A review on fluidization of Geldart Group C powders through nanoparticle modulation

Design, development, and technical considerations for dry powder inhaler devices

The dry powder inhaler (DPI) stands out as a highly patient-friendly and effective pulmonary formulation, surpassing traditional and other pulmonary dosage forms in certain disease conditions. The development of DPI products, however, presents more complexities than that of other dosage forms, particularly in device design and the integration of the drug formulation. This review focuses on the capabilities of DPI devices in pulmonary drug delivery, with a special emphasis on device design and formulation development. It also discusses into the principles of deep lung particle deposition and device engineering, and provides a current overview of the market for DPI devices. Furthermore, the review highlights the use of computational fluid dynamics (CFD) in DPI product design and discusses the regulatory environment surrounding these devices.

Fluidized Bed Chemical Vapor Deposition on Hard Carbon Powders to Produce Composite Energy Materials

Herein, we report a general route for the uniform coating of hard carbon (HC) powders via fluidized bed chemical vapor deposition. Carbon-based fine powders are excellent substrate materials for many catalytic and electrochemical applications but intrinsically difficult to fluidize and prone to elutriation. The reactor was designed to achieve as much retention of powders as possible, supported by a computational fluid dynamics study to assess the hydrodynamic behavior for varying gaseous flow rates. Solutions of the tin seleno- and thio-ether complexes [SnCl4{nBuSe(CH2)3SenBu}] and [SnCl4{nBuS(CH2)3SnBu}] were used as single source precursors and injected at high temperature into a fluidized bed of HC powders under nitrogen flow. The method allowed for the synthesis of HC-SnSx-SnSe2 composites at the gram scale with potential applications in electrocatalysis and sodium-ion battery anodes.

Enhanced blend uniformity and flowability of low drug loaded fine API blends via dry coating: The effect of mixing time and excipient size

Although previous research demonstrated improved flowability, packing, fluidization, etc. of individual powders via nanoparticle dry coating, none considered its impact on very low drug loaded blends. Here, fine ibuprofen at 1, 3, and 5 wt% drug loadings (DL) was used in multi-component blends to examine the impact of the excipients size, dry coating with hydrophilic or hydrophobic silica, and mixing times on the blend uniformity, flowability and drug release rates. For uncoated active pharmaceutical ingredients (API), the blend uniformity (BU) was poor for all blends regardless of the excipient size and mixing time. In contrast, for dry coated API having low agglomerate ratio (AR), BU was dramatically improved, more so for the fine excipient blends, at lesser mixing times. For dry coated API, the fine excipient blends mixed for 30 min had enhanced flowability and lower AR; better for the lowest DL having lesser silica, likely due to mixing induced synergy of silica redistribution. For the fine excipient tablets, dry coating led to fast API release rates even with hydrophobic silica coating. Remarkably, the low AR of the dry coated API even at very low DL and amounts of silica in the blend led to the enhanced blend uniformity, flow, and API release rate.

Numerical Simulation of the Operating Conditions for the Reduction of Iron Ore Powder in a Fluidized Bed Based on the CPFD Method

In this work, the computational particle fluid dynamics (CPFD) method is used to simulate the high-pressure visual fluidized bed experimental equipment independently designed and developed by the experimentation of the fluidized reduction process of iron ore powder. A numerical model for reducing iron ore fines in a three-dimensional fluidized bed is established, and the model is verified by combining numerical simulation and experimental testing. Moreover, the influences of different reducing factors on the reduction effect in the process of the fluidized reduction of iron ore fines are simulated in detail. Via the CPFD simulation of the fluidized reduction of iron ore fines, the optimal reduction pressure is found to be 0.2 MPa, and the optimal reducing gas is found to be H2. Moreover, the optimal gas velocity is 0.6 m/s, and the optimal reduction temperature is 923 K. This conclusion is consistent with the experimental measurements, so the simulation results can be used to verify the reliability of the optimal operating conditions.

Decompaction wave propagation in a vibrated fine-powder bed

We experimentally study the crack formation and decompaction-wave propagating in a vibrated powder bed consisting of glass beads of 5 μm in diameter. The vibrated powder bed exhibits three distinct phases depending on the vibration conditions: consolidation (CS), static fracture (SF), and dynamic fracture (DF). Particularly, we found an upward wave propagation in the DF regime when the powder bed is strongly vibrated. As a remarkable feature, we found that in fine cohesive powders, the decompaction-wave propagation speed normalized to gravitational speed is independent of the shaking strength. This result implies that the wave propagation speed is governed by the balance between gravity and cohesion effect rather than vibration strength. We also explore the universality of wave propagation phenomenon in coarser and low-density granular powders.