A STUDY OF PARTICLE ENGINEERING AND AEROSOLIZATION IN DRY POWDER INHALERS

Abstract

This project aimed to investigate various methods of producing dry powder inhaler particles and to study the particle aerosolization process in the inhaler device chamber. Conventional methods, such as sieving, classifying, classifying milling and spray drying, and new methods, such as pin milling, jet milling and roller compaction, were employed to produce coarse carrier particles. The jet milled coarse carrier particles produced were found to possess a unique shape that enabled better drug deposition to the target site. Jet milling roller compacted lactose produced superior coarse carrier particles due to roughened surfaces. Particle dispersion mechanism was elucidated by employing particle image velocimetry (PIV) technique. Conditions that facilitated particle impacts and collisions were beneficial for detachment of fine particles for delivery to the target site. A collision hypothesis was proposed for the dispersive mechanism of fines from coarse carriers.