TOLERABILITY, KINETICS, AND EFFICACY OF SUBCONJUNCTIVAL PEFLOXACIN INPIGMENTED RABBITS

Pefloxacin has been shown to have good intraocular penetration when gi ven systemically. In order to extend its clinical use, we have assesse d the tolerability, kinetics, and efficacy of subconjunctival pefloxac in in phakic pigmented rabbits, The tolerability of a single subconjun ctival injection of pefloxacin (0.8, 1.6, 8, or 16 mg in 0.2 ml) in th e right eyes of eight rabbits was evaluated by clinical and histopatho logical examination, The 0.8-mg dose of pefloxacin was well tolerated, The kinetics was evaluated after a single subconjunctival injection o f 0.8 mg in 18 rabbits, Animals were sacrificed at 1, 3, 5, 7, 12, or 18 h postinjection. Drug concentrations were measured by high-performa nce liquid chromatography. Pefloxacin was found in the cornea (maximum concentration, 18.13 mu g/ml; half-life, 3.92 h) and in the aqueous h umor (maximum concentration, 3.40 mu g/ml; half-life, 2.14 h), Pefloxa cin did not penetrate into the vitreous humor by this route. The effic acy,vas evaluated in an experimental model of staphylococcal corneal u lcers in eight rabbits which received two subconjunctival injections o f 0.8 mg of pefloxacin at 16 and 24 h after intrastromal inoculation. The results (expressed as mean log(10) CFU per milliliter +/- standard deviation) showed that pefloxacin significantly (P < 0.001) reduced t he bacterial counts (4.39 +/- 0.97) compared with those in control eye s (6.46 +/- 0.69). For phakic eyes, subconjunctival pefloxacin might b e of value for the treatment of corneal ulcers. Further studies are re quired to determine its penetration into the vitreous humor of aphakic eyes.