Natural Products-Based Inhaled Formulations for Treating Pulmonary Diseases

Jiangyan Yong,1,* Hongli Shu,1,* Xiao Zhang,2,* Kun Yang,3 Guining Luo,3 Lu Yu,3 Jiaqi Li,3 Hong Huang4 1Department of Clinical Laboratory, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, 610072, People’s Republic of China; 2Department of Clinical Laboratory, Chengdu Children Special Hospital, Chengdu, Sichuan, 610031, People’s Republic of China; 3Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, 611137, People’s Republic of China; 4Department of Clinical Laboratory, the People’s Hospital of Chongqing Liang Jiang New Area, Chongqing, 401121, People’s Republic of China*These authors contributed equally to this workCorrespondence: Hong Huang, Email hh1643689264@163.comAbstract: Given the unique physiological and pathological characteristics of the lung, the direct, inhalable route is more conducive to pulmonary drug delivery and disease control than traditional systemic drug delivery, significantly circumventing drug loss, off-target effects, systemic and organ toxicity, etc., and is widely regarded as the preferred regimen for pulmonary drug delivery. However, very few lung diseases are currently treated with the preferred inhaled formulations, such as asthma, chronic obstructive pulmonary disease and pulmonary hypertension. And there is a lack of appropriate inhaled formulations for other critical lung diseases, such as lung cancer and pulmonary fibrosis, due to the fact that the physicochemical properties of the drugs and their pharmacokinetic profiles do not match the physiology of the lung, and conventional inhalation devices are unable to deliver them to the specific parts of the lung. Phytochemicals of natural origin, due to their wide availability and clear safety profile, hold great promise for the preparation of inhalable formulations to improve the current dilemma in the treatment of lung diseases. In particular, the preparation of inhalable formulations based on