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Yissum - Research Development Company of the Hebrew University posted this:

Content-Specific Image Enhancement Project ID : 10-2011-2707
Content-Specific Image Enhancement

xrqtc posted this:

Current polymorphism studies are being carried out using one of the following three alternatives: atom-atom potentials, DFT (Density Functional Theory) calculations and ad-hoc potentials. However, all of them have serious disadvantatges. 1) with software that uses atom-atom potentials: Advantages: fast and capable of working with large molecules. Disadvantages: the "blind tests" carried out by the "Cambridge Crystallographic Data Centre" are giving a 50% maximum success in the predictions. 2) with software based on DFT calculations: Advantages: good results Disadvantages: they are computationally very slow, so they are only used for very simple molecules compared with drug molecules. In addition, they have errors predicting van der Waals interactions and weak hydrogen bridges if not corrected empirically. 3) with software using ad hoc potentials for each molecule obtained from systematic exploration of the surface potential of intermolecular interactions: Advantages: efficient and faster. Disadvantages: some potentials should be calculated for each molecule studied, which are complex and slow, and is not general. The approach presented here is new and unique because the potential Pixel has never been used before for drawing polymorphic predictions and it has shown to present the advantages of all the alternatives combined. This is the first research group which has brought the potential Pixel to this level of calculation. The potential calculations and the applicability of the methode based on pixels have the same quality that the sophisticated ab initio based potential calculations. Besides, this is much faster than DFT (Functional-Based Theory)-based and ad hoc potentials ..