Schmidt C, Kleinebudde P
Beiersdorf-Lilly GmbH, Department of Pharmaceutical Development, Hamburg, Germany.
Eur J Pharm Biopharm. 1998 Mar;45(2):173-9. doi: 10.1016/s0939-6411(97)00076-3.
The influence of different processing steps on pellet quality was investigated: granulation/extrusion and spheronization. Pellets were produced at two levels of water content on two different types of extruders: a twin screw extruder and a rotary ring die press. In order to control the spheronization process each extrudate was rounded in two spheronizers using two radial velocities, respectively. Pellet shape and size were selected to describe the pellet quality. Under constant spheronization conditions the extrudates behaved dissimilar on the two spheronizers. This could be attributed to the geometry of the friction plates. The spheronizer with the rougher surface applied more mechanical energy to the extrudate and wet pellets which reduced the water content necessary for the formation of good pellets. Eliminating the influence of the spheronization process, high differences were observed in the quality of the extrudates produced by the two extruders. This confirmed the results from the first part of this study. Due to the crystallite-gel-model the different extruder types apply different mechanical stress on the extrudate which affect the network structure of the microcrystalline cellulose gel. The twin-screw extruder produced a more delicate network with a lower water movement. This led to a shift of the optimal moisture content towards higher values. Compared with spheronization, process changes in the granulation/extrusion process were more critical.
制粒/挤出和滚圆。在两种不同类型的挤出机上，以两种含水量水平制备微丸：双螺杆挤出机和旋转环模压片机。为了控制滚圆过程，每种挤出物分别在两台滚圆机中以两种径向速度进行滚圆。选择微丸的形状和尺寸来描述微丸质量。在恒定的滚圆条件下，挤出物在两台滚圆机上的表现不同。这可能归因于摩擦板的几何形状。表面较粗糙的滚圆机对挤出物和湿微丸施加了更多的机械能，这降低了形成优质微丸所需的含水量。消除滚圆过程的影响后，观察到两种挤出机生产的挤出物质量存在很大差异。这证实了本研究第一部分的结果。根据微晶-凝胶模型，不同类型的挤出机对挤出物施加不同的机械应力，这会影响微晶纤维素凝胶的网络结构。双螺杆挤出机产生的网络更精细，水分移动较少。这导致最佳含水量向更高值偏移。与滚圆相比，制粒/挤出过程中的工艺变化更为关键。
