(666a) Particle Engineering Based Framework for Cohesion Reduction of Fine Pharmaceutical Powders Via Dry Coating

Flow and handling of fine powders is a topic of great interest to pharmaceutical industry. High cohesion observed in fine pharmaceutical powders lead to problems such as, agglomeration, poor flowability, electrostatic charging and low bulk density. These also lead to downstream problems such as poor content uniformity, marginal improvement in dissolution rate of fine API powders, and need for extra processing steps such as granulation. Some of these flow problems may be mitigated or kept under control via use of flow-aids and glidants. However, dry coating based surface modification is a more rigorous approach due to its ability to achieve precise surface coating of nano-silica and other flow-aides; making it very popular in recent academic research. 

In this presentation, we provide results using several devices, both based on batch and scalable continuous operation, for pharmaceutically relevant powders where the surface coating includes not only silica but also several types of “guest” materials. Dry coating devices are categorized in two approaches; the first approach is suitable for powders in 150 down to 10 micron sizes where attrition of powder size is minimal. In the second approach, suitable for even finer particles, including those used in the inhaler application having aerodynamic diameters in the size range of 2 ~ 5 microns, simultaneous micronization and surface modification is considered. Results of the bulk properties for these powders are presented to illustrate the improvement in flow, fluidization, dispersion, lack of agglomeration, bulk density, and electrostatic tendency, all leading to potentially significant cost benefits in industrial processing, handling, storage and transportation. Finally, we propose a 2-D phase-map based on key bulk powder properties to help make manufacturing decisions regarding the formulation strategy for solid pharmaceutical dosages.