Pharmacodynamic Equivalence of the Test and Reference Metered Dose Inhalers (MDIs) Containing Albuterol Sulfate in Adult Patients With Stable Mild Asthma

This study will be conducted using the single-dose, randomized, double-blind, double-dummy, four-sequence, four-treatment, and multiple-center study design to evaluate the PD bioequivalence between the test albuterol sulfate (T) inhalation aerosol 108 mcg per actuation (eq. to albuterol base 90 mcg/puff) and the reference albuterol sulfate (R) (ProAir HFA or FDA authorized generic: Albuterol Sulfate HFA \[Teva Pharmaceutical USA, Inc.\]) inhalation aerosol 108 mcg per actuation (equal to albuterol base 90 mcg/puff). The two products will be studied using a crossover design in patients with stable mild asthma by administering a minimum of 3 doses of reference product (0, 90, 180 mcg albuterol) and 2 doses of test product (0, 90 mcg albuterol). The bronchodilation potency of albuterol sulfate are measured by the inhibition effects of methacholine challenge on the bronchodilation, as indicated by increase in the provocative concentration of methacholine required to produce a 20% decrease in FEV1 (PC20).