Mulling of lactose, corn starch and 3% potato starch paste liquid with water as a binder has been carried out with various impellers under various mulling conditions. This is to elucidate the effect of the wet powder mulling state on the granule yield and characteristics of a granule. The mulled product mixtures were granulated by the disintegrator, and the tensiling process curves for the wet granular mixtures were experimentally obtained. The pore size distribution, apparent density and angle of repose etc. of the granules were also measured.
It has has been concluded that: 1) There is a correlation between the trend of the steady mulling power, the moisture content and the packing character of powder-liquid systems. 2) The funicular II state where the moisture content is found to be suited for granulation has been obtained. In a good state of mulling in which the lactose has been coated better with a corn starch and potato starch paste liquid, the better degree of mixing has been observed for the larger tensile strength of the wet granular mixtures, where the better granule yield and the narrow size distribution of the granules are of fair. A granule produced in the better mulling state has a closer size distributibution and higher flowability.

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