Preclinical and clinical antiallergic effect of olopatadine 0.2% solution 24 hours after topical ocular administration.

Pharmacologic studies examined the potential of a solution containing olopatadine to maintain and extend antiallergic efficacy after single topical ocular drop administration over 24 hours. Results of these preclinical experiments conducted in guinea pigs indicated that olopatadine 0.2% (wt/vol) solution was significantly effective 24 hours after dosing. This concentration of olopatadine provided significantly more efficacy than Patanol (olopatadine 0.1%) 24 hours after administration while being as effective as Patanol (olopatadine 0.1%) 5 minutes after administration. Results from a human conjunctival allergen challenge trial in sensitive subjects confirmed clinical efficacy of olopatadine 0.2% solution over 24 hours. When individuals were challenged with antigen at onset, 16 and 24 hours after drug administration onto the eye, significant reductions were observed in the scores for active drug as compared with placebo for pruritus (77, 77, and 61%), conjunctival redness (35, 28, and 20%), and chemosis (53, 41, and 31%), respectively. These data suggest that topically applied olopatadine 0.2% solution will be an effective once-a-day therapy for allergic conjunctivitis.