Crystallization of Organic Compounds, 2nd Edition

Chapter 2Properties

For pharmaceuticals and special fine organic chemicals, solution crystallization, in which solvents are used, is the primary method of crystallization in comparison to other crystallization techniques such as melt or supercritical crystallization. The goal of this chapter is to introduce basic properties of solution and crystals in order to better understand, design, and optimize the crystallization processes. The relevance of these basic properties to crystal qualities and crystallization operations will be highlighted accompanied with specific examples.

With regard to specific properties, we will focus on those that are more relevant to solution crystallization, and those that have direct impact on the quality of the final bulk pharmaceuticals such as purity, form, habit and size, based upon our own experience. We will leave readers to find other properties, such as miller index for crystal morphology, hardness of crystals, interfacial tension, etc. in other crystallization books (Mersmann 2001; Mullin 2001) which provide in‐depth theoretical discussion on these properties. In view of the recent development of solid dispersion, we also include relevant features of its crystallization properties. More detailed discussion of solid dispersions can be found in these references (Douroumis 2012; Shah et al. 2014; Newman 2015).

2.1 SOLUBILITY

Understanding the solubility behavior is an indispensable requirement for the successful development of crystallization ...