Purpose: To determine penetration of moxifloxacin 0.5% into human aqueous and vitreous via topical and collagen shield routes of administration.
Methods: Moxifloxacin 0.5% was administered prior to vitrectomy surgery through one of three routes: topical drops every 2 hours for 3 days, versus topical drops every 6 hours for 3 days, versus delivery using a 24-hour dissolvable cross-linked corneal collagen shield. Aqueous and vitreous moxifloxacin concentrations were assayed using high-performance liquid chromatography.
Results: Mean moxifloxacin concentrations in the every-2-hour group for aqueous (n = 9) and vitreous (n = 10) were 2.28 +/- 1.23 microg/mL and 0.11 +/- 0.05 microg/mL, respectively. Mean moxifloxacin concentrations in the every-6-hour group for aqueous (n = 10) and vitreous (n = 9) were 0.88 +/- 0.88 microg/mL and 0.06 +/- 0.06 microg/mL, respectively. Levels of minimum inhibitory concentration at which 90% of isolates are inhibited (MIC90) were far exceeded in the aqueous for a wide spectrum of pathogens that most commonly cause postoperative endophthalmitis. Moxifloxacin concentration in the vitreous did not exceed the MIC90 for several key organisms. Delivery of moxifloxacin via a collagen shield revealed a mean aqueous concentration of 0.30 +/- 0.17 microg/mL 4 hours after placement (n = 5). Vitreous levels at 4 hours, as well as aqueous and vitreous levels at 24 hours, were negligible using this route of administration.
Conclusions: The findings of this investigation reveal that topically administered moxifloxacin 0.5% can achieve relatively high aqueous concentrations. Although aqueous moxifloxacin levels achieved through the use of a collagen shield delivery device are lower, there are several advantages to this route of delivery that make it appealing in the immediate postoperative period. Future studies will be needed to precisely define the role of fourth-generation fluoroquinolones and presoaked collagen shields in the prophylaxis or management of intraocular infections.