PRESERVATIVES IN ANTIGLAUCOMA EYE DROPS MARKETED: USE PATTERNS AND OCULAR SURFACE SAFETY

Background: Glaucoma is a chronic ophthalmic disease that frequently requires long-term or lifelong topical therapy. Antimicrobial preservatives are commonly incorporated into multidose ophthalmic preparations to prevent microbial contamination during use. However, chronic exposure to certain preservatives, particularly benzalkonium chloride (BAK), has raised concerns regarding ocular surface toxicity.
Objective: This study aimed to identify the antimicrobial preservatives used in antiglaucoma eye drops marketed in Morocco and to assess their potential ocular toxicity, with particular emphasis on BAK and available preservative-reducing or preservative-free alternatives.
Methods: A descriptive cross-sectional study of antiglaucoma eye drops marketed in Morocco was conducted using publicly available pharmaceutical information from the Moroccan Agency for Medicines and Health Products (AMMPS) and Medicament.ma. Information regarding active substances, pharmaceutical presentation, fixed-dose combinations and antimicrobial preservatives was obtained from the Summary of Product Characteristics (SmPC) or package leaflet, when applicable. Published literature was additionally reviewed to characterize the ocular effects of the identified preservatives.
Results: Thirty antiglaucoma eye-drop presentations were identified. Of these, 29 (96.7%) were multidose preparations and only one (3.3%) was a single-dose formulation. Fixed-dose combinations accounted for 46% of products, whereas 54% contained a single active substance. Among the preservatives identified, BAK predominated (83%), followed by polyquaternium-1 (PQ-1; 11%) and benzododecinium bromide (BDD; 6%). BAK is a quaternary ammonium compound with detergent properties, and experimental and clinical evidence indicates that repeated exposure may adversely affect tear-film stability, corneal and conjunctival epithelial integrity and ocular surface inflammation. PQ-1, a high-molecular-weight polycationic preservative, appears to have a more favorable ocular surface tolerability profile.
Conclusion: Preserved multidose formulations, particularly BAK-containing preparations, predominated among the antiglaucoma eye drops evaluated in the Moroccan market. Considering the chronic nature of glaucoma treatment, cumulative preservative exposure should be considered when selecting topical therapy. Fixed-dose combinations, alternative preservatives, preservative-free formulations and preservative-free multidose delivery systems represent potential strategies for reducing preservative burden while maintaining effective intraocular pressure control.