Spherical Crystallization: An Overview

Introduction: In 1986, Kawashima developed the spherical crystallization technique for size enlargement of drugs in the field of pharmacy. Spherical crystallization is defined as “An agglomeration process that transforms crystalline drug directly into compact spherical forms for improving the flowability, solubility and compactability”. Methods: General methods for preparing spherical crystallization are spherical agglomeration, emulsion solvent diffusion method, ammonia diffusion method and neutralization method. Factors controlling the process of agglomeration include solubility profile, mode and intensity of agitation, temperature of the system and residence time. Results: Spherical crystals can be characterized by Optical microscopy, X-ray powder diffraction, Electron scanning microscopy, Fourier Transform Infrared spectrometer (FTIR) and differential scanning calorimeter (DSC).Spherical crystallization has wide applications in pharmaceuticals like improvement of flowability and compressibility of poorly compressible drugs, masking bitter taste of drugs and improving the solubility and dissolution rate of poorly soluble drugs. Conclusion: Spherically agglomerated crystals can be directly converted into a tablet thus saving time and reducing cost.