*2.2. Aminoglutethimide Eutectic Mixture Screening and Eutectic Composition Determination*

Multiple mixtures of AMG and the chosen coformer in different weight percentages, e.g., 50%, 55%, 60%, 65%, 70%, 75%, and 80%, were prepared. The needed amount of each component was added to a mortar to obtain 100 mg of the desired binary combination and grinded using mortar and pestle with a dropwise addition of acetonitrile for 30 min.

The melting behavior of the resulting solids and the eutectic formation was determined by means of a DSC linear heating run. Eutectic and pure compounds melting temperatures were considered from the corresponding peak onsets, and liquidus temperatures for mixtures were taken from the peak maximum. Therewith, the binary phase diagrams and corresponding Tammann plots were constructed to specify the eutectic composition of the respective drug-drug system. For the Tammann plot, the enthalpy of fusion of the eutectic melting effects in the DSC curves of the mixtures are used.

The melting of the eutectic mixture is characterized by a single melt peak in the DSC curve for the corresponding drug-drug, that is an eutectic composition. This is because the eutectic is an invariant point in the binary system in analogy to the melting point of a pure compound in a unary system.
