Yoshiki Seto1, Gen Suzuki1, Sharon Shui Yee Leung2, Hak-Kim Chan2, Satomi Onoue3. 1. Department of Pharmacokinetics and Pharmacodynamics, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan. 2. Advanced Drug Delivery Group, Faculty of Pharmacy, University of Sydney, Sydney, NSW, 2006, Australia. 3. Department of Pharmacokinetics and Pharmacodynamics, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan. onoue@u-shizuoka-ken.ac.jp.
Abstract
PURPOSE: Previously, a respirable powder (RP) formulation of pirfenidone (PFD) was developed for reducing phototoxic risk; however, PFD-RP demonstrated unacceptable in vitro inhalation performance. The present study aimed to develop a new RP system of PFD with favorable inhalation properties by spray-drying method. METHODS: Spray-dried PFD (SD/PFD) was prepared by spray-drying with L-leucine, and the physicochemical properties and efficacy in an antigen-sensitized airway inflammation model were assessed. A pharmacokinetic study was also conducted after intratracheal and oral administration of PFD formulations. RESULTS: Regarding powder characterization, SD/PFD had dimpled surface with the mean diameter of 1.793 μm. In next generation impactor analysis, SD/PFD demonstrated high in vitro inhalation performance without the need of carrier particles, and the fine particle fraction of SD/PFD was calculated to be 62.4%. Insufflated SD/PFD (0.3 mg-PFD/rat) attenuated antigen-evoked inflammatory events in the lung, including infiltration of inflammatory cells and myeloperoxidase activity. Systemic exposure level of PFD after insufflation of SD/PFD at the pharmacologically effective dose was 600-fold lower than that after oral administration of PFD at the phototoxic dose. CONCLUSION: SD/PFD would be suitable for inhalation, and the utilization of an RP system with SD/PFD would provide a safer medication compared with oral administration of PFD.
PURPOSE: Previously, a respirable powder (RP) formulation of pirfenidone (PFD) was developed for reducing phototoxic risk; however, PFD-RP demonstrated unacceptable in vitro inhalation performance. The present study aimed to develop a new RP system of PFD with favorable inhalation properties by spray-drying method. METHODS: Spray-dried PFD (SD/PFD) was prepared by spray-drying with L-leucine, and the physicochemical properties and efficacy in an antigen-sensitized airway inflammation model were assessed. A pharmacokinetic study was also conducted after intratracheal and oral administration of PFD formulations. RESULTS: Regarding powder characterization, SD/PFD had dimpled surface with the mean diameter of 1.793 μm. In next generation impactor analysis, SD/PFD demonstrated high in vitro inhalation performance without the need of carrier particles, and the fine particle fraction of SD/PFD was calculated to be 62.4%. Insufflated SD/PFD (0.3 mg-PFD/rat) attenuated antigen-evoked inflammatory events in the lung, including infiltration of inflammatory cells and myeloperoxidase activity. Systemic exposure level of PFD after insufflation of SD/PFD at the pharmacologically effective dose was 600-fold lower than that after oral administration of PFD at the phototoxic dose. CONCLUSION:SD/PFD would be suitable for inhalation, and the utilization of an RP system with SD/PFD would provide a safer medication compared with oral administration of PFD.