Dielectric Thermal Analysis of Pharmaceutical Solids. Electrical-Ionic Conductivity Properties of Crystalline and Amorphous Pharmaceuticals

      Аннотация: 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; 10>6 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.

Ключевые слова: Activation Energy, Amorphous, Dielectric Analysis (DEA), Differential Scanning Calorimetry (DSC), Electrical or Ionic Conductivity, Tan delta, Frequency (Hz), Crystalline, Semi-Crystalline, Crystalline Content, Polarization Times, Powder X-ray Diffraction (PXRD)