Safety of sodium hyaluronate eye drop with C12-benzalkonium chloride

In this study, we investigated the effects of commercially available multi-dose sodium hyaluronate 0.1% (Hyalein^®; Santen, Osaka, Japan) containing 0.003% C12-benzalkonium chloride (BAC) on the Corneal epithelium and its degree of safety.

Japanese white male rabbits were divided into four groups. The corneas of each group exposed to one of the following solutions: sodium hyaluronate 0.1%, C12-BAC, C12, 14, 16-BAC Mixture, and Hank's Balanced Salt Solution (HBSS) (as control), respectively. Corneal transepithelial electrical resistance (TER) changes after 60 s of exposure to the above solutions were measured in living rabbits. TER reflects the barrier function of the epithelium. In addition, scanning electron microscopy was used to examine the acute effects of the above solutions on the integrity of the corneal epithelium of four groups.

There was no significant decrease in the corneal TER after exposure of the cornea to Hyalein^® eye drops as compared to HBSS control eyes. Also, BAC mixture solution and C12-BAC did not produce any significant decrease in the corneal TER as compared to HBSS control eyes. All the corneal epithelium exposed to Hyalein^®, 0.003% C12-BAC and 0.003% BAC mixture exhibited a regular appearance of the superficial cells with a high density of microvilli.

This study confirms that Hyalein^® has no acute hazardous effect on corneal epithelium.