Effect of Binder Level and Granulating Liquid on Phenylbutazone Pellets Prepared by Extrusion-Spheronization

Abstract

The effects of type and amount of binding agent and different amounts of granulating liquid on the physical properties of uncoated beads of phenylbutazone were investigated. The binders used were polyvinylpyrrolidone (PVP) and gelatin/starch (G/S) at two levels, and each formulation at two percentages of granulating liquid; water/ethanol at 60/40 ratio. The ability of these binders to produce pellets of phenylbutazone by the extrusion-spheronization method was evaluated by two criteria. The first was physical properties such as particle size, yield between 710 and 1400 μm, friability, and density. The other criterion was the drug release profile. Generally 5% of gelatin/starch with 80% of solvent produced more uniform pellets with a narrower particle size range and a high yield of spheres between 710 and 1000 μm. Changing the type of the binder, its percentage, and the amount of granulating liquid had no significant effect on the pellet density. Changing the type of the binder or/and its percentage and also the effect of granulating liquid in combination with the other mentioned variables had significant effects on the friability of the pellets. The results show that the amount of granulating liquid and binder amount have the same influence on the drug release from pellets. A slower release rate was observed with increased amounts of these two variables. These differences in the release profiles were parallel to the differences in hardness and structure of the pellets. The difference between particle diameter and the percentage of drug released within 30 min was significant in all formulations.