Fabrication and characterization of pH-sensitive bio-nanocomposite beads havening folic acid intercalated LDH and chitosan: Drug release and mechanism evaluation

Abstract

In this paper, folic acid (FA) as drug model was intercalated in the structure of layered double hydroxide (LDH) as drug carrier with two coprecipitation and anion exchange methods. The existence of FA drug between the LDH layers was confirmed with FT-IR and XRD analyses. Also, the results of UV-Vis confirmed that the FA loading in the structure of LDH was about 33.35% and 15.57% for coprecipitation and anion exchange methods, respectively. Then, FA intercalated LDH (LDH-FA) was composited with different weights of chitosan (Cs) as bio-polymer and the obtained nanocomposite beads was characterized. Subsequence, the release of FA drug from obtained hybrids was examined at simulated condition similar to the gastrointestinal tract with different pHs. The achieved bio-composite beads showed the pH-sensitive swelling property and also the release test showed the higher shield of acidic pH and the release rate of FA drug was decreased with addition of Cs concentration. Also, several well-known kinetic models were examined in order to study the FA release mechanism which suggested some release processes such as diffusion controlled of flat surface by heterogeneous sites, ion exchange process, LDH intra-particle diffusion and also concurrent leaching of the FA anions from LDH structure.