Development of a Novel Curcumin-Vanillic Acid Eutectic: Physicochemical Characterization, Antioxidant Activity, and...

Curcumin, a well-known phyto-nutraceutical with broad therapeutic potential, faces critical formulation challenges, including poor aqueous solubility, low dissolution rate, and limited tablettability, leading to poor oral bioavailability and reduced therapeutic efficacy. This study presents a novel curcumin-vanillic acid eutectic system designed to overcome these limitations through a sustainable and green formulation approach.

Vanillic acid, a natural phenolic compound with potent antioxidant properties, was selected as a coformer based on in silico analysis demonstrating structural compatibility and potential therapeutic synergy with curcumin. The eutectic mixture was prepared via solvent-free solid-state grinding and characterized using X-ray diffraction, differential scanning calorimetry, Fourier-transform infrared spectroscopy, and proton/carbon nuclear magnetic resonance. Physicochemical, tablettability, and antioxidant properties were subsequently evaluated. DoE software was used to optimize the eutectic-based tablet formulation, followed by its pharmacokinetic evaluation.

Spectroscopic results supported eutectic formation, showing modifications in the solid-state characteristics of curcumin accompanied by a lower melting point. These modifications yielded significant improvements in solubility (tenfold, eightfold, and 11-fold in water, buffer pH 1.2, and buffer pH 6.8) and tablettability relative to pure curcumin. The eutectic also exhibited enhanced antioxidant activity (p < 0.05), which may be attributed to the combined intrinsic antioxidant properties of the drug and coformer compared to pure curcumin. DoE-optimized eutectic tablets suggested an enhanced bioavailability of curcumin compared to conventional curcumin tablets; however, warranting confirmation in a larger sample size.

Overall, the curcumin-vanillic acid eutectic represents a promising formulation approach for developing high-performance phyto-nutraceutical systems.