Crystal habit modifications of ibuprofen and their physicomechanical characteristics

Ibuprofen was crystallized from methanol, ethanol, isopropanol, and hexane at similar conditions. Marked differences in crystal habit of the samples obtained from these solvents were observed. The samples crystallized from methanol and ethanol had a polyhedral crystal habit, while those from hexane were needlelike. Those from isopropanol were elongated crystals. X-ray powder diffraction (XPD) and diferential scanning calorimetry (DSC) studies confirmed that these samples were structurally similar, therefore, polymorphic modifications were ruled out. The results showed that crystal habit modification had a great influence on the mechanical properties (compressibility, flow rate, and bulk density) of ibuprofen crystals. Samples obtained from methanol and ethanol exhibited the highest bulk density and the best flow rate, while those from hexane showed the lowest bulk density and the worst flow rate. The samples obtained from ethanol exhibited the best compression force/hardness profiles, and those obtained from hexane produced the softest tablets.