Formulation of Sustained Release Matrix Tablets of Diclofenac Sodium Using New Hydrophilic Gum Blends

The major objective of this study was to use pectin (high methoxylated) in combination with guar gum to control the burst effect by promoting gelation and also to examine the release pattern of guar-pectin matrices. Guar gum has long been used to prepare matrix tablets. But its uncontrolled rate of hydration and initial slow gelling results into undesirable burst effect. Various combination of drug: polymer ratios were tried, out of which the ratio 1:0.5 yielded best results. The ratio of gaur: pectin in the polymer blend which gave best results was found to be 1:1.The effects of various diluents on the drug release were also determined at the same polymer level. The matrix tablet were prepared by wet granulation method using distilled water, were subjected to physical characterization and in vitro release studies. Release kinetics was evaluated by using USP apparatus type II at 75 rpm in 900 ml of phosphate buffer (pH 6.8).The in-vitro drug release study revealed that (batch F3) combining pectin with guar gum sustained the drug release for 10 hours (81.24%). The kinetic treatment showed that the release of drug follows zero order kinetic (r2 = 0.9943). Korsmeyer and Peppas equation gave value of n = 0.9898 indicating that the drug was released by zero order kinetic. Stability studies (40±2oC/75±5%RH) for 3 months indicated that Diclofenac sodium was stable in the matrix tablets. The DSC and FTIR study revealed that there was no chemical interaction between drug and excipients. At the same polymer level the order of release fell in the following manner lactose, starch, avicel pH 101, and Emcompress®. So, the combination of pectin and guar gum shows better prosperity for preparation of sustained release tablets as compare to individual gums.