Combining a Drug and a Nutraceutical: A New Cocrystal of Praziquantel and Curcumin

This study explores the cocrystallization between the drug praziquantel (PZQ) and the nutraceutical curcumin (CU). The investigation revealed two novel solid forms: a cocrystal solvate with ethyl acetate and a non-solvated cocrystal. This novel drug-nutraceutical cocrystal is identi-fied as “generally recognized as safe” (GRAS) praziquantel-curcumin-ethyl acetate (2:1:1) co-crystal solvate. This latter undergoes desolvation, leading to the formation of the praziquan-tel-curcumin (2:1) cocrystal. The cocrystal solvate has ethyl acetate molecules occupying the voids with minimal interactions within the crystal lattice. The application of heat treatment induces solvent removal and prompts the transition to the non-solvated cocrystal, as highlighted by VT-XRD. Thermal analyses demonstrate the stability of the cocrystal solvate up to approximately 100°C, beyond which it transforms into the non-solvated phase, which eventually melts at 130°C.