Production of fine lactose particles from organic solvent in laboratory and commercial-scale spray dryers

A laboratory spray dryer and a commercial dryer with a production rate 50 times greater, both using two-fluid nozzles, were used to dry the same formulation from organic solvent. Both dryers generated particles of similar size, with tight particle size distributions (span <2), which varied with atomization gas flow rate, liquid flow rate, and solids concentration. Small-scale results with an external mixing nozzle were fitted to a correlation based on literature recommendations. This also fitted well for the commercial dryer with external mixing, and an internal mixing nozzle gave a tighter size distribution. Hence, successful verification at scale has been achieved.