γ-Cyclodextrin metal-organic framework enhanced the bioavailability of vitexin in rats by increasing solubility and inhibiting re-crystallization

Abstract

γ-Cyclodextrin metal-organic frameworks (γ-CD-MOFs) were prepared by using γ-CD and KOH as the raw materials. The γ-CD-MOFs showed a cubic shape with particle size in the range of 400~700 nm and Langmuir surface area of 406.88 m2/g. The γ-CD-MOFs were used as the carrier of vitexin through adsorption in methanol, and the loading capacity was 34.9 mg/g. XRD showed that vitexin lost its crystal structure and FTIR showed vitexin had secondary interaction with the carrier. The structure of γ-CD-MOFs collapsed quickly in water, thereby rapidly releasing the loaded vitexin. Through the carrier, the water solubility of vitexin was increased from 31.79 μg/mL to 581.78 μg/mL in simulated gastric fluid at 37 oC, which was increased by about 18.3 times. Meanwhile, the presence of γ-CD inhibited the re-crystallization of vitexin and maintained its supersaturated status through formation of complexes. A pharmacokinetic study showed that the oral bioavailability of vitexin was enhanced by 1.99 times in rats through γ-CD-MOFs carrier.