Particle Deposition in a Child Respiratory Tract Model: In Vivo Regional Deposition of Fine and Ultrafine Aerosols in Baboons

Abstract

To relate exposure to adverse health effects, it is necessary to know where particles in the submicron range deposit in the respiratory tract. The possibly higher vulnerability of children requires specific inhalation studies. However, radio-aerosol deposition experiments involving children are rare because of ethical restrictions related to radiation exposure. Thus, an in vivo study was conducted using three baboons as a child respiratory tract model to assess regional deposition patterns (thoracic region vs. extrathoracic region) of radioactive polydisperse aerosols ([d16–d84], equal to [0.15 µm–0.5 µm], [0.25 µm–1 µm], or [1 µm–9 µm]). Results clearly demonstrated that aerosol deposition within the thoracic region and the extrathoraic region varied substantially according to particle size. High deposition in the extrathoracic region was observed for the [1 µm–9 µm] aerosol (72%±17%). The [0.15 µm–0.5 µm] aerosol was associated almost exclusively with thoracic region deposition (84%±4%). Airborne particles in the range of [0.25 µm–1 µm] showed an intermediate deposition pattern, with 49%±8% in the extrathoracic region and 51%±8% in the thoracic region. Finally, comparison of baboon and human inhalation experiments for the [1 µm–9 µm] aerosol showed similar regional deposition, leading to the conclusion that regional deposition is species-independent for this airborne particle sizes.

Current options in aerosolised drug therapy for children receiving respiratory support

“…Conventionally, the majority of 0.5‐μm particles are believed to be exhaled, even when a breath hold is included. Animal work with nanoparticles suggests that particles in the size range of 0.15–5 μm may be more effective at depositing in the distal airways consistent with theoretical modelling (Brownian motion being the principle method of deposition ). It has been proposed that nanoparticles containing iron, when used in combination with a magnetic gradient, might permit targeting and enhance in vivo lung drug delivery .…”

Airflow and Particle Transport Prediction through Stenosis Airways

“…The respiratory system becomes a target of harmful air pollutants, including ozone, nitrogen dioxide, volatile organic compounds, and particulate matter, affecting the lungs specifically [1]. Lung functionality normally decays with age; however, air pollution is contributing to breathing problems and acute or chronic lung diseases [2]. The overall impact of exposure to pollutants on lung health and the treatment of respiratory diseases have become of increased interest to researchers.…”

Preparation of Complexes between Ovalbumin Nanoparticles and Retinoic Acid for Efficient Induction of Tolerogenic Dendritic Cells

“…18,19 We aimed to adjust the size of OVA NPs around 100 nm because it is ideal size for uptake by dendritic cells. 20,21 To achieve the aimed size, we screened preparation conditions based on the literature 16 and determined the optimum condition as follows: 10 mg/mL OVA in 50 mM NaCl (pH 7.0), and heating at 85 o C for 5 min. Characteristics of the obtained OVA NPs are summarized in Table 1 and Fig.…”