Pig Cornea for Drug Biocompatibility

A large number of ophthalmic drugs are applied by topical administration, making essential to assess their biocompatibility with the cornea. Ex vivo models of cornea are an excellent tool to this end. In this ex vivo model, freshly excised porcine corneas are used to test corneal biocompatibility. Porcine eyeballs from white pigs (age 6-7 months) are enucleated and the corneas are excised as corneo-scleral buttons. Then, the buttons are placed with the epithelial side down on tube caps and 4 % (w/v) agar in DMEM/F-12 cell culture medium is pipetted on endothelial side of each corneo-scleral button. After cooling and subsequent gelling of the agar solution the buttons are placed on a 6-well plate (endothelial side down) and maintained in the incubator with supplemented cell culture medium.

The next day, drugs can be added to the cornea by using silicone rings. At selected exposure times the samples are removed, and after washing the buttons with PBS the extent of any corneal damage is evaluated visually with the aid of fluorescein solution and a cobalt-blue lamp. This procedure can be repeated at several time points .