Pharmacokinetics of terbinafine in the rabbit ocular tissues after topical administration

To determine the distribution of terbinafine in the cornea and aqueous humor after topical administration.

A corn oil ointment of terbinafine 0.2% (resolved in sterile corn oil) was applied to the conjunctival sac of albino rabbits twice (with a 5-min interval). The concentration of terbinafine was determined with high-performance liquid chromatography (HPLC) 5, 15, 30, 60, 120 and 240 min after administration of terbinafine.

After topical administration, the concentration of terbinafine increased gradually, reached a peak (1.39 microg/ml at 30 min in the cornea and 82.9 ng/ml at 30 min in aqueous humor, respectively) and then decreased. The concentration was 0.18 microg/g at 240 min in the cornea, but terbinafine could not be tested at 120 min in aqueous humor.

Topical ophthalmic terbinafine 0.2% could penetrate into the cornea and aqueous humor at concentrations adequate for inhibition of fungus.