H. Takeuchi et al., SPRAY-DRIED COMPOSITE-PARTICLES OF LACTOSE AND SODIUM ALGINATE FOR DIRECT TABLETTING AND CONTROLLED RELEASING, International journal of pharmaceutics, 174(1-2), 1998, pp. 91-100
A novel composite particle suitable for the filler of controlled-relea
se matrix tablets was prepared by spray-drying an aqueous solution of
a-lactose monohydrate and sodium alginate. The spray-dried (SD) partic
les had an excellent flowing property due to their spherical shape and
sharp particle size distribution. When the SD particles were compress
ed into a tablet in a compressing pressure range of 100-400 MPa using
an Instron-type hydraulic press, the tensile strength of compacts was
much higher than that of a commercial lactose for direct tabletting an
d a physical mixture of lactose and sodium alginate particles with the
same formulating ratio as for the SD particles. The improvement in co
mpressibility of the SD particles was attributed to an increased defor
mability of particles with a decrease in crystallinity of lactose. The
rmal stability of amorphous form of lactose in the SD particles determ
ined by differential scanning calorimetry was dramatically enhanced wi
th the presence of sodium alginate in the particles. It was assumed th
at sodium alginate interacted with lactose molecules in SD particles.
The drug release from the matrix tablet prepared with the SD particles
and acetaminophen in JPXIII No. 1 medium (pH 1.2) was more prolonged
than that of a physically mixed tablet of lactose, sodium alginate and
the drug, because of the improved gel forming property of sodium algi
nate formulated in the SD particles. (C) 1998 Elsevier Science B.V. Al
l rights reserved.