Movement of fluorescein monoglucuronide in the rabbit cornea. Diffusion in the stroma and endothelial permeability

The movement of fluorescein monoglucuronide, a fluorescent metabolite of fluorescein, was studied in the rabbit cornea in vitro and in vivo. A stromal strip was exposed to fluorescein monoglucuronide, and the diffusion rate and the distribution in the stroma were measured every hr for 24 hr. The diffusion coefficient was 0.94 +/- 0.11 (+/- S.D.) X 10(-6) cm2/sec, and the saline/stroma distribution ratio was in a range of 0.67 to 0.69. The concentration of fluorescein monoglucuronide in the anterior chamber and the cornea was measured every hr for 8 hr following intravenous administration. The endothelial permeability was 4.7 +/- 1.0 X 10(-4) cm/min, and the aqueous/cornea distribution ratio was 0.56 +/- 0.05. It appears that the corneal endothelial permeability in the living eye determined hitherto from systemic administration of fluorescein is most likely the permeability to fluorescein monoglucuronide.