Advances in the Application of Additive Manufacturing in Respiratory Inhalation Therapy.

Inhalation therapy has become a cornerstone in the treatment of respiratory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis, owing to its rapid onset, direct pulmonary targeting, and avoidance of first-pass metabolism. Its clinical scope has expanded beyond conventional respiratory indications to emerging applications, including vaccine delivery, systemic disease management, and localized tumor therapy. However, traditional inhalation systems are often designed for the average patient, overlooking physiological variability that results in inconsistent drug deposition and therapeutic efficacy-particularly in children, elderly patients, and individuals with airway abnormalities. Additive manufacturing (AM), with its high design flexibility and capacity for personalization, offers new possibilities for structural optimization, particle engineering, and in vitro model fabrication in inhalation therapy. Growing evidence indicates that 3D-printed inhalation devices and formulation platforms can enhance drug deposition control, patient compliance, and delivery precision. This review provides a comprehensive overview of recent advances in AM applied to inhalation therapy, highlighting its roles in personalized device fabrication, microdose particle design, and in vitro model construction, as well as in the exploration of emerging therapeutic strategies. Furthermore, it discusses current technical challenges and translational barriers. Overall, AM is propelling the transition of inhalation therapy from standardized approaches toward intelligent, patient-centered delivery systems, offering both theoretical and technological foundations for next-generation respiratory healthcare.