Design and Evaluation of Xanthan Gum-based Sustained Release Matrix Tablets of Diclofenac Sodium

In the present investigation, an attempt has been made to increase therapeutic efficacy, reduce frequency of administration, and improve patient compliance, by developing sustained release matrix tablets of diclofenac sodium. Sustained release matrix tablets of diclofenac sodium, were developed by using different drug: polymer ratios, such as F1 (1:0.12), F2 (1:0.16), F3 (1:0.20), F4 (1:0.24) and F5 (1:0.28). Xanthan gum was used as matrix former, and microcrystalline cellulose as diluent. All the lubricated formulations were compressed using 8 mm flat faced punches. Compressed tablets were evaluated for uniformity of weight, content of active ingredient, friability, hardness, thickness, in vitro dissolution using basket method, and swelling index. All the formulations showed compliance with pharmacopoeial standards. Among different formulations, F1 showed sustained release of drug for 12 hours with 89.67% release. The effect of other parameters like addition of release modifier (PEG 6000), gum concentration, pH of dissolution medium, rotation speed and dissolution by paddle method, were also studied. Selected formulation (F1) was subjected to stability studies for three months at 0-4°, room temperature (28°), and 45° with RH 75±5%, and showed stability with respect to release pattern. The kinetic treatment showed that the release of drug follows zero order kinetic (R = 0.9758). Korsmeyer and Peppas equation gave value of n = 0.9409 which was close to one, indicating that the drug was released by zero order kinetic. Thus, Xanthan gum can be used as an effective matrix former, to extend the release of diclofenac sodium.