Studies on Influence of Coprocessed Excipients on Flow and Dissolution Kinetics of Diclofenac Sodium

Co-processed excipients with microcrystalline cellulose and guar gum, xanthan gum, almond gum, kondagogu in different ratios were fabricated by different methods and its influence on blend fluidity, friability of the tablet and dissolution characteristics of diclofenac sodium from direct compressible tablets was studied. The flow properties of the blends were determined by Carr's index and Hausner's ratio. Optimized co-processed formulation containing microcrystalline cellulose and guar gum in the ratio 1:3 was found to be more acceptable to formulate diclofenac sodium tablets. The co-processed excipients were prepared by using granulation technique. The preformulation parameters like flow property and the performance parameters were dependent on the proportion of components present in the co-processing excipient. The co-processed excipient prepared with granulation technique imparted the desired qualities to the tablet. The drug dissolution rate followed zero order kinetics. The mechanism of drug release was governed by peppas model. The dissolution exponent of release profiles(slope) has a value of 0.59-1.05(n>1), which indicates super case ц transport diffusion. The drug and excipient interaction studies were conducted with IR spectral studies and drug and the selected excipient were found to be compatible. The finished dosage form was subjected to short term stability studies as for ICH guidelines and optimized formulation was found to be quite stable. The results obtained in the present study thus indicate that the gums and its concentrations used in the preparation of tablets have shown significant influence on drug release rate.