Cytotoxicity Evaluation of Tear Substitutes Using in vitro System

Objective. The objective of the study is to evaluate in vitro the cytotoxic effect of different moisture eye drops (containing or without preservatives) on the epithelial cells of the conjunctiva and the cornea.

Materials and methods. The objects of the study are moisture eye drops: Hylabak®, Thealoz®, Sistane Ultra®, Kationorm®, Oftolik®, Artelak® Balance, Optiv®. As test systems there were used the transformed cells of normal eye tissues: constant conjunctiva transformed cell lines (Chang Conjunctiva, Clone 1-5c-4) and the human cornea (HCEC). The cytotoxicity of the “artificial tears” was assessed by the viability of cells, cultured in substratum containing the solutions of the objects at concentrations 1, 5 and 10%. Cell viability was assessed by their morphology and metabolic activity.

Results. The most sensitive to the investigated eye drops is considered to be the test system based on human corneal cells. Four of the seven investigated eye drops (Artelak® Balance, Optiv®, Kationorm®, Oftolik®) at a concentration of 10% (by volume) of the substratum showed a high degree of toxicity for cornea cells. Eyedrops Sistane Ultra® had moderate toxic effect on the cells of the cornea and conjunctiva at concentration 5 and 10% (by volume). Hylabak® and Thealoz® in this concentrations did not have any cytotoxic effect on the cells of all test system and showed the best results in the research. The most toxic of all cell types were eye drops Oftolik® and Artelak® balance.

Conclusion. A direct relationship between the concentration of drug in culture medium and cell cytotoxicity was investigated. Eye drops Hylabak® and Thealoz®, that do not contain in its composition a preservative, had no cytotoxic effect on the cells of both test systems at all concentrations used. The lowest toxic effect of the test had eye drop Sistane Ultra® containing “soft” preservative Poliquad®. Among the “artificial tears”, the greatest toxic effect on all cell types at all concentrations used, was observed in eye drops Oftolik (BAK 0.01%) and balance Artelak® (containing “soft” preservative Oxide). Studies have shown the possibility of using in vitro cell systems for the comparative evaluation of the cytotoxic effect of mousture eye drops. 

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