Advanced particle technologies in the preparation of dry powders for inhalation

Drug delivery via pulmonary inhalation can achieve targeted treatment by directly delivering the drugs to the area for treatment. The method is developing rapidly for the treatment of local and systemic diseases. However, dry powders for inhalation need to exhibit excellent aerodynamic performance. Particle size, morphology and density need to be tightly regulated to guarantee effective lung deposition and assure long-term chemical stability of the drug. In this work, the compositions and requirements of dry powders for inhalation are discussed. Furthermore, the state-of-art methods in particle technology for dry powders for inhalation, such as milling, droplet evaporation, direct crystallization, supercritical fluid and particle surface coating technologies, are reviewed. In addition, the application of process analytical techniques in the preparation of dry powders for inhalation, which can improve process capability and drug safety, is also discussed. Finally, current challenges in the field of dry powders for inhalation are discussed and some directional guidance is proposed to promote delivery efficiency, drug efficacy and process development.