Electrostatic Charge Effects on Pharmaceutical Aerosol Deposition in Human Nasal–Laryngeal Airways

Abstract

Electrostatic charging occurs in most aerosol generation processes and can significantly influence subsequent particle deposition rates and patterns in the respiratory tract through the image and space forces. The behavior of inhaled aerosols with charge is expected to be most affected in the upper airways, where particles come in close proximity to the narrow turbinate surface, and before charge dissipation occurs as a result of high humidity. The objective of this study was to quantitatively evaluate the deposition of charged aerosols in an MRI-based nasal–laryngeal airway model. Particle sizes of 5 nm–30 µm and charge levels ranging from neutralized to ten times the saturation limit were considered. A well-validated low Reynolds number (LRN) k–ω turbulence model and a discrete Lagrangian tracking approach that accounted for electrostatic image force were employed to simulate the nasal airflow and aerosol dynamics. For ultrafine aerosols, electrostatic charge was observed to exert a discernible but insignificant effect. In contrast, remarkably enhanced depositions were observed for micrometer particles with charge, which could be one order of magnitude larger than no-charge depositions. The deposition hot spots shifted towards the anterior part of the upper airway as the charge level increased. Results of this study have important implications for evaluating nasal drug delivery devices and for assessing doses received from pollutants, which often carry a certain level of electric charges.

In Vitro Study of the Effect of Breathing Pattern on Aerosol Delivery During High-Flow Nasal Therapy

“…A previously described airway model of the adult nose-throat region (nasal cavity, pharynx and larynx) based on the nasal cavity of a healthy non-smoking 53-year-old male (weight 73 kg, 173 cm) was used as the adult model [25][26][27]. A model of a small child nose-throat region (nasal cavity, pharynx and larynx) with a volume of * 22.3 cm 3 is based on a scan of a 5-year-old female, and was used as the small child model [28].…”

Molecular Binding Contributes to Concentration Dependent Acrolein Deposition in Rat Upper Airways: CFD and Molecular Dynamics Analyses

“…Therefore, molecular binding can only explain part of the deposition decrease, while the limited Michaelis–Menten metabolism rate is still the major reason. The influences of tidal breathing [30,31,32], dynamic airways [33,34,35,36], polydisperse aerosols [37,38], hygroscopic growth [39,40,41], electric charges [42,43], and intersubjective variability [44,45,46] on acrolein deposition are also important and should be considered in future studies. Imaging techniques such as phase-contrast MRI (magnetic resonance imaging) with hyperpolarized 3 He can be used to visualize respiratory flows [47,48].…”

Modeling of inertial deposition in scaled models of rat and human nasal airways: Towards in vitro regional dosimetry in small animals

“…Previous studies have emphasized the influences of tidal breathing (McRobbie & Pritchard, 2005), hygroscopic growth Xi et al, 2013), particle charge effects (Xi, Si, & Longest, 2014), dynamic glottis (Scheinherr et al, 2012), and intersubjective variability (Choi, Tawhai, Hoffman, & Lin, 2009;Xi et al, 2012) on the deposition of respiratory aerosols. Moreover, the respiration rates differ dramatically between rats and humans, e.g., 85 breaths per minute for rats and 12 breaths per minute for human adults (Xi et al, 2012).…”