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The current study focused 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.

The purpose of this paper is to develop a new technology for controlling the quenching deformation of light cast aluminum alloy wheels. First, based on the existing wheel heat treatment process, a gas–liquid–solid multi-phase flow coupling model was established through the ANSYS Workbench platform to analyze the gas–liquid phase change, heat exchange on wheel surface and quenching deformation characteristics during the process of wheel immersion into the water. The results show that heat exchange characteristics of the wheel surface are comprehensively affected by wheel structure, quenching fluid flow field and gas–liquid phase transition. There are a lot of non-uniform heat exchange areas in the outer rim, spoke area and center area, which affect the overall deformation characteristics. Affected by spoke structure, the maximum deformation occurs at the outer and inner rim end faces farthest away from the wheel. Based on the above research, this paper independently develops a new deformation control strategy of spray and water immersion composite step process. Through spraying, the influence of spoke structural stiffness on the overall deformation characteristics of the wheel is effectively reduced, and the wheel deformation control is realized by meeting the mechanical properties of the wheel, with the maximum deformation reduction of 39.2%. This study provides a new option for the integrated control of deformation and mechanical properties of aluminum alloy wheels.