By Peter Bouza
Particle analysis plays a key role in the pharmaceutical industry — in both product efficacy and manufacturing. Particle size can impact the dissolution rate of an excipient or active pharmaceutical ingredient (API) and can impact formulation or tableting of a drug. Various established techniques serve the particle sizing needs of the pharmaceutical market today.
However, in some situations, simply monitoring particle size is not enough to control a product’s final outcome. Particle shape may be even more important to monitor and control. In recent years, the desire for particle shape information has led to the consideration of image analysis for research and quality control in the pharmaceutical sector.
Most methods for particle size analysis assume particles are all spheres and report results as “equivalent spherical diameter.” This assumption is not acceptable in some applications. For example, monitoring particle size alone will not determine if a sample will travel and flow properly in production. Some particles may be spherical, and some may be rectangular; the spheres would flow much easier than the rectangular-shaped particles — and with much less energy. Rectangular-shaped particles present more of a challenge to ensure proper and homogeneous flow. Particle shape significantly affects flowability and the particle’s ability to mix properly with other sample components, affecting the outcome of the finished product.