Evaluation of diclofenac sodium release from matrix pellets compressed into MUPS tablets

The purpose of the study was to screen the effects of formulation factors on the in vitro release profile of diclofenac sodium from matrix pellets compressed into multiple unit pellet system (MUPS) tablets using design of experiment (DOE). Extended release of diclofenac sodium was accomplished using Carbopol 71G as matrix substance. According to Fractional Factorial Design FFD 2(3-1) four formulations of diclofenac sodium MUPS matrix tablets were prepared. The process of direct pelletization and subsequently compression of the pellets into tablets was applied in order to investigate a different approach in formulation of matrix systems and to achieve a better control of the process factors over the principal response - the release of the drug. The investigated factors were X1-the percentage of polymer Carbopol 71G, X2-crushing strength of the tablet and X3-different batches of the diclofenac sodium. In vitro dissolution time profiles at 6 different sampling times were chosen as responses. Results of drug release studies indicated that drug release rates vary between different formulations, with a range of 1 to 8 h to complete dissolution. The most important impact on the drug release had factor X1-the percentage of polymer Carbopol 71G. The polymer percentage is suggested as release regulator for diclofenac sodium release from MUPS matrix tablets. All other investigated factors had no significant influence on the release profile of diclofenac sodium.