Characterization of two polymorphs of lornoxicam

Objectives  The aim of the study was to prepare and to characterize two polymorphs of lornoxicam, a water-insoluble non-steroidal anti-inflammatory drug, which has thus far received no exploration of its polymorphs. Methods  Form I and form II of lornoxicam were prepared by recrystallization and characterized by X-ray powder diffractometry (XRPD), thermal analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. The solubility and dissolution of both polymorphs were also determined and compared to provide the basis for polymorph selection in formulation. Key findings  The crystal structures of the two polymorphs were established by the experimental XRPD patterns. Form I was demonstrated to be triclinic with two kinds of intermolecular hydrogen bonds, while form II was orthorhombic with two kinds of intramolecular hydrogen bonds. The morphologies of form I and form II were observed to be rectangle and approximately oval, respectively. Conclusions  Form II had the significantly higher solubility and dissolution and would be the suitable polymorph for the preparation of oral and injectable dosage forms of lornoxicam.