Kleinebudde P, Jumaa M, El Saleh F
Institute of Pharmaceutics & Biopharmaceutics, Martin-Luther-University, Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle, Germany.
AAPS PharmSci. 2000;2(3):E21. doi: 10.1208/ps020321.
The study objective was to investigate the influence of the degree of polymerization (DP) of cellulose materials (microcrystalline cellulose [MCC] and powder cellulose [PC]) on the behavior of these materials during homogenization and extrusion/spheronization processes. Suspensions of the cellulose types with different DP values were homogenized using a high-pressure homogenizer. The particle size, agglomeration index, and apparent viscosity of these suspensions was determined at different times after pouring. Additionally, these different cellulose types were processed into pellets using the extrusion/spheronization method, and the water content and power consumption as a function of the DP were determined. Cellulose types with a high DP value showed greater particle size after homogenization than the types with a low DP value. In contrast, no relevant relationship between the apparent viscosity and DP could be observed. During the extrusion process, water content in the extrudate and pellet porosity were increased as the DP was increased for the extrudates produced at the same level of power consumption. MCC types with various DPs compared with PC provided a novel way of understanding the role of cellulose in the extrusion process. The DP showed a remarkable influence on the physicochemical properties of the cellulose materials and, consequently, on the behavior of these materials during the extrusion/spheronization process. It is postulated that the sponge model is more appropriate for the cellulose type with high DP (PC), whereas the gel model is more applicable to cellulose types with lower DP (MCC).
本研究的目的是研究纤维素材料（微晶纤维素[MCC]和粉状纤维素[PC]）的聚合度（DP）对这些材料在均质化以及挤出/滚圆过程中行为的影响。使用高压均质机对具有不同DP值的纤维素类型的悬浮液进行均质化处理。在倾倒后的不同时间测定这些悬浮液的粒径、团聚指数和表观粘度。此外，使用挤出/滚圆法将这些不同的纤维素类型加工成颗粒，并测定作为DP函数的含水量和功耗。与低DP值的类型相比，高DP值的纤维素类型在均质化后显示出更大的粒径。相反，未观察到表观粘度与DP之间的相关关系。在挤出过程中，对于在相同功耗水平下生产的挤出物，随着DP的增加，挤出物中的含水量和颗粒孔隙率增加。与PC相比，具有各种DP的MCC类型为理解纤维素在挤出过程中的作用提供了一种新方法。DP对纤维素材料的物理化学性质有显著影响，因此对这些材料在挤出/滚圆过程中的行为也有显著影响。据推测，海绵模型更适用于高DP的纤维素类型（PC），而凝胶模型更适用于低DP的纤维素类型（MCC）。
