Use of process intensification concepts for targeted delivery of inhaled aerosolized medicines

Process intensification (PI) concepts have potential applications beyond the classic industrial problems solved by chemical engineering. This paper discusses the flow and mass transfer intensification using acoustic waves to enhance drug delivery to the nasal cavity. The efficiency of drug delivery to the nose still needs improvement, and the mechanisms related to using acoustic waves to increase it have yet to be studied. The influence of pressure pulsations induced by an acoustic wave (∼100 Hz) on the concentration, droplet size, and flow structure of the mists delivered from medical nebulizers was studied. The direct visualization showed that pulsations intensify aerosol deposition inside narrow channels due to particle displacement perpendicularly to the main flow direction. This motion also allows for particle penetration via narrow openings. UV-assisted observation of the intensified aerosol deposition inside the anatomical cast of the nasal cavity confirmed the importance of acoustic pulsations for intranasal drug delivery, also helping aerosol penetrate hard-to-reach areas (including the paranasal sinuses). A new idea regarding appropriate time control of acoustic pulsations has been proposed to improve the aerosol drug mass transfer in the nose. The study shows that PI has great potential to expand into new and interdisciplinary areas.