Session Speaker

Bionanocomposites as Drug Delivery Systems
Pilar Aranda, Ana C.S. Alcántara, Margarita Darder, Eduardo Ruiz-Hitzky
Spain

The improvement of controlled drug delivery systems (DDS) intends to use more efficient chemical or physical barriers to regulate the speed of liberation and to guarantee the desired dose of maintenance [1]. Among the many matrices studied as supports of drugs are liposomes, micelles, emulsions as well as hybrid and polymeric materials. Nanostructured organic-inorganic hybrid materials are a growing field of research in view to many diverse applications [2]. The versatility, biodegradability and biocompatibility of layered double hydroxides (LDH) make them especially attractive in the preparation of hybrid and biohybrid materials for diverse applications including Biomedicine [3]. Thus, anion-exchange properties of LDH are especially interesting for using them as support matrices of anionic drugs in order to improve their chemical, thermal and/or photochemical stability [4]. However, LDH are very sensitive to acid environments and the drug is often completely released in the stomach (pH 1.2). On the other hand, it is well known the use of biopolymers, for instance alginate, as protective systems for drug incorporation. However, some of these biopolymers are quite soluble in gastrointestinal media and so may release the drug in a sudden way [5]. Therefore, these two types of matrices show disadvantages for a sequential liberation of the active principle along the gastrointestinal tract.

To overcome this background, an approach that simultaneously combines the advantages of both inorganic and biopolymer matrices is an alternative of great interest in the search of new controlled DDS.

In this context, the present work introduces new LDH-biopolymer nanocomposites as effective DDS in comparison to the LDH or the biopolymers alone. Ibuprofen has been chosen as drug model and intercalated in an 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. Preliminary kinetic studies of ibuprofen liberation from bionanocomposites processed as beads show a better protection against drug liberation at the stomach pH and a controlled liberation in the intestinal tract conditions.

References:

[1] Ha, C. S., Gardella Jr. Chemical Reviews 105, 4205-4232 (2005).
[2] Ruiz-Hitzky, E. In Functional Hybrid Materials, Gómez-Romero, P., Sanchez, C., Chap.2, Wiley-VCH, Weinheim (2004).
[3] Darder, M., Lopez-Blanco, M., Aranda, P; Leroux F., Ruiz-Hitzky, E., Chem. Mater., 17, 1969–1977 (2005).
[4] Costantino, U., Nochetti, M., Sisani, M., Vivano, R., Zeitschrift fur Kristallographie 224, 273-281 (2009).
[5] Coviello,T., Matricardi, P., Marianecci, C., Alhaique, F., J. Control Release, 119, 5–24 (2007).