Summary: The exploration of a drug candidate’s ability to enter the eye by transcorneal route.
Assessment of the permeability of molecules across human corneal epithelial cell layer (in vitro) or across animal cornea (ex vivo) is important in evaluating of molecules ability to enter the eye by transcorneal route.
|Cells or tissues||1. Human corneal epithelial cells1 (HCE-T, RIKEN, Japan);|
2. Excised rabbit cornea or sclera.
The HCE-T cell cultures2-3 and excised rabbit corneas4-6 are the most used and best characterized corneal permeability models in vitro and ex vivo, respectively.
|Standard molecules||Low permeability: 6-carboxyfluorescein, FITC-dextran 4 000 Da, FITC-dextran 70 000 Da|
High permeability: Rhodamine B
|Permeability study||The permeability experiments across the HCE-T cell cultures or excised rabbit corneas are conducted either in NaviCyte vertical chamber system (Harvard Apparatus, Holliston, MA, USA; Figure 1) to measure the transport of study molecules and standard molecules.|
The HCE-T cell culture or excised rabbit cornea is inserted between two chambers and the cumulative amount of study molecules in the receiver chamber versus time is measured.
|Read-outs||The rate (apparent permeability coefficient, Papp) of the study molecules is compared to the Papp values of the low and high permeability markers.|
In addition, the Papp values of study compounds and standard molecules can be compared to the Papp values of known generic drug molecules across the excised rabbit cornea from the literature2,4-6.
Outcomes and Read-Outs
Reference values for standard molecules
The apparent permeability coefficient (Papp, cm/s) values for the standard molecules across HCE-T cells.
|Experimentica in-house||Reference values Papp × 106 (cm/s)|
|6-carboxyfluorescein||Papp × 106 (cm/s)#||6-carboxyfluorescein*|
|Rhodamine B||Papp × 106 (cm/s) #||Rhodamine B*|
|FITC-dextran 4000 Da||Papp × 106 (cm/s) #||FITC-dextran 4400 Da|
|FITC-dextran 70 000 Da||Papp × 106 (cm/s) #||FITC-dextran 70 000 Da|
# Permeation studies have been done in NaviCyte chambers. *Permeation studies were done in cell culture inserts.
The apparent permeability coefficient (Papp, cm/s) values for the standard molecules across excised rabbit corneas.
|Experimentica in-house Papp × 106 (cm/s)||Reference values Papp × 106 (cm/s)|
|Rhodamine B||Rhodamine B|
|FITC dextran 4000 Da||FITC-dextran 4400 Da|
- Hakkarainen JJ, Žiniauskaitė A, Cėpla V, Valiokas R, Kalesnykas G. Comparison and validation of ex vivo and in vitro corneal permeability models. ARVO 2019 poster. Investigative Ophthalmology & Visual Science July 2019, Vol.60, 5087.
- Žiniauskaitė A, Cėpla V, Valiokas R, Kalesnykas G, Hakkarainen JJ. Novel model for corneal permeability in vitro testing through the combined use of collagen-based hydrogels with stratified corneal epithelial cells. EVER 2018 poster.
- Hakkarainen JJ, Cėpla V, Žiniauskaitė A, Valiokas R, Kalesnykas G. Development of an artificial cornea for testing drug candidate permeability in early stages of drug development. ARVO 2017 poster. Investigative Ophthalmology & Visual Science June 2017, Vol.58, 4337.
- Žiniauskaitė A, Cėpla V, Valiokas R, Kalesnykas G, Hakkarainen JJ. Unique hydrogel technology – in vitro model representing corneal layers. AOPT 2017 poster and oral presentation.
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