The new bilastine eye drop formulation protects against conjunctival dehydration and promotes corneal wound healing in a comparative in vitro study

Bilastine is a non-sedating, highly selective H1-antihistamine with proven efficacy and safety in treating allergic rhinoconjunctivitis and urticaria in adults and children. Allergic conjunctivitis, a common ocular condition, negatively impacts quality of life. Topical eye drops are the standard treatment, though ocular bioavailability is often low. Incorporating biopolymers such as hyaluronic acid (HA) into topical formulations enhances adhesive properties, prolongs retention on the ocular surface, and ultimately improves drug bioavailability. This study evaluated the new multidose preservative-free bilastine 0.6% solution with sodium HA against eight commercially available antiallergic eye drops. Using an ex vivo bovine cornea model, bilastine 0.6% demonstrated the highest bioadhesion strength (0.025 mJ), indicating superior retention on the ocular surface. It also showed strong protective effects against in vitro dehydration, mainly due to the presence of HA, and did not exhibit cytotoxicity in human primary conjunctival cells. In wound healing assays, preservative-free ketotifen 0.025%, bilastine 0.6%, and azelastine 0.05% promoted corneal wound repair at 72 h, outperforming preserved formulations. Overall, preservative-free bilastine 0.6% with HA enhances corneal hydration, retention, and re-epithelialization in vitro, suggesting potential benefits for the management of allergic conjunctivitis and offering promising advancements in treating this widespread condition.