A study of powder adhesion to metal surfaces during compression of effervescent pharmaceutical tablets.

Effervescent tablets were produced using four different formulations containing citric and/or tartaric acid and sodium bicarbonate with povidone and macrogol 6000. The same formulations were prepared with the addition of 1% sucrose ester powder. The adhesion of each formulation to the metal faces of tableting machine punch tips was determined using electron microscopy, surface roughness measurements and quantification of punch weight variations during tablet production. The basic formulations were inherently adhesive and produced tablets with a weak, porous structure which were qualitatively and quantitatively rougher than conventional, non-effervescent compressed tablets. Both formulations containing tartaric acid produced tablets with a lower surface roughness and with less tendency to stick to tablet punch faces than the two formulations containing citric acid alone. The addition of a water-soluble sucrose ester had a beneficial effect especially on the formulations with inherently high adhesive tendencies.