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Morphological and thermodynamic transitions in drugs as well as their amorphous and crystalline content in the solid state have been distinguished by Thermal Analytical techniques, which include DEA, DSC and macro-photo-micrography. DEA measures and differentiates the crystalline solid (low; 10-2 pS/cm) and amorphous liquid (high; 106 pS/cm) API electrical ionic conductivity. Drug salts were investigated by DEA in order to evaluate the ionic conductivity and molecular mobility properties in pharmaceutical salts through the measurement of the characteristic activation energies Ea (k), Ea ( ) and polarization times ( ). These analyses can be used to predict the quality, stability and behavior of a drug salt. The dielectric science developed to understand the crystalline and amorphous components in pharmaceuticals would be validated by calorimetry, X-ray diffraction and scanning electron microscopy. It has been established that the crystalline and amorphous content measured by the DEA activation energy method is related to the DSC melting, glass-transition profile as well as the crystal structure by X-ray diffraction and scanning electron microscopic images.
About the author
Dr. Maheswaram received his B.S. in Pharmaceutical Sciences from Osmania University, India and his M.S. in Chemistry and Ph.D. in Bio-Analytical Chemistry from Cleveland State University, USA. Dr. Maheswaram's primary research interests include thermal methods, chromatographic techniques, polymer and organic synthesis and characterization.
