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Published on: March 30, 2017
Development of an Improved Inhalable Powder Formulation of Pirfenidone by Spray-Drying: In Vitro Characterization and
Yoshiki Seto1, Gen Suzuki1, Sharon Shui Yee Leung2
1Department of Pharmacokinetics and Pharmacodynamics, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
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.
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