Polymorphism Control of Carbamazepine Based on Deep Eutectic Solvents

Carbamazepine (CBZ) is a drug that exists in multiple crystal forms and hydrates. In this study, CBZ was used as the model drug, and an attempt was made to regulate the crystal form and morphology of the drug using the DES system. The effects of deep eutectic solvents (DESs) on the crystal form of CBZ were systematically investigated.

The solubility of CBZ in different DES mass ratios was determined. Single crystals of the CBZ crystal form VI were prepared and the structure were analyzed. The differences between the new crystal form of CBZ and other crystal forms have been discussed. Molecular electrostatic potential surface (MEPS), Hirshfeld surface (HS), and molecular dynamics calculation (MD) were conducted to elucidate these phenomena at the molecular level.

Form VI was successfully obtained under specific experimental conditions. The constitute and mass ratio of DES in methanol solution and the degree of supersaturation were found to influence the morphology of form VI.

The new crystal form VI of CBZ was obtained through the DES solvent system. The existence of DES can alter the interactions between molecules, thereby providing the possibility for the formation of new crystal forms and morphologies.