Intraocular penetration of oral levofloxacin in rabbits

The intraocular penetration of levofloxacin was studied in albino and pigmented rabbits after oral administration of 14C-levofloxacin at a dose of 20 mg/kg. The radioactivity of the eyeball of albino rabbits in the autoradiogram was much higher at 1 hr than at 2 or 6 hr after administration. On the other hand, the distribution of radioactivity in pigmented rabbits was similar at 1, 2, and 6 hr after administration. The radioactivity levels in melanin-containing tissues such as the iris-ciliary body and the choroid-retina were significantly higher in pigmented rabbits than in albino rabbits 2 hr after oral administration. The radioactivity levels in the ocular tissues without melanin except for the cornea were similar in albino and pigmented rabbits. These results indicate that the intraocular pharmacokinetics of levofloxacin are markedly affected by its affinity for melanin.