Development and evaluation of an inhalation chamber for in vivo tests

The bioavailability, toxicity, and therapeutic efficacy of a drug is directly related to its administration route. The pulmonary route can be accessed by inhalation after fumigation, vaporization or nebulization. Thus, pharmacological and toxicological evaluation accessed by an apparatus specifically designed and validated for this type of administration is extremely important. Based on pre-existing models, an inhalation chamber was developed. This presents a central structure with five animal holders. The nebulized air passes directly and continuously through these holders and subsequently to an outlet. Evaluation of its operation was performed using clove essential oil, a nebulizer, and a flow meter. The air within the chamber was collected by static headspace and analyzed by gas chromatography with a flame ionization detector. For this purpose, a 2.5 minutes chromatographic method was developed. The air flow in each of the five outputs was 0.92 liters per minute. During the first minute, the chamber became saturated with the nebulized material. Homogeneous and continuous operation of the chamber was observed without accumulation of volatile material inside it for 25 minutes. The inhalation chamber works satisfactorily for in vivo tests with medicines designed to be administrated by inhalation.