Relative efficacy of intracameral moxifloxacin injection methods

PURPOSE: To determine the amount of moxifloxacin remaining in the anterior chamber (AC), immediately after its injection using 3 current injection methods, assuming mixing and fluid exchange with the AC contents during injection of the drug, and to determine the most desirable injection method. SETTING: Department of Ophthalmology and Vision Sciences and Institute of Biomedical Engineering, University of Toronto, Toronto, Canada. DESIGN: Mathematical modeling. METHODS: Mathematical modeling using first-order mixing methods were used to assess mixing. RESULTS: The Kaiser method of injecting 0.5 mL × 100 μg/0.1 mL does not achieve the desired 500 μg level of moxifloxacin in the AC. The "straight from the bottle" method of injecting 0.1 mL × 500 μg/0.1 mL is fraught with potential error, yielding a relatively unreliable final amount in the AC. Injecting 0.5 to 0.6 mL × 150 μg/0.1 mL yields a result closest to the desired goal. CONCLUSIONS: Based on the calculation, the most accurate of current methods to deliver 500 μg moxifloxacin intracamerally is the method of 150 μg/0.1 mL × 0.5 to 0.6 mL.