Wanachat Chaiyasan, Sangly P. Srinivas, Pattravee Niamprem, Waree Tiyaboonchai


Objective: Sulforhodamine B (SRB) is a hydrophilic tracer whose fluorescence is unaffected by pH unlike that of carboxyfluorescein. Therefore, SRB may serve as a better tracer when there are significant changes in pH. Thus, in this study, the suitability of SRB to assess the barrier properties of the cellular layers of the cornea was examined using a custom-built confocal scanning micro-fluorometer (CSMF).

Methods: The dye solution (0.1% SRB) was prepared in PBS-Ca2+and three experiments were performed ex vivo using freshly isolated porcine eyes. First, we investigated the penetration of SRB across the endothelium by injection of the dye into the anterior chamber. Next, we measured the penetration of SRB across the epithelium after exposing the ocular surface to the dye. Finally, we examined the penetration after exposure to the dye with detergent (Tween 20) and exposure to the dye concomitant with microneedle injuries. The dye concentration profiles across the cornea were measured using CSMF.

Results: SRB penetrated the corneal endothelium readily into the stroma following injection into the anterior chamber in a time-dependent manner. Despite accumulation in the stroma, SRB did not partition into the epithelium. In agreement with these findings, the dye did not cross the epithelium after topical administration. Co-administration with Tween 20 and injury to the epithelium with microneedles, however, led to penetration of the dye into the stroma.

Conclusions: SRB is a hydrophilic dye that can be used as an alternative fluorescent tracer to assess the barrier function of the cellular layers of the cornea.


Sulforhodamine B, Cornea, Endothelium, Epithelium, Confocal scanning microfluorometry

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Sulforhodamine B, Cornea, Endothelium, Epithelium, Confocal scanning microfluorometry





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International Journal of Applied Pharmaceutics
Articles In Press [Scheduled in Nov-Dec 2018] Page: 94-102

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Authors & Affiliations

Wanachat Chaiyasan
Department of Optometry, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand,

Sangly P. Srinivas
School of Optometry, Indiana University, Bloomington, IN, United States,

Pattravee Niamprem
Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand,

Waree Tiyaboonchai
The Center of Excellence for Innovation in Chemistry (PERCH-CIC), Commission on High-Education, Ministry of Education, Thailand, The Center of Excellence in Medical Biotechnology, Naresuan University, Phitsanulok, Thailand


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