Comprehensive In Vitro and In Silico Aerodynamic Analysis of High-Dose Ibuprofen- and Mannitol-Containing Dry Powder Inhalers for the Treatment of Cystic Fibrosis

Background: Cystic fibrosis is a hereditary disease, which causes the accumulation of dense mucus in the lungs accompanied by frequent local inflammation. The non-steroidal anti-inflammatory drug ibuprofen (IBU) and the mucolytic mannitol (MAN) can treat these symptoms. Compared to per os administration, a lower dose of these drugs is sufficient to achieve the desired effect by delivering them in a pulmonary manner. However, it is still a challenge to administer high drug doses to the lungs. We aim to develop two inhaled powder formulations, a single-drug product of MAN and a combined formulation containing IBU and MAN. Methods: MAN was dissolved in an aqueous solution of Poloxamer-188 (POL). In the case of the combined formulation, a suspension was first prepared in a planetary mill via wet milling in POL medium. After the addition of leucine (LEU), the formulations were spray-dried. The prepared DPI samples were analyzed by using laser diffraction, scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, density tests, in vitro aerodynamic studies (Andersen Cascade Impactor, Spraytec^® device), in vitro dissolution tests in artificial lung fluid, and in silico tests with stochastic lung model. Results: The DPIs showed suitability for inhalation with low-density spherical particles of appropriate size. The LEU-containing systems were characterized by high lung deposition and adequate aerodynamic diameter. The amorphization during the procedures resulted in rapid drug release. Conclusions: We have successfully produced a single-drug formulation and an innovative combination formulation, which could provide complex treatment for patients with cystic fibrosis to improve their quality of life.