Pharyngeal aspiration

[2] Pharyngeal aspiration has benefits over the alternative methods of inhalation and intratracheal instillation, the introduction of the substance directly into the trachea.

Inhalation studies have the disadvantages that they are expensive and technically difficult, the dose and location of the substance has poor reproducibility, they require large amounts of material, and they potentially allow exposure to laboratory workers and to the skin of laboratory animals.

Intratracheal instillation overcomes some of these difficulties, but because a needle or tube is needed to access the trachea, it remains technically challenging and causes trauma to the animal, which can be a confounding factor.

It also results in a less uniform distribution of the substance than inhalation, and bypasses effects from the upper respiratory tract.

[1][3] In pharyngeal aspiration, the substance is placed in the pharynx, which is higher in the respiratory tract, avoiding the major source of technical difficulty and trauma to the animal.

A diagram showing parts of the human respiratory system
Pharyngeal aspiration introduces a substance into the pharynx for aspiration into the lungs. It is less technically difficult than intratracheal instillation the pharynx is higher in the respiratory system than the trachea .