Azelastine Hydrochloride
Azelastine Hydrochloride Prescribing Information
Azelastine hydrochloride ophthalmic solution is indicated for the treatment of itching of the eye associated with allergic conjunctivitis.
The recommended dose is one drop instilled into each affected eye twice a day.
Azelastine hydrochloride ophthalmic solution is contraindicated in persons with known or suspected hypersensitivity to any of its components.
The following events were reported in 1–10% of patients: asthma, conjunctivitis, dyspnea, eye pain, fatigue, influenza-like symptoms, pharyngitis, pruritus, rhinitis and temporary blurring. Some of these events were similar to the underlying disease being studied.
Azelastine hydrochloride ophthalmic solution, 0.05% is a sterile ophthalmic solution containing azelastine hydrochloride, a relatively selective H
1-receptor antagonist for topical administration to the eyes. Azelastine hydrochloride is a white crystalline powder with a molecular weight of 418.37. Azelastine hydrochloride is sparingly soluble in water, methanol and propylene glycol, and slightly soluble in ethanol, octanol, and glycerine. Azelastine hydrochloride is a racemic mixture with a melting point of 225°C. The chemical name for azelastine hydrochloride is (±)-1-(2H)-phthalazinone,4-[(4-chlorophenyl)methyl]-2-(hexahydro-1-methyl-1H-azepin-4-yl), monohydrochloride and is represented by the following chemical structure:
Empirical chemical structure: C
22H
24ClN
3O.HCl
Each mL of azelastine hydrochloride ophthalmic solution contains: Active: 0.5 mg azelastine hydrochloride, equivalent to 0.457 mg of azelastine base; Preservative: 0.125 mg benzalkonium chloride; Inactives: disodium edetate dihydrate, hypromellose, sorbitol solution, sodium hydroxide and water for injection. It has a pH of approximately 5.0 to 6.5 and an osmolarity of approximately 271 to 312 mOsmol/L.
Azelastine hydrochloride is a relatively selective histamine H
1 antagonist and an inhibitor of the release of histamine and other mediators from cells (e.g. mast cells) involved in the allergic response. Based on
Absorption of azelastine following ocular administration was relatively low. A study in symptomatic patients receiving one drop of azelastine hydrochloride ophthalmic solution in each eye two to four times a day (0.06 to 0.12 mg azelastine hydrochloride) demonstrated plasma concentrations of azelastine hydrochloride to generally be between 0.02 and 0.25 ng/mL after 56 days of treatment. Three of nineteen patients had quantifiable amounts of N-desmethylazelastine that ranged from 0.25–0.87 ng/mL at Day 56.
Based on intravenous and oral administration, the elimination half-life, steady-state volume of distribution and plasma clearance were 22 hours, 14.5 L/kg and 0.5 L/h/kg, respectively. Approximately 75% of an oral dose of radiolabeled azelastine hydrochloride was excreted in the feces with less than 10% as unchanged azelastine. Azelastine hydrochloride is oxidatively metabolized to the principal metabolite, N-desmethylazelastine, by the cytochrome P450 enzyme system.
In a conjunctival antigen challenge study, azelastine hydrochloride ophthalmic solution was more effective than its vehicle in preventing itching associated with allergic conjunctivitis. Azelastine hydrochloride ophthalmic solution had a rapid (within 3 minutes) onset of effect and a duration of effect of approximately 8 hours for the prevention of itching.
In environmental studies, adult and pediatric patients with seasonal allergic conjunctivitis were treated with azelastine hydrochloride ophthalmic solution for two to eight weeks. In these studies, azelastine hydrochloride ophthalmic solution was more effective than its vehicle in relieving itching associated with allergic conjunctivitis.