Design of a self-assembled curcumin nanoemulsion and construction of a micropellet delivery system for enhanced stability

Curcumin (CUR) exhibits broad pharmacological activities, including anti-inflammatory, antibacterial, and antioxidant effects, and shows promising therapeutic potential in diseases such as diabetes and liver injury. However, its poor water solubility and low stability significantly limit clinical application. Conventional nanoemulsion solidification techniques, such as spray-drying and lyophilization, often involve high energy input, drug degradation, and poor redispersibility, making it challenging to achieve both stability and performance. In this study, we developed a novel strategy combining design-of-experiments (DoE) optimized curcumin nanoemulsions (CUR-NE) with fluidized bed coating to systematically enhance solubility and stability. Plackett-Burman design was used to screen key variables, and Box-Behnken design further optimized these factors, revealing that formulation parameters exert a more pronounced effect on particle size and polydispersity index (PDI) than process variables. The optimized CUR-NE exhibited an extremely small droplet size (Z-Ave = 13.48 ± 0.20 nanometers) and uniform distribution (PDI = 0.064 ± 0.013), and maintained a low redispersibility index (109.95 ± 1.18 percent) when coated onto pellets (CUR-Ps). Structural characterization using FT-IR and XRD confirmed negligible drug and excipient interactions and partial amorphization of CUR. Unlike conventional solidification methods, fluidized bed coating significantly improved the storage stability of the nanoemulsion while preserving its excellent solubility. This approach not only provides a new technical pathway for the development of curcumin delivery systems but also offers an innovative reference for the industrial production and application of poorly soluble drugs.