifloxacin 400mg (Avelox^R) during the 18 hours prior to surgery. Patients were instructed to take one tablet the night before surgery, and the other approximately 3 hours before the scheduled start of their surgery. Quantitative assays were performed using high–performance liquid chromatography/tandem mass spectrometry. Results: The mean vitreous moxifloxacin concentration among the six patients sampled was 0.855 µg/ml (range 0.653–1.410 µg/ml). Control samples showed undetectable levels of moxifloxacin. The time between the last oral dose and tissue sampling ranged from 2–6 hours. Conclusions: Orally administered moxifloxacin has significant penetration into the vitreous humor at a level that far exceeds the MIC of the most common ocular pathogens. Even the lowest level achieved (0.653 µg/ml) far exceeds the MIC of most strains of S. epidermidis, S. aureus, S. pneumoniae, S. pyogenes, E. coli, P. acnes, H. influenzae, and B. cereus. However, these concentrations do not exceed the MIC of fluoroquinolone–resistant strains_especially Staphylococcus species. The findings of this investigation reveal that orally administered moxifloxacin can achieve relatively high vitreous levels. Like other fluoroquinolones, oral moxifloxacin may play a role in the treatment or prophylaxis of ocular infections such as endophthalmitis.

Keywords: antibiotics/antifungals/antiparasitics • vitreous