Future Developments

The renewed vigour with which polymorphism as a phenomenon is currently being investigated is motivated by the demand for reliable methods of reproducible crystallization of specific polymorphs of

Figure 8 Schematic representation of LDE on a single-crystal substrate and the role of LDE in selective nucleation of polymorphs. Symbols are defined in the original reference. (Reproduced with permission from Bonafede SJ and Ward MD (1995) Journal of the American Chemical Society 117: 7853, Copyright American Chemical Society.)

Figure 8 Schematic representation of LDE on a single-crystal substrate and the role of LDE in selective nucleation of polymorphs. Symbols are defined in the original reference. (Reproduced with permission from Bonafede SJ and Ward MD (1995) Journal of the American Chemical Society 117: 7853, Copyright American Chemical Society.)

industrially important compounds. In the case of pharmaceuticals, further motivation comes from drug-regulatory bodies (e.g. the FDA) which require details of crystallization procedures for specific drug polymorphs and pseudopolymorphs. It is vital that theoretical development of the subject of polymorphism continues to keep pace with these demands. Computational and experimental techniques, which have during the last decade led to substantial advances in the understanding of the primary event in the crystallization process, namely nucleation, are expected to improve in terms of the complexity of the models employed and in the systems investigated. The strategy of 'rational crystal seeding' epitomized by the LDE technique is likely to be applied more widely to the control of polymorphic crystallization. A consequent growth is expected in the number of reports documenting successful isolation of specific polymorphs utilizing approaches based on deliberate intervention at the nucleation stage. Detailed structural elucidation of metastable polymorphs and microcrystalline polymorphs will be facilitated by the combined use of methods such as computational crystal structure prediction, solid state NMR, highresolution X-ray and neutron powder diffraction, and single crystal X-ray methods employing synchrotron radiation sources. Accompanying the demand for isolation of particular polymorphs, methods for more rapid analysis and quantification will be needed to satisfy both production and legal requirements. An increase in the number and types of on-line systems for continuous monitoring of polymorphic purity in the industrial environment is also envisaged.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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