Spherical crystallization and its process optimization

S. K. Putta*1 and P. Srikumar2

Abstract

Spherical crystallization is the novel agglomeration technique that can transform directly the fine crystals produced in the crystallization process into a spherical shape. This technique of particle design of drugs has gained great attention and importance due to the fact that crystal habit (form, surface, size and particle size distribution) can be modified during the crystallization process. Crystal habit can be modified by optimizing the processing parameters like stirring rate, selection of solvent, pH, temperature etc. which affects the physico-chemical properties (solubility, dissolution rate, bioavailability and stability) and micrometric properties (bulk density, flow property, compactability) of crystals. Stirring rate affects the shape as well as size of the final agglomerates and solvent selection helps in the formation of maximum amount of agglomerates in the system. The factors like pH and temperature should be maintained in case of drugs which show polymorphism. Apart from this, several others physical phenomenon or parameters like interfacial tension and rate of crystallization are also important for thorough optimization of process. The spherical crystallization further developed use with hydrophilic polymers to enhance solubility and dissolution rate of poorly water soluble drugs. This article describe the over view of spherical crystallization along with way of optimizing the processing parameters to get effective spherical agglomerates.