Building dry powder formulations using supercritical CO₂ spray drying

This short review covers the most recent literature on the bottom-up assembling of composite dry powder formulations using supercritical carbon dioxide (scCO₂)-based technologies for pulmonary delivery. Special attention is given to the integration of scCO₂–assisted spray drying (SASD) with different technologies, namely living polymerization, layer-by-layer deposition and quality-by-design (QbD). Examples of inhalation drug delivery systems are provided to highlight specific advantages of the use of SASD versus traditional particle engineering technologies. The opportunities to generate release particles from small molecule therapeutics to biologic drugs and nucleic acids, the scale-up of processes and perspectives are examined.