The phase equilibrium diagram for the CuI + CsI system has been redetermined by differential scanning calorimetry and X-ray diffraction. The phase diagram exhibits three intermediate compoundsCs3Cu2I5, melting incongruently at 663.0 K, CsCu2I3, melting congruently at 656.0 K, and CsCu9I10, undergoing a solid-state disproportionation reaction to CuI + CsCu2I3 at 604.8 K. The existence of CsCu9I10, derived from DSC studies in accordance with the phase rule, is not shown by X-ray diffraction investigations.

Enhancement of the dissolution rate of poorly soluble compounds through the formation of drug-drug eutectics was investigated using fenofibrate and acetylsalicylic acid. Solid-liquid equilibria in the system under study were investigated by differential scanning calorimetry (DSC). The phase diagram for the whole range of compositions was constructed. In addition, existence of a metastable polymorph of fenofibrate has been confirmed. The investigation has revealed that acetylsalicylic acid and fenofibrate form a simple eutectic mixture containing 0.958 mol fraction of fenofibrate at the eutectic point. Dissolution rate improvement of fenofibrate correlated with the phase diagram. The amount of fenofibrate released from the solid dispersions that contained fenofibrate as the eutectic mixture with acetylsalicylic acid was at least threefold higher compared to untreated fenofibrate.

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