Laboratory methods for assessing API sensitivity to mechanical stress during agitated drying

Investigation into process-induced de-aggregation of cohesive micronised API particles

“…The elongation, defined by [1 -(width / length)], of the particles was compared and showed no significant change. This data, in conjunction with the corresponding size data, supports the widely accepted notion that finer particles are less prone to attrition than coarser materials (Kendall, 1978) which has been confirmed in previous experiments (Kwan et al, 2004, Lamberto et al, 2011.…”

The internal loads, moments, and stresses in rod-like particles in a low-speed, vertical axis mixer

“…This device was similar in design to the attrition cell discussed in the previous paragraph. Compared with Lamberto et al (2011), this group not only ranked materials according to attrition potential, but also investigated the influence of different operating parameters on material attrition, including blade speed, agitation time, sample volume, and applied normal force. They reported that increasing blade speed, agitation time, or normal force led to more attrition, with normal force being the most significant factor.…”

“…For both materials, size decreased with the number of agitator revolutions and approached a constant value after a large time, most likely because the crystals either became sufficiently rounded in the case of cubical KCl, or the L-threonine needles broke to a small enough aspect ratio that the loads were no longer sufficient to continue breakage. Lamberto et al (2011) developed an attrition cell for assessing API sensitivity to mechanical stress in an AFD. The attrition cells were similar in design to a scaled-down AFD.…”

Comparison of three rotational shear cell testers: Powder flowability and bulk density

“…Companies would like to predict how a given powder would flow in a given piece of process equipment or compare the flow of one powder to another powder. In the pharmaceutical industry, during the initial stages of development, one often has only a small amount available of active pharmaceutical ingredient, so companies would like to measure powder properties using lab scale tests to predict behavior in processing steps like agitated drying and blending [6,9,[13][14][15]. In the catalyst manufacturing industry, new formulations may dictate the use of new powders in existing process equipment for steps like impregnation, drying, mulling, and calcination [16,17].…”