Evidence for a New Crystalline Phase of Racemic Ibuprofen

Emeline Dudognon, Florence Danède, Marc N. Descamps, Natália de Fátima Teixeira Correia

Research output: Contribution to journalArticlepeer-review

114 Citations (Scopus)


Purpose. The aim of this work is to search for the existence of crystalline polymorphism for racemic Ibuprofen. Methods. The pharmaceutical material was studied by X-ray diffraction to identify crystalline phases, and by Differential Scanning Calorimetry to follow the thermodynamic evolution of these forms versus temperature. Results. Results presented here show that, in addition to the already known conventional crystalline phase, whose nucleation domain extends between 233 K and 263 K and which melts at 349 K, racemic Ibuprofen can crystallize in another polymorphic phase. The nucleation of this new polymorphic variety is triggered by a stay at least 60 degrees below the glass transition temperature Tg of Ibuprofen (Tg=228 K). This nucleation is probably of heterogeneous type. The new phase melts well below the conventional one, i. e. at 290 K. A schematic free energy diagram is provided allowing establishing the relative thermodynamic stability of the two polymorphs. Conclusions. These results establish, for the first time, that Ibuprofen can exist under two different crystalline phases which constitute a monotropic system, the new form being metastable.
Original languageEnglish
Pages (from-to)2853-2858
Number of pages6
JournalPharmaceutical Research
Issue number12
Publication statusPublished - 1 Dec 2008


  • Ibuprofen
  • Polymorphism
  • Glass transition
  • Nucleation


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