Drug delivery performance improvement of dry powder inhalers with a spiral channel featured mouthpiece.

A novel dry powder inhaler with a spiral channel featured mouthpiece (Swirling-DPI) is proposed in this work, designed to enhance drug particle deagglomeration and pulmonary delivery efficiency. Computational Fluid Dynamics (CFD) coupled with Discrete Particle Method (DPM) simulations are employed to systematically investigate the effects of spiral geometric parameters, such as pitch (5 mm-9 mm), channel inner diameter (3 mm-7 mm), and cross-section (trapezoidal and circular) on airflow dynamics and particle behavior. Results indicate that spiral geometric structures significantly alter flow fields and particle dynamics, and the impact effects of particles are optimized. The exit velocity of 200 µm carrier particles without drug effects in the 7 mm pitch Swirling-DPI is 2.44 times that of the Aerolizer, reducing the possibility of carrier particle entering the lungs and facilitating drug particle delivery. Compared with traditional Aerolizer, higher turbulent kinetic energy (TKE) is obtained in the Swirling-DPI with a pitch of 7 mm. The residence time of 200 µm carrier particles is increased by 43%, with higher impact energy, indicating enhanced potential for deagglomeration. The circular cross-section reduces flow resistance and the potential for particle retention, improving flow uniformity while maintaining high TKE levels. Comprehensive studies on particles and flow fields indicate that the spiral structure prolongs trajectories of large particles, increasing impact frequency. Comparative analysis confirms that Swirling-DPI is an effective strategy for optimizing drug aerodynamic properties and delivery efficacy, demonstrating excellent performance in promoting particle impact and enhancing turbulent kinetic energy.