Abstract

Abstract Purpose:

The aim of this study was to determine the scleral permeability of a commercially available version of 2′,7′-difluorofluorescein (OG) and compare it to that of sodium fluorescein (NaF).

Methods:

Both in vitro and in vivo experiments were performed. For the ex vivo experiment, a Lucite block perfusion chamber with human donor sclera was used. Two hundred microliters (200 μL) of 2.5 mg/ml OG or NaF was placed in the donor chamber. The OG and NaF concentration that diffused across the sclera was measured every 2 h for 24 h by fluorometry, and the fluorescence in the sclera was examined by fluorescent microscopy. In vivo experiments consisted of live rabbits treated with a 0.2-mL subtenon injection of 7.5 mg/ml solution of either OG or NaF in the right eye. Intraocular fluorescence was measured by ocular fluorophotometry.

Results:

The scleral permeability coefficient (K_trans) of OG was 3.93 ± 1.01 × 10⁻⁷ cm/sec and that of NaF was 4.41 ± 1.32 × 10⁻⁷ cm/s. Both OG and NaF were visible throughout the sclera after 24 hours. Peak vitreous concentration after subtenon injection in rabbits was 6.48 ± 2.65 ng/mL of OG at 2 min and 47.15 ± 13.3 ng/mL of NaF at 10 min.

Conclusions:

OG was able to diffuse across the sclera and thus could be potentially useful as a fluorescent tag for intraocular drug delivery studies. However, its permeability was substantially less than that of NaF.

Search results

Blood-Retinal Barrier

Trans-Scleral Permeability of Oregon Green 488®