The development and production of tablets containing high dose of active ingredients is a complex and extensive technological challenge. Dried plant extracts are often used as therapeutically active material in the manufacture of tablets. They are quite often very fine, poorly compressible and very hygroscopic powders. Additionally, tablets containing a high amount of dried extract show prolonged disintegrate times; therefore, the release of the active constituents is affected. Some alternatives have been proposed to minimize these problems.

The granulation seems to be the most appropriated technique to improve the technological properties of these products. However, due to their high hygroscopicity, extracts cannot be granulated using aqueous systems. Thus, dry granulation is a possible technique to produce granules from dried herbal extracts. Slugging is a simple dry granulation process, by which material is compacted in tablet press with subsequent milling process. Previously work showed that the use of lubricants during direct compression of vegetable dried extracts increasing the disintegration time. On the other hand, Rocksloh et al.and von Eggelkraut-Gottanka et al. showed that the incorporation of a high amount of magnesium stearate into the granules shortened the disintegration times compared to tablets containing the powdered mixture. Experimental design is a widely used tool for the systematic and effective evaluation of differences among formulations.