**4. Conclusions**

Solvent-assisted mechanochemical grinding of the drug aminoglutethimide with pharmaceutical coformers enabled the production of binary eutectic mixtures. Considerable lowering of the melting points in the eutectic mixtures was determined from DSC analysis. Analogously, the aqueous solubility of the binary eutectic mixtures was improved compared to the pure AMG. Solubilities at 25 ◦C were found to be 1.3–2.5 times higher than for the AMG. The final aim of the work was to improve the AMG solubility through physical form alteration, and this objective was achieved by the formation of binary eutectic mixtures with caffeine, nicotinamide and ethenzamide as drug-drug eutectics, with the most significant improvement for the AMG-CAF system.

**Supplementary Materials:** The following supporting information can be downloaded at: https:// www.mdpi.com/article/10.3390/cryst12010040/s1, Figure S1: Comparison of Hot Stage Microscopic images for the eutectic mixtures at room temperature, melting and subsequent cooling. Figure S2: Van't Hoff plot of ideal solubility values for the eutectics., Figure S3: PXRD of the AMG eutectics after solubility determinations.

**Author Contributions:** Conceptualization, B.S. and H.L.; methodology, B.S.; formal analysis, B.S.; investigation, B.S.; writing—original draft preparation, B.S.; writing—review and editing, B.S. and H.L.; supervision H.L. and A.S.-M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available in manuscript and Supplementary Materials.

**Acknowledgments:** We thank Stefanie Oberländer and Jacqueline Kaufmann for their help in PXRD and DSC measurements. Markus Ikert is acknowledged for his help in the collection of SEM images.

**Conflicts of Interest:** The authors declare no conflict of interest.
