this paper describes the influence of maize starch concentration on the physical characteristics and on in vitro release of acetaminophen from compressed tablets. the granulates were analyzed in relation to size distribution and bulk and compacted densities, and the tablets in relation to mean weight, thickness, hardness, friability and disintegration time. the tablets were prepared from granulates made by wet granulation with 10% starch paste in three formulations. although the tablets obtained have presented characteristics in accordance with pharmacopeial limits, the results indicate that variations on starch concentration cause differences on the several physical parameters studied. higher starch concentration probably originates an interaction among the ingredients of the formulations, interfering on the in vitro drug release.this fact demonstrates the importance in optimizing the concentration of the adjutants in a tablet formulation, because, although a short variation in this concentration has no significant effect on disintegration time, the amount of released drug can be substantially modified.