Thermally stimulated currents observed in pharmaceutical products

Stability and processing of pharmaceutical products are often related to the molecular mobility of the formulation. It is crucial to know all the transitions or relaxations of the products. Differential scanning calorimetry (DSC) measurements give valuable information about the melt of the substances. The challenge is actually to detect very weak glass transitions and even beta relaxations. The aim of this presentation is to show that thermally stimulated current (TSC) is a driven technique that provides a better sensitivity to glass transition and sub-glass relaxations. TSC was applied to the evaluation of the stress in tablets and on the measurement of low amorphous content (in the order of 2%). TSC complements DSC to obtain the relaxation/transition “spectrum” of a pharmaceutical product.