Formulation of diclofenac sodium sustained release tablet using coprocessed excipients of crosslinked amylose–xanthan gum as matrix

Objective: This present study was intended to design sustained release tablet containing diclofenac sodium using a matrix of excipient co-processed xanthan gum-crosslinked amylose. Methods: In the previous study, xanthan gum and amylose have been physically and chemically modified by the co-processed and crosslinking method, resulting co-processed excipient xanthan gum-crosslinked amylose are Co-CLA6-XG and Co-CLA12-XG (method A); CL6-Co-A-XG and CL12-Co-A-XG (method B) with each ratio 1:1, 1:2 and 2:1. All excipients had a good swelling index, high viscosity and good gel strength, good characteristics to be used as a matrix for sustained release tablet dosage form. In this study, a tablet with excipient Co-CLA6-XG, Co-CLA12-XG, CL6-Co-A-XG and CL12-Co-A-XG were formulated by direct compression method. The prepared formulations were evaluated for weight variation, thickness, and diameter, hardness, friability, drug content estimation, swelling index, in vitro drug release are within the acceptable standard. Results: The release profile of diclofenac sodium which contained matrix from Co-CLA6-XG (F1–F3), Co-CLA12-XG (F4–F6), CL6-Co-A-XG (F7–F9) and CL12-Co-A-XG (F10–F12) in phospate buffer medium for 8 h, showed that the sustained release profile followed zero order kinetics (F1–F6, F9, F11) and Korsmeyer-Peppas (F7, F8, F10, F12). Formula F1 to F6 tablet formulations could be applied as sustained release tablet formula and could retard drug release up to 16 h. Then, formula F7 to F12 could be applied as sustained release tablet formula and could retard drug release up to 32 h. Conclusion: It may be concluded that coprocessed excipients of crosslinked amylose–xanthan gum can be used for the preparation of sustained release tablets of diclofenac sodium and can retard the drug release for 16 h and 32 h.