Amorphous or Crystalline? A Comparison of Particle Engineering Methods and Selection

This review is intended to provide a critical account of the current goals and technologies of particle engineering regarding the production of crystalline and amorphous particles. The technologies discussed here cover traditional crystallization technologies, supercritical fluid technologies, spray drying, controlled solvent crystallization, and sonocrystallization. Also recent advancements in particle engineering including spray freezing into liquid, thin-film freeze-drying, PRINT technology are presented. The paper also examines the merits and limitations of these technologies with respect to their methods of characterization. Additionally a section discussing the utility of creating amorphous and crystalline formulation approaches in regards to bioavailability and utility in formulation is presented.