Hindawi Publishing Corporation Te Scientifc World Journal Volume 2013, Article ID 654829, 12 pages http://dx.doi.org/10.1155/2013/654829 Research Article Design, Development, and Optimization of Polymeric Based-Colonic Drug Delivery System of Naproxen Pooja Sharma, Anuj Chawla, and Pravin Pawar Chitkara College of Pharmacy, Chitkara University, Chandigarh-Patiala National Highway, Rajpura, Patiala, Punjab 140401, India Correspondence should be addressed to Pravin Pawar; pravin.pawar@chitkara.edu.in Received 7 August 2013; Accepted 28 August 2013 Academic Editors: J. Ali and A. Nokhodchi Copyright © 2013 Pooja Sharma et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te aim of present investigation deals with the development of time-dependent and pH sensitive press-coated tablets for colon specifc drug delivery of naproxen. Te core tablets were prepared by wet granulation method then press coated with hydroxypropyl cellulose (HPC) or Eudragit RSPO : RLPO mixture and further coated with Eudragit S-100 by dip immerse method. Te in vitro drug release study was conducted in diferent dissolution media such as pH 1.2, 6.8, and 7.4 with or without rat caecal content to simulate GIT conditions. Surface morphology and cross-sectional view of the tablets were visualized by scanning electron microscopy (SEM). All prepared batches were in compliance with the pharmacopoeial standards. Te tablets which are compression coated with HPC followed by Eudragit S-100 coated showed highest in vitro drug release of 98.10% in presence of rat caecal content. Te SEM of tablets suggested that the number of pores got increased in pH 7.4 medium followed by dissolution of coating layer. Te tablets coat erosion study suggested that the lag time depends upon the coating concentrations of polymers. A time-dependent hydrophilic polymer and pH sensitive polymer based press-coated tablets of naproxen were promising delivery for colon targeting. 1. Introduction Oral route of administration always receives more attention in comparison to the other drug delivery approaches [1]. Oral site-specifc drug delivery systems to the colon have been gaining interests during the past two decades [2]. Colon specifc drug delivery system ofers several advantages in the treatment of colonic diseases such as ulcerative colitis, amoe- biasis, Crohn’s disease, irritable bowel syndrome, and colorec- tal cancer [3]. Delivery of drugs to the colon helps in reducing side efect thereby, achieving high local drug concentration at the aficted site in the colon, hence resulting in optimal therapeutic efectiveness and good patient compliance [4, 5]. Diferent types of dosage forms have been used such as micro- spheres, nanoparticles, capsules, and hydrogels, have been used for colon specifc drug delivery system [6–9]. However, recently more emphasis was laid on the microporous osmotic tablet, matrix tablets, and compression-coated tablets for colon specifc drug delivery system because they are con- venient to manufacture and produces greater fexibility in designing the dosage form rather than other novel drug deliv- ery systems [10–12]. Te various approaches that have been studied for colon drug delivery system (CDDS) via oral route include use of pH-sensitive polymers (methacrylic resins and cellulose acetate phthalate) [13, 14], time-dependent delivery which includes use of hydroxypropyl cellulose and hydrox- ypropyl methyl cellulose [15, 16], and pressure-dependent system [17]. Time-dependent drug release systems can be formulated by applying coats onto drug cores which are capable of delay- ing the release through diferent mechanisms [18]. However, drawback associated with these deliveries is the lack of site specifcity due to large variation in gastric emptying time. Tus, time controlled and site specifcity are difcult. A simple pH-dependent approach is also not suitable to be used alone because of premature release of drug. Terefore, these problems can be overcome by using the combination of both time-dependent and pH-dependent polymers [19]. HPC is primarily used as a pharmaceutical additive for various purposes such as a tablet binder, flm-coating mate- rial, and as a delayed release system [20]. Te use of hydrox- ypropyl cellulose (HPC) has been reported earlier as a time released preparation, and the in vivo studies on beagle dogs demonstrated that the HPC press-coated tablets showed