Drug-excipient interactions crystalline

XRD is an excellent technique to study drug-excipient interactions, provided the drug and the excipients are crystalline. In a solid mixture, the powder pattern of each crystalline phase is produced independently of the other constituents. Thus the diffraction pattern of a powder mixture will be the summation of the diffraction patterns of the individual constituents. If the drug-excipient interaction results in a crystalline product, this will be characterized by the appearance of new peaks in the powder pattern. However, if the interaction results in an amorphous product, this will become evident from the broad halos in the pattern. 

Thermal analysis is an extremely important analytical tool for the pharmaceutical industry. All transitions in materials involve the flow of heat (either into the sample during an endothermic event or out of the sample during an exothermic event) and DSC is the universal detector for measuring a wide variety of transitions in pharmaceutical materials. These include measurement of amorphous structure, crystallinity (and polymorphs), drug-excipient interaction and many other applications. 

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