Lutein Loaded in β-Cyclodextrin Metal-Organic Frameworks for Stability and Solubility Enhancements

Lutein (Lut) is a recognized nutritional supplement known for its antioxidative and anti-inflammatory properties, crucial in mitigating ocular disease. However, enhancements to Lut stability and solubility remain challenges to be addressed in the healthcare industry. Herein, we fabricated and evaluated a food-grade highly porous β-cyclodextrin metal-organic framework (β-CD-MOF) for its ability to encapsulate Lut. Lut stability considerably improved when loaded into β-CD-MOF to form a Lut@β-CD-MOF complex, which exhibited better stability than Lut loaded into the γ-cyclodextrin metal-organic framework (Lut@γ-CD-MOF), Lut@β-CD, and commercial product (Blackmores™) at 40°C, 60°C, and 70°C, respectively. The solubility of Lut@β-CD-MOF in water increased by 26.8-fold compared to raw Lut at 37°C. Lut@β-CD-MOF exhibited greater hydrophilicity, as determined by measuring the water contact angle. Molecular docking and other characterizations of Fourier transform infrared spectroscopy and powder X-ray diffraction confirmed that Lut was successfully encapsulated in the chamber formed by the three cyclodextrins in β-CD-MOF. Thermogravimetric analysis and Raman spectroscopy demonstrated that Lut distributed in the β-CD-MOF cavity deeply improved Lut stability and solubility. In conclusion, our findings underscored the function of β-CD-MOF in enhancing Lut stability and solubility for formulation applications.