CIBTech Journal of Pharmaceutical Sciences ISSN: 2319–3891 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/cjps.htm 2016 Vol.5 (2) April-June, pp.36-47/Talukdar and Dey Research Article Centre for Info Bio Technology (CIBTech) 36 DESIGN AND OPTIMIZATION OF HYDROGEL BASED BILAYER ORAL CONTROLLED DRUG DELIVERY SYSTEM CONTAINING PARACETAMOL AND DICLOFENAC SODIUM AS A MODEL DRUG *A. Talukdar and B. K. Dey Department of Pharmacy, Assam Down Town University, Panikhaiti, Guwahati, Assam, PIN-781026 *Author for Correspondence ABSTRACT The aim of the present study was to prepare a bilayer hydrogel tablet formulation for controlled release of two NSAIDs namely Paracetamol and Diclofenac Sodium as a model drug. The hydrogels were prepared by using Natural polymers like Chitosan, Guar Gum, Ethyl Cellulose and synthetic polymer like PVP K30. The bilayer hydrogel tablets were prepared by conventional dry mixing and direct compression method. The concentration of polymers was varied in order to study the various preformulation parameters like angle of repose, bulk density, compressibility index and physical characteristics like hardness, friability, weight variation and drug content. The in vitro drug release studies were carried out in acidic buffer solution of pH 1.2 for initial 2 hours and then in phosphate buffer solution of pH 7.4 for next 10 hours. FTIR studies were carried out to find any drug and polymer interaction and polymer and polymer interaction. The optimized formula F4 showed a controlled release for both the drug as desired upto 12 hours. The drug release mechanism from the optimized formulation was found to follow diffusion control mechanism. Keywords: NSAIDs, Bilayer, Hydrogels, PVP K30 INTRODUCTION The Hydrogels (also known as Aqua gel) are the 3D, cross-linked polymeric networks of water absorbing polymer chains (Baek et al., 2001). These hydrogels are mostly consisting of various natural or synthetic polymers. Due to the large water absorbing property hydrogels have got a wide range of uses in the field of pharmacy (Chen and Park, 2000). Thus, the hydrogels are made from water-soluble polymer, which include various chemical compositions and physical properties. The hydrogels are prepared in a form of matrix tablet, slabs, implants, micro particles, micro needle, nanoparticles, and films (Peppas et al., 2006; Peppas et al., 2000). The hydrogels are widely applicable in clinical practice and therapeutic purposes for a wide range of applications, including processes like genetically engineering, cellular immobilization, regenerative medicine, diagnostic tools and as a targeted drug delivery device (Patel and Patel, 2010). Conventional tablet formulation containing paracetamol (Shirse, 2012; Rajesh et al., 2012) and diclofenac sodium (Biswas and Basu, 2010; Radhakrishnan et al., 2011) are commercially available in Indian market. A diclofenac sodium enteric-coated tablet is given 50 mg orally 2 or 3 times a day or 75 mg orally 2 times a day and maximum dose is 150 mg daily. In extended-release tablets 100 mg orally once a day is used (Gehanno et al., 2003; Efentakis et al., 2010). Paracetamol 1000 mg IV or orally every 6 hours or 650 mg IV, orally, or rectally every 4 hours and maximum Single dose is 1000 mg at every 4 hours’ interval. The extended release tablet contains 1300 mg orally every 8 hourly and maximum daily dose is 3900 mg (Gehanno et al., 2003; Ghosh et al., 2013). The treatment of various chronic diseases in the form of a combination drug therapy is often used. The fixed-dose combination formulations become available but should be used with the aims of improving patient compliance, less frequent dosing and improved patient care. The various literature studies indicate that though the combination drug therapy is beneficial for the treatment of many patients but ultimate care should be taken in prescribing and dispensing the medicine as there may be potential drug–drug interactions, contraindications leads to hepatic or renal problems, and unnecessary drug use (Ghosh et al., 2013). In the present study we have formulated a fixed dose combination of paracetamol and diclofenac sodium to obtain a controlled release upto 12 hours by formulation in a hydrogel based bilayer formulation.