The objective of this study is to evaluate the pharmacodynamic (PD) bioequivalence (BE) of albuterol inhalers, test formulation: Albuterol Sulfate HFA inhalation aerosol 108 mcg (equal to albuterol base 90 mcg) per actuation and reference formulation: ProAir HFA (albuterol sulfate) or FDA authorized generic: Albuterol Sulfate HFA (Teva Pharmaceutical USA, Inc.) Inhalation Aerosol 108 mcg (equal to albuterol base 90 mcg) per actuation manufactured by two different manufacturers using methacholine bronchoprovocation challenge test in patients with stable mild asthma.
Male, non-pregnant and non-lactating female subjects (20-65 years of age, inclusive).
A clinical diagnosis of mild asthma with historical documentation of the asthma diagnosis according to either: (1) the National Asthma Education and Prevention Program (NAEPP) guidelines (2007) or (2) the Global Initiative for Asthma (GINA) Global Strategy for Asthma Management and Prevention (2020).
Stable mild asthma receiving the following required inhaled medications for at least 1 month prior to screening: Low doses of ICS alone, or in combination with SABA, used regularly with a stable regimen.
Forced Expiratory Volume in 1 second (FEV1) ≥ 80% of the local predicted normal value after withholding SABA ≥ 8 hours.
Evidence of conditions altering airway reactivity to methacholine, including upper or lower respiratory tract infections (e.g., pneumonia, viral bronchitis, allergic rhinitis, sinobronchitis, etc.) within 6 weeks before Screening.
Evidence of a baseline FEV1 < 60% of the local predicted normal value or FEV1 < 1.5 L.
History of seasonal asthma exacerbations, in which case the subject should be studied outside of the relevant allergen season.
History of cystic fibrosis, bronchiectasis, COPD, or other respiratory diseases including COPD, chronic bronchitis, emphysema, tuberculosis, pulmonary carcinoma, pulmonary fibrosis, pulmonary hypertension that, in the opinion of the Investigator, would compromise subject safety or interfere with the evaluations.