Green synthesis of β-cyclodextrin metal–organic frameworks and the adsorption of quercetin and emodin

Cyclodextrin metal–organic frameworks (K-CD-MOFs) based on renewable β-cyclodextrin molecules (β-CD) and alkali metals (K) was prepared by modified methanol vapor diffusion method at temperature of 50 °C for 6 h, and this can shorten the reaction time compared with the previous reported. Then the quercetin and emodin were selected to investigate the loading characteristics of K-CD-MOFs and drugs adsorption behavior was studied by changing the reaction time, temperatures, MOFs quality, initial drugs concentration and pH. In results, the crystals showed high adsorption (150.2 and 199.8 mg/g) when the reaction time both at 48 h, the temperatures of 35 and 45 °C, 30 mg K-CD-MOFs, the initial concentration of quercetin and emodin was 3.2 and 2.3 mg/ml and pH 6. Furthermore, the adsorption kinetics of drugs matched a pseudo-second-order model well and chemisorption of quercetin and emodin. Most importantly, XRD pattern analysis showed that the drug loading process did not destroy the crystallinity of the material. In summary, on the basis of optimizing the synthesis of K-CD-MOFs, the crystal stability and drugs adsorption properties were evaluated, which provided a basis for the potential drug delivery.