Development and evaluation of an inhalation chamber for in vivo tests

ABSTRACT 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.摘要 药物的生物利用度、毒性与治疗效果，与其给药途径直接相关。经熏蒸、汽化或雾化方式实施的吸入给药，可实现经肺给药途径。因此，采用专为该给药方式设计并验证通过的装置开展药理学与毒理学评价，具有极为重要的研究意义。本研究基于已有模型，研发了一款吸入染毒舱，其主体结构包含五个动物固定架。雾化空气可直接且持续地流经这些固定架，随后从排气口排出。本研究采用丁香精油、雾化器与流量计对该装置的运行性能进行了评价：通过静态顶空采样法采集舱内空气，采用搭载火焰离子化检测器的气相色谱法开展分析，并据此开发了一段时长2.5分钟的色谱分析方法。结果显示，五个固定架对应的出气口气流流速均为0.92升/分钟；装置运行首分钟内，舱内即被雾化物质饱和；连续运行25分钟期间，舱内始终保持均匀稳定的运行状态，未出现挥发性物质累积。该吸入染毒舱可良好适用于吸入给药类药物的体内试验。