Ocular distribution of difluprednate ophthalmic emulsion 0.05% in rabbits.

Abstract Purpose: To evaluate ocular distribution and excretion of tritium-labeled difluprednate (3H-DFBA) ophthalmic emulsion 0.05% after a single or repeated instillation to pigmented rabbit eyes. Methods: 3H-DFBA ophthalmic emulsion 0.05% was instilled in the right eyes of pigmented rabbits, in either a single or repeated quater in die (QID) for 3 days or 7 days) dose of 25 μg/50 μL. The radioactivity in right and left ocular tissues, urine, blood, plasma, and feces were measured with a liquid scintillation counter. Additionally, the distribution of radioactivity around ocular tissues was investigated with autoradiography. Results: After a single instillation, the highest maximum radioactive concentrations were found in the cornea (2,081 ng eq./g), followed by the iris/ciliary body (926 ng eq./g), conjunctiva (330 ng eq./g), anterior retina/choroid (273 ng eq./g), sclera (222 ng eq./g), and aqueous humor (144 ng eq./mL) of treated eyes. The maximum radioactivity concentration of the posterior retina/ch...