Improving Pulmonary Nano-Therapeutics Using Helical Aerosol Streams - An In-Silico Study.

Abstract

The increasing prevalence of pulmonary ailments including asthma, chronic obstructive pulmonary disorder (COPD), lung tuberculosis and lung cancer, coupled with the success of pulmonary therapy has led to a plethora of scientific research focusing on improving the efficacy of pulmonary drug delivery systems. Recent advances in nanoscience and nanoengineering help achieve this by developing stable, potent, inhalable nano-size drug formulations that potentially increase dosages at target sites with significant therapeutic effects. In this study, we numerically analyze a novel methodology of incorporating helical air-nanoparticle streams for pulmonary nano-therapeutics, using a customized version of the open-source computational fluid dynamics (CFD) toolbox OpenFOAM. As nanoparticles predominantly follow streamlines, helical airflow transports them in a centralized core along the human upper respiratory tract, thereby minimizing deposition and hence waste on the oropharyngeal walls, potentially also reducing the risk of drug-induced toxicity in healthy tissues. Advancing our previous study on micron-particle dynamics, helical streams are shown to improve the delivery of nanodrugs, to deeper lung regions when compared to a purely axial fluid-particle jet. For example, an optimal helical stream featuring a volumetric flow rate of 30 l/min, increased the delivery of 300 nm-particles to regions beyond generation 3 by 5%, in comparison to a conventional axial jet. Results from regional deposition studies are presented, to demonstrate the robustness of helical flows in pulmonary drug delivery; thus, paving the way towards successful implementation of the novel methodology in nanotherapeutics.