Polymer-induced heteronucleation (PIHn), a powerful crystalline polymorph discovery method, has revealed two novel polymorphs of the low solubility bioenhancer piperine. Both of these forms exhibit enhanced solubility when compared to the commercial polymorph, thereby potentially improving the efficacy of piperine as a bioenhancer. Structural comparison of the three forms reveals that π-π interactions are only present in the two newly discovered forms. Combined with the stability data this reveals that despite the extended conjugation present in the moleculesuch interactions are not preferred in thesolid state.
Keywords: p olymorphism; polymer-induced heteronucleation.