Asian Journal of Applied Sciences (ISSN: 2321 – 0893) Volume 06 – Issue 02, April 2018 Asian Online Journals (www.ajouronline.com ) 86 Preparation of Shitosan/ Montmorillonite (MMt) Nanocomposite as a Drug Delivery Carrier of Podophyllotoxin Soheila Sedaghat Department of Chemistry, Islamic Azad University, North Tehran Branch, Tehran, Iran Email: s_sedaghat [AT] iau-tnb.ac.ir _______________________________________________________________________________ ABSTRACT--- Biopolymer composites have chosen for carrying drugs because they decrease the side effect of drug and enhance the appropriate concentration in the treatment sites. The biocompatibility and nontoxicity of biopolymers is a main reason to apply them in pharmaceutical fields. The aim of this work was to develop a biopolymer composite based on chitosan (CTS) and Montmorillonite (MMt) by a simple cross-linking reaction using glutaraldehyde as the cross-linker. The swelling ratio in two pH solutions, drug encapsulation efficiency and controlled release behavior were investigated by using Podophyllotoxin as a drug. The results show that the incorporation of MMt improved the swelling behavior, enhanced the drug entrapment efficiency, and decrease the drug release rate. The exfoliated clay could act as a physical cross-linker to facilitate the formation of network structure between the CTS and MMt. It is determined that MMt may be developed as an effective additive for fabricating a sustained drug delivery system. Keywords--- Chitosan, Podophyllotoxin, nanocomposite, release rate, montmorillonite (MMt), drug delivery carrier, Thermal analysis _______________________________________________________________________________________________ 1. INTRODUCTION Chitosan (CTS) , a polysaccharide consists of linear chain of D- glucosamine and N- Acetyl-D- glucosamine units(Fig.1). It is prepared by deacetylation of chitin (abundant natural polysaccharide found in the exo-skeleton of crustaceans such as crabs and shrimp). Depending on conditions of the deacetylation process, different forms of chitosan are available. Those forms vary in the deacetylation degree (DD) and the average molecular weight (Mw) of the polymer [1,2]. Both of those features, determine the physicochemical properties of the polymer and its application[3,4,5]. Chitosan is a polymer dissolved in dilute acid solutions and form a network of polymer chains by name hydrogel. They have the ability to sense changes of media acidity [6] or temperature and release their load as result of such a change [7]. The biocompatibility, biodegradability and swellability properties of chitosan polymer have been considered in the drug delivery carrier [8,9]. Chemical cross-linking is a straightforward method to produce permanent hydrogel networks using covalent bonding between polymer chains [10]. These networks can be formed by using small molecule cross-linkers, polymer–polymer reactions between activated functional groups [11], as well as photosensitive agents or enzyme-catalyzed reactions [12,13]. Cross-linked chitosan networks can be prepared by covalent bond formation between amine functional group in chitosan chain and aldehyde group from cross-linkers molecule like glutaraldehyde(Fig.2). Clay minerals have been used as excipients and active agents for the development of new drug delivery systems. Layered silicates as a drug delivery carrier have been used because their unique layer structure can accommodate polar organic molecules to form various intercalated compounds [14].The layer structure of the silicate can provide a large space to reserve neutral drug molecules via ion-dipole interaction and cationic or bio functional via ion exchange reaction. The idea is to store the drug in the interlayer region of the lamellar host and allow the drug release as a consequence of diffusion and/or de-intercalation process [15].