Improvement of the pharmacokinetics and antifibrotic effects of nintedanib by intrapulmonary administration of a nintedanib–hydroxypropyl-γ-cyclodextrin inclusion complex in mice with bleomycin-induced pulmonary fibrosis

[Display omitted] Idiopathic pulmonary fibrosis is a chronic lung disease that is characterized by progressive abnormal reprogramming following injury of the pulmonary structure. In this study, we prepared a nintedanib (antifibrotic agent) and cyclodextrin (CyD) inclusion complex to improve the pharmacokinetics and antifibrotic effects of nintedanib following intrapulmonary administration. Hydroxypropyl-γ-CyD (HP-γ-CyD) enhanced the solubility of nintedanib without cytotoxic effects on WI-38 cells (lung fibroblasts) and NCI-H441 cells (alveolar epithelium model). Compared with nintedanib ethanesulfonate salt, the nintedanib–HP-γ-CyD inclusion complex exhibited prolonged distribution in the lungs following intrapulmonary administration in mice with bleomycin-induced pulmonary fibrosis. In addition, compared with nintedanib ethanesulfonate salt, the nintedanib–HP-γ-CyD inclusion complex exhibited higher stability in the bronchoalveolar lavage fluid and lower permeability in NCI-H441 cell monolayers. These results suggested that the inclusion complexation of nintedanib into HP-γ-CyD improved its pharmacokinetics following intrapulmonary administration by increasing its stability in the lungs and reducing its permeability through the alveolar cell membrane. Intrapulmonary administration of the nintedanib–HP-γ-CyD inclusion complex significantly reduced the intrapulmonary hydroxyproline content and limited pathological fibrotic changes. Overall, this study indicates that antifibrotic agent–CyD inclusion complexation intended for intrapulmonary administration can be used to prolong distribution in the lungs and lead to the expansion of idiopathic pulmonary fibrosis therapy.