Pharmaceutical formulation is a process in which different chemical substances (excipients), including an active pharmaceutical ingredient (API), are combined to produce a final product. Understanding how these substances age as a function of time and temperature is critical to achieving consistent drug quality. Aging or disruption of the pharmaceutical product does typically not involve changes in the material’s crystalline structure, a property typically analyzed by XRD. Instead, aging of the product is related to changes of its self-organized, nano-sized structures, which can only be studied by small angle x-ray scattering (SAXS). Many pharmaceutical formulations contain excipients (e.g. lipids, stearates), which exhibit self-assembled, nano-sized structures, allowing them to be the perfect candidate for study by SAXS.