RESEARCH ARTICLE e-ISSN: 2249-622X *Corresponding author: Nandgude Tanaji D | Research Scholar, Department of Pharmacy (Pharmaceutics), Karpagam University, Coimbatore, TN, India |Email: tanajinandgude@gmail.com Page17 Page17 Characterization of Drug and Polymers for Development of Colon Specific Drug Delivery System Nandgude Tanaji D. 1* , Bhise Kiran S. 2 1. Research Scholar, Department of Pharmacy (Pharmaceutics), Karpagam University, Coimbatore, TN, India 2. Principal, Allana College of Pharmacy, Pune, MS, India ABSTRACT To dosage form design characterization of drug and polymers is an important aspect. The objective of this work was to characterize Capecitabine, natural polymers like, guar gum, xanthan gum, chitosan and other excipients. As a part of characterization studies of Capecitabine, Differential scanning calorimetry (DSC) was used to investigate thermal effects and nature of drug, supported by X-ray powder diffraction (X-RPD), showed two endothermic peaks and indicated crystalline nature of the drug. Scanning electron microphotographs (SEM) was used to study surface topography. Fourier - transform infrared (FT-IR), solubility study, flowability studies of drug and excipients were carried out as part of characterization. Solubility studies at different pH showed feasibility of drug at any pH. Drug excipient interaction studies carried out which shows there was no chemical interaction between the drug and the polymers. Stability of bulk drug at accelerated conditions was determined, good stability was observed. Key words: Characterization, DSC, X-RPD, Capecitabine, Polymers, Stability. 1. INTRODUCTION: Colon targeting is advantageous in treating diseases of colon (irritable bowel syndrome, inflammatory bowel disease, including Chron’s disease and ulcerative colitis), oral delivery of proteins and peptides where a delay in systemic absorption is therapeutically desirable (nocturnal asthma, arthritis, angina). 1,2 For the past five decades scientific data collectively known as characterization or preformulation studies have been developed for supporting the dosage form design of a new drug and its quality control. 3,4 Capecitabine, the first oral fluoropyrimidine derivative of 5-fluorouracil and is widely used in the treatment of metastatic colorectal and breast cancer. It is a pro-drug that is converted to fluorouracil in the body tissues following the oral administration. It is readily absorbed from the gastrointestinal tract, as drug is freely available at any pH and hence judicious selection of release retarding system like drug in matrix is necessary. The recommended daily dose is large i.e., 2.5 gm/m2and has a short elimination half-life of 0.5-1 h [5] . Xanthan gum is high molecular weight extracellular heteropolysaccharide, produced by fermentation with the gram-negative bacterium xanthomonas campestris. The primary structure of this naturally produced cellulose derivative contains a cellulosic backbone β-D-glucose residues) and a trisaccharide side chain of β-D-mannose-β- D-glucuronic acid-α-D-mannose attached with alternate glucose residues of he main chain 6,7 . Guar gum is a polysaccharide derived from the seeds of Cyamopsis tetragonolobus, family Leguminosae. It consists of linear chains of (1®4)- b-D-mannopyranosyl units with a-D-galac- topyranosyl units attached by (1®6) linkages 8 . Chitosan is a hydrophilic, biocompatible and biodegradable polysaccharide of low toxicity which in recent years has been used for development of drug delivery systems. It has been exploited for the preparation of microspheres for controlled release systems. Small chitosan microspheres were also developed for site specific delivery of anticancer agents, such as oxantrazole and 5- fluorouracil 9,10 . Parameters Capecitabine Guar gum Xanthan gum Bulk density(g/ml) 0.38 0.75 0.68 Tapped density(g/ml) 0.45 0.88 0.79 Carr’s compressibility Index(%) 15.55 14.33 13.92 Haussener’s ratio 1.18 1.17 1.16 Angle of repose(*) 39.09 31.06 33.16 *All values represent mean ± SD (n = 3). Table 1: Flowability of drug and polymers* In the present study, Capecitabine was characterized by thermal (DSC), crystallographic (X-RPD), microscopic (SEM) and spectroscopic (FT-IR). Drug excipient interactions studied by spectroscopic (FT-IR) evaluation. Influence of morphology of drug as well as polymers on flow behavior was also investigated. Capecitabine was also studied for pH dependent solubility and accelerated stability studies.