Crystallization processes, modified

Crystal growth is a diffusion and integration process, modified by the effect of the solid surfaces on which it occurs (Figure 5.3). Solute molecules/ions reach the growing faces of a crystal by diffusion through the liquid phase. At the surface, they must become organized into the space lattice through an... 

Many dry solid parenteral products, such as the cephalosporins, are prepared by sterile crystallization techniques. Control of the crystallization process to obtain a consistent and uniform crystal form, habit, density, and size distribution is particularly critical for drug substances to be utilized in sterile suspensions. For example, when the crystallization process for sterile ceftazidime pentahydrate was modified to increase the density and reduce the volume of the fill dose, the rate of dissolution increased significantly. 

Electrodes modified by underpotential deposition of metal were subjected as electrocatalysts to reduction of oxygen,oxidation of formic acid, and other processes in which polycrystalline metal substrates were used (see review in Ref. 151). Electrocatalysis of single-crystal electrodes modified by underpotential deposition was also investigated, as reviewed by Ad2iC. ... 

Platellke a-form crystals easily separate from the solvent In commercial operation but halrllke 3-form crystals are troublesome because their suspension Is extremely viscous. So the main purpose of this work Is to develop a modified crystallization process to obtain a-form crystal selectively. 

T0319 FTC Acqnisition Corporation, DirCon Freeze Crystallization Process T0394 Idaho National Engineering Laboratory/Brookhaven National Laboratory, Modified Snlfnr Cement Encapsnlation... 

Kinetics of nucleation and crystal growth can be modified to some extent to favor an efficient process, but in almost all commercial crystallization processes, this flexibility is limited by the needs of the users of the product. 

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