11 DESCRIPTION Wixela Inhub ® 100/50, Wixela Inhub ® 250/50, and Wixela Inhub ® 500/50 are combinations of fluticasone propionate and salmeterol xinafoate. One active component of Wixela Inhub ® is fluticasone propionate, a corticosteroid having the chemical name S -Fluoromethyl 6α,9α-difluoro-11β-hydroxy-16α-methyl-3-oxo-17α-propionyloxyandrosta-1,4-diene-17β-carbothioate and the following chemical structure: Fluticasone propionate, USP is a white to almost white powder with a molecular weight of 500.6, and the empirical formula is C 25 H 31 F 3 O 5 S. It is practically insoluble in water, freely soluble in dimethyl sulfoxide and dimethylformamide, and slightly soluble in methanol and 95% ethanol. The other active component of Wixela Inhub ® is salmeterol xinafoate, a beta 2 -adrenergic bronchodilator. Salmeterol xinafoate is the racemic form of the 1-hydroxy-2-naphthoic acid salt of salmeterol. It has the chemical name (±)-4-Hydroxy-α 1 -[[[6-(4-phenylbutoxy)hexyl]amino]methyl]- m -xylene-α,α'-diol 1-hydroxy-2-naphthoate (salt) and the following chemical structure: Salmeterol xinafoate, USP is a white to almost white powder with a molecular weight of 603.8, and the empirical formula is C 25 H 37 NO 4 •C 11 H 8 O 3 . It is freely soluble in methanol; slightly soluble in ethanol, chloroform, and isopropanol; and sparingly soluble in water. Wixela Inhub ® is a grey colored plastic inhaler containing two foil sealed discs, each disc containing 30 pre-metered doses. Each of the 60 doses contains a white to off white powder mix of micronized fluticasone propionate (100, 250, or 500 mcg) and micronized salmeterol xinafoate salt (72.5 mcg, equivalent to 50 mcg of salmeterol base) in 12.5 mg of formulation containing lactose monohydrate (which contains milk proteins). After the inhaler is activated, the powder is dispersed into the airstream created by the patient inhaling through the mouthpiece. Under standardized in vitro test conditions, Wixela Inhub ® delivers 93, 233, and 465 mcg of fluticasone propionate and 45 mcg of salmeterol base per dose from Wixela Inhub ® 100/50, Wixela Inhub ® 250/50, and Wixela Inhub ® 500/50, respectively, when tested at a flow rate of 60 L/min for 2 seconds. In adult subjects with obstructive lung disease and severely compromised lung function (mean FEV 1 20% to 30% of predicted), mean peak inspiratory flow (PIF) through another dry powder inhaler was 82.4 L/min (range: 46.1 to 115.3 L/min). Inhalation profiles for adolescent (N = 13, aged 12 to 17 years) and adult (N = 17, aged 18 to 50 years) subjects with asthma inhaling maximally through another dry powder inhaler show mean PIF of 122.2 L/min (range: 81.6 to 152.1 L/min). Inhalation profiles for pediatric subjects with asthma inhaling maximally through another dry powder inhaler show a mean PIF of 75.5 L/min (range: 49.0 to 104.8 L/min) for the 4-year-old subject set (N = 20) and 107.3 L/min (range: 82.8 to 125.6 L/min) for the 8-year-old subject set (N = 20). The actual amount of drug delivered to the lung will depend on patient factors, such as inspiratory flow profile. Meets USP Aerodynamic Particle Size Distribution Test 2. Fluticasone Propionate Structural Formula Salmeterol Zinofoate Structural Formula