Author(s): Nitan Bharti, Neeraj Bhandari, Pooja Sharma, Kulwinder Singh, Avneesh Kumar
Spherical crystallization is a fast developing technique of particle design in which crystallization and agglomeration can be achieved simultaneously in one step. It has been successfully utilized for improvement of flow ability and compactability of crystalline drugs. The principle steps involved in the process of spherical crystallization are flocculation zone, zero growth zone, fast growth zone and constant size zone. General methods of spherical crystallization are emulsion solvent diffusion, spherical agglomeration, ammonia diffusion method and neutralization method. Factors controlling the process of agglomeration are solubility profile, mode and intensity of agitation, temperature of the system and residence time. Characterization of spherical crystals can be carried out using Optical Microscopy, Scanning Electron Microscopy, X-ray Powder Diffraction, Fourier Transform Infrared spectroscopy, Differential Scanning Calorimetry and Thin layer Chromatography.