Preparation and evaluation of diclofenac sodium multiparticulate tablets by extrusion-spheronization

One of the most popular oral drug delivery systems is the multiparticulate tablets such as compacted pellets which their benefits over single unit dosage forms have been widely studied. One challenge in the production of such tablets is maintaining the desired drug release after compaction, as the application of compaction force can damage the pellets and alter the drug release. The aim of this study was to design diclofenac sodium multiparticulate tablets which upon oral ingestion rapidly disintegrate into comprising pellets. In the present work pellet formulations containing 10, 20, and 30% diclofenac sodium and 20, 40 and 60% of Eudragit RS PO:RL PO (1:1) were studied and manufactured based on full factorial design and using the extrusion spheronization. Detailed consideration was given to the effect of formulation variables on the physical and release properties of pellets. The effect of curing on the pellet properties also was studied. Increase in amount of drug in both uncured and cured pellets led to decrease in MDT, whereas increasing amount of eudragit in uncured pellets had no considerable effect on drug release but in cured pellets, specially at lower amounts of drug, led to increase in MDT or decrease in drug release rate. Tablets containing 60% pellets and 40% filler blend with acceptable hardness and disintegration time have been produced. Results showed that no apparent damage to the pellets has occurred as a result of the compaction process. Intact pellets were rapidly released from single unit dosage form upon contact with dissolution medium.