Alginate/Montmorillonite Nanocomposites for the Delivery of Curcumin

摘要

Exfoliated montmorillonite clay (MMT) was first prepared by stirring the clay in an aqueous suspension for 4 hours, followed by filtration and drying at 70°C. Exfoliation was confirmed by X-ray diffraction (XRD) and Fourier Transform infrared (FTIR) spectroscopy. Curcumin-loaded MMT was then prepared by dispersing the exfoliated clay into an ethanoic curcumin solution. Stirring exfoliated MMT into a curcumin solution of 1 mg/ml for 1 hour and in 5% wv ratio was found to be the best condition for maximum loading which was 6.56 mg/g, corresponding to an entrapment efficiency of 25.62 %. The curcumin-loaded MMT was then encapsulated into alginate beads with different clay to alginate ratios (w/w) using the ionotropic technique. The release of curcumin from different alginate/MMT nanocomposites was studied in different biorelevant media: fasting gastric, fasting intestinal, and fed intestinal media. Different release behaviors were found. These were influenced by the media pH, and the ratio of curcumin-loaded MMT to alginate. The percentage of curcumin released was lowest in the fasting gastric medium due to the low pH. In the intestinal media, the percentage release was higher in the fasting state than in the fed state due to the higher pH of the former medium. Sustained release was found to occur for 24 hours in the intestinal fasting medium, while curcumin release reached a plateau by 8 hours in the intestinal fed medium. The 1:20 (w/w) curcumin-MMT to alginate ratio nanocomposites showed the highest release percentage in both fasting and fed intestinal media, with the 1:2 (w/w) curcumin-MMT to alginate ratio nanocomposites showing the lowest release percentage in both media.