Comparative In Vitro Toxicology Study of Travoprost Polyquad-preserved, Travoprost BAK-preserved, and Latanoprost BAK-preserved Ophthalmic Solutions on Human Conjunctival Epithelial Cells

Abstract

Purpose: To compare the toxicological profile of a new formulation of travoprost 0.004% ophthalmic solution (travoprost PQ), containing the preservative polyquaternium-1(PQ, polyquad), with the commercially available formulation of benzalkonium chloride (BAK)-preserved travoprost 0.004% ophthalmic solution (travoprost BAK) and BAK-preserved latanoprost 0.005% ophthalmic solution (latanoprost BAK).

Materials and Methods: Human conjunctival epithelial cells were incubated with phosphate-buffered saline (PBS), BAK 0.015%, BAK 0.020%, PQ 0.001%, travoprost PQ preserved with PQ 0.001%, travoprost preserved with BAK 0.015%, or latanoprost preserved with BAK 0.020%. Six toxicological assays were used to assess: cell viability (neutral red, Alamar blue), apoptosis (YO-PRO-1, Hoechst 33342), and oxidative stress (H₂DCF-DA, hydroethidine). Apoptosis and oxidative stress were each reported according to cell viability as observed with neutral red and Alamar blue for a total of 10 analyses per treatment depending on the cell viability test used to interpret apoptosis and oxidative stress responses.

Results: There were no significant differences in toxicity between cells exposed to PBS and cells exposed to travoprost PQ (10/10 analyses) or PQ 0.001% (9/10 analyses). Ten out of 10 analyses revealed that travoprost PQ produced significantly less cytotoxicity than latanoprost BAK (p < 0.0001). Travoprost PQ produced significantly better cell viability and less apoptosis than travoprost BAK (6/6 analyses, p < 0.0001). Travoprost BAK was significantly less cytotoxic than latanoprost BAK in 7 of 10 analyses (p < 0.0001). All 10 of the analyses revealed that BAK 0.015%, BAK 0.020%, and latanoprost BAK produced significantly more cytotoxicity than PBS (p < 0.0001). Travoprost BAK was significantly less cytotoxic than its corresponding BAK 0.015% preservative solution in 9 of 10 analyses (p < 0.0001).

Conclusions: A panel of in vitro toxicity analyses supports the safety of travoprost PQ. Travoprost PQ may be better for ocular surface health than BAK-preserved formulations of latanoprost or travoprost but clinical studies are required to validate these comparisons.

Keywords::

• Glaucoma
• Xalatan
• Travatan
• Preservative
• Cytotoxicity

ACKNOWLEDGEMENT

The authors thank Heather S. Oliff, PhD (Science Consulting Group, LLC, North Tustin, CA) for assistance with writing this article.

Declaration of interest: This study was sponsored by an unrestricted grant from Alcon Research Inc, Fort Worth, TX. The research group in the Vision Institute, to which F. Brignole-Baudouin, L. Riancho, H. Liang, and C. Baudouin belong, has received research grants from Alcon, Allergan, Pfizer, MSD, Thea and Santen. Pr C. Baudouin is or has been consultant for Alcon, Allergan, Pfizer, MSD, Thea and Santen.