Assembly, structural characteristics and release behavior of supramolecular curcumin-intercalated Mg-Al layered double hydroxides

Supramolecular compounds on the basis of the concept of interaction and assembly were obtained by intercalation of curcumin into the magnesium aluminum layered double hydroxides. The intercalation was performed by three routes of co-precipitation, ion exchange and reconstruction. These materials were characterized by powder X-ray diffractometry, infrared and HPLC technigues. The results show that the interlayer spaces of the materials synthesized by the co-precipitation and the ion exchange methods are expanded to 0.82 similar to 1.36 nm. The curcumin guests are in the form of the horizontal (parallel to the layer) or monolayer vertical (perpendicular to the layer) orientations between layers. The release behavior was also studied in phosphate buffer solution with different pH values. The results indicate that the release mechanism is actually an anion exchange process between guest anions and phosphate anions of media solution. It suggests that layered double hydroxides may have application as the basis of a novel tunable drug delivery.