Abstract
Purpose: :
Eleven (11) generic versions of latanoprost ophthalmic solution available in Japan were evaluated for safety to cultured rabbit corneal epithelial cells (SIRC).
Methods: :
SIRC cells (2 x 105 cells), in a confluent state in 10% FBS-added DME medium at 37ºC with 5% CO2, were put into contact with the 12 of latanoprost ophthalmic solution and phosphate buffered saline for 0, 4, 8, 15, 30 and 60 minutes. Then, the numbers of cells were determined by the Coulter Counter method. With the number of cells put into contact with PBS assumed to be 100, cell survival rates (%) and 50% cell death times (CDT50 [min]) were calculated. For in vivo experiments, each ophthalmic solution was instilled into rabbit eyes, five times at intervals of five minutes. Corneal resistances (CR) two minutes after completion of instillation were measured, and corneal resistance rates (CR [%]) were calculated.
Results: :
While the cells were put into contact with the 12 latanoprost ophthalmic solutions, their survival rates decreased gradually in the course of time. The ophthalmic solutions were divided into two major groups according to the cell survival rates after 30 minutes of contact: one group having the cell survival rates decreased to 30% or lower and the other having the survival rates kept at 50% or higher. The group with the cell survival rates 30% or lower had CDT50 ≤ 15 min while the other with 50% or higher had CDT50 >30 min. In the in vivo experiments, CR (%) decreased significantly with the ophthalmic solutions having CDT50 ≤ 15 min.
Conclusions: :
The 12 latanoprost ophthalmic solutions were classified into two groups according to the class and quantity of the preservative used in them that could possibly affect the corneal epithelial cells. In the group with severe cell damages, possible association with benzalkonium chloride (BAK) used as preservative might exist.
Keywords: cornea: basic science