title: Respirable dry powder formulation of bleomycin for developing a pulmonary fibrosis animal model.
abstract: The main purpose of the present study was to develop a respirable powder (RP) formulation of bleomycin (BLM) as a research tool for developing a pulmonary fibrosis animal model. The BLM-RP was prepared with a jet-milling system, the physicochemical properties of which were characterized focusing on morphology, stability, particle size distribution, and inhalation performance. Under an accelerated condition, the BLM-RP was superior to BLM solution in terms of its stability. Cascade impactor analyses demonstrated high inhalation performance with emitted dose and fine particle fraction of approximately 99% and 46%, respectively. Intratracheal administration of the BLM-RP (3 mg BLM/kg) in rats led to significant increases in collagen production and recruitment of inflammatory cells in lung by approximately 1.5- and 29-fold, respectively. The collagen overexpression was consistent with the results from picrosirius red staining of lung tissues in the rats treated with BLM-RP. Inhaled tranilast (TL; 100 μg/rat), an antifibrotic agent, could ameliorate inflammatory/fibrotic responses with reductions of recruited inflammatory cells and collagen content by 32% and 59%, respectively, validating the pulmonary fibrosis animal model. From these findings, the BLM-RP with improved stability could be a beneficial research tool for developing a pulmonary fibrosis model in drug discovery for antifibrotic drug candidates.
authors.affiliation: Department of Pharmacokinetics and Pharmacodynamics and Global Center of Excellence Program, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Aoki
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kojo
authors.forename: Shizuo
authors.initials: S
authors.lastname: Yamada
authors.forename: Satomi
authors.initials: S
authors.lastname: Onoue
mesh_terms: D000818:Animals; D001761:Bleomycin / Q000737:chemistry / Q000633:toxicity*; D004195:Disease Models, Animal; D008297:Male; D011208:Powders; D011658:Pulmonary Fibrosis / Q000139:chemically induced*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D011208:Powders; D001761:Bleomycin