Bionanocomposites based on alginate-zein/layered double hydroxide materials as drug delivery systems

The present work introduces new hybrid materials based on the combination of layered double hydroxides (LDH) and two biopolymers (a protein and a polysaccharide) to produce LDH-biopolymer nanocomposites, able to act as effective drug delivery systems (DDS) in comparison to the LDH or the biopolymers alone. Ibuprofen (IBU) has been chosen as a model drug, being intercalated in a Mg-Al LDH matrix. The resulting hybrid is used to prepare bionanocomposite materials by association with two biopolymers: (i) zein, a highly hydrophobic protein, and (ii) alginate, a polysaccharide widely applied for encapsulating drugs. Characterization of the IBU/Mg-Al LDH intercalation compound and the bionanocomposites resulting from its incorporation into alginate-zein matrices of different composition was carried out by means of different experimental techniques: X-ray diffraction, infrared spectroscopy, chemical and thermal analysis, as well as optical and scanning electron microscopies. Preliminary kinetic studies of IBU liberation from bionanocomposites processed as beads show a better protection against drug release at the stomach pH and a controlled liberation in the intestinal tract conditions. This effect can be attributed to the hydrophobic nature of zein, which limits the passage of water and swelling of biocomposite beads prepared with such systems, delaying the release of the drug.