Flowability of wet granules is an important indicator for design and control of manufacturing processes. In this study, we aimed to develop a method to evaluate the flowability with simple equipment and operation. We measured the stirring torque under constant normal stress and the resistance force acting on the plate penetrating into the granules layer. The stirring operation did not properly measure the flowability of strongly cohesive wet granules because voids around the stirring impeller were generated. The penetration operation was able to evaluate the flowability over a wide range of water content conditions by two different indices. Furthermore, the theory of bearing capacity was applied to the penetration tests.

Our study described a new annealing approach for dry-coated formulations, which includes heating of the dosage forms in plasticizer vapor. First, coated tablets were produced by V-shaped blending of tablets and polymer particles without any solvents. Second, these tablets were placed in a desiccator, in which triethyl citrate in liquid state was pre-charged, followed by heating at various temperatures. The resulting tablets were characterized. The polymer particles layered on the surface of tablets coalesced by heating at 80°C or more in plasticizer vapor, indicating that using plasticizer vapor could lower heating temperature required for film formation of coated polymer. The weight of polymer compacts increased by heating in plasticizer vapor as heating temperature increased. These data were correlated with vaporization rate of the plasticizer, indicating that plasticizer in gas state was absorbed in polymer particles, promoting film formation due to a decrease in glass transition temperature of the polymer.

In this study, core-shell type particles with a membrane-like shell layer were prepared using a planetary ball mill. Tg = 63°C particles (8.7 μm) and Tg = 32°C particles (7.4 μm) containing a low melting point material were used for the core particles, and water suspension of acrylic particles (150 nm) were used for the shell material. Cross-sectional observation showed a membrane-like shell layer with no visible interfaces was produced on the core surface. This is because the shell particles uniformly adhered to the core particle surface, followed by the close packing and deformation due to the capillary force and curing during the vacuum drying. When the processed particles were heated in an oven at the temperature of the Tg of processed particles, no thermal aggregation and seepage of the low melting point material were observed. It was found that the shell layer effectively protected the core particles.

Hollow particles are widely used because they have different properties from solid particles, such as low density and high specific surface area. Here, we investigated the effects of the presence or absence of ultrasound irradiation and the amount of ammonia added in the synthesis process of hollow silica particles using calcite nanoparticles as a template. As a result, particles with thicker shells, higher particle density, and smaller specific surface area and pore volume can be synthesized by stirring with a stirrer while being irradiated with ultrasonic waves than by stirring with a stirrer alone. Furthermore, by increasing the amount of ammonia added, particles with thick shells can be synthesized.

The aggregation and dispersion structures of surface-modified nanoparticles in a solvent were visualized and analyzed using numerical simulations based on the discrete element method that takes into account the interaction between the surface-modifier and organic solvent. The interface structure between the surface-modifier and organic solvent was visualized using molecular dynamics simulations. The relationship between the interface structure and their affinity was analyzed.