Olopatadine hydrochloride

描述

Olopatadine hydrochloride (CAS: 140462-76-6) is a synthetic antihistamine and mast cell stabilizer, widely used as an active pharmaceutical ingredient (API) for treating allergic conditions such as allergic rhinitis, urticaria, and allergic conjunctivitis. Its molecular formula is C₂₁H₂₄ClNO₃, and it appears as a white to off-white crystalline powder with a melting point of 242–245°C. As a selective H₁-receptor antagonist, it inhibits histamine release and reduces inflammatory responses, making it effective in both oral and ophthalmic formulations. The drug was developed by Kyowa Hakko Kirin and later commercialized by Alcon (e.g., Patanol® eye drops). It is stable under standard storage conditions (sealed, dry, and at room temperature) and complies with pharmacopeial standards (e.g., ≥99% purity).‌