Understanding and Avoidance of Agglomeration During Drying Processes: A Case Study

A systematic investigation into possible causes of agglomeration during drying was carried out, with a view to reduce the amount of agglomerates present in an active pharmaceutical ingredient. Several tools used in this study are described, including rheology to elucidate how the interplay of agitation (during drying and critical solvent levels) can aggravate agglomeration, and sieving to quantify the extent of agglomeration and the hardness of the resulting agglomerates. Finally, the implementation of a modified wash and the use of a blow-through protocol were demonstrated at pilot-plant scale to be effective in dramatically reducing the extent of agglomeration.