A novel method to measure the glass and melting transitions of pharmaceutical powders

A method to measure thermo-mechanical properties of pharmaceutical and polymeric powders was developed. The measurements are conducted by characterizing the material's response to applied acoustic waves. Measurements were performed using griseofulvin, felodipine and indomethacin as model drugs and polyethylene oxide (MW = 200,000, 900,000, 2,000,000 Da) as model polymers. The method employed measures the mechanical impedance enabled the calculation of the powder rheological and thermo-mechanical properties. Measurements attained with this new technique are compared with measurements made using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The new method detects the melting and glass transitions events while providing complementary information to that provided by DSC and DMA.