Molecular Mobility and Stability Studies of Amorphous Imatinib Mesylate

The proposed study examined the characterization and stability of solid-state amorphous imatinib
mesylate (IM) after 15 months under controlled relative humidity (60 ± 5%) and temperature (25 ±
2°C) conditions. The most common methods of amorphization include rapid precipitation from
solution, quench-cooling, spray-drying, freeze-drying, and hot melt extrusion. After 2 weeks, and 1, 3,
6, and 15 months, the samples were characterized using differential scanning calorimetry (DSC),
thermogravimetric analysis (TGA), X-ray powder diffractometry (XRPD), attenuated total reflectance-
Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM).
Additionally, the amorphous form of imatinib mesylate was obtained via supercooling of the melt in a
DSC apparatus, and aged at various temperatures (3, 15, 25 and 30°C) and time periods (1–16 h).
Glass transition and enthalpy relaxation were used to calculate molecular-relaxation-time parameters.
The Kohlrausch–Williams–Watts (KWW) equation was applied to fit the experimental enthalpyrelaxation
data. The mean molecular-relaxation-time constant increased with decreasing ageing
temperature. The results showed a high stability of amorphous imatinib mesylate adequate to enable
its use in solid dosage form.