ABSTRACT
The primary particle size will determine which instrument can be used to provide optical particle size data. The volume diameter has relevance to pharmaceutical technology, especially in regard to delivery of particles in an aerosol. More than one measure of particle size and characteristics must be collected to predict performance, even if one measure of performance is taken. T. Foster and M. Leatherman discussed how multiple measures are needed to describe performance for particles created in a complex process such as spray drying. Diameters determined by optical imaging are one means of describing the primary particle size. Optical methods allow a determination of the particle size and morphology. The morphology and flowability of the spray-dried powders remained the same across multiple equipment parameters during scale-up. Overall performance, however, changed significantly due to changes in particle size and distribution and bulk density.
