Carbohydrate Polymers 98 (2013) 1083–1094 Contents lists available at SciVerse ScienceDirect Carbohydrate Polymers jo ur nal homep age: www.elsevier.com/locate/carbpol Microwave assisted synthesis of acrylamide grafted locust bean gum and its application in drug delivery Santanu Kaity a , Jinu Isaac a , P. Mahesh Kumar a , Anirbandeep Bose b,c , Tin Wui Wong b,c , Animesh Ghosh a,∗ a Department of Pharmaceutical Sciences, Birla Institute of Technology, Mesra, Ranchi 835215, India b Non-Destructive Biomedical and Pharmaceutical Research Centre, Universiti Teknologi MARA, 42300 Puncak Alam, Selangor, Malaysia c Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA, 42300 Puncak Alam, Selangor, Malaysia a r t i c l e i n f o Article history: Received 26 April 2013 Received in revised form 24 June 2013 Accepted 13 July 2013 Available online 18 July 2013 Keywords: Acrylamide grafted locust bean gum Biodegradable Buflomedil hydrochloride Controlled-release a b s t r a c t Acrylamide grafted copolymer of locust bean gum was prepared by microwave irradiation using ceric ammonium nitrate as redox initiator. The grafting process was optimized in terms of irradiation time, amount of initiator and acrylamide by using constant amount of native locust bean gum. The grafted gum was characterized by Fourier transform infrared spectroscopy (FT-IR), 13 C nuclear magnetic reso- nance (NMR), scanning electron microscopy (SEM), X-ray diffraction study (XRD), differential scanning calorimetry (DSC), elemental analysis, contact angle, viscosity, molecular weight, swelling and biodegrad- ability studies. The grafted gum was found to be biodegradable and non-toxic. It was further used to prepare controlled-release matrix tablet of buflomedil hydrochloride. The in vitro release profile of the tablet showed the rate controlling property of acrylamide grafted locust bean gum was similar to that of hydroxypropyl methylcellulose (HPMC-K15M). © 2013 Elsevier Ltd. All rights reserved. 1. Introduction Biopolymer grafting and its application have gained a great attention in drug delivery arena. The polymer is essentially mod- ified to tailor to target drug delivery applications, in conjunction with the aim to increase therapeutic effects, reduce adverse effects, improve patients’ compliance and develop new therapeutic strategies. Natural polymers are preferred for medical applica- tion over synthetic polymers because of their biodegradability, low cost, easy availability and non-toxicity (Bhardwaj, Kanwar, Lal, & Gupta, 2000; Vijan, Kaity, Biswas, Isaac, & Ghosh, 2012). However, they possess drawbacks such as uncontrolled hydration, microbial contamination, and drop in viscosity during storage. The properties of natural polymers can be modified through hybridiza- tion with the synthetic polymers via blending, grafting, and curing. ‘Blending’ refers to physical mixing of two (or more) polymers to obtain the requisite properties. ‘Grafting’ is a method where Abbreviations: LBG, locust bean gum; Am-g-LBG, acrylamide grafted locust bean gum; Am, acrylamide; CAN, ceric ammonium nitrate; BH, buflomedil hydrochlo- ride; HPMC, hydroxypropyl methylcellulose; FTIR, Fourier transform infrared; XRD, X-ray diffraction; DSC, differential scanning calorimetry; SEM, scanning electron microscopy; KBr, potassium bromide; UV–vis, ultraviolet–visible; C, carbon; N, nitrogen; O, oxygen. ∗ Corresponding author. Tel.: +91 947 033 9587; fax: +91 651 227 5290. E-mail addresses: aghosh@bitmesra.ac.in, anim 1607@yahoo.co.in (A. Ghosh). monomers are covalently bonded onto a parent polymer chain. Cur- ing proceeds with polymerization of an oligomer mixture to form a coat which adheres to a substrate by physical forces (Bhattacharya & Misra, 2004). A graft copolymer is a macromolecular chain with one or more species of block connected to the main chain as side chain(s). Thus, it can be described as, having the general struc- ture, where the main polymer backbone, commonly referred to as the trunk polymer, has branches of another polymeric chain emanating from different points along its length (Zohuriaan-Mehr, 2005). The Ce (IV) induces graft copolymerization of vinyl monomers onto polysaccharide substrates (Adhikary, Tiwari, & Singh, 2007; Mishra & Bajpai, 2006). The main constraint of graft copolymeriza- tion is the formation of concurrent homopolymer thereby resulting in low grafting yield. Apart from the redox initiator-induced graft copolymerization, microwave-assisted graft copolymerization has also been employed. The microwave irradiation is characterized by rapid transfer of energy in the bulk of a reaction mix- ture. The microwave-assisted graft copolymerization requires a very short reaction time and proceeds even in the absence of any redox initiator (Singh, Sethi, Tewari, Srivastava, & Sanghi, 2003). Natural gums are polysaccharides consisting of multiple sugar units linked together to create large molecules. Gums are frequently produced by higher plants for protection against injury. They are heterogeneous in composition. Upon hydrolysis, they yield sim- ple sugar units such as arabinose, galactose, glucose, mannose, 0144-8617/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.carbpol.2013.07.037