I&EC 116 |
| The ability to predict accurately the energetic ordering of polymorphs of organic crystals at any given temperature is of great technological importance, in particular in pharmaceutical research. A precise knowledge of the crystallographic arrangement of the organic compound is not only essential to key quantities as bioavaliability, shelf life, dissolution rate, etc, but is also required by the FDA as a pre-requisite for the commercialization of the actual drug. Density functional perturbation theory has been used to investigate the free energies of molecular crystals. Pairs of polymorphic forms of two drug molecules, resorcinol and tolfenamic acid, have been studied with respect to their relative energetic ordering at finite temperatures. The calculations show that the polymorphs of resorcinol undergo an enantiotropic change at 370 K. The unit cells of the polymorphs of tolfenamic acid contain 120 atoms, showing the applicability of this approach to systems sizes encountered in applied pharmaceutical research. |
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Computational Material Design in Chemical Industries, Sponsored by Novel Chemistry with Industrial Applications Sub-Division
1:30 PM-5:00 PM, Monday, 11 September 2006 Moscone Center -- Room 252/254, Oral
Division of Industrial & Engineering Chemistry |