Comparative evaluation of tablet lubricants: effect of application method on tablet hardness and ejectability after compression

The effect of four lubricants (stearic acid, magnesium stearate, calcium stearate, and talc) on the ejectability and hardness of statically compressed tablets of a lactose granulation was examined. Two methods of application of these lubricants, incorporation into the granulation and mixing with the granulation, were compared. In both methods, the energy consumption curves during ejection and the hardness curves with lubricant concentration were similar and showed complicated behavior at a lower concentration. The mixing method gave better results for ejectability and hardness than the incorporation method.