Development of a novel pelletization technique through an extremely high-shear process using a mechanical powder processor to produce high-dose small core granules suitable for film coating

Solventless granulation and spheronization of indomethacin crystals using a mechanical powder processor: Effects of mechanically induced amorphization on particle formation

Our aim was to reveal the effects of mechanically-induced amorphization on the solventless agglomeration and spheronization of drug crystals using a mechanical powder processor. This process can provide spherical particles comprising 100% drug. Indomethacin crystals were mechanically treated using various jacket temperatures and the resulting particles were characterized using particle and crystalline analyses. Also, the adhesive and mechanical properties of amorphous indomethacin were examined. At 20 °C, the indomethacin crystals fragmented and amorphized during processing, indicating that glassy-state indomethacin with no adhesiveness does not contribute to agglomeration or spheronization. At 40 °C, agglomeration occurred due to the transformation of mechanically-induced amorphous phases from non-adhesive glass to an adhesive supercooled liquid at around the glass transition temperature. However, at higher temperatures, the formation of agglomerates was suppressed by recrystallization of the amorphous surface. At 60 °C, the indomethacin crystals compacted and spheronized due to deformation of the particle surface, consistent with results showing that the stiffness of amorphous indomethacin decreased suddenly above 60 °C. The lifespan of the amorphous phase decreased due to enhanced recrystallization as the temperature increased, thereby reducing the degree of spheronization. In conclusion, agglomeration and spheronization are affected by the glass transition temperature and recrystallization of the mechanically-induced amorphous phase.