Adsorption of levocabastine eye drops by soft contact lenses and its effects in rabbit eyes.

We evaluated the adsorption of levocabastine (LEV) eye drops onto soft contact lenses in rabbit eyes to confirm the safety of this antihistaminic and antiallergic agent.Low- and high- water-content soft contact lenses were placed on the eyes of three rabbits for each type of soft contact lens (total: six rabbits) for 8 hours daily. LEV eye drops and physiological saline solution (used as a control) were instilled into the experimental eye and the fellow eye at a dosage of 0.1 mL per eye, at 1 hour intervals, eight times daily, for 6 consecutive days. Severity of possible eye injury was evaluated before soft contact lens insertion and after removal.After completion of the study, the amounts of LEV and the preservative benzalkonium chloride (BAK) adsorbed onto the soft contact lenses were assayed using high-performance liquid chromatography. There were no significant differences between the experimental solution and the control solution using Draize's method scores or slit lamp evaluation.LEV and BAK accumulated only slightly in the soft contact lenses, leading us to conclude that LEV eye drops could be used safely by soft contact lens wearers for about 1 week.