%0 Journal Article %T Optimization of Carboxymethyl-Xyloglucan-Based Tramadol Matrix Tablets Using Simplex Centroid Mixture Design %A Ashwini R. Madgulkar %A Mangesh R. Bhalekar %A Rahul R. Padalkar %A Mohseen Y. Shaikh %J Journal of Pharmaceutics %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/396468 %X The aim was to determine the release-modifying effect of carboxymethyl xyloglucan for oral drug delivery. Sustained release matrix tablets of tramadol HCl were prepared by wet granulation method using carboxymethyl xyloglucan as matrix forming polymer. HPMC K100M was used in a small amount to control the burst effect which is most commonly seen with natural hydrophilic polymers. A simplex centroid design with three independent variables and two dependent variables was employed to systematically optimize drug release profile. Carboxymethyl xyloglucan , HPMC K100M , and dicalcium phosphate were taken as independent variables. The dependent variables selected were percent of drug release at 2nd hour and at 8th hour . Response surface plots were developed, and optimum formulations were selected on the basis of desirability. The formulated tablets showed anomalous release mechanism and followed matrix drug release kinetics, resulting in regulated and complete release from the tablets within 8 to 10 hours. The polymer carboxymethyl xyloglucan and HPMC K100M had significant effect on drug release from the tablet ( ). Polynomial mathematical models, generated for various response variables using multiple regression analysis, were found to be statistically significant ( ). The statistical models developed for optimization were found to be valid. 1. Introduction Hydrophilic matrices are an interesting option while developing an oral sustained-release formulation. They can be used for controlled release of both water-soluble and water-insoluble drugs. The release behaviour of drugs varies with the nature of the matrix and it is the complex interaction of swelling, diffusion, and erosion processes [1]. Polysaccharides are the choice of material which has been evaluated as hydrophilic matrix for drug delivery system due to their nontoxicity and acceptance by regulating authorities. Xyloglucan is a natural polysaccharide isolated from seed kernel of Tamarindus indica. It is used as ingredient in food and pharmaceutical industry. It has been significantly evaluated for use in hydrophilic drug delivery system. It possesses high viscosity, broad pH tolerance, and swelling and binding properties [2]. This led to its application as release retardant polymer and binder in pharmaceutical industry. In addition to these, other important properties of xyloglucan have been identified recently, which include noncarcinogenicity [3], mucoadhesivity, biocompatibility [4], high drug holding capacity [5], and high thermal stability [6]. This led to its application as excipient in %U http://www.hindawi.com/journals/jphar/2013/396468/