Micromeritic and packing properties of diclofenac pellets and effects of some formulation variables

The effects of two common diluents, (microcrystalline cellulose and calcium phosphate dihydrate), two binding agents (gelatin and methacrylic polymer) , and spheronization on the micromeritic (size, shape, density), flow, and packing properties of sodium diclofenac pellets were examined. The shape it -as assessed as the aspect ratio and was correlated to the flow rate and to the deviation of the tapped porosity from the value of 26%, which correspo nds to the ideal rhombohedral packing of spheres. It was found that porosit y deviation decreased greatly with spheronization, but it increased with bi nder addition. Porosity deviation was proportional to the aspect ratio, whi le flow rate decreased logarithmically with porosity deviation. Porosity de viation may be a useful index for monitoring the quality of pellets, simila r to the aspect ratio, as a successful, simple, and indirect indication of sphericity and of surface roughness as well.