T. Makino et N. Kitamori, EFFECT OF STARCH PASTE CONCENTRATION ON PARTICLE-SIZE DISTRIBUTION OFFINE GRANULES PRODUCED BY AGITATION GRANULATION, Chemical and Pharmaceutical Bulletin, 43(7), 1995, pp. 1231-1233
Particle size distribution of fine granules produced by agitation gran
ulation was investigated as a function of the concentration of starch
paste, The time course of granulation was investigated in a high speed
type mixer using 5% starch paste having a good fluidity and 15% starc
h paste having no fluidity at all, like a gel, In agitation granulatio
n, aggregation and deaggregation of particles and/or granules occurred
simultaneously. At a low concentration of starch paste, massing of th
e granules, namely the growth of granules, occurred mainly during the
agitation granulation, since the relatively large amount of free water
was available from the paste, Therefore, in this case, only the mean
size shifted toward a larger measurement without any change in the wid
th of the granules during the granulation. At a high concentration of
starch paste, rapid deaggregation of granules by shear force applied o
ccurred following the formation of large granules immediately after th
e addition of paste, Since a small amount of water exudes from the pas
te during the agitation, massing proceeds slowly, This means that in t
he case of granulation using a high concentration of starch paste, dea
ggregation proceeds predominantly, so that the size distribution of th
e granules becomes more narrow, Fine granules may be produced by agita
tion granulation when a high concentration of starch paste is used and
when granulation is executed under sufficient shear or rotation speed
that guarantees satisfactory dispersion of the gel.