Spherical Crystallization:Novel Technique

Spherical crystallization is the novel agglomerated technique that can directly transform the fine crystals produced in the crystallization process into a spherical shape. It is the particle engineering technique by which crystallization and agglomeration can be carried out simultaneously in one step to transform crystals directly into compacted spherical form. This technique of particle design of drugs has emerged as one the areas of active research currently of interest in pharmaceutical manufacturing and came into the forefront of interest or gained interest due to the fact that crystal habit can be modified during crystallization process which would result in better micromeritic properties. Prepared spherical crystals can be compresses directly without performing granulation, drying and so many steps those are required in wet granulation and in dry granulation process of tablet manufacturing.

General methods of spherical crystallization are spherical agglomeration, emulsion solvent diffusion, and ammonia diffusion method. The principle steps involved in the process of spherical crystallization are flocculation zone, zero growth zone, fast growth zone, and constant size zone. Factors controlling the process of agglomeration are solubility profile, mode and intensity of agitation, temperature of the system, and residence time. Spherical crystallization is having wide applications in pharmaceuticals like improvement of flow ability and compressibility of poorly compressible drugs, masking bitter taste of drugs and improving the solubility and dissolution rate of poorly soluble drugs.