Airway Geometry

The caliber and tortuosity of the airway influences the flow of air through the segment and, thereby, affects aerosol particle impaction [1]. Disease states that alter airway caliber, such as obstructive airways disease, influence the pattern of aerosolized drug deposition in the airways by influencing airway geometry.

Aerosol particle Deposition diameter (mm) site

$ 10 Oropharynx

>5 Central airways (tracheobronchial)

<3 Peripheral airways (alveolus)

Figure 1 Fate of inhaled drugs depositing in the airways. Aerosolized compounds delivered to the lumenal surface of central (i.e., tracheobronchial) and peripheral (i.e., alveolus) airways may be subject to different pharmacokinetic pressures. The sites of loss of a drug in passage from the airway lumen to the site of therapeutic action in the central airways (e.g., smooth muscle) and peripheral airways (e.g., blood in pulmonary circulation) are depicted in upper and lower diagrams, respectively. In the central airways, a drug may (1) interact with the mucus layer, (2) be removed by the mucociliary escalator, (3) have restricted access through the epithelium and be biotransformed or be complexed by epithelium-associated

Figure 1 Fate of inhaled drugs depositing in the airways. Aerosolized compounds delivered to the lumenal surface of central (i.e., tracheobronchial) and peripheral (i.e., alveolus) airways may be subject to different pharmacokinetic pressures. The sites of loss of a drug in passage from the airway lumen to the site of therapeutic action in the central airways (e.g., smooth muscle) and peripheral airways (e.g., blood in pulmonary circulation) are depicted in upper and lower diagrams, respectively. In the central airways, a drug may (1) interact with the mucus layer, (2) be removed by the mucociliary escalator, (3) have restricted access through the epithelium and be biotransformed or be complexed by epithelium-associated

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

Get My Free Ebook


Post a comment