Permeability of cornea, sclera, and conjunctiva: A literature analysis fordrug delivery to the eye

The objective of this study was to collect a comprehensive database of ocul ar tissue permeability measurements found in a review of the literature to guide models for drug transport in the eye. Well over 300 permeability meas urements of cornea, sclera, and conjunctiva, as well as corneal epithelium, stroma, and endothelium, were obtained for almost 150 different compounds from more than 40 different studies. In agreement with previous work, the c orneal epithelium was shown generally to control transcorneal transport, wh ere corneal stroma and endothelium contribute significantly only to the bar rier for small, lipophilic compounds. In addition, other quantitative compa risons between ocular tissues are presented. This study provides an extensi ve database of ocular tissue permeabilities, which should be useful for fut ure development and validation of models to predict rates of drug delivery to the eye.