FORMULATION AND IN VITRO EVALUATION OF DICLOFENAC SODIUM SUSTAINED RELEASE MATRIX TABLETS USING CARNAUBA WAX AS A MATRIX FORMER

Objective: The main objectives of the present study is to develop sustained release matrix tablet of diclofenac sodium (DS) using carnauba wax (CW) as a matrix former, in addition, polyethylene glycol (PEG6000) and polyvinyl pyrrolidone (PVP k30) were used as channeling agents to modify and control the release of DS from CW based matrix system. Methods: The matrix tablet was prepared at different drug-polymer ratio namely 5:2, 5:3, 5:4 and 1:1. The physical properties and post compression parameters of all the prepared formulas were determined and studied. The in vitro dissolution studies were carried out for all formulas and compared to that of a reference marketed product using the similarity factor (f2) equation to choose the best formula. Results: Formula (F9) showed the highest similarity with the reference marketed product and thus selected as the optimized formula. The release rate of DS from CW based matrix system was found to be affected by many factors including the concentration of the rate retarding polymer in the formula, type and concentration of the channeling agent used, type of filler used, pH of the medium, compression force and method of preparation of the sustained release granules. It was observed that the release rate decreased as the amount of the polymer increased in the formula, also the release rate of DS was highest in formulas contain PEG6000, lactose and in formulas prepared by solvent evaporation method. The dissolution data of the optimized formula were fitted to various release kinetic models in order to determine the principal mechanism responsible for release of DS from CW based matrix system. Conclusion: Based on the results obtained from this study, it can be concluded that carnauba wax-polyethylene glycol (CW-PEG) system can be used successfully as a matrix former to sustain the release of DS to more than 8hrs. depending on amount of polymer used, PEG/CW ratio, pH of the system and method of preparation.