Using a Freeman FT4 rheometer and Electrical Capacitance Tomography to assess powder blending

A comprehensive review of characterization techniques for particle adhesion and powder flowability

The study of the flow properties of particles is crucial because it directly impacts the efficiency and product quality of various industrial particulate processes, such as continuous manufacturing of solid oral dosages. However, challenges arise due to the flow behavior of cohesive particles, which tend to adhere to surfaces or other particles, necessitating careful process design. The importance of selecting appropriate measurement pathways for accurate characterization has been overlooked. In response, an overview of measurement technologies for surface energy and cohesive/adhesive forces is provided in this work, aiming to establish a practical guide. Understanding these forces is crucial for optimizing continuous manufacturing processes to effectively mitigate flow-related issues such as obstructions, segregation, irregular flow, and flooding. Furthermore, various methods characterization experiments were conducted and compared to illuminate the methodological disparities. This analysis provides valuable insights into particle adhesion, cohesion, and powder flowability, potentially enhancing industrial particulate processes development.

General aspects of powder rheology applied to pharmaceutical formulations

Powder flowability is crucial in the pharmaceutical industry, strongly affecting solid dosage processing. Classical experimental techniques offer straightforward results for the rapid screening of formulations during development. However, they fail to describe powder properties under consolidation. Complex techniques, such as shear cell, accurately assess fundamental properties of particulate samples under realistic conditions, enabling prediction of their flow. Ideally, a combination of experimental methods should be used to comprehensively assess powder flowability, ensuring consistent product performance. Moreover, researchers and analytical scientists must have a solid understanding of powder rheology to effectively interpret acquired data. In this review, common techniques, experimental protocols, and typical results observed in a pharmaceutical context are described.

Control Strategy for Excipient Variability in the Quality by Design Approach Using Statistical Analysis and Predictive Model: Effect of Microcrystalline Cellulose Variability on Design Space

Although various quality by design (QbD) approaches have been used to establish a design space to obtain robust drug formulation and process parameters, the effect of excipient variability on the design space and drug product quality is unclear. In this study, the effect of microcrystalline cellulose (MCC) variability on drug product quality was examined using a design space for immediate-release tablets of amlodipine besylate. MCC variability was assessed by altering the manufacturer and grade. The formulation was developed by employing the QbD approach, which was optimized using a D-optimal mixture design. Using 36 different MCCs, the effect of MCC variability on the design space was assessed. The design space was shifted by different manufacturers and grades of MCC, which resulted in associations between the physicochemical properties of MCC and critical quality attributes (CQAs). The correlation between the physicochemical properties of MCCs and CQAs was assessed through a statistical analysis. A predictive model correlating the physicochemical properties of MCCs with dissolution was established using an artificial neural network (ANN). The ANN model accurately predicted dissolution with low absolute and relative errors. The present study described a comprehensive QbD approach, statistical analysis, and ANN to comprehend and manage the effect of excipient variability on the design space.

Ultrasound pretreatment prior to spray drying improve the flowability and water sorption properties of micellar casein concentrate

This research investigated the effect of ultrasound (US) pretreatment prior to spray drying on the powder flow and moisture sorption behaviour of micellar casein concentrate (MCC). MCC produced from skim milk microfiltration was sonicated at energy intensity of 0 (control), 47 J/mL (S-2000), 62 J/mL (S-3000) and 76 J/mL (S-4000). The results revealed that US pretreatment significantly increased the average particle size (D50) from 82.46 μm to 100.73 μm and reduced the surface fat content from 19.2% to 13.8%, resulting in decreased basic flow energy, cake energy and cohesion. Besides, the US treated samples showed relatively poor ability to acquire the moisture from the atmosphere than the control. Protein structure analysis showed that α-helix decreased with enhanced US power, while β-sheet and surface hydrophobicity increased, implying hydrophobic groups were exposed and water sorption rate was impeded. As a result, US pretreatment can improve the powder flow and potentially reduce the negative effect of cake formation at high humidity.

Evaluation of the physical properties of dry surface-modified ibuprofen using a powder rheometer (FT4) and analysis of the influence of pharmaceutical additives on improvement of the powder flowability

In this study, we examined the characteristics of glidant that affect the improvement of the flowability of APIs by using the dry surface modification of ibuprofen. In addition, the screening method of glidant suitable for improving flowability of APIs was examined. As a result of evaluation of mixed powder with surface modification using various inorganic fine particles with different physical properties, it became clear that the packing fraction had the most influence regardless of the component. This was thought to able to coat the surface with small quantities because the smaller the packing fraction, the more it was able to dispersed from the less contacts between the glidant particles. The packing fraction of glidant was correlated with the (SE/CBD)^-1 which was calculated value from the results measured with powder rheometer. From this results, when using any excipient as a glidant for dry surface modification, it is now possible to estimate the effect of improving flowability simply by measuring with a powder rheometer. Based on this study, it is possible to select excipients suitable for improving APIs flowability and to estimate the improvement effect, and therefore, it is expected to improve the efficiency of prescription design work.