Exploring the crystal form landscape

Chapter 3 deals with the theoretical background, the strategies, and the experimental techniques for exploring the crystal for landscape. The various and evolving models for aggregation and nucleation are discussed, followed by the description of thermodynamic (i.e., approximately equilibrium) and kinetic crystallization conditions, followed by the use of thermodynamic information obtained in Chapter 2 for designing crystallization strategies. The various aspects of solid form screens—design, composition, time frame, variables to consider, application of high throughput methods—are discussed, followed by a description of the screen on the specific example of axitinib. The chapter closes with discussions of concomitant polymorphs and disappearing polymorphs.

Parameters characterizing the kinetics of the non-isothermal crystallization of polyamide 5,6 determined by differential scanning calorimetry

The non-isothermal crystallization behavior of polyamide 5,6 (PA56) was investigated by differential scanning calorimeter (DSC), and the non-isothermal crystallization kinetics were analyzed using the modified Avrami equation, the Ozawa model, and the method combining the Avrami and Ozawa equations. It was found that the Avrami method modified by Jeziorny could only describe the primary stage of non-isothermal crystallization kinetics of PA56, the Ozawa model failed to describe the non-isothermal crystallization of PA56, while the combined approach could successfully describe the non-isothermal crystallization process much more effectively. Kinetic parameters, such as the Avrami exponent, kinetic crystallization rate constant, relative degree of crystallinity, the crystallization enthalpy, and activation energy, were also determined for PA56.

Unexpected crystallization of the metastable tubular coordination polymer of cucurbit[6]uril with magnesium ions which spontaneously transforms into a discrete coordination complex

We report on the kinetic crystallization of the tubular coordination polymer constructed from cucurbit[6]uril and magnesium ions. The metastable phase spontaneously converts into a thermodynamically favored discrete coordination complex.