Background: In vitro studies to investigate the effect of charged particle deposition in the oral pathway of human adults have demonstrated substantial increases in deposition due to an induced charge effect. In the current study, charged particle deposition in the oral pathway was incorporated in the stochastic human airway generation model IDEAL (Inhalation, Deposition, and Exhalation of Aerosols in the Lung) to quantify their effect on bronchial airways deposition.
Methods: Calculation of increased oral deposition due to charged particles was performed by a modified version of IDEAL for oral pathway, whereas deposition in the bronchial airways was carried out by the already employed efficiency equation. Deposition calculations were performed for 3, 4.5, and 6 μm particles at flow rates of 15 and 30 L/min.
Results: The enhancement in deposition is found to be 40 times higher in oral pathway and 6 times higher in bronchial airways for 3 μm size particles carrying 2500 elementary charges. For particles larger than 3 μm, deposition by impaction dominates over deposition by particle charges, and hence higher deposition in oral pathway is observed primarily due to impaction. As a consequence of this increased oral deposition, bronchial airways deposition decreases.
Conclusion: By controlling breathing, aerosol properties, and electrostatic charge, targeted deposition in the human airways can be improved. Hence, charged particles can therefore be utilized to give better control on regional drug delivery in the lungs or to filter out toxic constituents.
Keywords: bronchial airways; charged particles; deposition; oral pathway; stochastic lung model.