Coupling Between Chemical Reactivity and Structural Relaxation in Pharmaceutical Glasses.

<span class="AbstractHeading">Abstract</span><div class="AbstractSection"><div class=""><span class="AbstractSectionHeading"><a name="ASec1"></a>Purpose  </span>To test the hypothesis that the molecular motions associated with chemical degradation in glassy amorphous systems are governed by the molecular motions associated with structural relaxation. The extent to which a chemical process is linked to the motions associated with structural relaxation will depend on the nature of the chemical process and molecular motion requirements (e.g., translation of a complete molecule, rotational diffusion of a chemical functional group). In this study the chemical degradation and molecular mobility were measured in model systems to assess the degree of coupling between chemical reactivity and structural relaxation. The model systems included pure amorphous cephalosporin drugs, and amorphous molecular mixtures containing a chemically labile drug and an additive expected to moderate molecular mobility. [ABSTRACT FROM AUTHOR]