Current US Food and Drug Administration product specific guidance (PSG) bioequivalence (BE) recommendations for orally inhaled drug products such as metered dose inhalers (MDIs) and dry powder inhalers (DPIs) typically use a weight-of-evidence approach that includes in vitro studies, an in vivo pharmacokinetics (PK) study, and either an in vivo pharmacodynamics (PD) or comparative clinical endpoint (CCEP) study. To produce a generic MDI or DPI that is capable of passing all of these recommended studies, it would be useful to have...