Pelletization of needle-shaped phenylbutazone crystals

The flowability of needle- or plate-shaped crystals is very poor and the direct compression of these crystals is difficult. Commercial phenylbutazone consists of needle crystals and it has three polymorphs.The aim of this work was to investigate the solid-state thermal stability of phenylbutazone at condition of the pelletization process (40°C; 60 min). The other aim was the preparation of phenylbutazone pellets with centrifugal granulator.Based non the flowability and the other parameters of, the pellets, they are suitable for capsule filling or tabletting. The centrifugal granulation and the conditions were favourable for the preparation of pellets from phenylbutazone in the form of needle crystals.This revised version was published online in November 2005 with corrections to the Cover Date.