“Predicting” Crystal Forms of Pharmaceuticals Using Hydrogen Bond Propensities: Two Test Cases

The Cambridge Structural Database incorporates an algorithm, based on data mining and statistical analysis of the structures in the database, for evaluating the “risk of polymorphism” in any compound. We have applied that algorithm to a number of pharmaceutically important compounds from the European Pharmacopoeia for which multiple crystal forms have not been reported. The survey suggested the possibility of polymorphism in at least two compounds, bufexamac and meglumine. The statistical analysis and the subsequent experimental search for polymorphism are reported here. While polymorphism was detected and characterized in both cases, the structural results were not necessarily compatible with the basis for the measure of the “risk of polymorphism”.