Effect of Induced Charge on Deposition of Uniformly Charged Particles in a Pediatric Oral-Extrathoracic Airway

Abstract

An in vitro study was conducted in the Alberta idealized child mouth-throat, which mimics average deposition in a set of nine 6-14-year-old subjects, to examine the enhancement of deposition of monodisperse uniformly charged particles as a result of induced electrostatic forces. A purpose-based atomizer was designed and built for generating monodisperse, uniformly charged particles. The atomizer generates droplets by jet break up under the action of capillary waves and charges them via electrostatic induction. The experiments cover different particle aerodynamic diameters (d a = 3.6, 4.4, and 5.9 µm), at two flow rates (Q = 10 and 20 L/min), over a wide range of elementary charges per particle (0-10,000 e). The results show substantial increases in particle deposition in the present idealized pediatric mouth throat compared to neutral aerosols. Two empirical equations, as a function of Reynolds number, Stokes number, and induced charge number are introduced for the prediction of mouth-throat deposition in children, based on two different characteristic diameters of the airway.

Engineered Aerosol Medicine and Drug Delivery Methods for Optimal Respiratory Therapy

“…1,2 There are a number of mathematical models and computational tools developed to understand particle flow and to predict deposition patterns of particles in the whole lung or its specific region. [3][4][5][6][7][8][9] In silico study results using these modeling tools agreed with in vitro study results as well. 10,11 In the field of aerosol medicine, there have been several methods invented and marketed to improve pharmacokinetic efficacy and effectiveness in respiratory drug delivery, and to minimize losses in the delivery devices.…”

Generating charged pharmaceutical aerosols intended to improve targeted drug delivery in ventilated infants

“…Modifications included altering the vibration amplitude to reduce liquid output, thereby enabling evaporation to near submicrometer size at the low flow rates required for infant ventilation, and including an electrode positioned below the mesh to charge the aerosol by induction charging. Other studies have used induction charging with single orifice plates (Azhdarzadeh et al, 2014a; Azhdarzadeh et al, 2014b), but the application of induction charging to a vibrating mesh system with low airflow is a new advancement. Further details in device development and experimental testing methods for these new systems are described in the following sections.…”

“…The use of corona needles for electrospray discharge (Ijsebaert et al, 2001) is associated with ozone formation (Hinds 1999), making them impractical for use in inhalers. Vibrating orifice charged particle generators are limited by very low mass output (Azhdarzadeh et al, 2014a; Azhdarzadeh et al, 2014b; Reischl et al, 1977). …”

Production of Highly Charged Pharmaceutical Aerosols Using a New Aerosol Induction Charger

“…Previous studies have demonstrated the effect of charge on the deposition of micrometer (14, 18–20, 23, 26) and submicrometer particles (13, 16, 25) in human airways and on boundary surfaces (27–30). The study of Melandri et al (13) reported the deposition of charged monodisperse aerosols with diameters of 1 μm or less in the airways of human subjects breathing normally.…”

“…proposed a method for generating charged monodisperse particles by modifying a vibrating single orifice aerosol generator using an induction charging cap (34). This method has been used to study the penetration of monodisperse charged droplets, with a minimum size of 1 μm, through tubes of different lengths and diameters at various velocities (28), and the penetration of droplets with diameter sizes of 3–6 μm through the idealized extrathoracic airways of adults (19), children (20) and infants (23). However, a disadvantage of the single vibrating orifice system is typically low aerosol concentration (10 3 part/cm 3 ) and mass output, which may prolong or prevent the administration of pharmaceutical aerosols.…”