Influence of powder characteristics of bulk substance with pharmaceutical processing

The physicochemical properties of crystals can vary with the crystallization procedure employed in their isolation and purification. Moreover, the success of any direct-tableting procedure is directly effected by the quality of the crystals used in this process. We examined the conventional crystallization method employed in the isolation and purification of octotiamine crystals, the active component of the pharmaceutical compound Neuvita. Our objective was to determine under what crystallization conditions (i.e., supersaturation ratio [pH], temperature, impeller speed) octotiamine crystals with excellent direct-tableting potential could be obtained. Our results indicated that modifications in pH level (from 4.3 to 4.0), i.e., a reduction in the supersaturation ratio, and in impeller speed (from 100 to 78 rpm) are necessary to obtain octotiamine crystals with superior flowability and compressibility compared to the use of the conventional crystallization method. Thus, with these modifications in the conventional crystallization method, octotiamine crystals can be made that show dissolution rates similar to those of the conventionally made crystals, yet which can be manufactured into tablets using a simpler method (i.e., direct tableting). Also, the tableting powder made from the new crystal type proved to be less adhesive than the conventionally made crystal powder. This property attributed to the new crystal type will allow for more stable automated manufacturing than the conventional crystal type would allow.