Ocular Penetration and Efficacy of Levofloxacin Using Different Drug-Delivery Techniques for the Prevention of Endophthalmitis in Rabbit Eyes with Posterior Capsule Rupture

Purpose: To evaluate the effects of different drug-delivery techniques for levofloxacin (LVFX) in ocular penetration and the prevention of endophthalmitis using an aphakic rabbit model with posterior capsule rupture (PCR). Methods: LVFX was administered to aphakic rabbit eyes with or without PCR using eye drops (EDs), subconjunctival injection (SCI), or intracameral (IC) injection. The concentration of the drug in the vitreous and aqueous humors was estimated at 2h after injection. In another study, aphakic rabbit eyes with PCR were inoculated with Enterococcus faecalis, immediately followed by 0.5% LVFX ED, 0.5% moxifloxacin (MFLX) ED, LVFX IC (500g/0.1mL), or IC saline. EDs were administered 0, 3, and 6h after surgery. Changes on electroretinography (ERG) and intraocular bacterial growth were determined sequentially until 48h after inoculation. Results: The concentrations of LVFX at 2h after IC were higher in the aqueous humor and the vitreous cavity of eyes with or without PCR, compared with EDs or SCI. Eyes treated with LVFX ED, MFLX ED, or IC saline showed a significantly greater reduction in b-wave amplitude on ERG at 48h compared with eyes treated with LVFX IC. The number of bacteria recovered from the vitreous humor in eyes treated with IC LVFX at 48h was significantly less than from eyes that received other treatments. Conclusion: The LVFX IC was effective at suppressing endophthalmitis caused by E. faecalis in eyes with a PCR.