Variation in particle shape of active pharmaceutical ingredients prepared by fluidized-bed jet-milling.

In pharmaceutical industries, most active pharmaceutical ingredients are poorly water soluble, and therefore milling processes are important to obtain fine particles that can be easily dissolved in the body. However, the main purpose of milling is micronization of particles. From the viewpoint of fine particle preparation in the formulation process, milling has not been investigated sufficiently. In this paper, ethenzamide was milled under various operating conditions using a fluidized-bed jet-mill. It was found that not only the particle size but also the particle shape varied with the milling conditions. The relationship between particle shape and milling conditions has been obtained experimentally.