The effect of four commercially available preserved and unpreserved prostaglandin analogues on human corneal epithelial and human conjunctival epithelial cells in vitro

Purpose Four commercially available ophthalmic preparations of prostaglandin analogues: latanoprost, travoprost, bimatoprost, and the more recently developed prostaglandin analogue tafluprost as a BAC‐free unit dose formulation, were tested for cytotoxicity using cell culture methods. Methods The cells were exposed to eye drop concentrations diluted 0.1%‐10% in culture medium without fetal bovine serum for one hour. Correspondingly, the cells were exposed to 0.00008%‐0.005% BAC in serum‐free medium for one hour. Cytotoxicity was assessed by measuring mitochondrial activity with the tetrazolium salt WST‐1 assay for cellular growth and viability, and by measuring the lactate dehydrogenase (LDH) leakage in the culture medium. Results The order of decreasing cytotoxicity of the tested drugs, assessed with the WST‐1 test, was latanoprost > travoprost > bimatoprost > tafluprost. Conjunctival epithelial cells appeared to be more sensitive than corneal epithelial cells. The EC50 value of BAC, assessed with the WST‐1 assay, was 0.0013% in corneal epithelial cells and 0.00047% in conjunctival epithelial cells. In corneal cells, only the commercial preparation of latanoprost with the highest concentration tested (10%) increased LDH leakage. In conjunctival cells, LDH leakage was also very minor and was statistically significant only after 3‐10% travoprost and 10% latanoprost exposures. Conclusion The cytotoxic effects of the commercially available formulations of latanoprost, travoprost, and bimatoprost were dependent on the BAC concentration of the eye drop. Preservative‐free tafluprost had the least cytotoxic effects of the drugs tested.Commercial interest