Highly bioavailable curcumin preparation with a co-grinding and solvent-free process

Curcumin (Cur.) is a natural product isolated from the rhizome of Curcuma longa, with a variety of biological and pharmacological activities in food and pharmaceutical products. However, curcumin's poor solubility in water greatly limits its bioavailability and clinical applications. In this study, co-grinding curcumin with food additives produced a mixture, which was evaluated for the solubility in water, dissolution, material morphology, in vivo bioavailability, cell uptake and entry mechanism. We tested 9 food additives in total and found that poloxamers performed the best. The 2 co-grinding mixtures Cur./Kolliphor^® P407 and Cur./Kolliphor^® P188 with high drug loading at 65.5% significantly improved the curcumin aqueous solubility, subsequently increased its intestinal epithelial cell uptake and oral bioavailability. The relative bioavailabilities for the 2 co-grinding mixtures were 309% and 163%, respectively, compared with curcumin API. Co-grinding process has a broad application prospect and is suitable for industrial production.