Trans-scleral permeability of Oregon green 488.
OBJECTIVE
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 microL) 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 x 10(-7) cm/sec and that of NaF was 4.41 +/- 1.32 x 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.
Lee
Sung Jin
SJ
Department of Ophthalmology, College of Medicine, Soonchunhyang University, Seoul, Korea.
Kim
Stephen J
SJ
Kim
Esther S
ES
Geroski
Dayle H
DH
McCarey
Bernard E
BE
Edelhauser
Henry F
HF
D000042:Absorption; D000818:Animals; D002264:Carboxylic Acids / Q000493:pharmacokinetics*; D019793:Fluorescein / Q000493:pharmacokinetics; D006801:Humans; D010539:Permeability; D011817:Rabbits; D012590:Sclera / Q000378:metabolism*
D002264:Carboxylic Acids; C436864:Oregon Green 488 carboxylic acid; D019793:Fluorescein