Abstract
Purpose: :
To use an in vivo anesthetized rabbit model to compare the cornea and aqueous humor concentrations of besifloxacin versus moxifloxacin after topical instillation of a single drop of their commercial formulations.
Methods: :
After anesthetizing the rabbits, a single topical dose of either the new Besivance* [(besifloxacin ophthalmic suspension) 0.6%, Bausch & Lomb Inc.] or Vigamox® [(moxifloxacin hydrochloride ophthalmic solution) 0.5%, Alcon Laboratories Inc.] was instilled directly onto the cornea. This was followed by a 20-minute controlled period applying manual blinking (4 blinks/min) and a supplementary tear flow (2 µL/min) to emulate the drug concentration in human tears. Samples of the cornea and aqueous humor were collected at 0.25, 0.5, 1, 2, 4 and 6 hours post-dose, and the levels of the fluoroquinolones were determined using HPLC methods.
Results: :
The moxifloxacin Cmax (at 15 min) and AUC values in the cornea were (mean ± SE, n = 4) 44 ± 11 µg/mL and 35 µg*h/mL respectively which were 3.4- and 1.2-fold higher than the respective values of 13 ± 2 µg/mL (at 30 min) and 30 µg*h/mL for besifloxacin. In the aqueous humor, moxifloxacin Cmax (at 30 min and 1 hour) and AUC values were 2.0 ± 0.2 µg/mL and 5 µg*h/mL respectively which were 10- and 5-fold higher than the respective values of 0.2 ± 0.1 µg/mL (at 2 hours) and 1 µg*h/mL for besifloxacin.
Conclusions: :
In this anesthetized rabbit model, following a single topical dose, the aqueous humor and corneal concentrations of moxifloxacin are higher than besifloxacin. This indicates a greater bioavailability and ocular penetration of moxifloxacin in rabbits.* Trademarks are the property of their respective owners;moxifloxacin is licenced to Alcon, Inc. by Bayer HealthCare AG.
Keywords: antibiotics/antifungals/antiparasitics • cornea: tears/tear film/dry eye • aqueous