Abstract
Purpose::
Studies were conducted in rabbits and monkeys to ensure that intracameral moxifloxacin does not cause local toxicity. In addition, a comparison of the aqueous humor (AH) moxifloxacin concentrations achieved in these studies with the median MIC concentrations for fluoroquinolone resistant (FQR) S. aureus and coagulase negative FQR S. epidermidis is presented.
Methods::
A single injection was administered (up to 75 µL in rabbits; up to 40 µL in monkeys) of undiluted commercial moxifloxacin ophthalmic solution, 0.5% or balanced salt solution was administered directly into the anterior chamber (intracameral) and animals were monitored for 14 days. Ocular observations, including endothelial cell evaluation, biomicroscopy, ophthalmoscopy, corneal thickness and intraocular pressure measurements, were conducted at multiple time points to adequately assess ocular safety.
Results::
For both studies, ocular observations were within normal limits and comparable to the contralateral untreated eye. The average AH volume for New Zealand rabbits and young cynomologous monkeys is approximately 0.250 and 0.150 µL, respectively. Following injection the maximal moxifloxacin concentration was approximately 1500 µg/mL and 1300 µg/mL, respectively. Considering that the median MIC for FQR S. aureus is 1.75 µg/mL, and the MIC for CoagNeg FQR S. epidermidis is 2.5 µg/mL, the initial anterior chamber levels of moxifloxacin would be at least 800x and 750x greater in the rabbit and at least 750x and 500x greater in the monkey.
Conclusions::
A single intracameral injection of moxifloxacin ophthalmic solution, 0.5% was administered to rabbits (up to 75 µL) or to monkeys (up to 40 µL) and although these volumes allow for AH moxifloxacin concentrations greatly in excess of the median MIC for common endophthalmitis pathogens, there was no evidence of ocular toxicity over the 14 day study period. Additional study is warranted.
Keywords: antibiotics/antifungals/antiparasitics • cornea: basic science • endophthalmitis