Decrease in Corneal Damage due to Benzalkonium Chloride by the Addition of Mannitol into Timolol Maleate Eye Drops.

Area of Science:

• Ophthalmology
• Pharmacology
• Cell Biology

Background:

• Benzalkonium chloride (BAC) is a widely used preservative in ophthalmic solutions, but it can cause corneal damage.
• Timolol maleate eye drops, commonly prescribed for glaucoma, contain BAC as a preservative.
• Protecting the corneal epithelium is crucial for patients undergoing long-term ophthalmic treatment.

Purpose of the Study:

• To investigate the protective effects of mannitol on BAC-induced corneal damage.
• To evaluate the impact of mannitol on corneal wound healing, cell viability, and antimicrobial activity.
• To assess the influence of mannitol on the transcorneal penetration and intraocular pressure (IOP)-lowering effects of timolol maleate eye drops.

Main Methods:

• Utilized rat debrided corneal epithelium and a human cornea epithelial cell line (HCE-T) to model corneal damage.
• Monitored corneal wound healing using fundus photography.
• Assessed HCE-T cell viability and the antimicrobial activity of Escherichia coli.
• Determined transcorneal penetration and IOP effects in rabbits.

Main Results:

• Mannitol significantly enhanced corneal wound healing rate (kH) and HCE-T cell viability in the presence of BAC.
• Antimicrobial activity of BAC was not significantly affected by the addition of mannitol.
• In timolol maleate eye drops, mannitol improved corneal healing without altering corneal penetration or IOP-lowering efficacy.

Conclusions:

• A preservative system combining BAC and mannitol demonstrates protective effects on the corneal epithelium.
• Mannitol addition to BAC-containing eye drops can improve ocular surface health in patients.
• This combination holds promise for enhancing the long-term tolerability of anti-glaucoma medications.