Personalized Inhaler Selection in COPD and Asthma: Clinical Implications of Aerosol Characteristics and Device Performance

The management of chronic obstructive pulmonary disease (COPD) and asthma depends critically on the effective delivery of aerosolized medications to the respiratory tract. Clinical efficacy is determined not only by the active pharmaceutical ingredient but also by a complex interplay among drug formulation, aerosol particle size, inhaler device characteristics, dosing frequency, and patient-specific factors. This review evaluates the technical specifications and clinical performance of major inhaled therapeutic systems, including the Ellipta platform, the Respimat soft mist inhaler (SMI), conventional pressurized metered-dose inhalers (pMDIs), and dry powder inhalers (DPIs). We examine the impact of particle size and extra-fine formulations on peripheral deposition and small airway disease (SAD), and synthesize comparative clinical evidence linking deposition patterns to symptom control and exacerbation reduction. In addition, we explore clinically relevant determinants of personalized device selection, including peak inspiratory flow rate (PIFR) limitations, pneumonia risk, dosing frequency, and rescue inhaler requirements. By integrating inhaler design with real-world clinical considerations, this review provides a practical framework for individualized inhaler selection in obstructive lung disease. A patient-centered approach that accounts for airway phenotype, infection risk, inspiratory flow capability, and adherence patterns is essential to optimize drug delivery and improve long-term outcomes.