IEC 78 |
| Lian Yu, Eli Lilly and Company, Eli Lilly and Company, Lilly Research Labs, Lilly Corporate Center, Indianapolis, IN 46285 |
| Polymorphism, the existence of multiple crystallization pathways leading to different solid structures, enables molecular-level studies of structure-property relationships and selective nucleation. Using the polymorphs of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile, the current record holder for the highest number of polymorphs of known structures, we studied how thermodynamic stability and crystal color depend on crystal structure and demonstrated how epitaxy with single-crystal substrates aids the discovery and selective nucleation of polymorphs. We elucidated how pH change causes glycine to crystallize into different polymorphs and salts as a result of complex acid-base and agglomeration equilibria in solution. References: Yu, L.; Ng, K. J. Pharm. Sci. 2002, 91, 2367. Yu, L. J. Phys. Chem. A 2002, 106, 544. Mitchell, C. A.; Yu, L.; Ward, M. D. J. Am. Chem. Soc. 2001, 123, 10830. Yu, L. et al. J. Am. Chem. Soc. 2000, 122, 585. |
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Industrial Crystallization (sponsored by Separation Science & Technology Subdivision)
1:45 PM-5:00 PM, Monday, March 24, 2003 Convention Center -- Room 393, Oral
Division of Industrial and Engineering Chemistry |