(361d) Nanostructure of Individual Grains Affecting Movement in Densely Packed Material

Ultrathin nanolayers deposited on pharmaceutical particles during the mixing process were investigated with respect to their powder flow behavior. Multiple pharmaceutical formulations were exposed to various shear rate and shear strain conditions in a blender. Samples of lubricated and un-lubricated blends were collected from the blender after the mixing process and their micro and nanostructures were studied under field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The powders with such nanostructures tested for their flow properties in a gravitational displacement rheometer (GDR) showed that the powder flow depended not only on the density of packing of powder bed but also on nanostructures of individual grains. Velocity profiles of powder particles in a tumbling cylinder were tracked at different rotational rates ranging from 1 – 20 rpm. It was interesting to see that the ultra-thin nanolayers affected the velocity distribution of particles within the powder bed as a function of dilation and rotational rate. An attempt made to track the magnitude of each particle average velocity from the interior 3D system is expected to open an innovative approach in particle dynamics.