Experimental intravitreal application of trovafloxacin in rabbits

This study was performed to examine the retinal toxicity of trovafloxacin, a broad-spectrum fourth-generation fluoroquinolone, in rabbit eyes after in travitreal injection. The left eyes of 20 albino rabbits were divided into four groups, and each was injected intravitreally with 0.1 ml of trovafloxa cin in a 50-mug, 100-mug, 250-mug or 500-mug concentration. The right eyes of these rabbits served as control and received normal saline solution. Ret inal function was assessed from the electroretinogram (ERG), and retinal st ructure was also examined by ophthalmoscopy and histologic study (light mic roscopy). The intravitreal injections of 50 mug, 100 mug, and 250 mug trova floxacin did not significantly change the ERG a-wave, b-wave or the oscilla tory potential throughout the follow-up period of 4 weeks. While no ERG cha nges were observed at 4 weeks after injection, in the 3 eyes that received trovaloxacin 500 mug/0.1 ml, the a-wave amplitudes showed a diminution of 5 6-49% and those of b-waves one of 53-44% of the preinjection amplitudes at 4 weeks after injection, but oscillatory potentials remained unchanged in t he other 2 rabbits intravitreally injected with 500 mug trovafloxacin. Howe ver, in none of the injected eyes and the control eyes in all groups were o phthalmoscopically visible fundus changes and histologic abnormality observ ed. The results suggest that intravitreally injected trovafloxacin at a dos e of up to 500 mug is nontoxic to the rabbit retina. If future studies in o ther species confirm our findings, intravitreal trovafloxacin may be a good alternative in the treatment and prevention of clinical bacterial enclopht halmitis. Copyright (C) 2001 S. Karger AG, Basal.