Inhalable ciprofloxacin/polymyxin B dry powders in respiratory infection therapy

Announcing a new publication for Acta Materia Medica journal.  This study focuses on the formulation, physicochemical characterization, and antibacterial susceptibility testing of inhalable spray dried powders containing ciprofloxacin (CIP) and polymyxin B sulfate (PMB).

CIP nanosuspensions with an average particle diameter of 435.9 ± 9.3 nm were initially obtained using the wet-milling protocol and subsequently co-spray dried with PMB solutions to yield inhalable dry powders. The Powder X-Ray Diffraction (P-XRD) results showed that the wet-milled CIP nanoparticles were in a 4.8 hydrate state, which were transformed to 3.7 hydrates and amorphous materials after co-spray drying. The PMB remained in an amorphous state in the dry powders. Differential Scanning Calorimetry (DSC) analyses revealed that the glass transition temperatures (Tgs) of the co–spray dried formulations were higher than the Tg of CIP, but lower than the Tg of PMB. Fourier Transform Infrared Spectrometer (FTIR) studies suggested the existence of π – π interactions between CIP and PMB in the co-spray dried powders. These powders also retained antimicrobial effects against Pseudomonas aeruginosa strain PAO1. In addition, the spray-dried powder formulations exhibited satisfactory solid-state stability and aerodynamic characteristics when stored under 3% relative humidity and 20 ± 5 °C for 4 months.

Overall, the newly developed inhalable CIP/PMB dry powders are a promising therapeutic strategy for respiratory tract infections.

Acta Materia Medica welcomes the submission of research articles, review articles, databases, mini reviews, commentaries, editorials, short communications, case report articles and study protocols.

Submission Process

Submissions to Acta Materia Medica are made using ScholarOne, the online submission and peer review system. Registration and access are available at

Queries about the journal can be sent to

Please visit to learn more about the journal.

Editorial Board:

There are no author submission or article processing fees.

Follow Acta Materia Medica on Twitter; Facebook (

eISSN 2737-7946

Zhengqi Xu, Hriday Bera and Hengzhuang Wang et al. Inhalable ciprofloxacin/polymyxin B dry powders in respiratory infection therapy. Acta Materia Medica. 2023. Vol. 2(2):142-156. DOI: 10.15212/AMM-2022-0050